Need New Tires

[COMANCH3]

Need a new set of tires for the MJ. It is a stock 2x4 with the 2.5L, 4 speed manual transmission. Wanted to go with a bigger tire and possibly a small lift to sit a little higher off the ground. At the same time, this is a 4 banger 2x4. I’m not trying to get crazy and lose what power the 2.5 has. Any recommendations on tire size and lift?

[jdog]

What size do you have now?

[Pete M]

you're a bit hampered by the 3.55 gears.    a 5spd 2.5L would have 4.10s

[eaglescout526]

235/75r15 is the highest you can go with stock height and rims.

[COMANCH3]

I currently have 205/70/15.  I love the KO2's on my wrangler, but they are a heavier tire.  I was considering 235/75/15 or 30/9.5/15.

[Pete M]

be sure to add your truck's basic specs to your signature   

[fiatslug87]

And add it to the registry.

[WahooSteeler]

You could probably run 30x9.5's w/out any trouble if you put a 2 inch puck up front. Maybe the BFG Rugged Trails could be an alternate for the KO2's, may not be as heavy as it's not a true off-road tire but has a good look to it and "sidewall tread" if you're kind of going for that look. Plenty of other choices for tires too........

[COMANCH3]

Shooting for the off-road look.  I guess I wouldn’t need a true off-road tire for a 2WD.  I do need something that will grip though.  I have a steep, shared driveway that is a ¼ mile long, requiring one vehicle to pull off the road to allow the other to pass.  It doesn’t happen often, but I have gotten the MJ stuck in wet grass on the driveway.  So I’m looking for something that will grip when it start raining in the Puget Sound.

 

Any reason to go bigger than a 235/75/15 or 30/9.5/15 with the 2.5L, or is it pointless?  If I’m stuck to that size, I guess a lift would be pointless as well?  Again, would like to sit a litter higher off the ground and not sacrificing power if possible. 

[Pete M]

any increase in tire size will rob you of power.   getting bigger means needing a gear ratio change in the axle. 

 

have you given any thought about converting to 4wd?  maybe at least adding a locker?

 

this is my first MJ back when it was 2wd on 30" tires. 

 

 

[coheed]

I've got 235/75 Wildpeak AT3W's on my 5speed 2.8 and it's not horrible. It's also 1.5" in the front and 1" in the rear. The total lift cost was like $80 I think.

[Torq_Shep]

So not what you are asking per se but I run General Altimax RT43s on my van and recommend them heavily for price/on-road performance. 

 

All-Terrains look cool on our old trucks but are IMHO overrated for 2wd primarily street trucks. 

 

 

[COMANCH3]

I’ve thought about making it a 4.0L, 4x4, with a 5 speed manual. Just don’t know how much that would cost, time, and if it was worth while. If I did go that route, it would be years down the road. 

[Pete M]

it'd cost about as much as buying a donor XJ, plus rear shaft, plus anything that needs refreshing.

[WahooSteeler]

IMO, since you want a somewhat "off road truck" look, I'd go with 1.5"-2" puck up front, and "passenger" rated tires in the 235-265 range. You don't "need" any lift to accommodate the bigger tires but sounds like you want a little more of a visual stance to your truck. 265/70/15's are essentially 30/9.5's and while only an inch taller than a 235, it's amazing to me how much different the appearance can be with that extra inch. The key in your case with the 2.5L/4spd is getting the P-metric tires as they are much lighter than LT tires and it seems for your usage that would be fine. You'll save anywhere from @25-35lbs in tire weight with the P-metric tires over light truck tires such as the KO2s. You'd probably add about 40lbs total going from your current 205s, but that should not make any real noticeable difference.....likely. If you have a used tire dealer in your area, you could maybe pick up a set of the larger tires for cheap ($100 around here) and see if you like the look and if it affects performance before you plunk down $400-500 for a new set and don't like it. 

[COMANCH3]

1 hour ago, Pete M said:

it'd cost about as much as buying a donor XJ, plus rear shaft, plus anything that needs refreshing.

How much would a typical donor XJ run along with things that needed refreshing?  I'm assuming this would not include an inline 6.  

[COMANCH3]

I should also add that the MJ doesn't have power steering, which isn't a big deal once you're rolling.  But trying to parallel park is a workout!  

[Pete M]

too many variables.  There are XJs around me for 400 bucks.  but can't tell you what it needs without inspecting. 

