Shorter Coilover Springs

[dionkouki]

After a couple hours of searching I still haven't found an answer to what I'd think is a common question.

Swapped out my coilovers but the new ones dig into my front tires at the spring perch. They currently use a 7" spring and if I could swap it to a 6" spring it would clear fine. Is this a big no no?

I spoke to the company and "they can't recommend" going to a shorter spring. Is this just a CYA or is there a good reason someone knows of? If I remember the Swift spring chart correctly the 7" have a usable stroke of 3.8" and and the 6" a usable stroke of 3.5". 0.3" doesn't seem like anything to be concerned about. Also assuming since they're linear springs no valving adjustments would be needed. Only piston length if it exceeded the 6" springs travel stroke.

Already tried camber bolts with positive camber maxed and they cleared with 1mm clearance, not really a good safety margin.

5mm wheel spacer in addition to camber bolts would do it but then I'd have to have the fender pulled a little. Would rather not increase negative camber since I already have some inner tire wear. Plus wheel spacers, extended lug studs, and fender pulling would be over $100. Changing springs would be free since I already bought softer springs (7k/5k) and can exchange them.

Setup info:
S14, 17x9 +30 with 255/40/17. 1 finger wheel gap. Street use only at this time.

Thanks in advance. I wanted to cry when I had to put my old coils back on.

[Croustibat]

You are reducing the usable stroke. as long as you don't need more stroke than the sping can give, and the spring does not bottom out, i can't see a problem with it. but you have to make sure not to use more than what you already have.

Anyway there is the right way to do it, i.e pull fenders and use wheels with lower offset or smaller tyre, and the wrong way to do it, which is add spacer, camber bolts maxed in positive camber, and shorter spring.

Yes, one is "free" now. But there is always a price, and blown shocks or distorded springs because you ended up using the stroke you don't have will make you cry.

Your main problem is wrong wheel and tyre combination, so fix that. Get +20 wheels, or 235 - 245 tyres.

[dionkouki]

I appreciate the comments. I'll have to look into the usable stroke more. Shorter spring seems to be the "right" way to do it in this case IF its not shorter than the damper stroke and I may not even need the camber bolts if I go this route. Its disappointing that the zeals have a smaller offset from strut to knuckle and an oversized spring perch compared to the old teins.

Unfortunately if I went with a narrower tire up front I'd have to do the same to the rear to stay square and I already have traction issues at wot. If I went with a staggered setup I'd be increasing the rear

Anyone have experience running a shorter spring? Regrets? I'd even be willing to raise the car a little instead of getting shorter springs but my rear is as high as I can safely go and if I raised the front without raising the rear more I think bit would be imbalanced but I'll look into that option as well.

[e1_griego]

How much camber are you running now? 5mm spacer seems like the answer. 9 +30 will never really fit on the front of an s-chassis because of inner clearance. 9 +25 should fit though depending on the coilover you're running.

[dionkouki]

-1.1 camber. Funny thing is with my old teins everything fit perfectly. Im running r33 gtst brakes which I believe have a higher offset rotor than the stock rotor which makes up for the wheel spacer. The zeals now have shorter knuckle to strut distance plus an oversized spring perch. About 1/4" larger than spring. If it was the same as spring diameter I'd be fine. If I run a 5mm wheel spacer now the tire will hit the fender during suspension travel. So either more camber which I don't want since I'm already seeing some inner camber wear or pull fender.
I did come up with another idea. If I add helper springs it may lower the perch down below the lip of the wheel. I'll have to measure and find helper spring compressed length.

[e1_griego]

-1.1 is not killing tires. You can go to -2 at least without any problems.

[dionkouki]

I agree. I could go a little more. Was saying I can see camber wear with current camber setting and don't really want to increase the problem. Wheel spacers plus more camber is an option. I'd prob choose that over pulling the fender at this point.

[e1_griego]

You probably have toe issues if you're seeing tire wear. -1.1 isn't hurting the tire.

[!Zar!]

I agree. I could go a little more. Was saying I can see camber wear with current camber setting and don't really want to increase the problem. Wheel spacers plus more camber is an option. I'd prob choose that over pulling the fender at this point.

Your toe is killing your tires.

[dionkouki]

I wondered about that but last time I checked I was running almost 0. Almost non existent toe in. I'll have to look at my recorded numbers.

[dionkouki]

I gathered some more numbers and did some measurements.

Measured piston stroke at 80mm
Current 7" Swift 9k has a usable stroke 87mm and max stroke 113mm
New 6" Swift 7k has usable stroke 89mm max stroke 96mm

When I look at the numbers it seems I should see no difference in ride quality or suspension travel due to the shorter spring. Same usable stroke and though the max stroke is shorter it's still much larger than the piston stroke which would hit it's bump stop first. Am I oversimplifying it? If I were going to a shorter 9k spring then yes my usable stroke would be reduced to 78mm but dropping to a 8k or 7k would still put me above the piston stroke range.
When I called Endless the person I spoke with said the shorter spring would definitely change how the car felt. Can anyone explain it to me since I can't find any in depth info on this. Thanks.

[jedi03]

It's they way the coil is wound and compressed to achieve same travel distance usually a shorter spring would be a lot stiffer...I am using pbm sll springs and it rides way stiffer than my buddies car with their lower end longer spring...

[dionkouki]

Are you running stiffer spring rates than your friend?

Maybe I'm misunderstanding but I thought that swift springs being linear would feel the same regardless of length. In the example of a 7k spring if 392lbs are applied it will drop 1 inch regardless of length. The only difference being the total usable stroke. However the damper stroke is shorter than the usable stroke of both the 6" and 7" spring so the extra usable stroke of the 7" spring is going to waste with this damper. If the springs were both allowed to go their full stroke than the longer spring would have the advantage of a higher maximum load which is reflected in the swift spring chart. (1486lbs vs 1785lbs)