Power Rack Upright Sizes Explained: 2×2, 2×3, 3×3 and Metric Tubing

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You’ve found a landmine, a lat pulldown or a set of spotter arms you like, and the listing says it fits 3×3 uprights. Before you order, you need three numbers from your own rack: the tube size, the hole diameter and the hole spacing. This guide covers power rack upright sizes from the major brands, and how to check yours before you buy.

Those numbers matter because “about three inches” can mean a 2×3 tube the bracket won’t clamp, a metric tube that’s slightly undersized, or a true 3×3 with holes the wrong size for the pin.

Specs come from each maker’s own product pages and rack guides, checked September 22, 2026. Where a maker’s own pages disagree, that’s flagged.

Start with the tube: 2×2, 2×3 or 3×3?

Tube size comes first because an attachment wraps around or slides onto the upright. If the tube is the wrong shape, the hole and spacing checks don’t matter.

2×2″ tube is the entry-level size, used on REP’s PR-1000 and PR-1100 and Titan’s T-2 Series, all in 14-gauge steel. Attachments built for 2×3″ or 3×3″ are too big for it.

2×3″ tube is 2″ on one face and 3″ on the other. Rogue’s Infinity Series (R-3, R-4, R-6 and the R-3W fold-back rack) and Titan’s T-3 use it in 11-gauge. Because one face is narrow, you need attachments made for 2×3″: a 3×3″ bracket won’t clamp onto the 2″ face.

3×3″ tube is where most attachments are made. Every brand in the table below sells at least one 3×3″ line, and REP’s rack guide credits its 3×3″ PR-5000 with “the largest attachment ecosystem” in its range. Why 3×3 racks became the standard explains why so many serious racks settled on it.

Matching the tube gets you most of the way. Two racks sold as 3×3″ can still reject the same attachment, and the first reason is that “3×3” doesn’t always mean 3 inches.

Is your 3×3 really 3 inches?

A true 3×3″ upright measures 76.2mm on each face. Many imported racks sold as “3×3″ use metric 75mm tube, about 2.95”. The gap is 1.2mm per face, easy to miss with a tape measure. Bells of Steel is the brand that spells this out: it describes its Hydra and Manticore uprights as true 76.2mm tube and builds their attachments to that size.

Metric sizing turns up in other places too. Bells of Steel’s separate “2.3-inch” line fits “2.3″ x 2.3″ (60 x 60 mm) tubing with 5/8″ holes,” which matches none of the three imperial sizes. Titan’s product page gives the T-2’s hole diameter as 26mm (about 1.02″), while its comparison page lists 1″; the product page is the more specific of the two.

If a listing gives the tube size only in millimetres, or the seller can’t say whether “3×3” means 76.2mm or 75mm, measure it yourself before you buy another brand’s attachments.

Once the tube matches, the pin still has to go through the hole.

Will the pin fit? 5/8″ vs 1″ holes

3×3″ racks split between two hardware sizes. The 5/8″ group includes Rogue’s Monster Lite, REP’s PR-4000 and Bells of Steel’s Hydra. The 1″ group includes Rogue’s Monster, REP’s PR-5000, Bells of Steel’s Manticore, Sorinex’s XL and Titan’s top TITAN Series, which uses 1″ keyholes. Titan’s X-3 and T-3 list 11/16″ holes without naming the pin size, so confirm with Titan before you assume a 5/8″ attachment fits.

A 1″ pin won’t pass through a 5/8″ hole, and a 5/8″ pin sits loose in a 1″ hole. That’s why REP’s guide calls the PR-4000 “compatible with many (but not all)” of its PR-5000 attachments: same 3×3″ tube, different holes.

Some racks cover both standards with a second hole type. The Manticore adds 5/8″ side keyholes to its 1″ main holes, and Rogue’s Monster 2.0 uprights carry a side keyhole pattern for wider attachment fit. Power rack hole size: 5/8″ vs 1″ goes deeper on the two standards.

Tube and hole settle most single-pin attachments. Anything with two pins, or a bracket that spans several holes, needs a third check.

Does the hole spacing line up?

Hole spacing is the distance between hole centres. It sets how finely you can adjust J-cups and safeties, and it decides whether a two-pin attachment, such as a split squat roller, can lock in at all. Three patterns cover the racks in the table:

• Westside: 1″ spacing through the bench and pull zone, 2″ above and below. Rogue’s Monster Lite and Infinity racks, REP’s PR-4000, Titan’s T-3 and X-3 and Bells of Steel’s Hydra use it, or describe 1″ spacing in the bench zone.
• 2″ throughout: REP’s PR-5000 and PR-1000, and Bells of Steel’s Manticore.
• 3″ throughout: REP’s PR-1100.

Rogue’s full-size Monster line is the one to double-check. Its category page says Westside, but the FAQ on the RM-4 and RM-6 pages says 2″ spacing, so confirm the exact model. Side holes are a separate pattern again: Titan’s T-3 and X-3 have side holes every 6″ for attachments that mount to the outside face.

Here are all three numbers side by side.

Power rack upright sizes by brand: tube, holes and spacing

Sorinex’s XL page describes a “4-Way Hole System” but doesn’t give spacing figures, so that cell reads “not stated”.

Titan sells direct: Titan Fitness store. Some of these racks are also sold on Amazon: REP Fitness on Amazon. Racks come in several heights, depths and hole options, so match the exact model before you order.

How to check your own rack before you order

1. Measure both faces of the upright. Two different readings means a 2×3″ tube.
2. Check imperial against metric. A reading closer to 75mm than 76.2mm means metric tube.
3. Measure one hole and compare it with the hole size the attachment is listed for.
4. Measure centre-to-centre spacing if the attachment uses two pins or spans several holes.
5. Look for side holes if the attachment mounts to the side of the upright, and note how far apart they are.
6. Get the maker’s confirmation. Count a fit as confirmed only when the attachment’s maker lists your rack, or your exact tube, hole and spacing combination.

What to buy, depending on your rack

If the attachment’s maker lists your rack by name, order it. If your tube and hole size match but your rack isn’t listed, the fit is likely but unconfirmed: send the maker your three measurements before you order anything with two pins. If your tube is metric 75mm, or your holes don’t match the attachment’s standard, stick to attachments made for your rack’s own line.

If you haven’t bought a rack yet, work backwards: pick the tube and hole standard the attachments you want are built for. The Power Rack Buying Guide covers the other specs worth comparing, and 11-gauge vs 14-gauge steel explains the wall-thickness numbers in the table.

To check your numbers against attachments from Rogue, REP, Titan, Bells of Steel, Bulletproof and others, use the Rack Attachment Fit Checker. Pick your rack, or enter your tube and hole sizes yourself if it isn’t listed.

Specifications checked against manufacturer pages on September 22, 2026. Manufacturers change specs; confirm on the product page before ordering.