First, remember the TL is front drive with probably 60% of the weight on the fronts. This will help stability at the cost of terminal understeer.

Second: My G35S is usually fine , but I have noticed it tramlining on rutted highways.

Third: have you checked tire pressure? If the backs are low, and/or the fronts high, the result is to promote oversteer, which can cause wandering. By the same token, you could try 31 psi front/35 psi rear (vs spec of 33/33), which promotes understeer, and see if it helps. Oh, and at the risk of stating the obvious, don't depend on the TPMs to tell you all tires are at correct pressure.

 

Definate tramlining here in the Bay Area (CA).

The roads out here are pretty bad.

I've also noticed that if a road is grooved, my tires will catch them and backend wobble a slight amount, but it's felt through the steering wheel (which is very sensitive as has been mentioned).

 

Oh duh. That is so obvious... but of course I hadn't checked the pressure. I just went out (with a decent quality gauge, BTW) and 3 of the 4 tires were at about 36-37. Not huge, but who knows... I set the rears to 33 and the fronts to 32, and we'll see what it's like tomorrow. I suppose I could have the fronts at 31 with no issues. Thanks for your help...

kc

 

I heard some of the guys on the Lexus forum talking about this too with the IS350.

Seems they are finding that the bigger the tire, the more this occurs.
My X is still sporting the factory 17's and it's straight as an arrow on the highway, no matter the speed.

 

It's much better since adjusting the tire pressure! One of the fronts was inflated to around 36 or so; both rears were high. Who knows? Combined with the relatively quick steering, windy conditions and a new owner, it must have been enough for the car to seem darty and twitchy.... I may put the fronts at 31 and drive it on the Interstate this weekend. But for now it seems vastly improved.

 

Mine were close to 42 when I picked it up from the dealer... YIKES.
Once adjusted - MUCH better. Quiet and straight.

 

No problem here either. I've had the car to 100+ for a good 20+ times, at 135ish, the car does feel a tad not so much in control but that's 135+. At 110ish, it's stable as rock.

 

I also have noticed this issue in my 07 G35x (almost 7000 km's). Happens a little on rough roads, but really noticeable on streets with streetcar tracks (Toronto). I'll check the tire pressures....

 

I own a G35 Sport. When I had the clear bra installed, I got a Journey as a loaner. Noticed the same issue - on the same stretch of road (freeway), the steering required ongoing minor adjustments, whereas with the sport, I have perfect stability. The only difference I noticed is that the Journey had Goodyear tires, the sport has Bridgestone Potenzas. I'm thinking it's the tires, and a greater tendency to tramline with the Goodyears.

 

yup, I've got factory inst. goodyears

 

a good rule of thumb is to have the car aligned for the first time after 12-15k miles. many suspension parts need to seat in to their rubber bushings and this mostly happens in the first year a car is on the road. also, you don't know if the factory settings are holding or were done properly on a recently calibration machine. one could hope, but....

here is what i do and recommend.

take car in for first 4-wheel alignment after first year or 15000 miles. ask for before and after printouts off the machine. this will also give you the ranges set by the factory (unless some kind soul is willing to post them up here on the board, hint, hint....). check the newly adjusted settings carefully. are they equal left and right and roughly in the middle of the factory settings? probably not. within range, is not equal to properly aligned. most alignment shops do not take the time to properly set caster and camber on each wheels unless you specifically request they hit a certain number. they do a think called "set the toe and let it go". that way they can do more alignments per day and make more money. some vehicles are actually quite difficult to adjust camber on. if it's within range, most shops will not mess with it even if both sides are not equal. the dealer should have the tools and procedures, but many techs aren't properly trained. you have to take control and take responsibility for making your car right.

if all settings not right, take it back and request them to do it again for free and do it right. if settings decent and car drives well, be happy. if you need additional tweeking, now you have he specs and can, for example, ask them to increase the rear camber slightly for better cornering, or increase the front caster up near the max of the range for more straight line stability. you should pay for these custom adjustments yourself. the big advantage of having the spec ranges is they can't balk because you are asking for something outside of the factory recommended range.

if you have lowered, install the correct parts necessary to allow the settings to be brought back into range. you have no room to complain if you can't attain the manufacturers suggested settings the car was originally engineered to due to installation of aftermarket parts.

 

Absolutely. The FX jumps around more than a one legged man in an azz kicking contest on rough roads. The G, at least so I experienced, was much more composed. I didn't notice any problems.