CHINOTJ Posted December 12, 2009 Share Posted December 12, 2009 HI All I am new on the Jeep thing, I just bought an 88 comanche and I am wondering what tire size shoud i buy, it originally came with 235/75-R15 but they seem to be 2 small I want to go bigger, my comanche is a 2.5L 2wD, since its a 4 cilinder I don't want it to be 2 slow because the tires are 2 heavy so can you recomend me what tire size is recomended for a 4 cilinder as the biggest size? should I go with 30/9.5-R15 or 31/10.5-R15? Thanks, for your help Link to comment Share on other sites More sharing options...
socal1200r Posted December 12, 2009 Share Posted December 12, 2009 HI All I am new on the Jeep thing, I just bought an 88 comanche and I am wondering what tire size shoud i buy, it originally came with 235/75-R15 but they seem to be 2 small I want to go bigger, my comanche is a 2.5L 2wD, since its a 4 cilinder I don't want it to be 2 slow because the tires are 2 heavy so can you recomend me what tire size is recomended for a 4 cilinder as the biggest size? should I go with 30/9.5-R15 or 31/10.5-R15? Thanks, for your help I just went thru this same exact thing. I have an '88, 4wd, 5-speed, non-lifted, on Jeep alloys. If you don't replace the lower control arms, the biggest you should go is 30s. I replaced the LCAs with ones for a WJ (Grand Cherokee), and my new 31s clear just fine, including the fenders. Don't know if you're brand particular about tires, but go to your local WalMart and take a look at the Uniroyal Liberators and Goodyear Authoritys. They were $115 for the Uniroyals in 31x10.50, and $130 for the Goodyears. I ended up going with Firestone Destination ATs, because they were "buy three get one free", and I got a set for less than $500. Good luck! Link to comment Share on other sites More sharing options...
mnkyboy Posted December 12, 2009 Share Posted December 12, 2009 I have 33X12.50s on my 2.5L MJ I had 31X10.50s on there for a long time with and and without a lift. the WJ arm are only needed if you have stock wheels,most aftermarket wheels clear fine with 31s. Link to comment Share on other sites More sharing options...
deziped Posted December 12, 2009 Share Posted December 12, 2009 With 235's and 4:10 rear end my 2.5 was a gut less piece. It performed OK on flat stretches of road, but on small hills it was 2nd gear and pedal to metal in an effort to get out of the way of others. Link to comment Share on other sites More sharing options...
mnkyboy Posted December 12, 2009 Share Posted December 12, 2009 my truck isnt gutless and i have 33s and 3.55 gears. It was fairly peppy on 31s. it could burn the tires pretty good,bury the speedo ,and pass cars on steep grades. Link to comment Share on other sites More sharing options...
socal1200r Posted December 12, 2009 Share Posted December 12, 2009 ChinoTJ Make sure you read Mnkyboy's signature. He's able to run 33's because he has 5" of lift. What he said about 31's on non-stock wheels is correct to a point. You may not need WJ LCAs to prevent rubbing that way, but most aftermarket wheels have a different offset than Jeep wheels, so you won't rub on the LCAs, but most likely you could bottom out on the top of the fender. I'd rather play it safe and not hit the fenders. Again, this has been discussed in detail before, so I don't want to rehash it on your thread. I did this to help me decide about my new tires, and it couldn't hurt. Crawl under the front end, and measure how much travel you have before the bump stop bottoms out. On my MJ, it was about 65mm. Then, measure the distance between the top of your tire and the bottom of the fender. Mine was around 125mm. This told me I had 60mm of wheelwell gap still left after the bumpstop bottomed out at 65mm (125mm - 65mm). Convert that to inches, and it's a little over 2" of room left. Go to a tire calculator website like this one (http://www.1010tires.com/TireSizeCalcul ... ion=submit), and play around with some different tire sizes, and compare the overall diameters and speedo errors. In my case, the stock tire was 225/75-15, and putting a 31x10.50 was roughly 2.75" bigger in OD. Cut than number in half, and I was looking at about another 1.37" of tire at the top. Since I had over 2" of room to go, I had space to clear the 31s, at least at the top of the fender. The 31s on stock Jeep 15x7 alloys also cleared the rest of the fenders, not by much, but they still cleared. A wider rim, or one with a different offset, might have caused some fender-rubbing issues with 31s, but 30s would've probably worked. Not sure what kind of wheels you're running now, but you should take that into account when deciding on your tires. I think a set of 30s would pretty much clear everything, regardless of what kind of wheels you're running, so that should be a pretty safe bet. Link to comment Share on other sites More sharing options...
