Bilstein B6 rear shocks no bump stops

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Chrisd635
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Joined: Sun Jul 16, 2017 1:30 pm
Location: Staffordshire

Bilstein B6 rear shocks no bump stops

Post by Chrisd635 »

I have had a suspension refresh with new bilstein shocks (B6) and springs (not lowered at all). I know the front shocks have internal bump stops but the rears would require external bump stops (which I understand bilstein don't supply?). The garage in their wisdom decided not to fit any bump stops at the rear (I think these could have been sourced from BMW directly) on the basis that I won't be nailing round any race tracks and very unlikely to ever get the car airborne. The car feels great (admittedly the old original suspension on 1989 car was knackered) and no issues to complain of, fitted 17" alpine wheels at the same time as suspension refresh so all round very different feel. My question is - should this run ok without bump stops at the rear or am I in for problems in the future?
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Brucey
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Re: Bilstein B6 rear shocks no bump stops

Post by Brucey »

they made a very stupid decision for three reasons

1) your car will understeer badly if driven with enthusiasm in the corners; why bother spending money on good suspension if it is effed up like that?

2) no bump stops means no protection tubes and that will knacker your rear shocks prematurely; the shafts are chromed steel and will corrode horribly if they see salt spray.

3) the correct parts would have cost about £25 (less at trade prices) and could have been fitted in seconds when the rest of the shock absorber was being assembled. Probably they could have re-used the old protection tubes in fact which would have made the cost trivial.

Not impressed with that, not impressed at all.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Chrisd635
Posts: 7
Joined: Sun Jul 16, 2017 1:30 pm
Location: Staffordshire

Re: Bilstein B6 rear shocks no bump stops

Post by Chrisd635 »

Thanks Brucey, I thought as much, it is perplexing but I suppose they can still fit protection tubes and bump stops now? The car has only done about 40 dry miles since it was done. Can both be sourced from BMW and do you know parts numbers for these by any chance? Also, would the bump stops need to be adjusted at all to fit?
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Brucey
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Re: Bilstein B6 rear shocks no bump stops

Post by Brucey »

BMW pns are in the ETK, parts can only be fitted by incurring a labour time that is about the same as doing the job at the rear all over again.

You should only need to shorten the bumpstops if the car is lowered from standard ride height. If you have lowered the car much then all four bumpstops should be made a bit shorter, else you will have a somewhat jiggly ride.

If you have a lowered car with standard length bumpstops the car will usually handle OK (in terms of balance) vs stock but the ride quality will not be as good.

Note that

a) you can experiment with rear bump stop length effects by proxy, eg by varying the ride height using the adjustable spring perches and
b) you can make small trims to the bump stop in situ provided you are happy to reach in between the spring turns with a sharp knife, and recut the vent grooves where necessary.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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