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Old 01-24-2012, 07:52 PM   #1
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Default Spring unseating at droop

Rear springs unseat at full droop with a full 1.5" of play. Before I spend my limited Challenge budget to fix this, is it a problem? My concerns are:
1. Unsettling the car upon compression if the suspension is unloaded to the point to unseat the spring
2. Potential damage to the coilover sleeve, top hat, or spring perch.

I looked at tender springs, but they're expensive on my challenge budget, particularly the coupler ring prices are out of control.

I haven't installed the front springs yet, as I didn't want to install to possibly immediately remove and disassemble them.
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Old 01-24-2012, 07:57 PM   #2
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http://forum.miata.net/vb/showpost.p...6&postcount=21

Warning: no personal expereince, and I am also interested in this topic.

I think generally its acceptable, but it still scares me.
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Old 01-24-2012, 08:12 PM   #3
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Old 01-24-2012, 08:37 PM   #4
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I approve of your supplier. I knew Jeff when he was first starting up. Spent a lot of time at his shop

Me when I was 16:
http://www.240sxmotoring.com/dacls13bl.html

/ threadjack
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Old 01-24-2012, 09:24 PM   #5
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My springs do this on my track car and soon on my daily. The shock is "damp" so it will never, ever extend unless you jack the car up for a long time. When you're driving you have the force of the shock that will almost always hold the spring on the perch and the sway bar to do the same.
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Old 01-24-2012, 09:29 PM   #6
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Quote:
Originally Posted by y8s View Post
Those are a little different from a spring that does "real work" with a touch more spring rate, and he should not buy them.
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Old 01-24-2012, 09:45 PM   #7
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I don't actually believe spriings in this condition come unseated.
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Old 01-24-2012, 10:08 PM   #8
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There is no doubt there--the spring is completely free floating at full droop with 1.5" of clearance. That means that there is no spring pressing tire into pavement at droop, and there is nothing keeping the spring aligned until after initial compression after droop.

The data I've been harvesting seems to point in the direction of that it's a workable solution, but adding a tender spring would be more ideal.

Maybe I can find a cheap enough lathe to cost justify buying the lathe and material vs purchasing off the shelf retainers. I don't see why they're so expensive.
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Old 01-24-2012, 10:31 PM   #9
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if your on a tight budget.... not saying its the best plan but could do a simple limiting strap right at the limit of the spring fully unloading

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Old 01-24-2012, 10:45 PM   #10
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I'm sure that DIYautotune is owed a favor by SOMEBODY with a lathe who can let you make some coupler rings...

Last edited by vehicular; 01-26-2012 at 12:09 PM.
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Old 01-24-2012, 11:59 PM   #11
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Quote:
Originally Posted by Ben View Post
There is no doubt there
We're not saying it can't happen, we're saying it won't happen. Unless you're driving on two wheels for an extended amount of time.
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Old 01-25-2012, 02:08 PM   #12
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Quote:
Originally Posted by curly View Post
We're not saying it can't happen, we're saying it won't happen. Unless you're driving on two wheels for an extended amount of time.
The sway bars even do a pretty good job of holding the inside suspension compressed if your on two outside wheels wheels. It would take doing an extended wheelie, nose stand, or going 4 wheels airborn to unseat them while driving. It is pretty annoying having to get the springs to re-seat everytime you jack up the car however.

The zero rate helpers wont do anything for performance. Helpers with some rate to them might help a little for traction when bouncing of FIA curbing and stuff like that. It takes some spring force to actually overcome the damping, swaybar, and friction forces to actually push the tire back in contact with the ground when the inside tire becomes airborn.

Bob

Last edited by bbundy; 01-25-2012 at 06:44 PM.
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Old 01-25-2012, 02:18 PM   #13
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Quote:
Originally Posted by curly View Post
We're not saying it can't happen, we're saying it won't happen. Unless you're driving on two wheels for an extended amount of time.
Yes, I'm suggesting the tire doesn't extend further than the length of the uncompressed spring due to many factorz. Basically you just lose droop travel.
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Old 01-26-2012, 09:55 AM   #14
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Do you plan to jump your car? If you answer "No" then don't worry about it.
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Old 01-26-2012, 03:14 PM   #15
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i work on a second gen rx7 gt4 race car that runs bilstiens and has this same condition and in the past 7 years of traking the car it has not had an issue with the springs coming unseated while driving.
http://www.abrracing.com/
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Old 01-27-2012, 12:03 AM   #16
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No worries, I have the same thing its about an 1.5" of droop, maybe a tad more. No problems whatso ever on track. This is with both sides jacked up, so both have to be at full droop for it to even be a consideration. Once you weight the other side down, the sway bar should do the rest.

If you suspect otherwise, you can move to a stiffer sway and/or shorter endlinks. But then you have to be careful, because if you have enough grip you may lift one of the rear tires.
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Old 01-27-2012, 08:55 AM   #17
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Quote:
Originally Posted by Track View Post
If you suspect otherwise, you can move to a stiffer sway and/or shorter endlinks. But then you have to be careful, because if you have enough grip you may lift one of the rear tires.
I got time to install one of the front assemblies. Looks like at full droop I have 2" play front and 1.5" rear. That is with all 4 off the ground.

This is my Challenge suspension package, so budget is very sensitive. I would like to fab new sways and links, if I can fit them into my time and budget constraints.

Tires will be 205-50-15 Hoosier SM on stock wheels. Should be a decent amount of grip, considering the narrow wheels. I haz Torsen in this car, so lifting a wheel is failboat.
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Old 01-27-2012, 09:52 AM   #18
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doesn't sound like you will lift (I think you have to run a really stiff rear bar, maybe a FM on full stiff or something). I have the 949 endlinks, and 5.25" ride height on track. On full droop, if I forcefuly push on the tire, I may just be able to move the spring by hitting it.

I seriously don't think you will have any troubles if you are running a comparable set of swaybars to your springs. I am on the stock endlinks+sway bar in the rear (99 NB, 11mm), and I haven't had problems. I will say I still run street tires, 205/50 star specs and soon to be AD08s.

then with 205 hoosiers, I don't think you will have problems. Since you are on a budget, I would try it out first before worrying too much. I also don't run spring locators, so I would be more likely to have trouble anyway.
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Old 01-27-2012, 10:07 AM   #19
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Go buy a plastic cutting board and make some spacers, stack them up to fill the gap and glue them together and put them under the springs...just keep in mind this will raise the car up.
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Old 01-27-2012, 10:28 AM   #20
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http://www.carbibles.com/suspension_bible_pg5.html


Video rear shock under car. Miata running autocross no rear swaybar. I don't know anything else about the setup.
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