Questions and answers

One sized by your frame, not by liters. Apidura says frame pack size should be chosen by the frame's dimensions, and asks riders to include bottles and frame-mounted accessories when they measure. See how to size a frame or top-tube bag. More in Bike bags

Only if your bike has a rack whose tubes match the bag's hooks. ORTLIEB's QL2.1 hooks come with inserts for 8, 10 and 12 mm rack tubes, and it offers 20 mm hooks for 17-20 mm tubes, which it says are often used on e-bikes. See pannier hooks and rack tube sizes. More in Bike bags

Read the maker's rating and its condition. ORTLIEB rates the Back-Roller IP64 only with the closure rolled down three to four times and secured, and IP64 is not an immersion rating. Restrap lists an IP6K6 rating for its 18-liter Saddle Bag. More in Bike bags

The lower of the rack's and the bag's stated limits. Topeak lists a 22 kg total load for the TetraRack M2 HD, while ORTLIEB lists 9 kg per Back-Roller bag. Your rack and bag may state other figures, so read both. More in Bike bags

Brompton says the Electric uses a dedicated Front Carrier Block, so it needs an Electric-compatible Front Bag with space for the battery. Check each bag's listing for Electric compatibility. More in Brompton front bags: standard vs Electric carrier blocks

Brompton says its Front Bags can carry up to 10 kg, with the load sitting on the frame rather than the handlebars. More in Brompton front bags: standard vs Electric carrier blocks

Brompton's US listing gives fitment for the A Line, C Line Mk5 and Mk6, P Line Mk1, T Line and G Line. It lists no Electric models. More in Brompton front bags: standard vs Electric carrier blocks

Brompton's listing names a 5 mm and a 4 mm Allen key and a Phillips screwdriver as the tools required. If you are unsure, ask a Brompton dealer or bike shop to fit it. More in Brompton front bags: standard vs Electric carrier blocks

Measure the inside of the frame triangle along each tube and note where bottle cages and other fittings sit. Apidura says to choose frame pack size by the frame's dimensions, not by how much you want to carry, and offers a sizing tool and a printable template. More in How to size a frame bag or top-tube bag for your bike

Only if you size for them. Apidura's sizing instructions ask riders to include water bottles and frame-mounted accessories in the bike photo so clearance is accurate. More in How to size a frame bag or top-tube bag for your bike

Only for a bolt-on bag. Apidura's bolt-on top-tube pack uses two top-tube bolts plus a steerer strap, and Apidura directs bikes without those bolts to its strapped version. More in How to size a frame bag or top-tube bag for your bike

We found no source that sets one. Apidura gives no bolt spacing in its text and advises riders on smaller frames to check pack length, so compare your own bolt positions with each bag's. More in How to size a frame bag or top-tube bag for your bike

They will if your rack tube falls inside the hook system's stated range. ORTLIEB's QL2.2 hooks, for example, fit rack tubes from 8 to 16 mm, and Arkel says its Cam-Lock hooks fit 8 to 15 mm. More in Pannier fit: hook sizes, rack tube diameters and e-bike racks

Measure the rail where the upper hooks will sit, with calipers or a paper strip divided by pi. Check the lower mounting point too, since some systems state a separate limit for it. More in Pannier fit: hook sizes, rack tube diameters and e-bike racks

The rack tubes may be thicker than the hooks allow. ORTLIEB offers optional 20 mm QL2.1 hooks for 17-20 mm tubes, which it says are often used on e-bikes. More in Pannier fit: hook sizes, rack tube diameters and e-bike racks

Only the maker's rating, within its condition, tells you. ORTLIEB rates the Back-Roller IP64 provided the closure is rolled down three to four times and secured downward, and IP64 is not an immersion rating. More in Pannier fit: hook sizes, rack tube diameters and e-bike racks

Use the stated payload per bag. ORTLIEB lists 9 kg per bag for the Back-Roller pair, and the rack has its own limit too. More in Pannier fit: hook sizes, rack tube diameters and e-bike racks

Whatever its maker states for that model, and no more. Topeak, for example, lists a 22 kg (48.5 lb) total maximum load for the TetraRack M2 HD; your bags have their own limits as well. More in Rear racks: frame fit, load limits and MIK or MTX top bags

Check the rack maker's statement before anything else. Topeak says TetraRack is not recommended for carbon forks and seatstays. If your frame is carbon, ask the frame maker or a bike shop. More in Rear racks: frame fit, load limits and MIK or MTX top bags

MIK is a top-bag mounting system. Basil says its MIK adapter plate is fully compatible with bikes that have an MIK carrier, while other carriers need its separate MIK Carrier Plate, listed for 8-16 mm tubes and 100-170 mm outer width. More in Rear racks: frame fit, load limits and MIK or MTX top bags

No source we found makes them interchangeable. Topeak lists its TetraRack M2 HD as compatible with both MTX QuickTrack and KLICKfix/RackTime Snapit bags, which is a statement about that rack, not about the bags fitting each other's systems. More in Rear racks: frame fit, load limits and MIK or MTX top bags

None was approved for this site on 2026-10-14. For panniers, ORTLIEB's QL2.1 hooks take 8, 10 and 12 mm rack tubes with inserts; for frame bags, Apidura says to size by the frame, not by liters. More in Bike bags with published mounting and volume

Not for a strapped one. Bolt-on bags need bosses: Apidura's Expedition Bolt-On Top Tube Pack uses two bolts plus a steerer strap, and Apidura sends bikes without bolts to its strapped version. More in Bike bags with published mounting and volume

Check the exposed seatpost and the room above your rear tire. Restrap, for example, states no clearance or dropper-post compatibility for its 18-liter Saddle Bag, so measure your own bike. More in Bike bags with published mounting and volume

We cannot vouch for any AliExpress store in general. Among our sources, only CYCPLUS names an official AliExpress store on its own where-to-buy page. For other brands, check the maker's own site for the channels it lists. See buying on Amazon or AliExpress. More in Fit and buying

Possibly. As of 2026-10-14, US duty-free de minimis treatment has been suspended for all countries since August 29, 2025; check current CBP guidance. For Canada, courier shipments from the US or Mexico are free of duty and tax up to CAD $40 and duty-free but taxable up to $150. More in Fit and buying

TSA says spare lithium batteries and power banks go in carry-on bags only, and CO2 cartridges are not allowed in either bag unless clearly empty. For batteries built into a device, ask your airline. See flying or mailing a pump, light or CO2 kit. More in Fit and buying