[Eagle]

Between the 2.5-liter 4-speed and the lack of power steering, IMHO it would be an unhappy experience to jump into large tires and a lift. Keep it simple. You can fit up to 31x10.50-15 tires on the stock rims and not have interference with the fenders or flares, but the tires will rub the lower control arms on tight turns. Even 30x9.50-15s are likely to rub the LCAs, but not as badly. So the largest you can go without sacrificing something is 235/75-15.

 

But that's still three sizes larger than what you're on now. There WILL be a power loss (or, more accurately, a performance loss because you're effectively losing final drive ratio). My recommendation would be to look at 225/75-15 tires and find one that has an off-road-ish tread -- probably an all-terrain tire, rather than an all-season passenger car tire.

 

Which wheels do you have? My guess is that a 2.5L 4-speed with manual steering is going to have the 6-inch steel wheels, and that's another reason not to get into larger tires.

 

[rokinn]

I have a set of Firestone Destination A/T tires.  Great road performance, low noise, and a decently aggressive tread.  Very happy with them.

[PCO6]

2 hours ago, rokinn said:

I have a set of Firestone Destination A/T tires.  Great road performance, low noise, and a decently aggressive tread.  Very happy with them.

 

Same here and they're great.   I have 215/75R/15's on my '88 Eliminator 2WD with stock suspension, 3.55 gears and the original wheels.   It flies (in Jeep terms) but they look a bit puny.   I'm likely going up to 235's and would consider the same tires.

[rokinn]

15 minutes ago, PCO6 said:

 

Same here and they're great.   I have 215/75R/15's on my '88 Eliminator 2WD with stock suspension, 3.55 gears and the original wheels.   It flies (in Jeep terms) but they look a bit puny.   I'm likely going up to 235's and would consider the same tires.

I have the 215/75/15's also.  I will also go a bit larger next time, providing I live long enough to need new tires.

[PCO6]

28 minutes ago, rokinn said:

I have the 215/75/15's also.  I will also go a bit larger next time, providing I live long enough to need new tires.

 

I know what you mean.   I recently figured out that the next set of tires on each of my vehicles will pretty much take me up to when I'll need to start taking my driver's exam again!

 

 

[COMANCH3]

18 hours ago, Eagle said:

Between the 2.5-liter 4-speed and the lack of power steering, IMHO it would be an unhappy experience to jump into large tires and a lift. Keep it simple. You can fit up to 31x10.50-15 tires on the stock rims and not have interference with the fenders or flares, but the tires will rub the lower control arms on tight turns. Even 30x9.50-15s are likely to rub the LCAs, but not as badly. So the largest you can go without sacrificing something is 235/75-15.

 

But that's still three sizes larger than what you're on now. There WILL be a power loss (or, more accurately, a performance loss because you're effectively losing final drive ratio). My recommendation would be to look at 225/75-15 tires and find one that has an off-road-ish tread -- probably an all-terrain tire, rather than an all-season passenger car tire.

 

Which wheels do you have? My guess is that a 2.5L 4-speed with manual steering is going to have the 6-inch steel wheels, and that's another reason not to get into larger tires.

 

I have the OEM 15” x 6” steel 9 slot wheels.  

[Eagle]

On 8/31/2020 at 2:27 AM, COMANCH3 said:

I have the OEM 15” x 6” steel 9 slot wheels.  

 

That's what I thought. And that limits your options on tire sizes pretty significantly. We can get away with running up to 31x10.50-15 tires on the 7-inch factory rims, but it's actually pushing the envelope a bit. The 6-inch rims won't safely take tires that big. Check out specs from BF Goodrich, for example (scroll down, then click on a tire size for detailed specs):

 

https://www.bfgoodrichtires.com/tires/all-terrain/all-terrain-t-a-ko2.html

 

The recommended rim with for a 31x10.50-15 is 8.50". The safe rim width range is 7.00" to 9.00". Your wheels are wide enough.

 

The recommended rim with for a 30x9.50-15 is 7.50". The safe rim width range is 6.50" to 8.50". Getting closer, but not there yet.

 

Drop down to a 235/75-15 and the recommended rim width is 6.50" with a safe rim width range of 6.00" to 7.00". So that's the largest tire you should put on your wheels.

 

A 215/75-15 has a recommended rim width of 6.00" and an acceptable rim width range of 5.50" to 7.00". That's a better fit for a 4-cylinder 4-speed because it will fit the power band of that engine and transmission better. The All-Terrain T/A KO2 has a pretty aggressive tread with wide shoulders, so I think it will look right at home on your truck, and you won't take as big a hit on performance (or on your wallet).