I did a search for this but did not really know what to call it. I have sometimes wondered how the same size lift from different companies will clear different size tire's. For the most part, whenever you see a lift advertised it will say what size tire it will clear with no fender trimming or fender flares. I have been looking for another Cherokee or a Comanche for a while now and have looked at a ton of them on Craigslist. I recently looked at an early 90's Cherokee and it had a 6 inch lift and 35 inch tires and looked like it had plenty of room. I also looked at a Comanche with a Skyjacker lift and 35's and it looked like it would easily clear 36's. Then there are the others with 4 to 6 inches of lift and they are running 33's mostly. I have a RE 3.5 superflex lift and added the JKS ACOS to the front and JKS shackles on the rear for a total of about 5 inches and could probably get by with 32's and no trimming. It seems like the RC and Skyjacker lifts are clearing somewhat larger tires, this may just be a coincidence from the ones I have looked at lately.

I have wondered the same thing. I've seen Jeeps with 4-inch or so lifts running 33's with no trimming but have had to trim the crap out of ours with a 4.5 RE lift and 33's. I think some of it is due to control arm length, but there is a lot of variety of wheel offsets and tire widths too that also may factor in.

best way to explain it..

not all lifts come out to there advertised height...some more/some less

not all tires are there advertised size....i.e. some brands of 33's may measure as low as 31 1/2, while some may be near 34"'s

edit: and yes different wheel/backspacing combos, along with control arm length will also affect this