Mark Widdup2 Posted July 7, 2022 Share Posted July 7, 2022 Apologies if this is a silly question as I'm just trying to find my way around my new Roadsport after years of a live axle crossflow. I have read about a ride height rake of 15mm or 35mm for progressive springs. My question is, are my adjustable platform bilsteins progressive or not please?Many thanks as alwaysMark Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted July 7, 2022 Leadership Team Share Posted July 7, 2022 Mark, if you look under the rear of the car at the springs, if the coils are more open or spread towards one end, they're progressive springs. It actually has nothing to do with the shocks or adjustable platforms.Stu. Link to comment Share on other sites More sharing options...
StevehS3 Posted July 7, 2022 Share Posted July 7, 2022 Mark, I would check the build manual for the correct rake for your car. I think the 35mm came from a very early manual. My car with progressive springs requires a recommended 15mm rake. Link to comment Share on other sites More sharing options...
Graham Hutton Posted July 7, 2022 Share Posted July 7, 2022 Yes, I have about 15mm rake on my 310R with the progressive rear springs and adjustable platforms. The front springs as standard are not progressive. Ride height under my sump is about 85mm and everything feels good :-) Link to comment Share on other sites More sharing options...
Mark Widdup2 Posted July 7, 2022 Author Share Posted July 7, 2022 Thanks all I'm just trying to unpick a few problems so please let me know if you think I'm missing anything. the ride when I picked the car up was very skittish, with bumpsteer and tram lining even on relatively flowing roads. It was running 15 in wheels with zzz tyres. Speaking to the previous owner and looking at the history file, as an acadamy car the previous but one owner commented it was the best handiling Caterham he had driven but at that point was running 13 in wheels. Previous owner took it in the Caterham and ask for sump ride height increasing to clear speed bumps. I've put it back on 13s with 185 60 a539s and that gives me a sump clearance if 75mm but only 5mm of rake. My instinct is Caterham simply raised the front.so my plan is13 inch wheelsSump heightrakerack 9mm spacer is there anything else I should consider.thanksMark Link to comment Share on other sites More sharing options...
Graham Hutton Posted July 7, 2022 Share Posted July 7, 2022 Mine is an SV chassis so things may be different. However, I had all of the same symptoms as you when I first got it on the road. The kit comes with no guidance on what spring lengths/platform height to use and so I had to take a bit of advice from the caterham technical chap when building it. The springs lengths he gave me (161 front and 330 rear) looked pretty sensible but on the road it was skittish with loads of bump steer even though the ride height wasn't too far wrong. I then arranged to do a flat floor setup with a lformer motorport mechanic. I set it to about an 85mm sump clearance and a 15mm rake and the corner weights worked out really well with me sat in the driver seat. Hey presto, everything, and I mean everything was sorted. No need to pack under the steering rack or anything. In fact, he advised me against eliminating 100% of bump steer because it makes the steering feel a bit numb. Mine is on 15" ZZS tyres btw.In terms of the other suspension geometry we set the wheel s to point dead ahead with no toe in or toe out as this is a decent compromise for track and road driving. Front negative camber was about -1.75degrees from memory and we made no changes to castor or rear geometry. I really can't tell you how big a difference this made and to be honest I thoroughly enjoyed the process. It took us about 3 hours of workshop time and I worked with him all the time to get it just so.Hope that helps a bit Link to comment Share on other sites More sharing options...
StevehS3 Posted July 7, 2022 Share Posted July 7, 2022 My S3 310R setup is similar to Graham's. 84mm under the sump and 15mm rake. I am running 13" wheels with ZZS and wider rears. Link to comment Share on other sites More sharing options...
Stu Smith Posted August 16, 2022 Share Posted August 16, 2022 Hello not wishing to hijack this post, I'm looking for some advice on my front suspension set up.My knowledge is totally nil on any type of suspension set up. I too am suffering from bump steer on any spirited drive on the road, car seems okay on the two trackdays I've done. If you look at the attached images of the front dampers there is a big difference between the near side and offside. As above I'm clueless on whether this is correct or not?All so I would be very grateful for any recommendations on where to have my car suspension checked/set up, anywhere in the North West. Link to comment Share on other sites More sharing options...
Roger Ford Posted August 16, 2022 Share Posted August 16, 2022 Are there any shims under the steering rack? On K-series Academy cars, the steering rack was mounted too low as standard, which contributes to bump steer. Raising the rack height with shims helps with that. There are several articles in the Low Flying archive describing how to adjust it correctly. Link to comment Share on other sites More sharing options...
Tazio Posted August 16, 2022 Share Posted August 16, 2022 And tramlining is normally a feature of having the alignment set as toe out, which aids turn in at the expense of tramlining in the straight ahead, so returning the toe to parallel will make it more benign. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted August 16, 2022 Leadership Team Share Posted August 16, 2022 Stuart, in the North west you're close enough to get Dave Gemzoe to do a proper setup, money well spent.Stu. Link to comment Share on other sites More sharing options...
Stu Smith Posted August 16, 2022 Share Posted August 16, 2022 Thank you Stu.. Link to comment Share on other sites More sharing options...
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