JulietKilo

My Jeep is a lot of fun but it was kind of wearing off due to the lousy gas prices and small annoying issues I have been having such as the door striker noise, hardtop leak, clunky slow shifting transmission, etc.

Maybe I was nitpicking and work, deployments, etc were getting on my nerves but I think I have found the cure for the common JK and a way to look past all its small issues.

35/12.50R17 BFGoodrich Mud Terrain KM2's.

My Jeeps ride has softened up on the road and feels more controlled on the street even at the same PSI as stock 32's. It could be due to more sidewall or the fact that I have wider 8.5 inch rims now. I am not sure just yet. But that is not all it gets much better. In fact much much better.

My mileage has not changed from 32's and I am glad to say that I am still getting 16-17 mpg.

My Jeep also seems to shift better first gear is geared so LOW anymore and shifts smoother, the meats drive wonderfully with the manual transmission. Its as if Jeep designed the gearing for 35's and 4.10 axles. My sixth gear is still strong and keeps me going on the highway with ease. The RPMS are lower too, allowing me better gas mileage. I was at 2500 rpm's at 70 mph but now I am down to about 2300 and still rolling fine.

Oh and the HUM is so sweet its almost elegant. I actually turned my radio off to listen to them tonight on my way home from the base. They are louder then stock 32" Rubi muds but they are not annoying!

All I can say is wow! BFG did their homework on this tire. The sidewall is thicker to stop the problems the old ones had. And the tread design is like the Krawler, very cool looking. I am one happy customer.

EDIT:
Hypertech, K&N helped make up some power loss. so I must take this into account also. In therory a larger rolling mass stays rolling longer kind of like those kids toys that you speed up and then let go. I think the additional centrifcal force has helped my driving style. With a manual I just have to say that this setup is really yeilding me better MPG on my commute to work. I am seeing 2 mpg better and possibly more. I will have to update that after I have had them longer.

UPDATE: The mpg has went back down to about what it was with my 32's. But it did NOT go lower! I am pleased with my 16-17 mpg city/highway mix.

Ryno

Congrats on the new tires!

So let's get this straight...
1) They ride better.
2) They help you achieve better gas mileage.
3) They make your Jeep feel more powerful.

Sounds like the boys at BFG have a real winner on their hands! I refuse to be the first Doubting Thomas. I'll let someone else step up to the plate and call BS on those latter two claims.


Speculation time!

Ride characteristics are completely subjective. Something that rides and handles good to you may ride like crap to someone else, so I don't think anyone can question you on that.

Maybe the bigger tires are causing you to shift at more "fuel efficient" speed intervals.

I don't know why your Jeep would feel torquier with bigger tires (it shouldn't). Without getting into discussions about angular inertia (any physics majors in the house?), I'll simply say that it should be harder for the engine to accelerate tires that are heavier and have a larger diameter... by a noticeable margin.

All of this is really irrelevant though. If your new tires perform well and you're satisfied, that's all that matters.

The_Captain

I know the feelin' only on a smaller scale.... I went from station wagon 30's to mud terrain 32's and I felt a mile taller.... And for some reason, it feels quicker... Milage stayed about the same... I don't know why, but from stop to go, I felt a noticable change....

Momma T

You would think more to push, but as my husband constantly tells me to get bigger tires because bigger footprint means better traction, the engine my actually be working less to move more if that makes sense. Think about it, I did and yes it does makes sense bc I had a TJ that I put just a little wider bigger better tread tires on and it worked less and moved better and that was a 4 banger so it does work. Soon I'll have wider rims and bigger tires and will test it again with my JK. So no doubts here, you know your rig and I'm sure you know how it's doing.

RedneckJeep

No need for mileage speculation. That part is simple. The larger the diameter, the slower the tire turns. The slower it turns, the less RPM at the same speed as the smaller tire. Of course there's the extra weight of the larger tire, blah blah blah, but obviously, you found that "sweet spot" of compromise.

Geeper4x4

JK (NATO phonetic alphabet) if your happier with the the 35's that is all that matters. I have 33's and I know the day I drove home with them I was just on cloud 9. I had those stock x steelie 16 slicks. The difference was so great I drove the long way home. I loved the ride height, feel, and the song they hum. Congrats of getting back this is MY Jeep feeling.

racer83l

congrats on the 35's. post some pics.

jkkat

WOW!!!!!!!!!!!!!!!!!!

If your review is this good, i can not wait till i get mine!!!!!!!!!!

Noticed that the Hypertech is added as well, why?

FuLcRuM

yeah I noticed the same thing when shifting with the 315/70/17 BFG AT's. We swap back and forth for wheeling and 1st gear is much better on the 35's.
I don't notice a difference in milage, but don't pay to close attention either, seems about the same.

While I don't feel much of a difference when accelerating I DO feel a differance when braking, the bigger heavier rims/tires are noticably harder to get stopped.

JulietKilo

Thank you all for replying.

TO RYNO:
I can understand someone calling BS. I wouldnt believe it myself had I not seen it for myself.

I dont believe I have more torque seriously big heavy tires are not helping our mini-van engine. But I have noticed that people that have dynoed there jeeps gained low end torque due to 35's because the tire is an "ARM" and has "moments" when multiplied mathmatically creates torque. (Air Force Flight School) I just feel that the gearing in the manual is better suited for these tires.

I replied to lots of threads stating that if someone had 35's, drove moderately (hypermiling), and retained the 4.10's you could get better gas mileage due to lower RPM's and the inertia of larger tires. I had a TJ for years and over on Jeepforum they had constant testimonials of people getting better gas mileage when they found the proper tire and gear combo. In my case (now a JK) i have found the 6 speed, 4.10's and 35's are my sweet spot.

TO JKKAT:
The Hypertech allows me to not only add a few more horsepower but allows me to dial in the 35's for an accurate speedo.

CONCLUSION
As everyone always says here if you are happy with it that is all that matters. I concur, and in this case I want everyone else to know that feeling.