Eagle Posted December 12, 2009 Share Posted December 12, 2009 HI All I am new on the Jeep thing, I just bought an 88 comanche and I am wondering what tire size shoud i buy, it originally came with 235/75-R15 but they seem to be 2 small I want to go bigger, my comanche is a 2.5L 2wD, since its a 4 cilinder I don't want it to be 2 slow because the tires are 2 heavy so can you recomend me what tire size is recomended for a 4 cilinder as the biggest size? should I go with 30/9.5-R15 or 31/10.5-R15? Thanks, for your help It may have come to you wearing 235/75-15s, but from the factory a 4-cylinder would have been wearing 205/75s or 215/75s. 235/75 is already larger than the largest tire used by the factory on the 6-cylinder XJs and MJs. Just to put it in perspective. Next thing, compare the dimensions of a 30x9.50-15 with a 235/75-15. The 30 is slightly wider, otherwise they are almost identical. Hate to be a party pooper, but I suggest you stay with 235/75-15. Link to comment Share on other sites More sharing options...
freakjeep93 Posted December 12, 2009 Share Posted December 12, 2009 :agree: 100% thats all I'm going to runn on my trucks and I'm going smaller with my resto project as it is 4cy wit 3.07 gears Link to comment Share on other sites More sharing options...
socal1200r Posted December 12, 2009 Share Posted December 12, 2009 :agree: 100% thats all I'm going to runn on my trucks and I'm going smaller with my resto project as it is 4cy wit 3.07 gears My 4-cyl has 4.10 gearing, so it can handle the bigger tires better, and the 31s look so much better than the 225/75s. I hope he's considering some long term things, like if he's going to lift it or not, get different rims, spend more time off-road, etc. Answers to questions like that could have an impact on what tires to get now. Hmmm, didn't know 235s and 30s were so close, and I'm sure 235s are less expensive and have a better selection to choose from than 30s... Link to comment Share on other sites More sharing options...
mnkyboy Posted December 12, 2009 Share Posted December 12, 2009 What is the hieght difference on a 2wd vs. 4wd? mine is a 4X4 and 31s were about as big as i would want to go on stock suspension also yes the wider offset wheels stick out more but they should not rub on a 4cyl truck unless you were doing some serious offroading,my truck has been airborne with 31s on stock suspension and 4" back spaced wheels without rubbing on landing. Link to comment Share on other sites More sharing options...
Pete M Posted December 13, 2009 Share Posted December 13, 2009 4wds are about an inch taller than 2wds. Link to comment Share on other sites More sharing options...
mnkyboy Posted December 13, 2009 Share Posted December 13, 2009 4wds are about an inch taller than 2wds. then 31s might be pushing it on a 2wd,I'm gonna have to agree with eagle. stick with whats on there. or do a 2" budget boost and go to 31s Link to comment Share on other sites More sharing options...
Pete M Posted December 13, 2009 Share Posted December 13, 2009 30s fit just fine on my 2wd 88 (with alloy Jeep rims). no rubbing whatsoever. :D Link to comment Share on other sites More sharing options...
freakjeep93 Posted December 13, 2009 Share Posted December 13, 2009 yea but were sayin that 31s may rub Link to comment Share on other sites More sharing options...
