I've been reading threads about 35s for hours now, but haven't cleared up my questions yet with definitive answers.

I have a 2" spacer lift / BB with 'upgraded' shocks, and recently threw on 315/70R17s.
What else is necessary to prevent damage to my jeep, or to optimize the handling / drivability?

I'm not talking fender flares or stubby bumpers, I mean mechanically / structurally.
Gears needn't be mentioned unless sticking with my stock 3.73s can lead to overheating the tranny (which i am unclear about)
C-gussets? (whether it is mainly on-road or off-road)
Steering stabilizer?
Track bar / track bar bracket?
Anything else?

Also, as far as alignment goes, I currently have a moderate shimmy at / approaching highway speeds. I haven't ruled out tire balancing as an issue, but I did remove the retaining washers from the rotors and this only helped slightly. Is this possibly a toe / caster issue, and will I / the alignment shop be able to remedy it without adjustable control arms?

I love my new tires but I don't want to do any damage, plus I would like to fix these handling issues.

Thanks.

 

Did you lift the jeep and add the tires at the same time??? Or add tires to an already lifted jeep with no shimy at highway speeds?? I'm guessing the shimy started after the 35 install... You did have your front end alignmented after the lift?? Tires may need to be re-balanced. I'd start with that.

 

I purchased the jeep with the lift already on, and I put on the 35s. The shimmy did not exist before, but the steering was flighty, and going over bumps was sometimes scary.

 

If the lift was installed without adjustable control arms, it sounds like you don't have enough castor. It should be 5 degrees or above to be stable on the road.

 

Open the suspension FAQ's and read this one:

Q: What is Caster? How much do I need?
(top of this modified section)

Does that sounds like what you are experiencing?

Also, what pressure are you running the tires at?
(there's another one in the wheels/tires faq's concerning the appropriate pressure to run)

Concerning the alignment, the only thing they can do is re-center the steering wheel and set the toe. If you add adj control arms, then you/they can adjust the caster. (refer back to the caster section of the faq's). If you get adj track bars, you/they can recenter the axles.

Browse this one when you get some time:

Basic Do-it-Yourself Jeep JK Wrangler Front End Alignment
(jk write-ups - Index - Suspension & Steering...)

 

I'm in for answers to the original questions. I just purchased the Teraflex Leveling kit which should arrive on Monday and I'm debating between 34 & 35 inch tires. Daily driver with 85% highway mileage (2008 with 75K miles)

 

Daily driver, light to moderate wheeling eventually after a fender chop.

I'm running 315/70R17 Goodyear duratracs on Rugged ridge 17x9 wheels. Not sure of the PSI, they've been on a whole 4 days now. I also don't have an accurate pressure meter, so it will be a day or two until I can find out. I ordered from and had them installed by a 4x4 shop if that makes a difference.

 

I appreciate the responses planman.
I had actually created this thread hoping you would chime in, as you were very knowledgable in past threads and I saw you were online when I created it.

The flashpaq is already on order, and I have been looking at options for the spare, though it is on order so I still have some time. Eventually I will probably go with the AEV tire carrier for the stock bumper.
As far as rubbing goes, I think they may be rubbing the front bumper as well on full turn, but I will make sure.

In regards to highway and OD off, the past couple of days I have left it on on the way to and from work. On flat and down hills I can get up to 135km/h effortlessly whithout downshifting, and up hills i simply move over as I drop to 100km/h and everyone blows past me. I will downshift maybe twice per trip, if that. Does this sound like a safe alternative to driving OD off?

I will air down to ~26 and see how many issues are alleviated. As i said before, the steering was pretty flighty with stockers, the only new issue is the shimmy; hopefully it isn't an alignment issue.

Once again thanks to all who have replied.

EDIT: After going for lunch and a drive, I should mention that it also pulls to the right (or left at times) and pulls left hard when coming to a stop from any decent speed.