Only if the seller is an authorized dealer or retailer and you keep proof of purchase. Lezyne's US warranty and Topeak's warranty both say so, and neither names a marketplace seller as authorized. More in Fit and buying

Search CPSC's recall list and Health Canada's recalls database by maker and model. Recent examples include Lezyne Pressure Over Drive floor pumps (November 2025) and Malker bicycle light sets (April 2026). More in Bike accessory recalls and safety rules: coin cells, pumps and chargers

We cannot rate a product. What the federal rule requires is clear: for products made or imported on or after October 23, 2023, compartments holding replaceable coin cells must need a tool or two simultaneous hand movements to open, with warnings on the packaging and in the instructions. More in Bike accessory recalls and safety rules: coin cells, pumps and chargers

None of our sources names one for standalone bike accessories. 16 CFR part 1512 covers bicycles, UL 2849 and UL 2272 cover e-mobility electrical systems, and FCC authorization covers radios, not electrical safety. More in Bike accessory recalls and safety rules: coin cells, pumps and chargers

Some are sold by the brand and some are not, and a listing alone does not tell you. Among our sources, only CYCPLUS names an official AliExpress store, on its own where-to-buy page. For other brands, start from the maker's site. More in Buying bike accessories on Amazon or AliExpress: sellers, returns and import costs

Find the maker's own where-to-buy page and follow its links. CYCPLUS lists its Amazon US and Canada stores, and Magicshine links its Amazon US storefront. On Amazon, then check that 'Ships from / Sold by' shows Amazon.com or the brand on the offer you buy. More in Buying bike accessories on Amazon or AliExpress: sellers, returns and import costs

It depends on how it ships and from where. CBSA says courier shipments from the US or Mexico are free of duty and tax up to CAD $40, and duty-free but taxable up to $150. Mail, and couriers from other countries, are free only up to CAD $20. More in Buying bike accessories on Amazon or AliExpress: sellers, returns and import costs

Only for items with a Free Return label, under terms AliExpress can change. Those terms, effective November 1, 2022, give 15 days from receipt to request and limit free return shipping to three uses a month. More in Buying bike accessories on Amazon or AliExpress: sellers, returns and import costs

Follow the light maker's charging instructions first. CPSC's warning against 'universal' chargers is about e-bikes and other micromobility products, not USB bike lights. In Canada, Health Canada advises plug-in chargers with a Canadian certification mark such as CSA, cUL or cETL. More in Charging and recycling bike light and electric pump batteries

Not in the household trash or regular recycling. CPSC says lithium batteries should go to a battery recycler or a hazardous-waste collection site. More in Charging and recycling bike light and electric pump batteries

Start with the pump maker's instructions. For e-bikes and other micromobility products, CPSC advises being present while charging, never charging while asleep, and unplugging when charging is done. That advice is written for micromobility batteries, not pumps, but it is the regulator's general caution on lithium charging. More in Charging and recycling bike light and electric pump batteries

Front and rear lights that meet the rules where you ride, a pump that fits your valve, a bag that fits your rack or frame, a mount that fits your bar if you navigate by phone, and tire levers with a basic tool. Each item has one fit check on your own bike. More in Commuter bike kit checklist: lights, pump, bag and mount that fit together

The rules we cite apply in darkness: California, for example, requires a front lamp and rear reflector or light when riding in darkness. If a ride could run past dusk, the darkness rules apply to it. We make no promise that a light prevents a crash. More in Commuter bike kit checklist: lights, pump, bag and mount that fit together

The one that fits your bike. With a rack, panniers whose hooks match your rack tubes; ORTLIEB's QL2.1 hooks take 8, 10 and 12 mm tubes with inserts. Without one, a top-tube or frame bag sized to your frame. More in Commuter bike kit checklist: lights, pump, bag and mount that fit together

TSA lists CO2 cartridges as not allowed in carry-on or checked bags unless the cylinder is clearly empty, and the officer has the final say. Plan to buy cartridges at your destination or carry a hand pump. More in Flying or mailing a bike pump, light or CO2 kit

For a battery built into a device, TSA defers to FAA device rules, which we could not read, so ask your airline before you fly. TSA's own limits cover spare lithium batteries: carry-on only, and 100 watt-hours each. More in Flying or mailing a bike pump, light or CO2 kit

USPS bars damaged, defective or recalled lithium batteries. Internationally, it allows small consumer lithium batteries only when installed in the equipment they power and within its limits. Read USPS Publication 52 for your shipment. More in Flying or mailing a bike pump, light or CO2 kit

A lumen figure on the box is the maker's own. Even an ANSI FL 1 figure comes from a voluntary standard under which each company runs its own tests. Treat it as a claim unless a named publication measured the light and said how. More in Maker claims vs measured results: how to read bike accessory specs

Not directly. BikeRadar used 32 or 35 mm tubeless tires to about 51-53 psi, TOUR a 700x30c tire to 4 and 7 bar, and road.cc a 30 mm tire to 60 psi. Different tires and targets give different times. More in Maker claims vs measured results: how to read bike accessory specs

That the maker says it measured the light to the ANSI/PLATO FL 1 method. Following the standard is voluntary and each company runs its own tests. Its runtime ends when output falls to 10 percent, and its beam distance is where the beam falls to 0.25 lux. More in Maker claims vs measured results: how to read bike accessory specs

It covers lights, inflation, carrying, a phone and tire removal. Add a puncture repair that suits your tubes, and check the lighting rules where you ride. See the commuter kit checklist. More in A commuter kit shortlist: one pick per job

None was approved for this site on 2026-10-14. Panniers fit by rack tube size: ORTLIEB's QL2.1 hooks come with inserts for 8, 10 and 12 mm tubes. More in A commuter kit shortlist: one pick per job

We make no safety promise. A Cochrane review found that trials of visibility aids measured driver detection, and none measured collisions or injuries. More in A commuter kit shortlist: one pick per job

No source we use says which valve is typical for a kind of bike, so check your own. Park Tool describes Presta stems as nominally 6 mm with a locknut at the top, and Schrader stems as about 8 mm. The valve finder walks you through it. More in Kit finder by bike type

Because no source we checked states it for that kind of bike. We leave the field open rather than guess. More in Kit finder by bike type

Sometimes, because of the rack tube size. ORTLIEB offers optional 20 mm QL2.1 hooks for racks with 17-20 mm tubes, which it says are often used on e-bikes. Measure your rack tube. More in Kit finder by bike type

