Progressive Bump Stops for Spring Damper Units

[Laurence7]

I'm looking for a supplier of progressive bump stops for some spring damper units on a bike-engined sports racer, the idea being to build in some rising rate effect as the suspension loads up under the action of aero down force.
Powerflex used to do them, and provided detailed information on dimensions and, importantly, load-deflection data, enabling a rational choice to be made. Unfortunately, they've stopped doing them.
Does anyone know another supplier who provides the same service?
Thanks
Laurence

[Sam_68]

Try contacting Penske and Koni.

[Count Johnny]

Hi Lawrence

Nigel Rees (GSD Racedyn) did a load of clever stuff with the springing, damping and bump stopping of my Speads. He also works for F1 Historic Masters teams helping Arrows A4's and the like to go quicker.

He's a good chap, seem to recall he's down your way. nlr784(at)yahoo.co.uk. Tell him 'Count Johnny' sent you.

Edited by Count Johnny on Monday 5th March 05:53

[Josh Smith]

Paul Drake at Raceline Suspension (Koni workshop) will be able to help

[randy]

nitron carry a range

[Laurence7]

Thanks All. There are some good contacts there.

Once I've got the car on its feet again (it's currently up on stands) and set it to ride height, I'll be able to see how much bump displacement I have in the dampers, so I'll probably delay purchase of bump stops 'til then.

My current thought is to have only a small amount of free travel before the bump stops begin to work, but to go for a relatively soft progressive bump stop, so that I have a near-immediate but gentle progression to the desired rising rate effect.

Does that chime with anyone else's experience?

[Sam_68]

Laurence7 said:

My current thought is to have only a small amount of free travel before the bump stops begin to work, but to go for a relatively soft progressive bump stop, so that I have a near-immediate but gentle progression to the desired rising rate effect.

Does that chime with anyone else's experience?

That's great if you can make the numbers work, but you'll usually find that the force:deflection curve rises pretty steeply with most bump rubbers, therefore to acheive what you're suggesting means that the suspension leverages need to be arranged so that a fairly large amount of wheel movement translates into a fairly small amount of compression of the coilover and bump rubbers.... this then leads to problems with damper inconsistencies and 'stiction', because even the best dampers aren't precise enough to mete our finely calibrated doese of damping for very small shaft movements.

[Count Johnny]

Hi Lawrence

Are you still playing with the Clubsport and is it still in standard form aero-wise? If so, the download that you are intending to manage may not be so great.

Also, are you intending to run in BikeSports, or in the Club Cup?

If it’s BikeSports – and you’re not intending to run to 2004 spec - you are free to do as you wish with dampers so may want to spend your time and dollar on really controlling your wheels and achieving much improved mechanical grip and drivability with quality dampers, like Koni 2812s, and proper anti-roll bars.

[Josh Smith]

If you still plan to pop over to look at the Pr6 on Friday, you can see the progressive rubbers that are on our konis.

[tristancliffe]

I believe the Dynamic Suspension bump stops are considered very good, but it's hard to find a UK website, or a list of what they have. But I'm sure they'd help you if you phoned them... They're in Thetford.

[BertBert]

Club cup is no longer an option for clubsports.
BErt

[Count Johnny]

BertBert said:

Club cup is no longer an option for clubsports.
BErt

Didn't know that. Thanks, BErt.