Advantages of shorter springs / pre-load

[aMaff]

On the front of the Miata I've got 6.5" springs. They're a pain to adjust, as to move the collars on the GC sleeves I've got to fight the springs to get to the height I want. I'm essentially compressing the spring.

1. Is that pre-load a bad thing?
2. What advantages / disadvangages would moving to a shorter (6"?) spring give me (besides ease of adjustability)?

 

[aMaff]

no one??

 

[gavin_leslie]

Are you adjusting the collars with the car on the ground? Are you adjusting the collars upwards or down?

1: pre-load is a buzzword. Dont even bother with it.

2:Mainly spring length is a combination of weight of spring, spring rate, weight of the car, coil bind and....something else Im forgetting.

For example you had a 50/50 car that weighs 2000lbs on mcstruts. So thats 1000lbs on the front, 500lbs at the wheel. A 200lb 6" spring would compress 2.5" leaving the spring at a 3.5" compressed height. But if the coils are of a thickness that means that the fully compressed spring only reaches 3.75" tall?.. then you have no spring whatsoever. You will need longer springs than 6" so that the weight of the car does not compress the springs to the point where they become coil bound.

Same thing in the opposite. 10" long 1000lb springs on each corner will only compress 1/2" with the weight of the car. Itll be great for 33" super swampers, but you may want to get some 6" or 7" springs so you actually can get down to a decent ride height.

Something like that at least

Gavin

 

[aMaff]

Adjusting with the car in the air.

 

[gavin_leslie]

If you are compressing the spring, I am assuming you are going for more ride hight. If this is the case get some longer 8" springs. Going to 6" springs(you have 7" springs now correct?) would make the issue worse.

Gavin

 

[aMaff]

lol I couldn't fit 8" springs down there. That, or I could put a 6" spring (instead of 6.5, reading good...) and have the collar on the sleeve a half inch higher. However in either case, that would still have the spring in a 'compressed' state with the car off of the ground and probably be no easier to adjust.

 

[gavin_leslie]

Im not sure who makes a 6.5" long spring, but if thats the case of what you have, get a 7" long spring. This one is pretty easy, if you cant get the ride height you want, get a longer spring or raise the spring collar to a new height.

What spring rates are you using anyway? Most miatae use 600lb+ fronts and 300lb+ rears for competition. With 600lb springs I dont see the front of a miata compressing the springs to the point where they will coil bind, much less run out of adjustment range.

What shock(shock/sleeve) combo are you using? Konis? Do they have a circlip to mount the adjuster sleeves? Are there multiple points of attachment for the circlip (like VWs or Hondas) to adjust the ride height?

Something is amiss. What is it?

Gavin

 

[apexlater]

If you are already compressing the spring now, you will need a shorter spring in order to raise the collar more. You can only raise the height of the car as far as the shock will travel on a given spring length. If you are already compressing the spring and you raise the perch, then all you are doing is compressing the spring and not raising the ride height.

Granted, you will a little since the spring will compress once it is static loaded.

Hmmm...the more I think about it, maybe you should look into some shorter bumpstops also.

What you need to do is figure out your shock travel with your given spring rate and go as short as you can without binding the spring, then you can raise it up.

Sigh, I'm going to have to get you over to our scales pretty quick huh....so you can figure out the corner weights and loads and such.....

 

[aMaff]

That's along the lines of what I'm thinking. My bumpstops are pretty short right now actually. hopefully not too short lol

Im not sure who makes a 6.5" long spring

Eibach does. Ever heard of 'em?

 

[gavin_leslie]

Actually I have heard of eibach. I have not seen a 6.5" spring from them however. Perhaps this is a specific application that I have not seen or a new item. Either way, Thats not terribly relevant(except to say that your choices will be 6" springs or 7+" springs)

You still havent answered the question I asked in post #5. Are you raising the car or lowering the car? What is it that you are trying to attempt?

The implication that you give by saying you are compressing the spring is that you are attempting to raise the adjusters(increasing the cars ride height). If this is the case, then shorter springs will only reduce the amount of threads that the adjuster can move upwards.

PS: what of the other questions I posted?

Gavin