Car bouncy.... advice please

[kungfupanda]

I have an issue here which I hope to get some advice. I am driving a 325 on stock springs and 17inch oem rims. I have upgraded the shocks to bilsteins B6 to match the springs. However, I find the ride very bouncy (particularly at low to moderate spped) as though the rebound is too strong for the springs.

My brother driving a similarcar with exactly the same setup ie stock springs and B6 shocks but on 19 inch tyres ... I find his ride not bouncy at all (no doubt can feel the firmness) and cornering is also much more composed. I find it 'weird' that a car on 19inch is actually more comfortable than mine with 17 inch. Even the wife has the same feeling.

Can someone pls advice why this is so? Or there is something wrong with my shocks or the installation is somewhat not right?

 

[ac323]

Re: Car bouncy.... advice please

I have an issue here which I hope to get some advice. I am driving a 325 on stock springs and 17inch oem rims. I have upgraded the shocks to bilsteins B6 to match the springs. However, I find the ride very bouncy (particularly at low to moderate spped) as though the rebound is too strong for the springs.

My brother driving a similarcar with exactly the same setup ie stock springs and B6 shocks but on 19 inch tyres ... I find his ride not bouncy at all (no doubt can feel the firmness) and cornering is also much more composed. I find it 'weird' that a car on 19inch is actually more comfortable than mine with 17 inch. Even the wife has the same feeling.

Can someone pls advice why this is so? Or there is something wrong with my shocks or the installation is somewhat not right?

what tyres are you on? and what tyre is your bro ride on?


cheers

 

[totoseow]

Re: Car bouncy.... advice please

dun hv chech in car too much

 

[Terry]

Re: Car bouncy.... advice please

change to 19inch... 17 inch RFT ? RFT are a nightmare... pls change them

 

[kungfupanda]

Re: Car bouncy.... advice please

My tyres are the german F1 Asymmentric (225/45/R17) whereas he's on S-Drives (235/35/R19). Can this be the difference coupled with his bigger rims? All I can say is that his ride feels much more stable and composed (it actually feels more comfortable), whereas mine bounce at evey undulation on the road.

I think notice is that his wheel gaps are quite small whereas mine is even higher than stock (ie the front left is acutally a 4 finger gap). Mechanic says its due to the 'strong' bilsteins which pushes the car upwards. My brother's car on comparision looks 'lowered'.

The reason why I kept to 17inch was to retain the comfort but resulted in a bouncy ride. Its as though the spring and the damping rates are mismatched.

 

[Jason8822]

Re: Car bouncy.... advice please

i think its the rim size therefore tire sidewall height giving his issue.
believe its the sidewall having a different rebound rate compared to the spring thus giving this bouncy effect.

rode on a fellow forumer's E60 with 19in and KW3 which is more pliant than my E60 with KW Street comfort running on 17in rim.

change the rim !!!!

 

[kungfupanda]

Re: Car bouncy.... advice please

So this is a tyre and rim size issue? Really contrary to the norm that bigger is harsher.

 

[zorro]

Re: Car bouncy.... advice please

Bridgestone RE050 RFT 17" sucks big time..super hard and i tried the Continental CSC 2 RFT and its much better and not so bouncy even with higher air presuure 240 psi.. so changing to non RFT will surely help further

 

[pengful]

Re: Car bouncy.... advice please

17 inches are usually more bouncy regardless of what shocks/ coilovers you use.

 

[zorro]

Re: Car bouncy.... advice please

I dont think it has anything to do with the rim diameter ...its the tire itself..

17 inches are usually more bouncy regardless of what shocks/ coilovers you use.

 

[tom_ting]

Re: Car bouncy.... advice please

Go Michelin PS2 with 18" oem msport 193 rims. Sure you like the combo.

 

[pengful]

Re: Car bouncy.... advice please

I dont think it has anything to do with the rim diameter ...its the tire itself..

Yes it does. When I was on 19", the ride was hard as a rock while 18" gives me slightly better comfort. I am taking reference from the same suspension setup.

 

[zorro]

Re: Car bouncy.... advice please

The smaller the rim or the higher profile the tire, the more comfortable the ride meaning as you upsiize your rim you will get harder rides wih the same type/brand of tire cos less rubber to absorb the shock.

WIth his 17" rim, he should gets better cushy rides but he claims that his car is bouncing and hard which is similar to my experience with the Bridgestone RE050 RFT my ride is so harsh and jarring.

I have since chenged to Conti CSC2 SSR (RFT) and the ride is now so comfortable with the same rim but noise level gone up a bit on rough surface.. So I think he is having problem with the tire rather than the rims.

Maybe he needs to clarify what is bouncy???

Yes it does. When I was on 19", the ride was hard as a rock while 18" gives me slightly better comfort. I am taking reference from the same suspension setup.

 

[kungfupanda]

Re: Car bouncy.... advice please

When I meant bouncy ride...its as though the undulations on the roads creates 'unwanted' up and down movements. I lowered the tire pressures and it did helped in lessening the bounce but the ride is still not as stable and composed.

Hence I decided to upgrade to 235/40/R18 all round. What is the ideal rim width for 235 tyres? 8 or 8.5 inch? What offset will be correct in this case?

 

[ac323]

Re: Car bouncy.... advice please

When I meant bouncy ride...its as though the undulations on the roads creates 'unwanted' up and down movements. I lowered the tire pressures and it did helped in lessening the bounce but the ride is still not as stable and composed.

Hence I decided to upgrade to 235/40/R18 all round. What is the ideal rim width for 235 tyres? 8 or 8.5 inch? What offset will be correct in this case?

Hi kungfupanda,

do you mean it is bouncy on all the road you travelled? or only certain road?



cheers

 

[pengful]

Re: Car bouncy.... advice please

What I am understanding now is the fault could be the shocks.

 

[zorro]

Re: Car bouncy.... advice please

Bilstein is supposed to be hard...He uses B6 which meant to work with stock spring and should stop the bouncing.. I have used Bilstein in my 95 and its really hard and can feel every crack of the road...

 

[detach8]

Re: Car bouncy.... advice please

i used to have a jap ride, changed the stock rims and had a tyre of a different offset. yeah, looks nice, but the ride was bouncy as hell. of course the tyres made a difference. my hankooks were bad, and i changed to bridgestone gr-90 it was slighly better. so it might be a combination of both tyre and rim offset.

 

[ac323]

Re: Car bouncy.... advice please

Bilstein is supposed to be hard...He uses B6 which meant to work with stock spring and should stop the bouncing.. I have used Bilstein in my 95 and its really hard and can feel every crack of the road...

I've used B6 before, firm ride but not so bouncy................




cheers

 

[zorro]

Re: Car bouncy.... advice please

Thats my point..Bilstein should be firmer/harder than stock so should be less bouncy but harsher ride...