Suspension Tuning: Coilovers

1778 Views 11 Replies 5 Participants Last post by  Matt [exz3owner]
I'm looking for places/books to read up on about suspension tuning. I have Tein Flex and want to get the best performance possible out of these coilovers. From reading other threads about coilovers, I've heard a lot of things regarding coilovers with the abillity to pre-load the spring. IIRC, there was something about the right and wrong way to use the pre-load.

If anyone has any reference links or book titles, please share them(I know there is one really good book out there, but I can't remember the name of it).

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The basic rule of preload is don't get too caught up in it.

Here's some info tha I've found very helpful: <---Excellent discussion <<---General suspension tunung <--yes, its a bike, but physics is physics.

Icehawk from seems to have done the most research on the Flexes. <---Page 16
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preload is over rated.
^^Werd. More marketing hype then anything.
ok ok... preload asside. Any other info?

Anyone remember the name/author of the book that I still can't remember the name of? It probably had "suspension" in the title... #-o
I have had my Tein Flex's on the car for almost a year, I'd be happy to provide you my settings which have worked for me and why. PM me if you're interested I have a lot of documentation... (I do it for a living so its easy, umm documentation that is) I'm actually writing a working paper for my team on suspension tuning since I have been the first to venture away from lowering springs to coilovers. There are a lot of different things to adjust but the majority of it depends on the conditions and your driving style/ location etc. Trust me I wish there was one definative SOURCE for suspension tuning. But if there was... Crew Chief's and Tuners in racing would never make any money.

That being said I'd be happy to share my baseline with you.
You will want to read every book by Carroll Smith. And then you can decide for yourself if preload is marketing hype or not.
I'm not saying there is no such thing as preload. I'm just saying that there are soooo many mroe things that make a larger difference to worry about first.

damping curves
spring rate
bump vs rebound
tire choice
tire pressure
front end ride hieght
rear ride hieght
areo work
suspension travel
sway bar stiffness
diff settings

all of these matter more than preload. If you get all of these right, then maybe that is what is holding you back.

In my experience, tuning suspension isn't something you can learn from a book. Its about the feel of the car and understandign what changes effect how it behaves.
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And I'm not trying to discredit anyone. I just don't like blanket statements like "marketing hype" or preload is over rated. How do you think that comment sounds to someone asking a legitimate question?

Yes, there are other things to be concerned with maybe preload isn't at the top of the list. I personally don't like my springs to become unseated at full extension so I put in a little preload.

No tuning suspension is not necessarily something you can learn from a book, but a book is a pretty good place to start. At least he can learn basic cause and effect. Then he can take that cause and effect theory and put it to use at a test and tune or his favorite empty parking lot.
And I'm not trying to discredit anyone. I just don't like blanket statements like "marketing hype" or preload is over rated. How do you think that comment sounds to someone asking a legitimate question?

I personally don't like my springs to become unseated at full extension so I put in a little preload.
Which is exactly what I have mine set for. Glorified helper-springs.

In my first response I listed some very technical links for him to research on his own (and I can list more). It's up to him how far he wants to take the information. Like Matt said, there are other things you need to worry about first before seeing if 1mm of preload adjustment makes any difference to your driving style.

Like I said, don't get too caught up in it.

DRFT MX5, I'd be happy to see what you have done!
PreLoad is defintely not the main point I'm aiming at. It was merely an example, to get more depth than just the basics. I get what you guys mean, and on a level I want to learn everything suspension related, but I just don't have the time or resources

I've got the books coming soon, and I'll be reading up on those when not by a computer.

I purchased the Tein Flex on a review basis, much by what has been stated here (Also the good deal I got on them ) :mrgreen:

DRFT MX5: I'll definitely contact you for the information you mentioned.

Thank you all for your detailed replies, I have a much better scope of the things I need to look into. :D

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Dlad you got what you are looking for.

I know this wasn't your question, but here is a little more background on where all the JDM hype on preload comes from:

In japan, there is a "road legal law" which states that at full droop, the spring can not become unseated. There are 2 ways to address this: adding helper springs, or adding just a tad of preload. Most cheap(er) coilovers manufactures chose the more cost effective route and started to add preload. At time attack style events, there were a couple cars that inspite of the reduced travel from preload layed down some impressive numbers. Thus the hype was born.

If your springs are linear, which 99% of coilover springs are, preload does not effect spring rates at all. The only thing it does is reduce your droop travel and limit wheel motion. On an EXTREMELY smooth track, you can tune this to be very fast (but unforgiving). However, I haven't been on a track in the US that this would apply to, and it definately doesn't apply to street driven cars.

So there you go. A slightly longer explination than "its marketing hype". Now maybe you can see why the false concepts exist.

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