Those OEM stoppers are pretty soft. Add an inch for them to compress, not half inch. I just did this, once I put my spacers in and flexed it into the stops, they compressed way further than I thought. Plus, if you hit into something rather than a slow flex, it'd probably compress even more.

But, you're figuring it right. Just add more height to compensate for the soft OEM bumps.

 

I just got my bump stops in last night and cycled the suspension to make sure everything looked ok. The front is perfect. The rear, not so much. The rear stopper is pointed, so when it hits the IRO extension, the point doesn?t his center of the spacer and defects off to the side. I think the amount of spacer I added is the right length but the stopper itself doesn?t compress into it but rather gets pushed out of the way thus making the rears ineffective.

 

I can confirm they will compress 100% flat. This is worse case scenario but can be common if you hit a something at speed. Why not just call IRO and buy the ones they sell in the 3" kit? No need to measure.

 

Those OEM stoppers are pretty soft. Add an inch for them to compress, not half inch. I just did this, once I put my spacers in and flexed it into the stops, they compressed way further than I thought. Plus, if you hit into something rather than a slow flex, it'd probably compress even more. But, you're figuring it right. Just add more height to compensate for the soft OEM bumps.

Awesome, great info. I ended up ordering 3.5" for the front and 2.5" for the rear. Thanks!

 

I can confirm they will compress 100% flat. This is worse case scenario but can be common if you hit a something at speed. Why not just call IRO and buy the ones they sell in the 3" kit? No need to measure.

I wasn't aware their lift kits came with bump stops. I don't think there is a standard bump stop versus lift size because it's going to depend on what you want to get out of the suspension plus what shocks you are running. Some may want to limit up travel or some may need more pending shock travel.

Thanks for the info on the stock stoppers though. Good to know they are that soft.

 

I may be wrong, but I don't think the bump stop extension options vary much for 3" based on shocks etc. Some shocks (doetsche tech) do come with built in bumpstops so you may not need external bump stops. The bump stop is for limiting up travel only and that should be about the same (3") for all 3" lifts and a stock axle. The uptravel limit will prevent your tires from hitting the fenders (you can trim for this and maybe get away with shorter bump stops) and also steering components from hitting oil pans, etc. It looks like a 3" lift should have 3" bump stop extensions all else equal, so you could order that. Here's a quick read from iron rock offroad on measuring https://www.ironrockoffroad.com/product/wj-front-custom-bump-stops.html

 

I may be wrong, but I don't think the bump stop extension options vary much for 3" based on shocks etc. Some shocks (doetsche tech) do come with built in bumpstops so you may not need external bump stops. The bump stop is for limiting up travel only and that should be about the same (3") for all 3" lifts and a stock axle. The uptravel limit will prevent your tires from hitting the fenders (you can trim for this and maybe get away with shorter bump stops) and also steering components from hitting oil pans, etc. It looks like a 3" lift should have 3" bump stop extensions all else equal, so you could order that. Here's a quick read from iron rock offroad on measuring https://www.ironrockoffroad.com/product/wj-front-custom-bump-stops.html

It says right in the IRO article you sent to not rely on the advertised lift height. I agree if you are just looking for stock uptravel, the I should go with a 3" extension ASSUMING the lift kit got me exactly 3" of lift and the shocks I'm running will allow for it. Shock travel can vary depending on what you are running. The bump stop prevents you from bottoming out on the shock and thus blowing it out or damaging the shock mounts.

If you want more uptravel, then you would add less bump stop. My main concern was how much the stock stoppers compress which to your point is a lot since they are soft. Therefore, if I only add 3" to the front, I know I'm going to rub more than I already do.

I only need 2.5" in the rear as I have about 3/4" of shock left and about an inch until I hit the bump stop. So 2.5" should take into account an inch for stopper compression, the inch of travel I have left, and a half inch to reduce rear uptravel since I'm rubbing now.

 

Good points. The bump stops on these WJ's are overall a pain in the butt and not very well designed for wheeling.