Jake Purdy

Compatibility issues between different brand 3×3” upright racks with 1” holes

Many different brands today make racks with 3×3” tubing and 1” holes spaced 2” on center, this allows attachments from different brands to be used on the same rack as there is a standard size across the industry. This also allows for a true modular system as all rack tubing is 3×3″ with 1″ holes.  3×3” upright 1” hole racks have become the most popular size of racks on the market over the last 10 years due to their strong structure and large holes that make creating attachments easier and provided a bullet proof lifting station that will last for decades. 

Styles of 3x3" tubing 1" hole racks

There are two main kinds of 3×3” racks with 1” holes, offset holes or inline holes. This refers to the hole on the side of the upright and its relation to the hole on the front. Stray Dog racks are inline meaning the hole on the side is at the same height as the hole on the front, making the 10th hole on all 4 sides at the same height off the ground (Sorinex and other Brands also use Inline Holes). Rogue and many other brands use Offset hole spacing, meaning that their hole on the side is slightly above the hole on the front of the upright.

Offset hole racks

The Red Upright Pictured above has offset holes meaning that the hole on the side is higher than the hole on the front. The offset hole pattern makes some attachments not compatible such as our Spotter Arms, which are designed for Inline Holes causing the hitch pin hole to not lineup on offset hole racks. Our GOAT Attachment and Nordic Plate Attachment use a threaded pin so they can work on both Offset or Inline hole racks! Any attachment that uses a single pin such as Bar Cups, Dual Utility Rollers or others will work with offset hole or inline hole uprights as the side hole location does not matter. 

Import/metric racks

Import/Metric Racks are a more budget friendly option, but at what cost to the consumer? Those who are rack enthusiasts know that import companies do not use true 3×3” tubing with 1” holes as they are made overseas using the metric system. But the average consumer would have no idea because these companies advertise their products as 3×3” and 1” holes which they are NOT. The tubing is often 2.95276” x 2.95276” which is 75 MM, 3” in MM is 76.2 so the tubing on most import racks are slightly smaller than the  3” advertised. Many customers have reached out to us with their frustrations of buying an import rack that has different specs than advertised. 

Also a 1” hole is 25.4 MM, in manufacturing they  often round down making import racks have 25 mm holes, making them smaller than 1” (0.984252″). This is not an issue for every attachment, our GOAT Attachment and Bar cups work with no issues, but attachments with tighter tolerances such as Utility Loops or Storage Hooks may not work with your metric rack for the reasons mentioned above. If you have a question regarding compatibility of a Stray Dog Attachment on an Import Rack please reach out. 

Width Compatibility

Pictured above are two 43″ Flat Trays added to the back of an Alpha Full Rack, all our racks are 49″ wide. The two most popular widths of racks are 47″ and 49″ wide, REP and Sorinex use 47″ and Stray Dog and Rogue use 49″ Wide racks. Few of our Attachments can only be added to 49″ racks (Utility Seat Pad, 43″ DB Tray, 43″ Flat Trays and Straight Chin Up).

Connecting two different brand racks

As I mentioned in paragraph 2 different brand uprights even if they both are 3×3″ with 1″ holes 2″ on center cannot be connected with a regular crossmember. You can connect two different brand racks with out Universal Crossmember Bracket and 3×3 tubes. This bracket has a slot instead of a hole allowing the bolt to go wherever the hole is. These brackets can connect an ATR unit or any two brand uprights together. Checkout our article that goes in-depth on our Custom Length Crossmembers/Custom Crossmmeber Brackets.

Location of First hole

An often over looked issue with compatibility is that all brands start their first hole at different heights off the ground. So even though different brands use 2″ hole spacing on 1″ holes the holes will not line up. That is where our Universal Crossmember Brackets and other slotted attachments come in. Any product that touches the ground and connects to an upright will not work on different brands unless it has slotted holes to account for the slight hole height differences between brands. 

Rack mounted machines

Our Rack Mounted Cable Columns, Lat Pull Downs and Belt Squats now have a slotted 20″ Crossmember to allow them to connect to different brand uprights. This is similar to the Universal Bracket but is welded to the tube not bolted like the Universal Brackets and 3×3 tubes are. Any product that touches the ground and connects to an upright will not work on different brands unless it has slotted holes to account for the slight hole height differences between brands. 

Our Half Rack Band Attachments are an example of an attachment that only works with Stray Dog Strength Racks. The Band Attachments have 3 holes but not a slot to allow them to be added to different brand uprights. Any attachment that touches both the floor and connects to a rack will not work on another brands rack unless it has slotted holes or a threaded pin with various locations such as the GOAT which has an offset and inline 1″ hole positions for the threaded pin. 


At Stray Dog Strength we specialize in Rack Systems and attachments that make those systems more versatile and also save space. We have over 25 attachments that work on both our racks and other Brand 1″ or 5/8″ hole 3×3″ tubing racks. There are a few attachments that are not compatible with Import/Metric Racks even though they should as the specs they advertise are not accurate. The Attachments that we know do not work on Import/Metric Racks are our Utility Loops and 1″ Storage Hooks the rest of them fit but may be a little too snug due to having actual not 1″ holes as mentioned above. If you have a question about the compatibility of an attachment of ours and your rack please email or call us. 

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