Upright size
3x3 in rack uprights: 5/8 in vs 1 in hardware and what fits
3x3 in uprights work out to 76.2 mm, 1.2 mm larger per side than 75 mm. They come with 5/8 in or 1 in hardware; the systems in each class and parts sold for them.
Also listed as 3x3, 3 x 3 in
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Short answer
A 3x3 in upright works out to 76.2 x 76.2 mm, calculated from 25.4 mm per inch, which is 1.2 mm larger per side than a 75 x 75 mm tube. 3x3 tubing comes in two hardware classes: 5/8 in (Rogue Monster Lite, REP PR-4000, Bells of Steel Hydra, PRx Profile CORE) and 1 in (Rogue Monster, REP PR-5000, Bells of Steel Manticore), and Titan's X-3 has 11/16 in holes. Pick an attachment version by hole or pin size as well as tube size.
What fitsAll 6 items that fit
- J-cupsSynergee J-Cups, pair (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Check price on Amazon
- Safety armsSynergee Safety Arms, pair (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Check price on Amazon
- Dip handlesSynergee Rack Dip Handles, pair (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Check price on Amazon
Key facts
- Calculated other unit
- 76.2 x 76.2 mm (calculated from 25.4 mm per inch)[3][4]Bells of Steel also prints 3 x 3 in as 76.2 x 76.2 mm. A calculation, never a tolerance.
- Often confused with
- 75 x 75 mm tubing: 3x3 in is 1.2 mm larger per side by label[3]The difference is between labels; it is not a fit tolerance.
- Hole diameters makers list
- 5/8 in: Rogue SML-2, Bells of Steel Hydra, PRx Profile CORE. 1 in: Bells of Steel Manticore (keyholes with a 5/8 in opening), Titan TITAN Series (keyholes). 11/16 in: Titan X-3.[2][4][5][6][7]
- Pin sizes makers list
- 5/8 in hardware: Rogue RML-690 and SML-2, REP PR-4000. 1 in hardware: Rogue RM-6, REP PR-5000. Parts: REP Round Sandwich J-cups 5/8 in; Rogue Ghost Roller J-Cups 2.0 in 5/8 in and 1 in versions.[8][2][1][9][10][11]A hardware class is a pin and bolt size, not a measured hole.
- Spacing makers list
- Rogue SML-2: Westside, 1 in through the bench and clean-pull zone, 2 in above and below. REP PR-4000: 2 in, 1 in in the bench zone. REP PR-5000: 2 in. PRx Profile CORE: 2 in front, 4 in side. Titan X-3: side holes every 6 in.[2][1][5][7]
- Rack systems with this upright
- Rogue SML-2, Monster Lite and Monster; REP PR-4000 and PR-5000; Titan X-3 and TITAN Series; Bells of Steel Hydra and Manticore; PRx Profile CORE and PRO[2][8][9][1][7][6][4][5][12]
- Attachments sold for this size
- Bells of Steel standard and Sandwich J-cups (Hydra and Manticore versions); REP Round Sandwich J-cups (4000 Series); Rogue Monster Safety Spotter Arms 2.0 and Monster Landmine 2.0 (Monster Series only); Bells of Steel change plate pegs; Synergee J-cups in a 3x3 version (3.4 in shelf)[13][14][10][15][16][17][18]
- How to check yours
- Measure the outside of the upright, then the hole diameter: it tells you whether you need a 5/8 in or a 1 in part. Then measure the center-to-center spacing where you will mount. For straps, Synergee tells buyers to measure the rack's inside depth.[19][3]Convert with 25.4 mm per inch; a converted figure is not a fit allowance.
- Not confirmed
- Not confirmedNo maker in our sources publishes a tube tolerance or coated outside size. Rogue gives no hole diameter for the RM-6 or RML-690.
Watch out for
- 3x3 is not one system: the same tube comes with 5/8 in or 1 in hardware, and Titan's X-3 has 11/16 in holes. Order the version for your hole or pin size.
- Bells of Steel says its Hydra standard J-cups fit other brands' racks only with true 3x3 in uprights and 5/8 in holes; both conditions must hold.
- A 2020-era REP ISO arm FAQ describes 75 x 75 mm REP racks, while REP's rack guide lists its 4000 and 5000 Series as 3x3 in. A metric label is not the same size.
What fits
Product details below are the seller's own description unless a source is shown. Pick the variant named for each item.
J-cups
Synergee J-Cups, pair (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Choose the 3x3 in version with the 5/8 in / 1 in converter (JHOOKC-3X3), or JHOOK-3X3-NC if your holes are 5/8 in.
Synergee lists 3x3 in uprights with 5/8 in or 1 in holes; rated 750 lb per pair, combined, at equal heights. Confirm the converter is in the variant you select.
J-cups
Fringe Sport J-Cups 3x3 pair, 1 in holes (JCUP‑FS‑3x3‑Black)Choose the 3x3 in pair for 1 in holes (JCUP-FS-3x3-Black).
Fringe Sport lists 3x3 in racks with 1 in holes, naming Rogue Monster racks, the REP PR-5000 and the Titan TITAN Series. Not for 5/8 in holes.
Safety arms
Synergee Safety Arms, pair (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Choose the 3x3 in version with converter (24 in arms), or the 3x3 5/8 in-only version.
Synergee lists 3x3 in uprights with 5/8 in or 1 in holes.
Dip handles
Synergee Rack Dip Handles, pair (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Choose the 3x3 in version with converter, or the 3x3 5/8 in-only version.
Synergee lists a 350 lb weight capacity.
Landmine
Synergee Landmine Attachment (2x2, 2x3 or 3x3; 5/8 in or 1 in converter)Choose the 3x3 in version with converter, or the 3x3 5/8 in version.
Synergee says it locks into the upright with an included pin and is rated to support up to 500 lb.
Plate storage
Synergee Weight Plate Storage Attachment, pair of pegs (2x2, 2x3 or 3x3)Choose the 3x3 in version with converter, or the 3x3 5/8 in-only version.
Synergee rates the pegs at 250 lb per peg and 500 lb per pair.
Rack pages for each 3x3 system: Rogue SML-2, Rogue Monster Lite, Rogue Monster, REP PR-4000, REP PR-5000, Titan X-3, Titan TITAN Series, Bells of Steel Hydra, Bells of Steel Manticore and PRx Profile.
Questions
Is 3x3 in the same as 75 mm?
No. Calculated from 25.4 mm per inch, 3 in is 76.2 mm, so a 3x3 in upright is 1.2 mm larger per side than a 75 x 75 mm tube by label. That difference is not a fit tolerance.[3]