This is such a niche problem that I didn’t expect anyone had created an off-the-shelf solution. Here’s an example of what some of us have dealt with.

groove cut into steel in power rack J-cups

My Titan X-3 squat stand’s J-cups were only mostly protected with UHMW liners as shown above. The inside front lip is not protected at all. I can roll my bar right into the exposed steel on the lip. Not only do I roll it out to set up for each set, I also spin the bar against either the lip or backplate to help move it side-to-side to re-center it, as we all do. This cut a groove into the steel as shown.

UHMW = Ultra High Molecular Weight plastic, used all the time nowadays as protective liners on power rack J-cups and safety bars to protect the bar’s knurling and cut noise. Known for exceptional durability and impact resistance.

I discovered Aperture Engineering, a little store entirely dedicated to selling inexpensive 3D-printed protectors to solve this very issue, protecting not only the inside lip but all the way around the front as well.

protection for front lip of power rack J-cups

Above is the grey colored protector installed onto my J-cup. Nice!

Full disclosure: They gave these to me as a free sample. One of the perks of having a blog!

Because the protector wraps around the front of the lip, he makes these protectors even for J-cup models that have a UHMW lined inside lip, which Titan’s current J-cups have but not their older 2017 J-cups I have. These protectors will protect your bar when you attempt to re-rack it too low into the front of the J-cups. Up until now the only solution offered for this has been sandwich J-cups, which are nice but very expensive if they’re available at all for your particular rack.

Most of these protectors are only about $9-10 per pair, all custom sized to fit Rogue, Sorinex, and a growing list of other brands.

To solve the exposed steel issue before these were available, people have tried buying UHMW sheets, cutting them to size, and gluing them into place. I’m not the only person who took issue with the exposed steel. I never bothered to try retrofitting it with extra UHMW, but when I ran across these protectors I emailed a bit with the owner Greg Eakins and eventually (after a few months) decided I wanted a pair.

The first pair of protectors I got didn’t fit quite right. Apparently Titan has changed things a couple times, and I have a version of J-cups made with thicker steel than the specs Greg was making them to. I took a measurement with calipers and Greg made a new pair for me that fits great!

power rack safety arms with exposed steel lip
older Titan X-3 safety arms

Unfortunately he doesn’t make protectors for the lip of my older Titan X-3 safety arms. He does make some for Titan’s current version with a taller lip.

custom 3d printed J-cup lip protectors

As for the material, he 3D prints these out of PLA (polylactic acid), a biodegradable plastic that is popular for 3D printing, with an impact modifier chemical added to the mix to make it hold up better for the kind of abuse that lifters will put them through.

Durability-wise, they feel fairly good to me. Slamming the bar against them makes about the same quiet sound as UHMW. Definitely not as hard nor as durable as UHMW though. To see how the material would hold up, I spun the bar shaft against it roughly, as we all do when trying to re-center the bar, and it was starting to shave off. Don’t do that. Better to spin your bar against the rear UHMW backplate instead.

Installation is simple. Remove the existing UHMW liner by removing the allen screws holding it on, or remove more than one UHMW liner depending on the model, and seat the protector onto the bare steel. Then re-install the UHMW liner(s) on top of it. The existing allen screw should be long enough that it can go through the protector and screw in securely into the steel without a problem. In my case I only had to remove a single screw of a single UHMW liner on each J-cup, with a 5/32″ (4mm) allen key.

For the price, and for something custom shaped into a curve like this, which you can’t easily get with UHMW, I feel like it’s a good deal even though it isn’t as tough as UHMW.

home gym with J-hook protectors installed

I’ll definitely be keeping these protectors on the J-cups for as long as I have them. Nice little upgrade.

extra J-hook protectors
spare white ones

As for the first pair that didn’t fit, I have no use for them. If anyone has a pair of older Titan X-3 J-cups with 10mm steel, leave a comment below and I’ll send them to you, no charge. They won’t fit any other model right. I’ll hang onto them for a little while.