rear springs

[Culminator]

I currently have 220lb rear springs and these seem far too harsh, even with my AVO's on the softest settings. Would 150lb be a much better bet for mainly road with occaisional track day?

[Shaun_E]

Or lower still. I've got 140 lb/in used mostly for sprint/hillclimb with some road and track and would probably try 130 if I were to change. However 150 is probably fine.

[ECR]

Don't forget that softer rear springs are likely to reduce oversteer ( or increase under steer) which may not be a problem for you but learn how the new setup handles before leaning on the car

[DJ.]

Alternatively, the standard springs are rising rate I believe, so you might get the best of both worlds.

I am no expert, but just a thought.

Duncan

[Pendennis]

You've got a Freestyle car haven't you?

220 is too stiff yes

[Culminator]

*coffee*Thanks for all the insight, I think I know where I'm going now. My car is indeed a Freestyle car and I've never been happy with the suspension, seems harsh and wooden and both ends and steering lacks the feel of a decently set up 7. I'm going to try 175lb on the front, instead of 250lb and 150lb on the rear instead of 220lb. 

I'll feedback the outcome. 

[BBL]

I'll feedback the outcome. 

Looking forward to that!  

[Culminator]

Ok, initial feedback is the ride quality seems far better, both front and rear. I can actually see the front suspension working now, which I couldn't before. Car rides a bit too low still and I've run out of adjusting thread on the platforms, so possibly have too soft a spring as its compressing when it comes off the jack. Will have a further think but it's not quite right and I'm concerned I can't get more than 65 mm under the sump, 130mm under the front chassis rail under the wishbone.

[Simon.Rogers]

Did you measure the wheel rate as I suggested prior to ordering your replacement springs?

If you do not know the wheel rate you may as well be blindfolded whilst playing darts.

[Richard Price]

If you've run out of threads, and the ride height is still too low, then your springs are not necessarily too soft, but they're definitely too short.

The softer the spring, the longer the free length needs to be.

Are the two legs of the bellcranks that link the pushrod to the top of the damper equal lengths?

Do you have the standard wide track Freestyle wishbones or the superwide? If its the standard Freestyle width, and the bellcranks are 1:1, then you can compare your spring rates with those used on normal Caterham wide track.

If not, then I'm with Simon. You need to calculate the relationship between the spring rate and the wheel rate.

[Culminator]

Simon, thanks, I'll give you a buzz in the week. I didn't measure wheel rate but did try and call you to have a chat. Guess i need to get to the bottom of this properly.

Richard, I have freestyle superwide. One of the really annoying things is, the AVO dampers seem to have different thread depths on them. Not sure of the history behind that but now thinking of taking front and rear off again and measuring up. With 250lb front springs, the front was solid. Front springs are 6" long and rears are 9"