Yes, preload matters even on a linear spring. It does nothing to the spring rate, but it will change the dampening characteristics of the shock. Different preload will affect the travel of the shock. From what I have read, you never want to have a setup with zero preload even with linear springs, i.e. you never want to completely top out the spring.

Do these coilovers have dampening adjustability? I have worked more with dialing in motorcycle suspensions, so this may not be relevant. But when adjusting suspension and making those measurements, it might have mattered if you had rebound on the shock. It might prevent it from fully extending and giving you a true measurement. I was going to tell you to take all the rebound out of the shock before you do preload adjustment. Not sure if that has any relevance. Obviously motorcycles are easier to set up than cars most likely haha

 

Thx for the response man. I did a lot more reading and yes indeed, the preload will affect the dampening in the sense that you will get a proportional amount of reduced shock travel to preload.

With this said, I still fussed the the suspension according to the Tein diagram and whether I was drunk when measuring (it's a joke I wasn't) or some type of a fluke, but those measurements suggested by Tein didn't work out at all! The amount they ask you to put on preload (290mm front / 255mm rear from bottom bolt/hole on the strut to the base of the spring seat lock nut) is way too aggressive, but get this, only for certain wheels! It was a session at the gym trying to get that the lock nut to sit that high as the spring and shock was fighting with all it's might for my passenger front and the passenger rear wasn't a walk in the park either.

When I took it out for a test drive, horrendous results. Over a speed bump the front passeger wheel would ricochet violently back towards the ground due to the amount of preload.

Besides the fact i raised and lower the car at least 5-6 times and taken wheels off my car countless times now (holy crap a garage lift would have been a gift from jesus) to get the rear not to rub because I'm not rolled aggressively enough, I spent the entire night last night again raising and lowering another 6-8 times and redoing every single coil again! $%#%@#$@$@$

This time ignoring Tein's set "A" value but just getting the spring to sit with 0 preload (turning the bottom perch by hand until tight and spring snug without tension), then going 7 turns up in the front, and 6 turns up in the rear which gave the spring a solid preloaded seating without breaking my back (which was about 10 turns up).

I haven't gotten a chance to test out the car yet due to rain these few days but will chime in my results. Hopefully my wheels will rebound correctly like a regular car now and also the clunking noise from the rear right strut will stop (when I back up and put in 1st gear to move forward, there was a loud clunk sound).

 

Hi, I'm interested to hear more about TEIN Type FLEX and preload/heigh settings, I got the same suspension and since I readjusted the heigh I also added 5 turn of preload rear, 9 front and I'm planning to remove some as I don't like how the ride feel with so much preload.

Can anyone having played with preload with TEIN Flex suspension chime in ?

thanks for pointing out that TEIN reference settings are wrong as I was going to try to go back to these instead of the reference I writen of the previous heigh

 

I was going to buy Tein Flex also, but now im worryid ;(

i have written to Tein, and given them url to this post, they need to sort this out, it cannot be accepted that the installation info is bad..

I also like to hear from you that got them installed, and spend all this time trying settings what you end up whit to get a nice ride settings

 

I have Tein Flex and in the front put on the OEM bump stops to remedy wheel rubbing issues. I had no problem using the Tein reference settings but did move away from them slightly.

 

Japanese Tuning in Plain English

There's no such thing as the "correct setting", each car varies and each driver will have a different preference. There's also nothing wrong with TEIN's reference settings, they provide a good starting point. No matter what model car, all the TEIN's I've ever installed have required more preload if any at all.

Without being too technical... the lower it goes, the more preload I will apply... It's not a golden rule... that's just what I always end up doing. Less preload will produce a bouncier ride and to reduce the bounce or reduce the shock travel, you need to increase the preload. If your tires are rubbing the fenders, then you are either/and/or way too low, wheel offset is incorrect, tires are too big.

Yes, increasing preload is not easy... that's why the TEIN "tool" has a 1/2" square socket on the handle so that you can insert a 1/2" drive rachet or breaker bar for added leverage. It also helps to air blow or brush the "Seat Lock" threads clean of any dirt and spray something on it to lubricate the threads.

When I took it out for a test drive, horrendous results. Over a speed bump the front passeger wheel would ricochet violently back towards the ground due to the amount of preload."

Determing your suspension setting based on how it reacts when going over a speed bump makes no sense at all. If your suspension is reacting violently over a speedbump, then you're simply driving over speed bumps way too fast. If something is clunking then something is moving loosely... inspect for it and correct it.

I would think most JZ80's will be comfortable with rear preload measurements (A) somewhere between 10" to 11.5". Last Supra I did has 4 audio amps, 3 10W7's and dual full size batteries in rear. With a full tank, the final rear settings were approximately:

A = 11.5"
B = 14.5"
C = 3.5" (this Supra sits higher in the rear than most would want)
D = 6.5"