Need New Tires

[COMANCH3]

14 hours ago, Eagle said:

 

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).

It looks like the max tire width on a 6” wheel is 205.  If I went with a wider wheel, would you go 225 or 235, or still stick with the 215?  Would you go with a “p” rating tire to save weight?  
 

[Pete M]

Jeepers are infamous for not paying attention to the tire manufacturer's recommendations.    we all know there are plenty of 33x12.5s on 7" rims out there.   the super important thing is to not go the other way and have a narrow tire on a too-wide rim as you can lose the bead pretty easily. 

[COMANCH3]

On 8/30/2020 at 12:46 PM, 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.

Do you guys have the "p" rated 215/75/15? I'm assuming you both have the wider wheel with the 4.0?

[PCO6]

46 minutes ago, COMANCH3 said:

Do you guys have the "p" rated 215/75/15? I'm assuming you both have the wider wheel with the 4.0?

 

We do.   I replaced my tires today.   I had the Firestone Destination AT's that I mentioned above.   They were P215/75/15's and apart from the size I had I liked them.   I replaced them with Motomaster Total Terrain AT3's.   They are 235/75/15's M+S LT tires.   Both sets were/are on the original MJ 10 hole 7" aluminum wheels.   My suspension is stock and I like the look (I will post a pic tomorrow) and so far I like the ride ... all 40 minutes of it!   lol

 

Motomaster won't mean much outside of Canada.   It's Canadian Tire's house brand for tires, batteries, parts, etc.   The Total Terrain AT3's have the same tread and sidewall as Cooper Discoverer ATP's.   I put a set on my tear drop trailer (same size) and I like them so I thought I'd try them on my MJ.   They get good reviews from guys with much larger trucks than ours and they're cheap - $117 CDN on sale, which is about 1 week in every four.    

 

https://www.canadiantire.ca/en/tires/pdp/motomaster-total-terrain-a-t3-tire-0051004p.html

[WahooSteeler]

There are a few "LT" tires in the 235 size, but anything below size that I've never seen with the LT designation. 

[Eagle]

1 hour ago, COMANCH3 said:

It looks like the max tire width on a 6” wheel is 205.  If I went with a wider wheel, would you go 225 or 235, or still stick with the 215?  Would you go with a “p” rating tire to save weight?  
 

 

I don't know what you're reading but it's not the link I gave you. I quoted Goodrich directly:

 

Quote

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.

 

You can safely put 235s on your 6-inch rims.

 

Addressing Pete's comment about exceeding the recommendations: Yes, we do often exceed them. It's not a good idea. When you put a wide tire on a narrow rim, the rim pulls the sidewalls in. That pulls the tread shoulders up, so instead of being flat to the road it's curved, with good pavement contact only toward the center of the tread. This hurts tread life (the center of the tread wears out long before the shoulders), and it reduces traction because you're not effectively using the full width of the tread.

 

So we compromise by lowering the tire pressure to get the shoulders back on the pavement. Once you exceed the safe rim range, to do this you have to drop the pressure too low, which results in the tires overheating at high speed or in hot weather. That's exactly what happened with the Ford Explorers a few years ago when their tires were exploding. Ford blamed it in Firestone's tires but the reality is Ford reduced the tire pressure below what Firestone said was safe, because Ford wanted a softer ride. The result was tires overheating on the highway with disastrous results.

 

Bottom line: You can go to 235s and be within the safe range. A 235 is about the same diameter as a 30x9.50. Personally, I think that's too much for a 2.5L 4-speed. I don't think you'll enjoy driving it. I think you'll be happier with a 215 or maybe a 225 if you really want the tire to fill the opening a bit more. Going to a more squared-off, blockier tread will do a lot to make it look more like a Jeep and less like a passenger vehicle.

 

I would get the LT-rated tires rather than P-rated. The tread will be tougher, and the sidewalls will be stronger.