No source we use sets a lumen number for cycling. California sets its front-lamp rule as a visibility distance (300 feet), not lumens, and a lumen rating is the maker's own figure. Choose by the runtime of the mode you will use and the beam shape. See lumens, lux and candela. More in Bike lights

It depends where you ride. California allows a solid or flashing red rear light with a built-in reflector, while Germany's StVZO prohibits flashing bicycle headlights and tail lights. Check the rules of your own state or province; see bike light and reflector rules. More in Bike lights

It is an IP code under IEC 60529, the standard that classifies the protection an enclosure gives. An IP figure on a light is the maker's rating, with whatever condition the maker attaches: Fenix, for example, says the BC25R's IP66 applies only with the port cover in place. More in Bike lights

Look at the maker's runtime for the mode you will use, not the headline. Knog rates the Blinder 1400 at 1.5 hours in High Steady and 8 hours in Low Steady. Under ANSI FL 1, runtime runs until output falls to 10 percent, so it is not time at full brightness. More in Bike lights

In the places we cite, yes, at night, but each state or province sets its own rule. California requires a white front lamp visible from 300 feet when riding in darkness, while Oregon sets 500 feet in limited visibility. More in Bike light and reflector rules in the US and Canada: examples, not a list

It depends where you ride. California's code accepts a solid or flashing red rear light with a built-in reflector, while Germany prohibits flashing bicycle lights. Check your own state or province. More in Bike light and reflector rules in the US and Canada: examples, not a list

California's code lets a white lamp "attached to the operator" be used instead of a bicycle-mounted front lamp. It does not name helmets, and other places may differ. More in Bike light and reflector rules in the US and Canada: examples, not a list

New bicycles sold in the US must carry reflectors under 16 CFR 1512.16, and some riding rules ask for reflectors too. California, for example, also requires pedal, shoe or ankle reflectors in darkness. Keep the reflectors and check your local rule. More in Bike light and reflector rules in the US and Canada: examples, not a list

We cite Ontario only. Ontario's government lists a white front light, a red rear light or reflector, and reflective tape on the front and rear forks as required equipment. Other provinces set their own rules. More in Bike light and reflector rules in the US and Canada: examples, not a list

Neither is better; they measure different things. Lumens describe the light's total output, while lux describes how much light lands on a surface at one distance, so a lux figure is only useful with its distance. More in Lumens, lux and candela: what a bike light's numbers measure

We found no source that sets a lumen number for commuting. Your route, street lighting and the beam's shape matter as much as the total, so compare beam photos and the modes you will actually use. More in Lumens, lux and candela: what a bike light's numbers measure

Busch + Müller, for example, rates its StVZO-approved IQ-X dynamo light at 100 lux low beam rather than in lumens. Lux describes light landing on the road ahead, but we found no source that states why German makers prefer it. More in Lumens, lux and candela: what a bike light's numbers measure

Only when both were taken at the same distance with the same setup. Illuminance falls with the square of distance, and road.cc says even its own beam photos compare only within one year's test. More in Lumens, lux and candela: what a bike light's numbers measure

Under ANSI/PLATO FL 1, beam distance is the distance at which the beam falls to 0.25 lux. It says how far a faint glow reaches, not how far you can see clearly. More in Lumens, lux and candela: what a bike light's numbers measure

It depends on the mode. Knog, for example, rates the Blinder 1400 at 1.5 hours in High Steady and 8 hours in Low Steady, so read the runtime for the mode you plan to ride in. More in Bike light runtime: maker claims, ANSI FL 1 and what reviewers recorded

Under ANSI/PLATO FL 1, runtime runs from the output 30 seconds after switch-on until output falls to 10 percent of that value. A rated runtime is not time at full brightness, so a light can dim well before it reaches the number on the box. More in Bike light runtime: maker claims, ANSI FL 1 and what reviewers recorded

It is the time from the 30-second output reading until output drops to 10 percent of it, starting with fresh batteries. Following FL 1 is voluntary and each company runs its own tests. More in Bike light runtime: maker claims, ANSI FL 1 and what reviewers recorded

We found no bike-light test on this. In one flashlight test by 1Lumen, cooling changed the high-mode result a great deal, so conditions matter, but that result is for that flashlight only. More in Bike light runtime: maker claims, ANSI FL 1 and what reviewers recorded

Not always. A road.cc reviewer reported that the Magicshine EVO 1700 shut off after its run with no reduced limp-home mode. Check the maker's manual for your light. More in Bike light runtime: maker claims, ANSI FL 1 and what reviewers recorded

A light approved under Germany's road-vehicle rules. StVZO section 67 requires low-beam headlights aimed so they do not dazzle other road users, and the lighting devices must meet a type-approval requirement. More in Cutoff beams and StVZO: what an anti-glare bike light is

StVZO is a German rule and says nothing about US or Canadian requirements. State and provincial rules set what you need where you ride; see our guide to bike light and reflector rules. More in Cutoff beams and StVZO: what an anti-glare bike light is

We found no measurement that settles it for every light. Compare beam photos taken on one reviewer's fixed setup in the same year, and check the light's output in the mode you will use. More in Cutoff beams and StVZO: what an anti-glare bike light is

No. StVZO section 67 prohibits flashing bicycle headlights and flashing tail lights. More in Cutoff beams and StVZO: what an anti-glare bike light is

Not necessarily. A BikeRadar tester saw a clearly defined cutoff on the Ravemen CR1000 and noted it is not StVZO compliant. Approval is a separate claim the maker has to state. More in Cutoff beams and StVZO: what an anti-glare bike light is

One Danish experiment found a 19 percent lower injury-accident rate among cyclists with permanent running lights over 12 months. That is one study in one setting, with self-reported accidents, so treat it as encouraging rather than proof for any product. More in Do daytime bike lights help? What the research measured

No study we cite compares the two. The Cochrane review found that, at night, lamps, flashing lights and retroreflective materials all improved driver detection, but it did not rank them. More in Do daytime bike lights help? What the research measured

No study we found proves that. A Cochrane review of 42 trials found every one measured driver detection and recognition, and none measured collisions or injuries. More in Do daytime bike lights help? What the research measured

A mode some makers list for riding in daylight. Garmin, for example, rates the Varia RTL515 at 65 lumens for up to 16 hours in day flash. More in Do daytime bike lights help? What the research measured

