e90 suspension built around run flats?

[Darth Vader]

read an article in e90.post regarding e90 suspension built around runflats.

these may partly explain why your car feels less stiff whenever you change to non-run flats.

so my guess is the springs and dampers are softer and the sway bars are thinner to accomodate the stiff runflats.

so if changing to non runflats.suspension and sway bars can be upgraded to stiffer ones without degrading comfort.thats my humble opinion.

 

[Jadis]

Re: e90 suspension built around run flats?

So if I change the suspension and sway bars and still with the runflats, will the ride too stiff?

 

[Darth Vader]

Re: e90 suspension built around run flats?

So if I change the suspension and sway bars and still with the runflats, will the ride too stiff?

most likely.

 

[Azrielsc]

Re: e90 suspension built around run flats?

But when u change to coilovers, u can dial in the damping to compensate for the perceived increased stiffness?

 

[Darth Vader]

Re: e90 suspension built around run flats?

But when u change to coilovers, u can dial in the damping to compensate for the perceived increased stiffness?

ok what about sway bars ?

 

[Jadis]

Re: e90 suspension built around run flats?

Jia lat, I already changed to the H & R sway bars and strut bar. But, H & R should be aware of this issue right? I also don't find anything wrong with the ride. May be the experts here in this forum can give some comments.

 

[Azrielsc]

Re: e90 suspension built around run flats?

ARBs helps to help the car planted (as well as ur coilovers) but I don't see how they can lessen the stiffness of the ride.

 

[Jadis]

Re: e90 suspension built around run flats?

ok what about sway bars ?

I thought you just ordered the sway bars? hahahaha

 

[Jadis]

Re: e90 suspension built around run flats?

ARBs helps to help the car planted (as well as ur coilovers) but I don't see how they can lessen the stiffness of the ride.

I don't think the ARB should affect the stiffness of the ride. it helps to stabilize the car. I may be wrong !

 

[T6]

Re: e90 suspension built around run flats?

I don't think the ARB should affect the stiffness of the ride. it helps to stabilize the car. I may be wrong !

It does in the sense that the chassis will feel "tighter". At the end of the day, as long as you know your own car and its limits can liao.

 

[Jadis]

Re: e90 suspension built around run flats?

IMO, streets driving in Singapore PSS9 enough liao! we don't really need the sway bars and strut bar unless you intend to go tracking. like to hear more comments.

 

[T6]

Re: e90 suspension built around run flats?

IMO, streets driving in Singapore PSS9 enough liao! we don't really need the sway bars and strut bar unless you intend to go tracking. like to hear more comments.

I used to think so too until I tried them. Then u will realise cornering can be alot more fun even during street driving. Now, they have become a must-have mod on my mod list.

 

[Jadis]

Re: e90 suspension built around run flats?

On E90, H & R front sway is about the size of OEM, only the rear one is bigger. What is your coment? thanks.

 

[Ahbengdriver]

Re: e90 suspension built around run flats?

so if changing to non runflats.suspension and sway bars can be upgraded to stiffer ones without degrading comfort.thats my humble opinion.

So u have put on PSS9 already? How is it now?

I find my E92 OEM sports suspension very comfortable, so quite relectant to change that. Otherwise, the wifey would said I nothing better to mod:laughlik:

 

[Jadis]

Re: e90 suspension built around run flats?

If you have M suspension, just leave it. If comes with sport suspension, may change to coilovers, IMO

 

[centurion]

Re: e90 suspension built around run flats?

lighter wheels and rims = better suspension compliance. It may feel softer if the suspension is made to compensate for the sidewall stiffness, but the suspension still works better.

ARB - study the structure, it's used to help the car corner flatter - it links the left and right suspension. It will also affect stiffness during straightline driving, because of this linkage - left wheel kenna bump right wheel also will get it and you will feel it overall. This is why the 7- has dynamic ARB, which softens the ARB during straightline and increase the stiffness during cornering.

Stiff ARB in front promotes understeer, and stiff ARB in the rear promotes oversteer.

Mac F1 has NO rear ARB because having a rear ARB made it undriveable. Witness NSX-R at the limit you know what I mean (there's a best motoring video on this, 2006 April I think). It cannot be controlled at the limit, will oversteer.

 

[Ahbengdriver]

Re: e90 suspension built around run flats?

lighter wheels and rims = better suspension compliance. It may feel softer if the suspension is made to compensate for the sidewall stiffness, but the suspension still works better.

ARB - study the structure, it's used to help the car corner flatter - it links the left and right suspension. It will also affect stiffness during straightline driving, because of this linkage - left wheel kenna bump right wheel also will get it and you will feel it overall. This is why the 7- has dynamic ARB, which softens the ARB during straightline and increase the stiffness during cornering.

Stiff ARB in front promotes understeer, and stiff ARB in the rear promotes oversteer.

Mac F1 has NO rear ARB because having a rear ARB made it undriveable. Witness NSX-R at the limit you know what I mean (there's a best motoring video on this, 2006 April I think). It cannot be controlled at the limit, will oversteer.

errhmmm so can you summarise...good or bad

 

[Jadis]

Re: e90 suspension built around run flats?

To make it simple, just advise us whether to install PSS9, ARB etc? thanks

 

[centurion]

Re: e90 suspension built around run flats?

wa liao you have to decide for yourself lah! go drive friends' car. trial and error. nobody can advise you one. it's all personal taste. I never mod my car anymore for suspension because last time i waste so much money to trial and error like hell.

elma's car is the best balance BMW I've ever driven in long time. you replicate his car you will achieve `my' taste. but this is not your taste. I like car to have `less grip' and `4 wheel slide'. I don't like oversteer. But many people drive my car type is boring or they say have to work very hard.

Also after you do all that suspension shit, you have to f around with the tyres.

One good compromise, if the Bilstein ride control, adaptative suspension. It is damn stiff in max mode, can give me 4 wheel slide, but when in comfort mode it will understeer comfortably. This is PSS9 with solenoids controlling valving.

 

[Azrielsc]

Re: e90 suspension built around run flats?

On E90, H & R front sway is about the size of OEM, only the rear one is bigger. What is your coment? thanks.

That's right. Hence, in USA, a lot of pple ust buy the rear H&R ARB and fit it on. Dials out understeer and dials in oversteer, in the end, making the car more neutral.