Will The Tires Fit?

[Eagle]

But to answer the OP's question, based on the chart (which is just a general idea), I'd say that 4.10's would be optimal for 32" tires.

Not with a 2.5 liter engine. The 2.5 doesn't have enough torque or horsepower to turn tires that large through 4.10 gears.

[Eagle]

That's not necessarily true... His sig says he has an '86 Custom.

And his original post in this thread specifically states that he has a 2.5L.

[onlyinajeep726]

 

That's not necessarily true... His sig says he has an '86 Custom.

And his original post in this thread specifically states that he has a 2.5L.

 

 

Yes, but that wasn't the question posed when I responded with this answer... The question at that point was about current gear ratio based on current transmission.  That part was not stated by the OP, and Rockfrog claimed he already had 4.10's which isn't always the case.  Having an 2.5L is not an automatic indication that it has 4.10's.  That's what I was getting at there.

[benjy_26]

255/75R17 Goodyear Wrangler SRA. They measure right at 32 Inches tall.

Yep. Those should be 32's, but they're narrow 32's. On top of that, the tread is mild, and they're probably kind of light, being that they're biased towards street use. I'd give em a shot, personally. I bet they wouldn't be too bad.

[92tanMJ]

 

255/75R17 Goodyear Wrangler SRA. They measure right at 32 Inches tall.

Yep. Those should be 32's, but they're narrow 32's. On top of that, the tread is mild, and they're probably kind of light, being that they're biased towards street use. I'd give em a shot, personally. I bet they wouldn't be too bad.

 

^ this. And Lmao at the person that said you will need 4" - 5" of lift to fit 32's.

 

OP this is how my 31's fit on mine. Pretty sure I could fit an extra inch or two in there..

Image Not Found

[HOrnbrod]

^ this. And Lmao at the person that said you will need 4" - 5" of lift to fit 32's.

And just who is this person to whom you are Lmao at sport?

[benjy_26]

 

 

255/75R17 Goodyear Wrangler SRA. They measure right at 32 Inches tall.

Yep. Those should be 32's, but they're narrow 32's. On top of that, the tread is mild, and they're probably kind of light, being that they're biased towards street use. I'd give em a shot, personally. I bet they wouldn't be too bad.

^ this. And Lmao at the person that said you will need 4" - 5" of lift to fit 32's. OP this is how my 31's fit on mine. Pretty sure I could fit an extra inch or two in there..Image Not Found

That looks sweet! Right now I'm running 31's on mine with a 3" lift in the front and very slight trimming of the bottom of the flares. Honestly, without flares, I would have left my suspension alone and gotten a lift courtesy of Sawzall and BFH, but I think my MJ will be the first Jeep I own that will remain uncut..... for now

[onlyinajeep726]

I suggested 4" of lift based on the fact that he will using different rims and based on not trimming fenders at all.  You have 31's on stock 15"x6" rims and your flares are removed and fenders trimmed.  I know an inch may not seem like much, but when you're turning and flexing simultaneously, it makes a difference.

 

I like the look of your truck by the way... :thumbsup: 

[92tanMJ]

 

^ this. And Lmao at the person that said you will need 4" - 5" of lift to fit 32's.

And just who is this person to whom you are Lmao at sport?

 

 

I was loling at the fact that they suggest that much lift for that small of a tire. That much lift is completely unneeded. So it really wasnt at them but what they said.

 

 

I suggested 4" of lift based on the fact that he will using different rims and based on not trimming fenders at all.  You have 31's on stock 15"x6" rims and your flares are removed and fenders trimmed.  I know an inch may not seem like much, but when you're turning and flexing simultaneously, it makes a difference.

 

I like the look of your truck by the way... :thumbsup: 

 

My flares are removed but my fenders are NOT trimmed fyi. And I know what you mean about the turning and flexing. On the stock offset mine would run at full lock. And now with 2" of backspacing they only rub on the bottom edge of the fender but a little hammering took care of that a couple of months ago.

 

And thank you sir, it is not as nice as yours Mr. MJOTM lol ;)

[Incommando]

 

That 2.5 will be gutless without a regear... And unless you want to trim the hell out of your fenders, a lift will be needed to fit that sized tire, especially since the wheel adapters will make them stick out further.

The stock JK wheels have a deeper backspacing (6.25") than earlier jeeps. With the 1.25" spidertrax spacer adapters I used to run on the XJ the wheels were equivalent to the stock 5" bs wheels.

That said even my 4.0 had trouble turning them with stock gearing until I went to 4.56. With the 2.5 ... 4.88 would be the minimum ratio. 5.13 may prove better but would need axle swaps to accomplish.

