Vibration From Rear Of Car.......

[andyhart21]

I really dont know on that one Nick, but I cant get my head round why there would be adjustment in excess of 35 or 50mm if it was not suitable for the car

Thanks again

[Nick]

Good point Andy, but I suppose raising the car to say 50mm lowered and trying it would be the first thing to try. Also maybe the adjustment mechanism is the same as on other TTE products with bigger allowable drops, and you just have to go by their guidelines. By the way, when your speed increases do you drive out of it, so at say 75-80 it has gone. I also wonder if your soundproofing is making it less easier to trace, but hey we like a challenge!

[andyhart21]

No I cannot 'drive out' of the vibration Nick, BUT (you have just reminded me of something else here :) ) If it vibrates badly and I lift off the accelerator, put the peddle straight back down to the floor, most of the time the vibration is not as bad the second time. AND if I change up or down a gear when it vibrates it does not seem as bad. What gear were you in when it vibrated on you? It seems to happen in 4th most of the time on me.

[Monster-Mat]

ok my hugely technical imput

this rumbling will have nothing to do with the coiover kit.

there is a slight possability of a bearing wearing or running dry

could be your exhaust vibrating, uphill under load the car will generate more vibrations, now these could be felt due to several reasons.

1/ your front strut brace will be stiffening the body

2/ there is some component slightly rubbing

3/ either an engine or gearbox rubber is dry

4/ propshaft has an issue

[andyhart21]

ok my hugely technical imput

this rumbling will have nothing to do with the coiover kit.

there is a slight possability of a bearing wearing or running dry

could be your exhaust vibrating, uphill under load the car will generate more vibrations, now these could be felt due to several reasons.

1/ your front strut brace will be stiffening the body

2/ there is some component slightly rubbing

3/ either an engine or gearbox rubber is dry

4/ propshaft has an issue

I know it will not be my front strut brace because it is leaning up against the side of your car at TDI you gimp

There are some more suggestions there for you Nick if the raising of my car does not work :)

[Monster-Mat]

a few other things.............

is the diff level correct

and im no gimp harty....however that brace was fitted when the problem was first noted.

[andyhart21]

Yesterday I fitted my borrowed set of 17" rims (thanks Zee and Ifraz) and raised the rear of the car about 30mm. Guess what? the vibration has totally disappeared :(

Although the low ride height made this vibration occur, I still do not think it is a fault with the coilover kit, I think it just makes another fault rear its head <_<

It looks really wierd being sat up in the air again, and the handling has suffered a bit as well :( but hopefully a full wheel alignment when I get my new rims may help.

Thanks again to Lexus Leicester for their help :)

[LavaIS]

Hi!

I have the same problem with my car, and posted a topic on this about a year ago.

http://www.lexusownersclub.co.uk/forum/ind...&f=50&t=756&hl=

Sadly, the vibrations still occur when the car is loaded, and I have given up all hope :( of getting it fixed....

Rgds,

LavaIS

[Monster-Mat]

i think the problem is 18" wheels.

i bet if you lowered the car again with the 17" wheels fitted you will still have no vibration, i belive the majority of 18" alloy wheels are heavy, and are putting strain on the wheel bearings.

zee has also noticed a vibration since fitting his wheels, i however have not had any vibration, i think this is due to the fact that the Volk wheels are a magnesium alloy which makes them very light, infact with tyres fitted there still lighter than the factory 17" wheels

the coilover kit only amplified the harmonics of the vibration created by having a higher unsprung weight on your rear hubs

[LavaIS]

Hi!

Due to the fact that I've tried 5 sets of wheels (16", 17" and 18"), I don't think andyhart21's vibrationproblems are related to the wheels. I've concluded that my problems are caused by the lowering (I had the vibes when the car was stock too, but I had to load it a little more to get them...), not by the lowering parts themselves, but that the IS rear chassis don't like being lowered too much, either by short springs or heavy load. What piece exactly causes the problem I don't now, but it might be related to the angle of the joint on the driveshafts. But if they are the problem, it must be a construction fault (since mine are changed), and I'm then quite surprised so few people have this problem.

andyhart21, if you still are running on 17", I'd recommend you to try loading up your car with people (or the boot with 100 - 200 kg). My guess then, is that your vibes are back.

My vibrations are worst when accelrating around 100km/h, in 3'rd.

Rgds,

LavaIS

[DUNCAN]

I agree with LavaIS,

Sounds to me like its the angle of the the propshaft rather than driveshafts. As the car is lowered past a certain point, the propshaft angle becomes greater pushing the shaft further into the diff, causing a greater load on the diff bearing. The prop also moves back and forth when you accelerate, which will cause more stress on the diff bearing.

As you know, I'm running 19's with a -40mm drop. At the moment i don't have any vibrations at all. When I get my TTE coilovers in a couple of weeks I'll let you know what happens!!!

[Monster-Mat]

the prop angle doesnt change.

the rear diff is fixed in the rear subframe, the only angle that changes is the driveshafts, the prop slides on a slip joint