Experience with 39” BFGoodrich KM3’s Mud Terrain Tires

[JeepinJason33]

The problem with the KM3's is that the true size is at least an inch off. My 37 KM3's measured 36"... What is the mounted height on the 39"?

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[Glamisfan]

I’m happy with mine!

 

[JeepinJason33]

So your 39's measure 37 and a quarter inch?

 

[SG19JLUR]

So your 39's measure 37 and a quarter inch?

All tires measure smaller when they’re mounted and compressed by the weight of the vehicle. That being said, BFG’s in general run a little smaller than most brands. The 39” KM3 is probably closer to a 38 in most brands, and that’s ok with me. It weighs considerably less than most 40’s and is a lot less stressful on the drivetrain. I wouldn’t run 40’s without upgraded axles, but I feel comfortable running the 39” KM3’s

 

[Glamisfan]

All tires measure smaller when they’re mounted and compressed by the weight of the vehicle. That being said, BFG’s in general run a little smaller than most brands. The 39” KM3 is probably closer to a 38 in most brands, and that’s ok with me. It weighs considerably less than most 40’s and is a lot less stressful on the drivetrain. I wouldn’t run 40’s without upgraded axles, but I feel comfortable running the 39” KM3’s

100% agree! These are 86 or 88 lbs. Nitto 40’s are 104 lbs!
37 1/4” on a narrow 7.5” wheel. I personally don’t count a tires height with the vehicle weight on it. But it seems a lot of people do?

 

[Some Random Guy]

Anyone have issues with rear pinch seams? Mine looks like it will be tight once I flex, or might rub. It is hard to tell just sitting in the ground.

 

[Glamisfan]

How much rear bump stop do you have?

 

[OBJLU]

So your 39's measure 37 and a quarter inch?

My cooper stt pro 37’s measured 35 mounted, the only true size tires I know of are competition sticky tires and they’re still off a tad.

 

[Some Random Guy]

How much rear bump stop do you have?

I think 3” right now.

 

[Glamisfan]

You might be fine, but you’ll probably have to cut the lower corners a bit. I am only running 3/8” bump stops, and I had to cut as much as I possibly could. You need to flex it out and check before you go off road so you don’t tear things up.

 

[OBJLU]

I tore off my driver side light bracket a second later. Not enough bump im at 3 in the front

 

[Some Random Guy]

I was totally fine up front with 3” bumpstop and 3.5” of lift (true 3.5, not just advertised). I do contact in the front of the rear tire wells. I posted up another thread to see if lengthening control arms would get me out of the pinch seam. However, from re-reading this whole thread it sounds like trimming is the only way. In the interest of only doing it once I might wait until I figure out a fender choice and do the major trimming. Maybe then I can decrease my bumpstop, shocks dependent!

 

[boogie]

I did 37x13.5x17’s and so far so good. Like um so far

 

[JeepinJason33]

I did 37x13.5x17’s and so far so good. Like um so far

Those are E rated, right? Notice much difference between that and the D's? I could not get the D's to flex as much on my TJ that weighed nearly the same as my JL.

 

[boogie]

No they feel the same as the coopers to me

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