 

 

 

4.0 auto with 3.55's will turn 32x11.5's just fine on and off-road. I would not try it with the 2.5 even with 4.10's. 

 

http://www.grimmjeeper.com/gears.html You can go to that site and play with different axle ratios and tire sizes to see the effect the various changes will have on your jeep. 

[Rockfrog]

That 2.5 will be gutless without a regear... And unless you want to trim the hell out of your fenders, a lift will be needed to fit that sized tire, especially since the wheel adapters will make them stick out further.

The stock JK wheels have a deeper backspacing (6.25") than earlier jeeps. With the 1.25" spidertrax spacer adapters I used to run on the XJ the wheels were equivalent to the stock 5" bs wheels.

That said even my 4.0 had trouble turning them with stock gearing until I went to 4.56. With the 2.5 ... 4.88 would be the minimum ratio. 5.13 may prove better but would need axle swaps to accomplish.

 

 

4.0 auto with 3.55's will turn 32x11.5's just fine on and off-road. I would not try it with the 2.5 even with 4.10's.

http://www.grimmjeeper.com/gears.html You can go to that site and play with different axle ratios and tire sizes to see the effect the various changes will have on your jeep.

 

What you think is fine, and what I think is fine, are apparently different. I ran JK 32s on my 4.0 XJ for about 3 months before the regear. Compared to stock it was a dog. After the regear it was much better. Now rolling the same gears (4.56) with 35s I'm much happier.

Either way at least we can agree the 2.5 will need gearing.

From past 2.5 experience ... you can roll then in stock form, but you WILL lose use of 5th in all but a looong downhill run (may need a strong tail wind as well) and you may possible lose 4th in many situations. The motor is going to work hard just to roll them so expect to get 60s/70s era fuel mileage.

[Incommando]

Something from earlier in the thread: The Goodyear SR/A's are not something I would recommend. They managed to suck on road almost as badly as they do off-road. Wet weather traction on pavement was horrible. They are one reason I lifted my KJ so early in the warranty period because if I was going to buy tires I was only going to do it once and I could not live with those. 

It is true that not only don't most flotation tires "measure up" another important factor is the aggressiveness of the tread. Large shoulder lugs will cause you much more headaches than the typical all-season tread. 

Rockfrog: I can see why you would like the move to 4.56 gears. That is a great improvement over the 3.55's even with the 225/75/15 stockers. It even moves your RPM range up into a more usable range in 5th than the stock configuration. Some of the "feel" difference could be the 5spd/automatic difference, as well. 

[dasbulliwagen]

Going by this tire size gear ratio spreadsheet http://comancheclub.com/topic/27178-tire-size-gear-ratio-rpm/   which shows me the same as i saw on another thing like that, that the original 215 tires I had and 4 speed with three.55 axle give me near equal to 32 inch tires in 4th at four.10 geared axle. Yeah the tires are bigger which has an effect, and the Goodyears arent ideal tires, but i don't really go offroad, and I havent had complaints at the dealership about the Wrangler SR-A's being a problem on the JK's. My sister in law recently just replaced the original ones on her 2007 JK with another set of the same, and never had an issue. If they do seem to be too much i have a set of 255/60R17's that have a little good tread on them. They are betwen 28-29 inches tall with a fairly wide footprint. They would fit good on the JK wheels if it comes to it and would bring back any lost power. I have a rebuild of a spare 2.5 in the works with some power upgrades, that may make this all null and void about power issues. So time will tell.  

[benjy_26]

Going by this tire size gear ratio spreadsheet http://comancheclub.com/topic/27178-tire-size-gear-ratio-rpm/   which shows me the same as i saw on another thing like that, that the original 215 tires I had and 4 speed with three.55 axle give me near equal to 32 inch tires in 4th at four.10 geared axle. Yeah the tires are bigger which has an effect, and the Goodyears arent ideal tires, but i don't really go offroad, and I havent had complaints at the dealership about the Wrangler SR-A's being a problem on the JK's. My sister in law recently just replaced the original ones on her 2007 JK with another set of the same, and never had an issue. If they do seem to be too much i have a set of 255/60R17's that have a little good tread on them. They are betwen 28-29 inches tall with a fairly wide footprint. They would fit good on the JK wheels if it comes to it and would bring back any lost power. I have a rebuild of a spare 2.5 in the works with some power upgrades, that may make this all null and void about power issues. So time will tell.

