pre load


R

rayy

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Jul 9, 2009
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i was wondering would having pre load on coilovers make the car even stiffer?
as iv just brought a yaris t sport with D2's with 16inch gt3 with 195 40 toyos and the ride is so crashy i have to drive like 1mph every where,

i had a look at the coilovers and it seems that there is hell of alot of preload on it, i had to wind the spriong down a good inch to start to be able to spin the spring freely

will putting zero preload help the ride and comfort?
thanks
 
Well d2's are known to be harsh enough but you are running 40 profile tyre so that wont help either
 
i used to have a set of d2s on my jordan with 55 tires they seemed fine, iv swop the old wheels back on the yaris which are 15inch with 55 tires and its made it better but it still seems very very harsh, but im goin to take all the suspension off and reset them as see how they are
just wanted to know if having preload will man it even stiffer
 
Have you tried winding the damping back?

If the damping is set too high then it will feel crashy as the dampers are rebounding too fast and not actually damping the ride

High spring rates/preload don't mean crashy, they just mean stiff
 
stevenEK9 said:
Have you tried winding the damping back?

If the damping is set too high then it will feel crashy as the dampers are rebounding too fast and not actually damping the ride

High spring rates/preload don't mean crashy, they just mean stiff
Click to expand...

If we want to get technical, (I always do :)) ) the increased damping actually makes the damper rebound slower as what you are actually doing is adding a compression force to the rebound stroke. This can be witnessed as the suspension 'jacking down' on full stiffness as it doesn't have time to fully rebound before the next bump.

Damping is definately a culprit of a crashy ride though. Sadly D2 dampers aren't renowned for being especially great...
 
^^ i want to hear more.

Explain How making your damping "stiffer" will affect handling, Positive and negative effects if you could as you seem clued up on the tech side of things :)
 
It's a fairly involved subject, I amassed my knowledge on suspension tech over quite a few years, so it's difficult to sum up in a few lines. It really requires quite a lengthy explanation but I would be happy to write one up one evening, I'm sad like that... :D
 
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I look forward to reading it!

Make a thread about pre-load & Dampening :)
 
Here is my take on the easy explanation:

1. Springs Rate control how MUCH movement your suspension will have, Damping Rate control how FAST things happen.

When you increase the rebound rate of a damping, you SLOW the movement down.
So you have less weight transfer, and a harsher ride.
If you have alot of rebound force and are going over a series of bumps, the damper actually hold the wheel in the air so your will momentary lose traction as your wheel are not in contact with the ground before the next bump hit.

This is why you see alot of JDM coilovers with stiff damping skip over the uneven road surfaces we have in this country... the rebound rate is too strong on those dampers.

If you have a very hard springs and not enough damping force, then when you hit the bump you car will oscillate up and down as your damper are not strong enough to control the movement of the springs.

The way I setup the suspension is use as soft as a springs you can get away with... then use the damper to make the fine adjustments and the overall chassis balance.

So for roads use, the soft springs may be 6kg/mm or 8kg/mm, where for track use, the soft springs may be 16kg/mm
 
thanks for the input, the d2's just have hard and soft damping setting no rebound setting, so if i just set the spring to zero preload and at its softest setting will it mean il have less of a crashy ride?

i cont get the power down on to the road if the road just ever so slightly bumpy, it seems like when i go over a very little bump the wheel seems to be lifted up meaning theres not weight on it to give it traction, so i can be accelerating hard and the revs can shoot up till i regain traction this can happen in 3rd and 4th gears and its only a 1.5 so no the most powerful engine
 
Most of the adjustment on the damper are rebound adjustments.
If you set your springs to 0 pre-load, that is as soft as the springs will ever get.

After that, put your damper on the softest... find a bumpy road that you know and drive over it.
Your car should move up and down after hitting the bumps as there aren't enough damper force to control the springs.

Keep putting the damping harder slowly until that movement are controlled.

However, it may be a point where the damper become so hard that it no longer give traction after hitting a bump.

In which case, it is just because the spring rate is too hard and it isn't a good match with the damper adjustment range for the surfaces you are driving your car on... and there isn't much you can do at that point on.
 
So a JDM damper with very hard springs on, which may seem a bit "bouncy" or "harsh" on daily driven roads & Kick a wheel up on big bumps may actually be very good on track as its alot smoother surface ?? As its fixed damping i assume its fixed at a hard end of the spectrum as its JDM Dampers & Not designed for theese shite roads ?

What is the maximum spring rate you would recommend for track on your ZetaR coilovers?
 
NeilVtec said:
So a JDM damper with very hard springs on, which may seem a bit "bouncy" or "harsh" on daily driven roads & Kick a wheel up on big bumps may actually be very good on track as its alot smoother surface ?? As its fixed damping i assume its fixed at a hard end of the spectrum as its JDM Dampers & Not designed for theese shite roads ?

What is the maximum spring rate you would recommend for track on your ZetaR coilovers?
Click to expand...

Well... yes and no...
It also depends on alot of things... weight of the car, tyre compound, etc....

We find very hard suspension on road tyres will just load up the tyres quickly causing it to loose traction.
A softer springs actually put the load on more progressively leading to more traction actually.

Don't forget... even the track here isn't truly smooth.
Tracks like Lydden Hill and Brand Hatch actually have bumps on the track that can unsettle very hard suspension... where softer suspension will soak up those bumps.

I wouldn't really use anything more than 12/10 on the Zeta-R mainly because the window of adjustment get smaller and smaller as you use harder spring rate (because you will need to use the harder damping range for the harder springs rate).

End of the day... the suspension work as a package...
When you drive it and it feels good and you are confident with it, then that is the best package.

And if you feel improvement can be made, then make adjustment as necessary.
But remember like everything in car, it is always a balance.
Where you improve in one section of the performance, it will almost always make another section worst off.
 
well sorted the preload out on the car today there at least 1 3/4inch of preload on the spring it made the ride alot better but now the springs wofter when i put the car on the ground its lowered the car back a fair bit to the piont when i put full lock on the tire touches the fender

i cont seem to get the lower locking coller lose iv tryed everything iv try banging it with a hammer and c spanner and screw driver method no luck any other tips?
thanks
 
Get something over your C-spanner, When my old teins seized i got some old bike handle bars (any bar will do), hit the end with a hammer so it became oval and slotted over my C-spanner, That way you can get ALOT more torque on it and what seemed impossible to move was made pretty damn easy :) All about extra leverage!
 
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