Does this suspension make sense to you?

[Andy69]

Ok, I've got some specifics on the suspension setup on my 7.

 

Front:

260# springs, unknown dampers, .71" ARB

 

Rear:

90# springs (not progressive rate), Bilstein dampers, .45" adjustable ARB, set on the 2nd softest of 4 settings.

 

Is a differential like that between front and rear springs normal on these cars? Seems to me the front is way too stiff with those springs and the bigger ARB, even accounting for the spring angle

Edited July 15, 2019 by Andy69

[yellowss7]

On my 2000 S3 Caterham, I think i have stock 200lb fronts and 150 rear with Stock Bilstein shocks. And the green bush front sway bar and the rear bar set to the stiffest setting. Handles like it's on rails.

 

It is sprung softer than my Orange SV which was set up with Nitron Adjustible shocks and who knows what spring rates. probably a lot stiffer springs as it's got way less roll than the Yellow car.

[BlueBDA]

Not to hijack your thread (ok I guess I am), but can anyone tell me how to determine my spring rates by visual inspection?

[Andy69]

Not to hijack your thread (ok I guess I am), but can anyone tell me how to determine my spring rates by visual inspection?

 

I measured the length, diameter, number of active coils, and wire diameter and used an online spring calculator. The one variable that I couldn’t get was the type of wire which didn’t make a huge difference in the end result

 

 

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[Andy69]

On my 2000 S3 Caterham, I think i have stock 200lb fronts and 150 rear with Stock Bilstein shocks. And the green bush front sway bar and the rear bar set to the stiffest setting. Handles like it's on rails.

 

It is sprung softer than my Orange SV which was set up with Nitron Adjustible shocks and who knows what spring rates. probably a lot stiffer springs as it's got way less roll than the Yellow car.

 

If I did my calculations right it sounds like someone set this car up to be soft and comfortable in the rear and handle well enough for fun on winding roads but not for any kind of track use.

 

Looks like a set of good coil overs should fix the issue

 

 

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[Andy69]

Well ok, like a dummy I shot off my mouth prematurely. I didn’t think to lift the car up and take the weight off the springs before measuring :clonk: and I also counted the non active coils.

 

Fronts 350#

Rear 180#

 

ARBs look to be the biggest available from Caterham.

 

So, it still seems there is too much front roll resistance. I’m going to order some 170# springs for the front and see what that does.

 

 

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[Croc]

350lbs on the front? OMG!

 

You use that in a car 3 times plus the weight...

[Andy69]

350lbs on the front? OMG!

 

You use that in a car 3 times plus the weight...

 

I keep thinking I must have measured that wrong but I double and triple checked.

 

It would certainly explain the ridiculous understeer.

 

 

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[yellowss7]

Andy, I just saw that you have a K series in your car. That engine is really light and the lighter springs would definitely be more appropriate to your car. My K series car seems tightly sprung on normal road driving, but on track it handles beautifully with a bit of roll that transmits excellent feel.

 

Tom

[Andy69]

Andy, I just saw that you have a K series in your car. That engine is really light and the lighter springs would definitely be more appropriate to your car. My K series car seems tightly sprung on normal road driving, but on track it handles beautifully with a bit of roll that transmits excellent feel.

 

Tom

 

I’ve been emailing with Simon from Meteor about what to do about the springs/dampers. Should get it straightened out in short order.

 

It’s a bit baffling to me that the springs are so stiff in the front. I keep thinking I measured them wrong, but it does understeer A LOT - worse than my compact GM totally stock 4 door sedan did.

 

 

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[Croc]

You are in good hands with Simon - he knows his stuff. Helped me dial in my ex-maroon SV and is helping me on a small upgrade project currently.