Because you ride in one mode at a time, and the headline runtime usually belongs to the dimmest. Knog rates the Blinder 1400 at 1.5 hours in High Steady but 8 hours in Low Steady. More in Bike lights with published runtime by mode

We cannot say. A Cochrane review of visibility aids found trials measured driver detection, and none measured collisions or injuries. Garmin's ratings describe the light, not an outcome. More in Bike lights with published runtime by mode

Rules differ by place: California sets 300 feet for a front lamp and Oregon 500 feet. Check the rules where you ride; no light is legal everywhere. More in Bike lights with published runtime by mode

Measure yours where the mount will clamp; bars change diameter along their length. Then compare it with the maker's stated range: Quad Lock lists 25-40 mm for its Handlebar/Stem Mount and CatEye lists 22-35 mm for its H-34N bracket. See how to measure your handlebar diameter. More in Bike mounts

Not directly. Wahoo says its ELEMNT, BOLT and ROAM computers do not work directly with Garmin mounts, and for the ELEMNT it warns that doing so will damage the computer's mount interface. See Garmin vs Wahoo computer mounts. More in Bike mounts

We cannot say either way. Apple's vibration note covers high-power motorcycles, mopeds and scooters and does not mention bicycles. Quad Lock says the camera-vibration issue it knows of is with some motorcycles, not bicycles. More in Bike mounts

Only where its maker says so. Quad Lock sells a Flat Bar Adaptor separately for flat stems, and SP Connect includes one flat and one round adapter with its bike mount. Aero and other non-round bars need the maker's explicit word. More in Bike mounts

Neither wins outright; fit decides. Each needs its own case or adapter, and Quad Lock states a 25-40 mm range for its Handlebar/Stem Mount, while we could not confirm a millimeter range for Peak Design's Out Front V2. More in Bike phone mounts: Quad Lock, Peak Design and SP Connect fit, and vibration

Apple's vibration warning covers motorcycles, mopeds and scooters and does not mention bicycles, so it neither warns about nor clears bike mounts. Quad Lock says the camera-vibration issue it knows of is with some motorcycles, not bicycles. More in Bike phone mounts: Quad Lock, Peak Design and SP Connect fit, and vibration

For Quad Lock, Peak Design and SP Connect, yes, or the maker's adapter. Peak Design's Out Front V2 uses its SlimLink system, and SP Connect's mount needs an SP Connect case or adapter. More in Bike phone mounts: Quad Lock, Peak Design and SP Connect fit, and vibration

SP Connect lists its Universal Bike Mount for handlebars or stems of approximately 20-44 mm, attached without tools, with one flat and one round adapter included. More in Bike phone mounts: Quad Lock, Peak Design and SP Connect fit, and vibration

Quad Lock says its Handlebar/Stem Mount is not compatible with its Vibration Dampener and does not recommend one on a bicycle mount, though it notes the dampener can go on its Stem Cap and Out Front cycle mounts if you want it. More in Bike phone mounts: Quad Lock, Peak Design and SP Connect fit, and vibration

Wahoo says its ELEMNT, BOLT and ROAM computers do not work directly with Garmin mounts. For the ELEMNT, it warns that direct use will damage the computer's mount interface. More in Garmin vs Wahoo computer mounts: similar shape, different systems

A BOLT 2 mount, yes; a BOLT 1 mount, no. Wahoo says the BOLT 3 fits stock BOLT 2 mounts but not BOLT 1 mounts, because the longer BOLT 3 lacks clearance. More in Garmin vs Wahoo computer mounts: similar shape, different systems

Wahoo says it checks third-party mounts for fit only and does not stress- or weight-test them or their interfaces. Strength is up to the mount's own maker. More in Garmin vs Wahoo computer mounts: similar shape, different systems

We could not read Garmin's own compatibility list, so we do not list devices. Check the product page for your exact Edge model before you buy. More in Garmin vs Wahoo computer mounts: similar shape, different systems

Measure it at the exact spot the clamp will sit, with calipers or a paper strip wrapped once around the bar. Divide the strip's length by pi (about 3.14) to get the diameter in millimeters. More in How to measure your handlebar diameter for a light or phone mount

Only if your measurement falls inside the range the maker states for that mount. Quad Lock states 25-40 mm for its Handlebar/Stem Mount, and SP Connect lists about 20-44 mm for its Universal Bike Mount. More in How to measure your handlebar diameter for a light or phone mount

Some mounts are made for it. Quad Lock says its Handlebar/Stem Mount fits handlebars or stems from 25 to 40 mm and sells a Flat Bar Adaptor separately for flat stems, and SP Connect includes a flat adapter with its Universal Bike Mount. More in How to measure your handlebar diameter for a light or phone mount

A diameter range only describes round tubes. Look for a maker-supplied flat or shaped adapter, such as Quad Lock's Flat Bar Adaptor or SP Connect's included flat adapter, and ask a bike shop if your bar or stem is aero-shaped. More in How to measure your handlebar diameter for a light or phone mount

Among these, SP Connect lists about 20-44 mm and CatEye lists 22-35 mm for its light bracket. Wahoo's out-front mount is for 31.8 mm round bars only. More in Phone, computer and light mounts with a stated bar range

Not directly. Wahoo says its ELEMNT, BOLT and ROAM computers do not work directly with Garmin mounts. More in Phone, computer and light mounts with a stated bar range

We cannot say either way. Apple's vibration note covers motorcycles, mopeds and scooters and does not mention bicycles. More in Phone, computer and light mounts with a stated bar range

Check each maker's range. CatEye lists its H-34N bracket for 22-35 mm bars and Knog lists 22.2-35 mm for the Blinder 1400, while Quad Lock's Handlebar/Stem Mount starts at 25 mm. Open the 22.2 mm page for the full list. More in Handlebar size finder

No. A range is the maker's statement for round tubes in that span. Quad Lock says its zip ties fit most tubes outside its 25-40 mm range, which is not a promise for any particular bar shape. More in Handlebar size finder

Because those makers do not list it. Wahoo's out-front mount for the BOLT 3 and ROAM 3 is for 31.8 mm round bars only. More in Handlebar size finder

One whose maker names Presta for its head. Lezyne, for example, describes its Dual Valve floor-pump head as fitting Presta, Dunlop and Schrader, while its Slip Fit head on hand pumps is Presta-only. Unthread the Presta locknut before pumping. See how to identify your valve. More in Bike pumps

