When to replace Bilstein springs

[Rygar]

I have 2 leaking rear shocks at the moment on my 2005 111S. I was thinking of getting get all 4 rebuilt while I'm at it. What im wondering is, do the springs need replacement after 14 years? and if so would it be a better option financially to go for new NSS?

[timbo]

A decent shock rebuild company should have a spring rate tester, so you could get them to check them out (assuming you know the spec to compare data against). Also look at overall condition, whether pairs (front, rears) are still same length, etc.

[Rygar]

I was going to get them done with bilstein so I guess they will advise of condition. 

I would nearly spend the extra few hundred to get new Nitrton street series but I really like the oem level of comfort. I still can't find any definitive info online as to whether the NSS are an improvement over the bilstein and if they can be set to a comfortable road setting

[The Cakes]

From what I’ve read, street series aren’t great on the road in comparison to Bilstein. If you’re prepared to go up the next level Nitron NTR, which I have on my Exige are great and absorb bumpy roads quite well, certainly better than Bilstein on the correct setting. Don’t ask me what my spring rates are as I can’t remember. 

[Rygar]

Maybe Il just go for the rebuild. Budget doesn't stretch to the ntr's. If I thought I could achieve the same ride as oem with the nss and also give a very slight drop in ride height then I'd definitely go down that road, but as you say it doesn't seem to be the case.

[Broadside]

Springs are pretty cheap in relation to dampers, so if you think they're ready for change they probably won't break the bank.

[Jonathan E]

If it was me I’d go with the Bilsteins, Never been impressed with street series and have removed them from two previous cars, in fact the one set were only 18 months old and were in a terrible state. Bilsteins will also last longer.
 

 

[Martin R]

If its just for road use, stick to Bilsteins no question. Not surprisingly Lotus do know a bit about ride and handling. New Bilsteins and a decent road geo when funds allow would be my advice.

[Rygar]

Finally got around to removing the old shocks and springs. They are a bit tatty looking but hopefully it's just surface corrosion where the paint has lifted. They are being shipped off to Bilstein in Leicester for a rebuild. Will see how it goes.

[DeanB]

Just seen this thread. Good advice from Martin and the guys.  I have Street Series and they are rubbish on the road.  Oem Billies are great.

[winthattt]

Ferrous springs should never wear out if they don’t go beyond their yield point, if you take them past the yield point they will wear out very quickly.  If they do fail it will be from corrosion or damage.   They don’t sag either, bushes and the like may wear and people blame the springs.   They can look horrid with corrosion, but new ones look the same pretty quickly, at least eibach and Nitron ones on my cars did.