Pete M Posted December 13, 2009 Share Posted December 13, 2009 I know. I just wanted to show an old photo of my 88. :D Link to comment Share on other sites More sharing options...
freakjeep93 Posted December 13, 2009 Share Posted December 13, 2009 lol it looks nice in that photo Link to comment Share on other sites More sharing options...
socal1200r Posted December 13, 2009 Share Posted December 13, 2009 I think we have a winner here...stock Jeep alloys and 30's would be the perfect setup for him...that gets my vote... Link to comment Share on other sites More sharing options...
CHINOTJ Posted December 13, 2009 Author Share Posted December 13, 2009 Thank you all for your advising, today I went out to look for some tires and I found some General Grabber AT2 and some Euzkadi all terrain that I liked since most of the time I would be using my truck on the road, for my daily driving to work, I am planning on lifting it up a little, some 2 inches or so. Thanks Again for your advising, I would see you around the forum from now on. :cheers: Link to comment Share on other sites More sharing options...
socal1200r Posted December 15, 2009 Share Posted December 15, 2009 Here are some pics for reference: When I first got my MJ, it had stock steel wheels with 235/75s, which looked okay: Then I found a set of Jeep alloys on Craig's List, with 225/75s, but they looked too skinny: Now I'm running Firestone Destination ATs, in 31x10.50: Definitely needed to install those WJ lower control arms, in order to clear the 31s: Now I just have to figure out what Chevy shackles will give me about 2" of lift on the back, and combine those with 2" spacers for the front, and call it a day... Link to comment Share on other sites More sharing options...
Eagle Posted December 15, 2009 Share Posted December 15, 2009 Now I just have to figure out what Chevy shackles will give me about 2" of lift on the back, and combine those with 2" spacers for the front, and call it a day... Why? It looks perfect just the way it sits in that last photo. Link to comment Share on other sites More sharing options...
socal1200r Posted December 15, 2009 Share Posted December 15, 2009 Now I just have to figure out what Chevy shackles will give me about 2" of lift on the back, and combine those with 2" spacers for the front, and call it a day... Why? It looks perfect just the way it sits in that last photo. Thanks...I haven't made up my mind 100% about a small lift, just figured spacers and shackles were an inexpensive way to get a little bit of lift. 'Course my finances will determine if even that happens, lol...but thanks for the feedback... Link to comment Share on other sites More sharing options...
Eagle Posted December 15, 2009 Share Posted December 15, 2009 just figured spacers and shackles were an inexpensive way to get a little bit of lift. They are. Shackles are also an excellent way to ruin your springs. Yes, I know the shackle advocates will flame me, but I've been playing with cars for over 50 years now, we had extended shackles back when Fred Flintstone and I attended high school together. They killed springs then, and there's nothing about leaf spring technology that makes them any more resistant to sag when run with extended shackles today. "If it ain't broke ... don't fix it." Remember, the corollary to the above is, "If it ain't broke ... fix it 'til it is." Take your pick. Link to comment Share on other sites More sharing options...
Pete M Posted December 15, 2009 Share Posted December 15, 2009 and some of us are just partial to the look of a stock MJ on big ol' 31s. :D Link to comment Share on other sites More sharing options...
socal1200r Posted December 15, 2009 Share Posted December 15, 2009 Pete - that's what I'm talkin' bout, lol! Eagle - your point is well taken. Not sure how shackles would increase spring sag, but you're right, that was an easy way to jack up the rear end of cars and trucks back when I was in high school in the 70's, lol! Wish I still had my '69 Pontiac GTO with 400 cid small block, Muncie 4-speed, 6-pack intake off a '66 389, etc. But it had an odd rear suspenson, so I couldn't put shackles on it even if I wanted to, which was probably a good thing! The MJ actually rides fine the way it is, and since it'll spend MOST of it's time on-road, there's no real NEED for additional lift. The occasional drive on beach sand and fire roads shouldn't bottom it out, especially if my oldest daughter is driving. We'll see... Link to comment Share on other sites More sharing options...
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