 

The again, how much power is enough? When I bought my MJ, I had made up my mind to get rid of the 2.5/AX combo in it as soon as I got it home. After driving it with the stock drivetrain for a bit, I've grown to like it, even with 31's. It's not as powerfull as my SBC in he K5, as smooth as the 3SGTE in my MR, nor is it as torquey and flexible as the stroked 4.0 in my ZJ, but it has a certain old school charm to it that's hard not to like. It reminds me a bit of my old man's Willys pickup with a flat 4, actually. Except that this one can cruise at 60 on the interstate!

[dasbulliwagen]

don't get me wrong, I love my 2.5, I just want a little more, which is my plan for the rebuild. Ive done a few things already to mu current one, CAI, elec fan conv, "free flow" cat, Flowmaster 50 series muffler. It has all helped a little, just want a little more so it doesnt seem like its struggling so much.

 

And for the reason of this update... I just ordered my Spidertrax wheel adapters from Quadratec.... I ordered from them because of free shipping and no sales tax. Hopefully I won't have any issues.

[Rockfrog]

I used the same spacer/adapters on my XJ before I got the 35's on 15" wheels

 

 

 

Use Red loctite to mount the adapters, a screwdrivwer in the .rotor vents works to stop the fronts from spinning if you don't have a helper to hold the brakes on.

[benjy_26]

don't get me wrong, I love my 2.5, I just want a little more, which is my plan for the rebuild. Ive done a few things already to mu current one, CAI, elec fan conv, "free flow" cat, Flowmaster 50 series muffler. It has all helped a little, just want a little more so it doesnt seem like its struggling so much.

 

And for the reason of this update... I just ordered my Spidertrax wheel adapters from Quadratec.... I ordered from them because of free shipping and no sales tax. Hopefully I won't have any issues.

Dude, I am ALL for more power, but lately, I think that gettinjg that power without completely killing the vehicle's original feel and, for lack of a better word, "personality" is a better way to go than the mega-builds i used to pull off. A fresh 2.5 rebuild with some head work, a slightly more aggressive cam, and s bump in piston diameter and comp ratioi would be pretty cool, if you ask me.  

[benjy_26]

I used the same spacer/adapters on my XJ before I got the 35's on 15" wheels

 

 

 

Use Red loctite to mount the adapters, a screwdrivwer in the .rotor vents works to stop the fronts from spinning if you don't have a helper to hold the brakes on.

That looks/looked SICK!!!

[dasbulliwagen]

Got my adapters and wheels on today. There is slight rubbing while turning and driving, nothing I don't think some slight trimming won't take care of. And as for power loss, it wasnt noticable, at least on the short trip from the dealership to home. Though I never made it to fifth. We will see how that goes later. The old 235 BFG's were all but done for. There was still a little tread, but the dry rot was getting bad. I got 6 years of driving out of them, and considering I got them used and for free, I think I did pretty good! The new JK wheels look good, but now my truck looks dirty and old compared to them. Its a couple of inches taller now too! Ill try to get some pics tommorow to post.

[benjy_26]

Awesome! Pics are DEFINATELY needed. I was considering some JK wheels for one of my own Heeps too...

[Incommando]

Side rant: I hate that jeep moved to a greater positive offset the moved the face of the rim out further where it is less protected by the rim lip. If you don't use aftermarket wheels with less back spacing you run the risk of scratching the hell out of your rim faces off road.

:mad:

[benjy_26]

Side rant: I hate that jeep moved to a greater positive offset the moved the face of the rim out further where it is less protected by the rim lip. If you don't use aftermarket wheels with less back spacing you run the risk of scratching the hell out of your rim faces off road.

:mad:

Never thought of that.... but it's true. As it is, even running tires with "bead protectors" my wheels get scuffed and scratched pretty badly by the sand and small rocks around here. A set of JK take offs would look like poo within a week on my ride. :-\

[Lee21490]

My biggest debate lately has been, 12.5 or 10.5 wide 33's :/

[benjy_26]

I say skip 33's altogether. I forget where I read this, but according to some testing done by someone (sorry), when aired down, 32's and 33's have pretty much the same footprint on the soft stuff. Unless you really need that extra inch of clearance, I'd go 32's.

[Incommando]

Actually 33's only give you a half inch of extra lift over 32's. Although 1" taller at any given time half of that increase is above the axle line and does not provide extra height.

 

The width debate is as old as the hills. A common line of thought is that a narrower tread works better in soft stuff like mud and deep snow where digging works while a wider tread works better on hard ground, sand, and rocks. Keeping the above height info in mind maybe go with a 32x11.5 to split the difference? If you need rims anyway you could get some junkyard rims from KJ or something and run 265/75/16's as they are the metric equivalent of those 32's. If you want 33's the 10.5's could be mounted on factory rims which would save some money. Narrower tires also cause fewer clearance issues and may stuff better when flexed.