Hello...Just picked up 5 KM2's that are 38x14.5x17. I was wondering if you knew how much backspacing I would need to install without any rubbing? I would really like to run Hutchenson beadlocks, but not sure if they will rub. I am installing a 6" lift next week and trying to decide on wheels. Thanks,
Brian

BTW I attached an image I took tonight with the tires next to a lotus exige, size difference really puts things into perspective LOL


I Have a 2008 JK Unlimited Rubicon....
How much of a risk do you think I run of breaking axels? I will be running the Superior 5:13 gears and axle shafts. Thanks

 

You strand a pretty good chance of breaking an axle. i would say not if but when.

 

thanks for the reply...I was hoping that if I ran the superior axle shafts it would at least last longer....I usually wheel 1-2 times a month...I had 37's on my tj rubicon unlimited, drove it quite a bit and didn't have any issues. hmmm...

 

I think you'll be fine. D44's should hold up to 38" tires as long as you don't get too carried away. Just be smart with the throttle: spinning your tires and then suddenly getting traction is what breaks axles a lot of the time.

Also, I'm interested to see how those KM2's perform as a year-round Utah tire. After you've tested them out for a few months you should post a review.

 

I wouldnt sweat it too much as its not much of a difference vs 37's. Your 38's are actually ~37.7 which is not much of a difference at all. After some tread wear it will be insignificant as well.


To answer your BS question.... The tires are 1" wider than most 37's that people run. So figure the tire will bulge out 1/2" more on each side of the rim. So you need about ~1/2" more BS. With 4" of BS you might still get minimal rubbing at full wheel tilt. 3.75" BS would be better...

 

Hmmm

14.5" vs most people's 12.5" = 2" wider total, so ONE MORE INCH on either side.



So, 1" more BS than the 1.5" spacer and the 6.25" BS'd oem rim = 3.75" BS, minimum.

If in a state with laws that do not allow the tire to protrude out from under the fenders...you would need wider fender flares to be legal. If you live in the other states, the one's where you can marry your sister if your Mom says its OK, let the tires stick out, etc...well, enjoy!

 

Hmmm, no.

Almost all 37's are 13.5 only two or three tire models out there are 12.5 and from what I've seen, most are running 4.25" BS with 13.5's. Regardless, that still puts the BS recommendation at 3.75".


Go take a look at the 37" tire thread...

 

Maybe take a look at the post itself we're in?

Its a 38 x 14.5 x17...as in 38", not 37", and its 14.5" section width, not 13.5", etc.



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38 x 14.5 x 17 would indicate that he has 14.5" section width tires...I have to trust that's why he asked...if he's really got 13.5's, and accidentally posted that he had 13.5's...well, then THAT math would come into play instead.

AS BFG DOES make this 14.5" size, but does NOT make a 13.5" Version:

http://www.bfgoodrichtires.com/specs...-km2/3930.html

I have no reason to doubt him.



(So - your math is correct for a 13.5" section width, but BFG KM2's do not COME in that size, so, I think we need to go with the stated 14.5" size)

 

Thanks for all of the info! They are in fact 14.5" in width. I am not running the tires yet, I just bought them last night...I will let you know how they run/fit next week when I get them installed, i am going to try and get wheels with 3.75" backspacing....

 

I believe the Pintler wide stance use that BS.