Rock slider measurement question

I've tried searching this forum and found nothing on this topic, so forgive me if I missed the answer in another thread.

I'm shopping for rock sliders for my XJ, and since most sliders seem to attach to the unibody frame rail and the pinch weld, I decided to measure that space on my XJ just to make sure I'd be in for no surprises when I ordered and received the sliders.

It turns out, I have a gap of 8 3/8" from the unibody frame rail to the outside of the pinch on the passenger side and a gap of 8 5/8" on the drivers side. The difference is 1/4", and considering most rock sliders seem to be welded, one-piece units, I'm thinking this could be a problem should I order some from the likes of JCR or AJ's...or anyone that uses these two mounting points.

Does anyone have any advice or suggestions or faced a similar problem?

Every XJ is a little different, sort of like chicken eggs. They still all look ok sitting in the carton though

That .250" probably isn't going to be a huge problem. I think once you get everything in place you'll find its less of a gap than that, and a little tweaking will line it all up.

Thats nothing,measure the front to back taper (body)and youll really suprised!

Thanks for the info...I'm glad it's not just my XJ that's wonky. I'm thinking I'll get the sliders and just be prepared to make small spacers should I not be able to bend everything into place.

If you didn't measure at the same place on each side the measurements will be different because of the taper, you may want to double check your measurements. Either way I don't think it's going to be an issue.

Hellbilly04 in Huntington Beach makes sliders so he can make them to the right dimensions. Send him a PM. they are real nice and he can do lots of different stuff. Even build them IN the rockers.

I took the measurements from the same places, one at the front and one at the rear on each side (before the unibody frame's little overlay at the rear). The front to rear measurements were the same on left and on the right, but comparing left to right there was a consistent difference. I checked three times because I was hoping I was just crazy.

And thanks for the tip about Hellbilly04. I'll look into it. Custom sliders would definitely be a solution.

1/4" isn't really that bad and you'd probably find that once you got the hardware started things would "pull" themselves into place. If it was something you wanted to make sure of though it wouldn't take much to make up a set where one side is 3/16-1/4" different.

Hit it with a hammer and remeasure.

So here's an update: Thanks to AJ’s input, I decided to order a set of AJ’s Super Rails. AJ offered to make an adjusted set for my XJ, but I opted for ones right off the jig. It took about 8 business days for the sliders to arrive.

The test fit of the sliders revealed where the variances in my XJ were. The driver’s side is almost perfect -- the passenger’s side unibody frame rail, however, is 1/4 inch closer to the pinch weld then it should be, which made using the supplied pinch weld nuts and bolts a little tricky because there was a 1/4 gap. Rather than buying longer bolts, I clamped the pinch and bent it toward the slider and tightened down the bolts. (As a side note, I e-mailed AJ and he offered to make up some spacers for me, but I decided to see if I could get it to fit.)

The result is the passenger’s side slider sticks out about 1/4 inch more than the driver’s side, but you only notice it if you’re looking for it. (It’s important to iterate that the variance is due to my XJ, not the sliders.) I could fix the problem by spacing out the slider on the driver’s side, but I probably won’t because that seems like a lot of unnecessary work.

A quick note about installation: The instructions say to test fit the sliders, mark all the holes, remove and paint the sliders, drill the holes and then install everything. This method works. However, I discovered the more holes you mark and then drill, the more you increase your chance for error. I found myself marking two holes on the unibody frame rail (one at the front and one at the back) and then all the pinch weld holes. I removed the sliders, drilled those holes, then installed the sliders and drilled out the remaining frame rail mounts and the rear suspension mount. I’m sure there’s a good reason not to do it the way I did, but it allowed me to make sure all the holes lined up.

And for holding the sliders in place during text fitting and the installation, I lined the stock XJ jack and a scissor jack up with the slider arms that go to the frame rail (but close to the pinch) and elevated the slider into place by cranking up the jacks (protecting the slider from the jacks via scrap cloth). This held it firmly in place during the test fitting and the mounting. If your XJ is lifted in any way, you'll need to elevate the jacks.

And for anyone considering AJ’s sliders...they’re exactly like they appear on the website and the service, communication and finished product were all impeccable.

Im impressed you can distinguish a 1/4'' difference by looking at it.



Congrats on the AJ rails. I have some on mine, and love them. I drive by braille, and they are holding up fine.

Not that it helps you now, but the JKS SuperNerfs have two piece mounting arms where the tubes on the slider fit over the tubes bolted to the frame rail. You line everything up to fit your individual XJ and then can either weld or bolt the two tubes together.

When I discovered my XJ was uneven, I thought someone should design something just like that...and I guess someone did.