Only up to what your tire and rim allow. Schwalbe says the sidewall range must never be exceeded, and hookless road rims have a 5 bar maximum even when the tire says more. BikeRadar notes that a higher-pressure pump is often a trade-off against volume per stroke. More in Bike pumps

They save effort, but their speed and gauge figures are the makers' claims until a named test reports otherwise. CYCPLUS, Topeak and Fumpa each list a 120 psi maximum and USB-C charging for their models. Compare the options in electric pump vs mini pump vs CO2. More in Bike pumps

Only named tests can say, and only for their setup. BikeRadar's October 2026 test used 32 mm tubeless tires with a 53 psi target, yet its results quote 51 psi on a 35 mm tire, so read its times with that conflict in mind. See what published inflation tests found. More in Bike pumps

Only if your tire's sidewall range calls for pressures near the top of a smaller pump's rating. Schwalbe says the permissible range is printed on the sidewall, and that range, not the pump's maximum, sets your target. More in Pump max psi vs your tire's and rim's pressure limits

Within the range printed on your tire's sidewall, never above or below it, and never above your rim's maximum. Schwalbe gives no general recommendation, because the right pressure depends mainly on rider and luggage weight. More in Pump max psi vs your tire's and rim's pressure limits

Schwalbe, citing ETRTO, says hookless road rims have a 5 bar maximum (about 72.5 psi), which applies even when the tire sidewall shows a higher maximum. More in Pump max psi vs your tire's and rim's pressure limits

Schwalbe advises checking pressure at least once a month and considers a loss of about 1 bar a month normal. It says latex tubes should be checked before each ride. More in Pump max psi vs your tire's and rim's pressure limits

Gauge accuracy on a pump is the maker's claim. CYCPLUS claims plus or minus 1 psi for the AS2 Pro and Topeak plus or minus 2 psi for the E-BOOSTER DIGITAL; neither is a calibration result we can confirm. More in Pump max psi vs your tire's and rim's pressure limits

No. Genuine Innovations says its threaded cartridges use standard 3/8"-24 threading, and Lezyne says threadless cartridges do not work with its CO2 inflators. Match the cartridge type to what your inflator's maker names. More in CO2 inflators: threaded cartridges, cold heads, tubeless and TPU

Genuine Innovations explains that cartridges become ice cold as the gas is released, and recommends a cupped head or sheath to protect fingers from cold burns. More in CO2 inflators: threaded cartridges, cold heads, tubeless and TPU

As an emergency fill. Stan's NoTubes says prolonged CO2 exposure can make sealant separate or shorten its life, so it should be replaced with air when you get home. More in CO2 inflators: threaded cartridges, cold heads, tubeless and TPU

TSA lists CO2 cartridges as not allowed in either carry-on or checked bags unless the cylinder is clearly empty, and the officer makes the final call. We could not read the FAA's own rules, so we do not describe any exceptions. More in CO2 inflators: threaded cartridges, cold heads, tubeless and TPU

Tubolito says its tubes can be inflated with CO2, but CO2 escapes faster than air, so they need reinflating sooner. More in CO2 inflators: threaded cartridges, cold heads, tubeless and TPU

It depends on the model. CYCPLUS says the AS2 Pro switches between the two without extra parts, and Topeak says the E-BOOSTER DIGITAL's SmartHead fits both. Read the maker's page for your pump. More in Dual-valve pump heads: what "Presta and Schrader" really covers

Park Tool says a Dunlop/Woods valve can be inflated with a Presta-compatible head without unthreading its ring. Lezyne's Dual Valve floor-pump head names Dunlop along with Presta and Schrader. More in Dual-valve pump heads: what "Presta and Schrader" really covers

Only where the pump's maker says so. Lezyne lists the Clik Drive HP with a Clik Valve compatible hose. We could not confirm Clik Valve support for other products, including SKS's AIRCHECKER gauge. More in Dual-valve pump heads: what "Presta and Schrader" really covers

First check the head is made for a threaded Presta valve: Lezyne warns its Speed Chuck is for valve extenders only and will fail on a regular Presta valve. Also make sure the locknut is unthreaded, as Park Tool describes, and follow your pump maker's instructions. More in Dual-valve pump heads: what "Presta and Schrader" really covers

It depends on the pump, tire and target. TOUR measured the CYCPLUS AS2 Pro reaching 4 bar in 59 seconds and 7 bar in 161 seconds on a 700x30c tire, and a road.cc reviewer found about 50 seconds to 60 psi on a 30 mm tire. Those are different conditions, so the numbers are not comparable. More in Electric bike pumps: what published inflation tests found, and what they did not

In BikeRadar's 2026 results, the AS2 Pro averaged 43.4 seconds to 51 psi and the AS2 took 59.3 seconds. BikeRadar's method and results disagree on tire size and target, and it is not explicit that both timings used the same tire, so treat this as one publication's report. More in Electric bike pumps: what published inflation tests found, and what they did not

Makers claim figures under their own conditions: CYCPLUS claims up to two 110 psi or four 80 psi fills on 700x25c tires for the AS2 Pro. A road.cc reviewer managed four 60 psi fills of a 30 mm tire, and TOUR reported about 4.25 tires per charge. More in Electric bike pumps: what published inflation tests found, and what they did not

They describe the maker's own protocol, which is not published in full and is not comparable with third-party times. Read them as claims, and compare only results from the same test. More in Electric bike pumps: what published inflation tests found, and what they did not

Follow your pump maker's instructions. Topeak tells E-BOOSTER DIGITAL users to fit the extender hose on TPU tubes with resin valves so the valve does not overheat and melt. Other makers may say something different, or nothing. More in Electric pump heat and TPU tubes with plastic valves

TOUR measured the CYCPLUS AS2 Pro's housing at 35 °C at 4 bar and 62 °C at 7 bar on a 700x30c tire. That is one sample and the housing only, not the head or valve. More in Electric pump heat and TPU tubes with plastic valves

Topeak says so for the E-BOOSTER DIGITAL on TPU tubes with resin valves. We could not read a matching instruction for the CYCPLUS AS2 Pro, so check your own pump's manual. More in Electric pump heat and TPU tubes with plastic valves

Not in the FAQ we read. Tubolito's FAQ covers CO2 and valve cores but says nothing about electric pumps or valve heat, so the heat warning comes from Topeak, not Tubolito. More in Electric pump heat and TPU tubes with plastic valves

