Anyone have experience with DeDion shims?
Discussion
I got a set of camber/toe shims from Jack Webb- He and all the other purveyors of these shims all say how it can be done quickly trackside without disassembly. I must be missing something, because it seems I will need to disassemble a lot in order to slip the shims in. Does anyone have any experience with these and can give me some pointers?
You just need to loosen the two bolts holding the ear onto the de-dion, and the two nylocs on the rear bolts for the hub, and then the ear will be free enough to slot the shims in between the ear and de-dion. You might find you want slightly longer bolts on both though, depending on how much you need to shim it.
These things are all relative in how easy they are to do - for a race team it's a routine 10 minute job, for a trackday enthusiast it may be daunting to do at the track. After ten year of tracking the Caterham and other cars, I now work to the rule of doing minimum at the track. Shimming the ears would only be done on a flat floor with any changes being small and fully evaluated over a complete test session. Unless you've got the support of a race team, it's too easy to lose track of multiple changes over a short period.
Edited by DCL on Monday 30th May 10:07
It's an interesting topic, for me you'd need to know what camber and toe you started with. Then if you made a change you'd at least want to check what the geo looked like after the shims went in (or out) even if roughly.
And then I'm curious how much the rear geo would need to be changed and what could be achieved with it? You'd need to be testing or racing to benefit?
And then I'm curious how much the rear geo would need to be changed and what could be achieved with it? You'd need to be testing or racing to benefit?
Shad said:
You just need to loosen the two bolts holding the ear onto the de-dion, and the two nylocs on the rear bolts for the hub, and then the ear will be free enough to slot the shims in between the ear and de-dion. You might find you want slightly longer bolts on both though, depending on how much you need to shim it.
I was told that the shims go between the hub/bearing and the ear, not between the ear and the dedion. I'm not sure how it would go between the ear and dedion, tbh.If that's how Jack has said his shims fit then go with that. The DPR shims (which is what I use) fit as I described, between the ear and the DD. Looking at Jacks shims I'd hazard a guess they're the same but go with whichever method he advises.
With regards to flat floor etc. - yes, obviously do it properly and use the shims in conjunction with a full geometry and/or corner weighting session. But the advantage is you can then whip them out for using the car on the road so you don't destroy the tyres, and then slot them back in again for a track day. It's very easy then to switch from road to track use.
With regards to flat floor etc. - yes, obviously do it properly and use the shims in conjunction with a full geometry and/or corner weighting session. But the advantage is you can then whip them out for using the car on the road so you don't destroy the tyres, and then slot them back in again for a track day. It's very easy then to switch from road to track use.
As said go with what you've been advised, but IMHO it's bad engineering practice to shim the bearing housing as (to introduce camber) it will misalign the brake assembly. Add to that the risk that it might introduce distortion to the bearing housing and it seems madness to do it that way. Much better to shim the ear and keep the bearing housings on a flat surface and the calipers true.
Edited by DCL on Wednesday 1st June 11:38
I had wondered about misalignment between caliper and disc, but just figured that the brake pad would have to re-bed a little given a minor angle change. Also DPR says this on their site: "DPR shims have a specific shape to facilitate rapid and reliable set up changes and ensure a consistent fit between the hub and De Dion ear." https://www.dpr-motorsport.com/parts/caterham_shim...
I think the wording on the DPR site is confusing things. The shims go between the ear and the DD. Here's a picture:
https://i.imgur.com/o4AkueO.jpeg
Red line underneath a toe shim currently fitted (to create toe out). Yellow line highlighting where camber shims go to create negative camber. This is where DPR fit their shims - this is where they fitted them when they setup my car.
https://i.imgur.com/o4AkueO.jpeg
Red line underneath a toe shim currently fitted (to create toe out). Yellow line highlighting where camber shims go to create negative camber. This is where DPR fit their shims - this is where they fitted them when they setup my car.
Gassing Station | Caterham | Top of Page | What's New | My Stuff