bump springs

[riddle28]

Thanks man I’ll check those out now

[Matt49]

This is what I had in my head and it may be completely wrong:
Take a block lead that weighs about 10 pounds figure out how to attach a bump stop to it.
Then take another block of lead the same weight and figure out how to attach a bump spring to it (one that achieves the same load numbers your looking for at your travel). No drop both of these from about 6 feet in the air so they both land on the bumpy side and see which one bounces highest. My guess (and it is just that, a guess) is that that you better have your head on a swivel for the bump spring one to hit you in the jewels on the way back up but the one with rubber bump stop is going to put on far less of a show.
If anybody decides to actually do this, please video and post for educational and comedic purposes.
But in all seriousness, this bounce is exactly what the shock is attempting to control for maximum grip. So if I'm right in my guess above, they would require drastically different rebound curves to achieve critical dampening.

[TheJet-09]

I'm starting to worry about you Matt, with your test procedures for aerodynamics and now bump springs! Lol!

Good information overall though.

[billetbirdcage]

This is what I had in my head and it may be completely wrong:
Take a block lead that weighs about 10 pounds figure out how to attach a bump stop to it.
Then take another block of lead the same weight and figure out how to attach a bump spring to it (one that achieves the same load numbers your looking for at your travel). No drop both of these from about 6 feet in the air so they both land on the bumpy side and see which one bounces highest. My guess (and it is just that, a guess) is that that you better have your head on a swivel for the bump spring one to hit you in the jewels on the way back up but the one with rubber bump stop is going to put on far less of a show.
If anybody decides to actually do this, please video and post for educational and comedic purposes.
But in all seriousness, this bounce is exactly what the shock is attempting to control for maximum grip. So if I'm right in my guess above, they would require drastically different rebound curves to achieve critical dampening.

You don't need to put 10# on top of them to get a fairly accurate assumption, just drop both of them.

[TheJet-09]

Hopefully not high jacking too bad, somewhat related, but I'm new to actually being able to put a number (force) with travel. My question is, at say 3 1/2" of travel on the RF, if one set-up (shock/spring) I have with a bump is only at 1680 lbs, and a second set-up I have is right at 1900 lbs, is that enough you would notice a difference on the track (at least to the driver)?

Or I guess, how sensitive to change around that travel does any set-up need to be to make a difference?

[Punisher88]

I'd say in certain track conditions the higher number would go in the corner and want to shear traction on the rf and push the nose. And the lighter one won't. But that's on slicker conditions. On a tacky track you'd probably want the higher number and dif the nose on the softer.

[TheJet-09]

Okay. So along those lines, I've also heard that you can start with the bump engaging at say 2 1/2" of travel when the track is fast, then when it slicks off remove some shims so it engages later (say at 3" of travel). Is that to keep the RF soft for a longer time to aid in its turning ability (and because there is realistically less force going into the corner when slick as opposed to heavy)?

Thanks for any and all input, everyone!

[7uptruckracer]

Its because the track has slowed down so the force that travels the car is less. Your goal is always max travel. So you need to take shims out so it still travels to your max number.

Okay. So along those lines, I've also heard that you can start with the bump engaging at say 2 1/2" of travel when the track is fast, then when it slicks off remove some shims so it engages later (say at 3" of travel). Is that to keep the RF soft for a longer time to aid in its turning ability (and because there is realistically less force going into the corner when slick as opposed to heavy)?

Thanks for any and all input, everyone!

[TheJet-09]

Makes sense. With that in mind, is it fairly guaranteed that an adjustment to the LR will then be necessary when taking shims out of the RF, to keep the car tight enough coming off the corner?

Thanks.

[MasterSbilt_Racer]

Makes sense. With that in mind, is it fairly guaranteed that an adjustment to the LR will then be necessary when taking shims out of the RF, to keep the car tight enough coming off the corner?

Thanks.

If you lose rf travel because the track is slick and then take your bump stop further away from the shock body to compensate, you potentially lost a whole lot of dynamic wedge. I don't want to talk to much about what to do specifically, but certainly you need to do something.

[TheJet-09]

Excellent! That makes me think I at least understand what I have experienced, so still very helpful.

Thank you!

[7uptruckracer]

Its Definitely a slippery slope. You want max travel but the correct load. Softer ride spring well get you to your bump. I've seen guys run a spring rubber on the ride spring and remove rubbers and keep air gap on the bump the same as well. Its not just final load but also the timing off it all too. It can make your head spin. On asphalt if we find a bump load that works we change ride spring load to control travel distance. If i engage my bump 3/4 and I go elsewhere and i don't have the same engagement or too much engagement i change the ride spring. Smooth tracks you can run harder bumps and hold your aero platform rough tracks you cannot because you spike loads.

Excellent! That makes me think I at least understand what I have experienced, so still very helpful.

Thank you!

[TheJet-09]

^^^ Excellent info, and actually what I was thinking but needed someone else to explain it better than I can. The examples help greatly too.

Thanks!

[fastford]

the more you lower the right frt , the more rear steer you will get with out changing any thing else , which is a good thing some times , like with a slight throttle push on the bump.......

[Kromulous]

Lowering the RF (to much) then get into the bump and then hit the limiter on the LR to soon would be counter productive i would think? Always thought that hitting the Limiter on LR on exit is a bad thing?

I guess it all speaks to the engagement timing of the bump stop.