It saves effort but needs charging, and makers' fills per charge are claims. CYCPLUS claims up to two 110 psi or four 80 psi fills on 700x25c tires per charge for the AS2 Pro, so plan charging before long rides. More in Electric pump, mini pump or CO2 for your ride kit

It is faster but single-use. Genuine Innovations says cartridges get ice cold during release, Stan's calls CO2 an emergency option for tubeless and says to replace it with air, and Tubolito says CO2 escapes faster from its TPU tubes. Many riders carry a mini pump as backup. More in Electric pump, mini pump or CO2 for your ride kit

TSA lists CO2 cartridges as not allowed in carry-on or checked bags unless clearly empty. It says spare lithium batteries, including power banks, must go in carry-on only. For a pump with a built-in battery, check with your airline. More in Electric pump, mini pump or CO2 for your ride kit

It varies by pump and tire. In a 2015 test, BikeRadar recorded about 70-80 psi after 200 strokes with the largest Lezyne Road Drive, one historical sample. More in Electric pump, mini pump or CO2 for your ride kit

On a removable-core valve, a threaded pump head can unscrew a loose core. Lezyne's FAQ blames many cases on tube makers not tightening cores enough at assembly and advises checking that cores are tight. More in Presta valve core came out with the pump head? Removable cores and core tools

Park Tool says removable Presta cores can be recognized by two wrench flats at the end of the valve, and that not all Presta cores are removable. More in Presta valve core came out with the pump head? Removable cores and core tools

A valve core tool. Park Tool's VC-1 removes and installs Schrader cores, removable Presta cores and Presta extenders with 5 mm flats. Wolf Tooth's Pack Pliers and the Topeak HybridRocket HP Mini's cap also include a Presta core tool. More in Presta valve core came out with the pump head? Removable cores and core tools

For Tubolito tubes, only through its Schrader (AV) valves: Tubolito says its Presta (SV) cores are glued in. That statement covers Tubolito only. More in Presta valve core came out with the pump head? Removable cores and core tools

None of the sources we read publishes a torque value for a valve core, so we give none. Lezyne's FAQ says to check cores are tight and not to over-tighten the pump onto the valve. More in Presta valve core came out with the pump head? Removable cores and core tools

Look at the stem. Park Tool describes Presta stems as nominally 6 mm, with a small locknut at the tip that you unthread before inflating, and Schrader stems as about 8 mm (5/16 in), like a car tire valve. More in Presta vs Schrader vs Dunlop: identify your valve before buying a pump

No. Park Tool describes the Woods/Dunlop valve as a narrow stem top over a large locking ring, a different valve. It also says a Presta-compatible head can inflate it without unthreading the ring. More in Presta vs Schrader vs Dunlop: identify your valve before buying a pump

Schwalbe uses SV for Sclaverand (Presta), AV for car (Schrader), DV for Dunlop and SCV for its own Clik Valve. More in Presta vs Schrader vs Dunlop: identify your valve before buying a pump

We found no source among those we read that covers rim valve-hole sizes for this swap, so we do not give an answer. Ask a bike shop to check your rim before you change valve type. More in Presta vs Schrader vs Dunlop: identify your valve before buying a pump

No. Park Tool says only some Presta valves have removable cores, recognized by two wrench flats at the end of the valve, and Tubolito says the cores in its Presta tubes are glued in. More in Presta vs Schrader vs Dunlop: identify your valve before buying a pump

Schwalbe says first inflation needs a strong blast of air from a floor pump, compressor or Tire Booster, and does not list a mini pump. A mini pump is for topping up a tire that is already seated. More in Seating a tubeless tire vs topping it up: which pump does which job

Not always. Schwalbe lists a floor pump, compressor or Tire Booster for first inflation, and Stan's says some tires may need a compressor. If a tire will not seat, stop and ask a bike shop. More in Seating a tubeless tire vs topping it up: which pump does which job

Stan's NoTubes says removing the valve core increases airflow, which helps seat a tubeless tire. More in Seating a tubeless tire vs topping it up: which pump does which job

CPSC announced a recall of Lezyne Pressure Over Drive and Digital Pressure Over Drive floor pumps in November 2025 because the canister can forcefully eject from the base. It covers only pumps with a bleed valve on the front of the base; check Lezyne's recall notice and stop using an affected pump. More in Seating a tubeless tire vs topping it up: which pump does which job

CYCPLUS says the AS2 Pro switches between Presta and Schrader without extra parts. For the others, read the maker's page for the valves its head lists before you order. More in Bike pumps with a stated valve fit and pressure

No. Your tire's sidewall range and your rim's maximum set the pressure. BikeRadar notes that a higher-pressure pump is often a trade-off against volume per stroke. More in Bike pumps with a stated valve fit and pressure

Because only named tests can supply one, with their own tire and target. TOUR, for example, measured the AS2 Pro reaching 4 bar in 59 seconds on a 700x30c tire. We have no comparable test for the others. More in Bike pumps with a stated valve fit and pressure

Look at the stem. Park Tool describes Presta as a thin stem, nominally 6 mm, with a small locknut at the top, and Schrader as about 8 mm (5/16 inch). Woods/Dunlop has a narrow stem top with a large locking ring beneath it. More in Valve finder

They are Schwalbe's codes: SV for Sclaverand (Presta), AV for car (Schrader), DV for Dunlop, and SCV for its own Clik Valve. More in Valve finder

Only if it is a removable type. Park Tool says removable Presta cores have two wrench flats at the end of the valve, and not all Presta cores are removable. Tubolito says its Presta cores are glued in. More in Valve finder

A repair kit that matches your tires, tire levers, and a multitool with the bits your bolts need. Tube riders need patches or a spare tube; tubeless riders need a plug tool. See the road and gravel ride repair kit. More in Carry tools

Only if you would fix a chain on the road, and only if the tool's maker lists your chain. Topeak lists the Mini 20 Pro's chain tool for chains up to 12-speed, excluding Campagnolo hollow-pin chains. SRAM says its Eagle PowerLock is single-use. More in Carry tools

The makers disagree. Tubolito says butyl-tube repair kits do not work on its tubes and supplies its own kit with special glue, while Park Tool says its GP-2 glueless patches work on butyl and TPU tubes as a temporary fix. Follow your tube maker. See tube patch vs tubeless plug. More in Carry tools

