Does it rub?
We see this question asked and answered every day in online forums with respect to wheel-and-tire packages, especially when it comes to lowered cars.
The answers often provide conflicting information due to varied alignment, ride height, spring rates and coil-over packaging. Having the right combination of parts on your car is only half the battle. Dialing it …
What is the spring rate of your helper springs? Is it actually enough to overcome the shocks rebound control and keep that tire in contact with the ground over bumps/dips when the effective spring rate for the combination main/helper in series is so low when the helper is not locked out?
Bumps stops as suspension, that will never work.
Mmm Tom, don't you race a Formula 500?
(sorry couldn't help it).
I always thought it was better to put helper springs (especially the super-soft ones you can compress with your bare hands, not so much a concern with the thicker/stiffer ones like in this article) on top of the main spring so that the weight of the spring itself isn't pressing on the helper spring, unless the car is in negative Gs which should never happen. I worry that when the shock is fully extended the main spring might compress the helper spring a bit with its own weight and float off its seat.
Also it's relatively easy to make snap-on shims of different thicknesses you can install or remove from your shocks with almost no disassembly, Delrin is a great material for this:
adam525i said:What is the spring rate of your helper springs? Is it actually enough to overcome the shocks rebound control and keep that tire in contact with the ground over bumps/dips when the effective spring rate for the combination main/helper in series is so low when the helper is not locked out?
Dampers are time-based so any amount of spring force will eventually extend the damper. We found that it worked fine over the bump/dips at our local track...which is know for being quite bumpy (I should post a video...you'd be shocked. Oh, look what I just did there :) )
Here's some 411 from Chris at Redshift. We are only running the low rate helpers. He also sent some higher rate helpers which we'll play with at a future time.
Swift is sending the following springs:
H65-060-015 (x2) - these are 1.5k helpers with spring adapters which can be used front or rear.
H65-060-030 (x2) - these are 3k helpers with spring adapters which can be used in front.
Generally helpers/assist springs are either almost no rate or they are 20-30% of the main spring rate and can be engaged while the car is in motion. So, I am sending 4 helpers along with the 203L 5k springs. 2 helpers are 1.5k and would work well in back but can also be used as low rate helpers for the front. The other 2 helpers are 3k and would be a good match for the front. So that gives you some options.
The higher rate helper will engage earlier, but when it does, the combined spring rate plummets (non-linear) and changes how the car feels. So the 3k spring on the front may engage at times depending on swaybar, etc.... and it could help the tire stay in touch with the ground but will do so at the expense of doing it at a lower rate, and the balance of what helper spring rates to use is best done through testing.
GameboyRMH said:Also it's relatively easy to make snap-on shims of different thicknesses you can install or remove from your shocks with almost no disassembly, Delrin is a great material for this:
Yep. Commonly called "packers". And the print version of this story has a follow-on with commercial sourcing for these and other dial-in bits.
In reply to Andy Hollis :
Thanks for the follow up! Very helpful.
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