GS300.ru

I have switched from gs300 stock 16 to 17 chrome stock with Dunlop 9000 235x35x17. Nice handling on freeway have not tried rain driving yet. Very happy with the setup accept:
1. I?m getting very rough feedback on steering wheel driving in the city on ?bad? surface (potholes, road cracks) .
2. Driving on the side of the road with side angle, car pools to the side strongly. Every pothole tends to turn steering wheel.
My steering should be as strong as gs400 is, is it any different? Has anybody experienced this behavior on gs 300/400? Will changing to less sporty tires make my car more stable on the road? Should I keep 33psi in cold or hot tires?
How do you drive yore gs400? Does your car shifts to the left and right under potholes? Does you car shifts when you break and start on uneven surface? Does your steering wheel moves when going on uneven surface? Any tires suggestions?
Steering ECU greatly enchanted my steering feel but still getting strong feedback on the wheel.

On the freeway car does pull a little bit to the right, do I need an alignment? My 16-inch setup was ok.
It might be hard driving gs 400 on 17 if it behaves like my car does.
Thanks for your help

The new ECU is a must have for you driving pleasure

TMitchell

[QUOTE]Originally posted by GS300.ru
[B]I have switched from gs300 stock 16 to 17 chrome stock with Dunlop 9000 235x35x17. Nice handling on freeway have not tried rain driving yet. Very happy with the setup accept:
1. I?m getting very rough feedback on steering wheel driving in the city on ?bad? surface (potholes, road cracks) .


Did you mean 235x45x17? I am sure you would get a pretty crappy ride with 235x35x17. I have none of your complaints.

mooretorque

GS, the phenomenon that you are experiencing is a fairly common problem with low(er) profile tires called "tramlining". It refers to the tendency for the tires to follow road contours such as grooves, undulations, truck ruts, etc. Net effect is a feeling of instability and various tuggings at the steering wheel. Lower profile tires will also tend to unmask any alignment problems. And different tire brands/tread patterns can be vary remarkably in their tendencies to do this. Had Dunlop SP8000 on my previous Lex. They were pretty bad about hunting around plus damn loud. Good traction wet and dry as well as good wear though. EVERY aspect of a tire's performance represents a tradeoff somewhere else.

Also, many cars will tend to "fall off" to the right, since roads are crowned (raised in the midde) to facilitate drainage. While your car can be aligned to compensate for the road crown, you will then occasionally have circumstances where the car will pull to the left (flatter roads).

And if you are indeed on a 35 series tire, you'll have all of the above plus a pretty stiff ride which will be VERY crappy on bad roads.

mooretorque

Clarification: I mentioned that low(er) profile tires tend to be poster children for any alignment problems. GS3, first thing you ought to do is have the car aligned. Also, if you are on the Bridgestone RE030s that are the OEM choice by Lexus for the 17" wheel option, please be aware that a lot of the members have, shall we say, issues with these tires. They really are pretty good from wet and dry traction standpoint (relative to some so-called high performance tires) but there ahve been balancing difficulties and their steering feel ain't the greatest.

Sorry about rambling. Just one of those things I do......

GS300.ru

Thanks for help!!!

I guess alignment will help plus another set of tires. What tires would you suggest? Should I go with 235x45x17 instead of 235x35x17? I have much of truction, more than I need. I want to make a car more stable on potholes and bad roads.

Johnny Mo

I agree with what mooretorque said, and you will cettainly be asking for problems going with 235/35/17. If traction is not an issue then I would stay with the 235, but your aspect ratio should not go lower than 45 with a 235 crosssection, it'll be to rough of a ride, as well as not provide enough impact absorption for your rims on crappy roads - you will bend them. The stock 17" size is 235/45/17. That being the case you should never change aspect ratio without changing something else in the equation to compensate.

In case you didn't know the tire size is basically filled with all kinds of information:

P=passenger tire
235 is the width of the tire in mm
45 is the aspect ratio height in mm from the rim (it means the first number, 235 times 45%)
17 is the rim diameter in inches
then there is the speed rating GS3 should use nothing lower than H speed rated, GS4 nothing lower than V (usually W or Z)