If a component maker states a torque for a bolt, a torque tool is how you meet it. Park Tool aims its ATD-1.2 driver at carbon parts and low torque specs, and Topeak lists accuracy for its Torq Stick Pro. Take the value from the component maker, never from us. See pocket torque tools. More in Carry tools

The hex and Torx bits your bike's bolts use, plus a chain tool if your chain and the tool's listed compatibility match. Check the maker's tool list against your bolts rather than counting functions. More in Multitools, chain tools and tire levers: what each one covers

Only if its maker says so. Topeak lists the Mini 20 Pro and Mini PT30 chain tools for chains up to 12-speed, excluding Campagnolo hollow-pin chains. More in Multitools, chain tools and tire levers: what each one covers

Check with your rim maker first. Topeak describes the Mini 20 Pro's metal tire levers as for emergency use only, and Wolf Tooth says the Pack Pliers' lever is not recommended for carbon rims. Follow your rim maker's instructions. More in Multitools, chain tools and tire levers: what each one covers

SRAM says its Eagle PowerLock is designed for single use and a new one should be installed each time a chain is installed. That covers the Eagle PowerLock only; check your own link maker's instructions for other links. More in Multitools, chain tools and tire levers: what each one covers

If you tighten bolts on parts whose makers print a torque figure, a torque tool lets you match it. Wahoo, for example, warns that over-torquing can strip the threads of its BOLT 3 and ROAM 3 out-front mount. More in Pocket torque tools for bikes: preset drivers vs adjustable wrenches

The figure your component's maker prints on the part or in its instructions. We give no torque values for any component; if you cannot find the figure, ask the maker or a bike shop. More in Pocket torque tools for bikes: preset drivers vs adjustable wrenches

Makers state their own figures. Park Tool says the ATD-1.2 is calibrated to within plus or minus 4 percent, and Topeak lists plus or minus 4 percent for the Torq Stick Pro 2-10 Nm for 5,000 cycles, with recalibration recommended after that. More in Pocket torque tools for bikes: preset drivers vs adjustable wrenches

Park Tool's ATD-1.2 has five settings from 4 to 6 Nm and clicks and stops at the set value; Topeak's Torq Stick Pro covers 2 to 10 Nm. Choose the range that covers the figures your parts' makers print. More in Pocket torque tools for bikes: preset drivers vs adjustable wrenches

A pump or CO2 that fits your valve, tire levers, a spare tube or a patch kit that suits your tube, and a multitool with your bike's bits. Check each item fits before the ride. More in Road and gravel ride repair kit: what to carry for your tires

A plug tool for small punctures, plus a way to reinflate. Park Tool says its TPT-1 is for small punctures in tubeless tires with sealant, and Stan's says its DART reacts with latex-based sealants and was developed for Stan's sealant. More in Road and gravel ride repair kit: what to carry for your tires

Many riders do, as a fallback when a plug will not hold. Plug tools such as Park Tool's TPT-1 are for small punctures only, and Park Tool gives no maximum hole size. More in Road and gravel ride repair kit: what to carry for your tires

Not with full CO2 cartridges: TSA lists them as not allowed in carry-on or checked bags unless clearly empty. Pack a pump instead and buy cartridges at your destination. More in Road and gravel ride repair kit: what to carry for your tires

The makers disagree. Park Tool says its GP-2 glueless patches work on butyl and TPU tubes, while Tubolito says repair kits made for butyl tubes are not compatible with its tubes and supplies its own kit. For a Tubolito tube, follow Tubolito. More in Tube patch or tubeless plug? Match the repair to the tire and tube

No. Park Tool says its TPT-1 plug tool is for small punctures in tubeless tires with sealant and is not compatible with inner tube systems. More in Tube patch or tubeless plug? Match the repair to the tire and tube

Park Tool says its GP-2 glueless patches should be considered a temporary fix, and that they do not work on latex tubes or tubeless tires. More in Tube patch or tubeless plug? Match the repair to the tire and tube

Stan's says the DART reacts with latex-based sealants and was developed for Stan's sealant, and that results with other latex sealants may vary. More in Tube patch or tubeless plug? Match the repair to the tire and tube

Park Tool describes the TPT-1 as for small punctures and gives no maximum size; Stan's DART page does not address hole size. If a plug will not hold, use a tube to get home and ask a shop about the tire. More in Tube patch or tubeless plug? Match the repair to the tire and tube

No. Park Tool says the TPT-1 is not compatible with inner tube systems. For tubes, carry patches suited to your tube or a spare. More in Multitools and repair tools with listed functions

Makers are cautious. Topeak calls the Mini 20 Pro's metal levers emergency-use only, and Wolf Tooth does not recommend its Pack Pliers' lever for carbon rims. Follow your rim maker. More in Multitools and repair tools with listed functions

Only if your components have maker-stated torque figures you need to meet on the road. Park Tool aims its ATD-1.2 at carbon parts and low torque specs; Topeak lists plus or minus 4 percent for its Torq Stick Pro. Neither tells you a bolt's value. More in Multitools and repair tools with listed functions

No source we read says which valve is usual on commuter bikes. A small locknut at the top of a thin stem means Presta; a wider stem with an internal pin is Schrader. The valve finder walks through it. More in Commuter bikes

Compare the hook size with your rack tube. ORTLIEB's QL2.1 hooks take 8, 10 and 12 mm tubes with inserts, and its QL2.2 hooks take 8 to 16 mm. See pannier hooks and rack tube sizes. More in Commuter bikes

It depends on where you ride. California's code accepts a solid or flashing red rear light with a built-in reflector, while Germany's StVZO bans flashing tail lights. Check your own state or province. More in Commuter bikes

Schwalbe advises at least once a month, and before each ride with latex tubes. It treats a loss of about 1 bar a month as normal. More in Commuter bikes

No source we read says which valve road bikes usually have. If the stem has a small locknut at the top that you unthread before pumping, it is Presta. The valve finder walks through it. More in Road bikes

Not above the rim's limit. Schwalbe, citing ETRTO, gives hookless road rims a 5 bar maximum that applies even when the sidewall shows more. More in Road bikes

Wahoo makes its BOLT 3 / ROAM 3 out-front mount for 31.8 mm round bars. Measure your bar first. More in Road bikes

No. Park Tool says its TPT-1 repairs small tubeless punctures and is not compatible with inner tube systems. For tubes, see tube patch or tubeless plug. More in Gravel bikes

Apidura says to choose by the frame's dimensions, not by the capacity you want, and to include bottles and frame-mounted accessories when sizing. See how to size frame and top-tube bags. More in Gravel bikes

