Boucing rear wheels

[Davenotouring]

If I accelerate hard in first, then once the car gets to about 4500rpm, the rear wheels seem to bounce up and down quickly for about 1000rpm, then for a second when you change into third.....

Is this cos the wheels are out of balance? And the dampers are sh1te?

Any other reasons?

Also, my high speed braking seems a little wayward at the back, is this a sign that the trailing arm bushes are worn?

Thanks....

[E30Adam]

It's probably due to the coupe springs that you have fitted. Ideally you need touring specific springs to handle the additional weight at the back of the car over the coupe. It has the same effect as having a heavy load in the boot of a coupe.

It could also be the rear subframe bushes but you'd know if these were shot because the rear would feel very vague.

[Davenotouring]

Adam,

I changed the springs back to the Touring -40 PI Springs on Friday, and it still does it, not as bad mind.

But the high speed vaugeness at the rear isn't particularly nice.

However, the LSD is making up for these problems for the time being!

[320Touring]

yup dave E30ADAm is right-us touring blokes require a firmer spring than our lighter car'd friends.

possibly also LSD playing up?

[Davenotouring]

yup dave E30ADAm is right-us touring blokes require a firmer spring than our lighter car'd friends.

possibly also LSD playing up?

Hi mate,

I know the springs should be stronger

I've gone back to touring springs now! I guess you didn't see my first reply

The LSD is thankfully silent, which is great.

It was doing it with the open diff too.

I will get a proper suspension kit in summer, I hope that solves the problem!!

[E30Adam]

In that case mate it's definately one of 2 things. Either your rear dampers are shagged or your rear subframe bushes are knackered. Does the car bounce if you push down on it at the back or does it depress and then settle?

Could be a combination of both!

[Davenotouring]

To be honest, they are both probably worn.

I will get the rear bushes and other bits and bobs replaced in summer, probably at MoT time, either through nesscessity, or voluntarily!

The car doesn't bounce around badly though, the shock test doesn't show that the dampers are too bad.

I will hopefully be getting the BBS's refurbed, new suspension kit, and new bushes all round in Summer

[cros]

I think the touring has only an extra 80kg over the back axle unladen - which is the same as an average passenger.

The stronger springs would really only become important fully laden, where a touring could have a total of 300kg more than a packed saloon over the back axle.

All these figures are just from memory though. I could be talking rubbish.

[Geeman]

Sounds like shagged dampers.

I often see cars on the motorway with 'bouncing' rear wheels... looks VERY dangerous, not to mention the discomfort it must cause while driving...

I swapped the Alpinas off the Sport becasue of the annoying vibrations I was getting every now and again... BBS's make is so much nicer to drive. Not that this has anything to do with your problem, just the annoying-ness of both problems...

[Davenotouring]

Cros,

You may well be correct.

But when I put in -60mm Saloon springs, it dropped the car about -80mm. If I had -60mm Touring Springs, I don't think an 80kg passenger would drop it 20mm?

But anyway!

I will have a look at the weekend to make sure there is nothing obvious wrong!

[Karan]

worn rear shock top mounts may also be to blame

[Demlotcrew]

worn rear shock top mounts may also be to blame

thats a good idea, i would have a look at those dave!

Andrew

[E30Adam]

Top mounts wouldn't cause bouncing, they'd just knock.

My money's on the dampers.

[Davenotouring]

Giles,

I've gone back to BBS's too now, and the ride is SO much better.

I'll have a proper look around at the weekend.

Like I said, I'm gonna get the BBS's refurbed and trued, suspension kit, replace lots of bushes too.

Hopefully all will be sweet then

[Simon13]

i've gone to bbs for a while too! must be a new trend. 17's must be nasty compared to bbs, Dave, Giles?

[Davenotouring]

i've gone to bbs for a while too! must be a new trend. 17's must be nasty compared to bbs, Dave, Giles?

Hmmmm.

Not nasty at all.

The ride is bumpier.

I can't comment on grip levels because I'm running different makes of tyres, and often overlooked factor when comparing wheel size

It drifted nicely on seventeens to be honest, I'm getting used to the BBS's.

I like the look of my touring on BBS's now though. Will get them refurbed for the summer I think.

[gareth]

i'm actually doing the opposite soon! my bbs's are being swapped for 17" alpina replicas. teh biggest difference i reckon i'll notice is going to be the unsprung weight. the 17's are soooo much heavier than the bbs's.

maybe because they're replicas. are the genuine ones so heavy i wonder...?



oh yeah... my money's on shocks! they should be easy to change though

[greg325]

worn rear shock top mounts may also be to blame

i just had that same prob and those where my prob .... easy to see fast if its them
thay caused boucing at first , i really dind't care that much at the time , but got noisier and noiser till clinging noises apeared and i found it was them.....

[Richy325iTouring]

gen pinas dont seem much heavyer than bbs
but ive not avtually wheighed them

[Brianmoooore]

I thought my rear dampers were fine untill I did a lap of the Nurburgring last August. That will test your suspension for you,(and also test whether you can drive as well as you think you can).

[Simon13]

15x7 inch bbs with tyre about 15kgs
16x7 inch Alpina with tyre also 15kgs
16x8 alpina with tyre 16.5kgs
16x7.5 hartge with tyre 15kgs

These weights are mine and Demlotcrew "wondering how these wheels weigh on your bathroom scales!". Seems to prove that the Hartge's are not lightweight like alot of people say although they do feel lighter when u lift one and then a bbs wheel.

Someone weigh a 17 inch alpina be interesting......................
+ 14 bottletop or 14bbs