Well, here I go again. I have a 2008 Sahara 4 dr. I am passing it down to my son and wanted to get up back up to speed before I did that. I had BFG MT on it and was experiencing some vibrations and looseness. I started by trying to get them road force balanced. Discount tire told me they were cupped and it wouldn't help. I then got an alignment and bought new tires. I got the BFG AT KO2 because I wanted a better street feel than the MT. I also did the following:
Replaced the draglink as the bushing was shot.
Replaced the steering damper with OME heavy duty.
Replaced the trackbar as bushings were shot.
Put a new AEV 2.5" full lift kit on it and replaced my adjustable control arms with OEM fixed arms.
Replaced LOD front bumper and rear with tire carrier with AEV front and back and tire carrier.


Put the new 315x70x17 KO2's on 17" AEV Pintlers.

Rides like crap. Took them to another tire shop that does semi's and they told me that they can't be road force balanced, but they could do a dynamic balance if I didn't mind weights on the inside and outside. I told them to do whatever gave me the best balance. Most tires have a combined weight of around 5-6 oz. BFG says they are not out of round until they exceed 8 oz.

Most techs tell me that it rides better than most Jeeps, but I think that is bs.

At low speeds it is a gravel road feel. Vibes. As speed increases, it gets more pronounced. At 60-65 it seems to ovulate. Aty 75 it is full on vibration I can feel in the wheel and in my seat.

Is the 315 so much different than the stock 255 that you can't get a good street ride? This sucks. I am running them at 28 psi.

I know that I need to swap them out with some other tires to see if it still there, but I don't know of an extra set I can use right now.

Any suggestions would be helpful! Thanks in advance, Blaine

I have one other piece of info. I had it geared with a 5.13 which was fine on the original engine. Blew that and Chrysler made a deal on a new one, but I am wondering if the gears are off? Would that cause a vibe or just different rpm?

 

Are you running stock or OEM drive shafts? Have you checked them? No play in the wheel bearings? Have you ridden in a similarly equipped Jeep to get a baseline expectation of the NVH you should feel?

 

aftermarket front drive shaft. Replaced it about 20k miles ago. How do I check the wheel bearings? No I have not ridden in a similar jeep.

 

When you installed the 2.5" kit, did you install the control arm drop brackets for the stock arms? A bad castor angle will throw it out pretty bad. A 35" tire does ride a lot worse than the stock tire sizes. If you have a 2008, another thing you might want to look at is getting a sector shaft brace from synergy and if your new trackbar was an OEM, replace it with a heavy duty one from a good MFG like JKS.

When you get to larger tires you should expect some extra wobble, noise and wondering. If it is excessive (5-10 degrees on your steering wheel) then you should take it to a good 4x4 shop so they can diagnose.

 

Post your current alignment measurements taken. That will be the most useful for keyboard diagnosis, otherwise with all the changes you mentioned we're really just taking shots in the dark.

I have BFG A/T KO2's 315/70/R17's currently on the way to my house via UPS. They likely won't be on until next week-end but I can provide some feedback after that, as I have a similar setup as you. 2009 Sahara JKU. I'm currently running stock wheels/tires and wheel spacers with my lift.

 

My 315/70r17 ko2's ride great. And so did my 285/70 ko2's. So I doubt your problem is with the tire.

 

I just talked to a sales rep from Discount Tire Direct yesterday when I placed my order, where he stated he's put 11 sets of these tires on JK's this past year and everyone has been extremely happy with these tires and the ride quality. They were the best combo onroad/offroad tire available in his opinion.

 

I'm running 35" KO2's and I definitely need to replace my OEM balljoints, but I still have a nice, quiet, smooth ride. I'm waiting for some kind of actual fall/winter weather here in Colorado so I can test out their capabilities in the snow, but they've been great so far both on and off pavement.

 

Thanks for the responses. I will respond to the individual ones....

 

Running a teraflex 2.5" spring/shock lift. 17" rockstars 315/70/17 BFg k02's. less road noise than oem and smooth. 2014 jku.