Schwalbe says first inflation needs a strong blast of air from a floor pump, compressor or Tire Booster, and Stan's says some tires may need a compressor. Neither names a mini pump. More in Gravel bikes

Use the mode the maker lists for tires. Topeak's Mountain Digital 2Stage has a shock mode rated to 300 psi and a separate tire mode listed at 0-30 psi recommended. More in Mountain bikes

Topeak rates some of its Mountain mini pumps to 60 psi. Compare your pump maker's maximum with the range printed on your tire's sidewall. More in Mountain bikes

No. Park Tool says its TPT-1 plug tool is for tubeless tires and is not compatible with inner tube systems. More in Mountain bikes

That is a Dunlop (Woods) valve: Park Tool describes a narrow stem top with a large locking ring beneath it, and says a Presta-compatible head inflates it without unthreading the ring. More in Casual and hybrid bikes

Measure the bar first. Quad Lock designs its Handlebar/Stem Mount for 25-40 mm, and SP Connect lists its Universal Bike Mount for about 20-44 mm. See how to measure your handlebar. More in Casual and hybrid bikes

Not if the pump's maker lists Schrader. Lezyne lists Presta, Dunlop and Schrader on its Dual Valve floor head; SILCA's Pocket Impero works only with Presta. More in Casual and hybrid bikes

Measure the rack tube. ORTLIEB offers optional 20 mm QL2.1 hooks for 17-20 mm tubes, which it says are often used on e-bikes; its standard inserts cover 8, 10 and 12 mm. More in E-bikes

CPSC urges e-bike owners not to use chargers marketed as universal unless tested and approved for their specific device, and to use the supplied charger or a manufacturer-approved replacement. More in E-bikes

No. UL describes UL 2849 as its standard for e-bike electrical systems; it is a vehicle-system standard, not one for standalone accessories such as USB lights or pumps. More in E-bikes

Brompton says its Front Bags can carry up to 10 kg, with the load on the frame rather than the handlebars. More in Folding bikes (Brompton)

Brompton says Brompton Electric uses a dedicated Front Carrier Block, so it needs an Electric-compatible Front Bag with space for the battery. See Brompton front bags, standard vs Electric. More in Folding bikes (Brompton)

Brompton's US listing gives A Line, C Line Mk5 and Mk6, P Line Mk1, T Line and G Line, and lists no Electric models. More in Folding bikes (Brompton)

Lezyne attributes many such cases to cores not tightened enough at assembly and advises checking that cores are tight. A removable core has two wrench flats. See Presta core came out with the pump?. More in Presta

Park Tool says removable Presta cores have two wrench flats at the end of the valve, and that not all Presta cores are removable. More in Presta

Only on a valve extender. Lezyne says the Speed Chuck will fail on a regular threaded Presta valve. More in Presta

Only if its maker lists Schrader. SILCA says its Pocket Impero works only with Presta, while Lezyne lists Schrader on its Dual Valve floor head. More in Schrader

Through a removable core, yes: Tubolito says its Schrader (AV) cores come out to accept sealant, and Park Tool's VC-1 removes Schrader cores. More in Schrader

Yes, according to Park Tool: a Presta-compatible head inflates a Woods/Dunlop valve without unthreading its ring. More in Dunlop / Woods

Park Tool says the Woods/Dunlop valve is found on less expensive bikes outside the United States. Check your own valve rather than going by the bike. More in Dunlop / Woods

Schwalbe uses DV for Dunlop, alongside SV for Presta, AV for Schrader and SCV for its Clik Valve. More in Dunlop / Woods

Schwalbe's page does not say which pumps work with Clik Valve. Use a pump whose maker lists it, such as Lezyne's Clik Drive HP with its Clik Valve compatible hose. More in Schwalbe Clik Valve

SCV is Schwalbe's code for its own Clik Valve, alongside SV for Presta, AV for Schrader and DV for Dunlop. More in Schwalbe Clik Valve

Follow your pump maker. Topeak says to use its extender hose with resin-valve TPU tubes on the E-BOOSTER DIGITAL to keep the valve from overheating and melting; CYCPLUS's AS2 Pro page states no such warning. See electric pump heat and TPU tubes. More in Plastic (resin) valves on TPU tubes

Tubolito says its tubes can be inflated with CO2, but CO2 escapes faster than air, so they need reinflating sooner. More in Plastic (resin) valves on TPU tubes

The makers differ. Tubolito says butyl-tube kits are not compatible with its tubes and sells its own kit; Park Tool says its GP-2 glueless patches work on TPU tubes as a temporary fix. More in Plastic (resin) valves on TPU tubes

22.2 mm is below the 25-40 mm range Quad Lock states for its Handlebar/Stem Mount. Quad Lock says its zip ties can fit most tubes outside that range, which is not a guarantee for your bar. More in 22.2 mm

Knog lists a 22.2-35 mm bar mount, so 22.2 mm is at the bottom of its stated range. More in 22.2 mm

Measure where the clamp will sit with a caliper, or wrap a paper strip around the bar and divide its length by pi. See how to measure your handlebar. More in 22.2 mm

Wahoo makes its BOLT 3 / ROAM 3 out-front mount for 31.8 mm round bars, so 25.4 mm is not a size it lists. More in 25.4 mm

Quad Lock designs its Handlebar/Stem Mount for 25-40 mm, so 25.4 mm is inside that range, near the bottom. More in 25.4 mm

Wahoo makes it for 31.8 mm round bars. Measure your bar where the mount will sit, and do not over-tighten it: Wahoo warns that over-torquing can strip its threads. More in 31.8 mm

Wahoo says its ELEMNT, BOLT and ROAM computers do not work directly with Garmin mounts. See Garmin vs Wahoo computer mounts. More in 31.8 mm

CatEye lists the H-34N for 22-35 mm handlebars, so 35 mm is the top of its stated range. More in 35 mm

Wahoo makes its BOLT 3 / ROAM 3 out-front mount for 31.8 mm round bars; we read no Wahoo statement about a 35 mm version. More in 35 mm

Quad Lock sells a Flat Bar Adaptor separately for mounting its Handlebar/Stem Mount on flat stems. More in Flat stems, aero and non-round bars

Quad Lock says its zip ties can fit most tubes outside 25-40 mm. That is not a promise for any specific shape, so check with Quad Lock for yours. More in Flat stems, aero and non-round bars