Suspension Theory/Chat Thread

[Highrev1]

1.1:1 Motion ratio in the rear....the RSX ratio was 1.7:1 525= a 477.27 pound acutal spring rate. And with the fronts being a 450 thats a 27.27 pound difference NOT that much. BUt should allow for some nice rotation esp. witht he NOICE dampers...

Yeah I Got the figures for the rear motion ratio's btw...I am pretty darn close with my estimates on the spring rates...What do you want? MORE than that?

[Sirbelch]

Soooo, could up the rear rate to 550 for a 50 lbs difference in front to rear. I don't want to have to much fakie spring rates. I'm scared.

[Highrev1]

Of what??? What have I ALWAYS ALWAYS SAID....Lower suspension frequencies=more traction....Don't make me tell you to go re-read the stickys If you want a 50 pound difference I would Lower the front 25 pounds.... Only cause I can to YOU

But seriously streets are bumpy...Keep the rates LOW or Lower for now and then up them if you are unhappy...

[Sirbelch]

Scared of the unknown. I will leave it as is for now. I change my mind a lot on buying stuff but i'm always happy with the first choice (unless its Tein SS and Tein Flex, insert your "I told you so" here _________)

[Sirbelch]

Also, a 27 lbs difference is more than i have now. Plus, the difference in damper quality will increase rotation too as well as the fact that I will be running more front camber.

[Highrev1]

Originally Posted by Sirbelch

I change my mind a lot on buying stuff but i'm always happy with the first choice (unless its Tein SS and Tein Flex,
insert your "I told you so" here)

The unknown is scary dam I m afraid of the new dampers I am gonna end up with

[Sirbelch]

I can always change springs. Springs are less than a sway bar.

[Forklift352]

Ow! once the formulas started flying I I I got dizzy!
I m going to read the blue pages.....again then Ill come back and reread
pages 1-25. I got the sportlines I think those are progresive....No.

[Highrev1]

:) We will get Belch to translate the equations to be more easily understood.

[Sirbelch]

As i understand it, the motion ratio of the wheel/suspension combo goes like this. We will use the RSX example with a ratio (which is just a fraction) of 1.7 to 1. The first number relates to how much the wheel moves and the last number relates to how much the suspension moves. So using the above example, the wheel moves 1.7 inches every time the suspension moves 1 in. So to calculate the spring rate at the wheels, you need to divide the spring rate by the motion ratio. So using a 500 lbs/in spring, to get the spring rate at the wheel we go 500 / 1.7 = 294.11 lbs/in. Hope that helps.

[Highrev1]

^^ I am congused by your calculations Calculator on Windows was busted out, yeah thats it...Brining this back from the deead....Lots of goo discucions in here. Also lets continue to discuss suspenisons.

[LucasBlack]

Originally Posted by Highrev1

^^ I am congused by your calculations Calculator on Windows was busted out, yeah thats it...Brining this back from the deead....Lots of goo discucions in here. Also lets continue to discuss suspenisons.

"thread from the dead" - indeed...although it is stickied, so not quite.
edit: nevermind...this is one of those "should be stickied but isn't yet" threads...


and um....Greg....are we a bit under the influence of concocted beverages with those special feel-good ingredients?

[SiViC81]

Originally Posted by LucasBlack

and um....Greg....are we a bit under the influence of concocted beverages with those special feel-good ingredients?

[Sirbelch]

Originally Posted by Highrev1

^^ I am congused by your calculations Calculator on Windows was busted out, yeah thats it...Brining this back from the deead....Lots of goo discucions in here. Also lets continue to discuss suspenisons.

I was using your equations to make those numbers. If its wrong, i was simply using the equation given to me, twas not my one. Although, after a month and a half, that paragraph needs some revision.


How do short stroke suspensions work? On Tein's website you can get your dampers converted to a short stroke design. What would be the advantage of that? I thought that you wanted as much suspension travel as you could get.

What is range? What does it mean to have a damper operate in a low range as apposed to a high range? Are there advantages to one or the other?

Did anyone read the Article in this months Turbo about the $20,000 Evo suspension based around Motons? Good stuff. Doesn't really help us out, but does explain how important it is to return a car to near stock suspension geometry after it has been lowered to get the best handling out of the car. They changes springs/shocks, sway bars, wheels/tires, control arms, a bunch of bushings, roll center adjusters, steering rack bushings etc. Also, they put more braces than i new existed on the car. Its almost like a roll cage. There is a brace that is just a plate under the engine. One set of braces goes from the front suspension all the way to the rear. This is one of the few cars that sticks well enough to use the braces. They said the class that they race in does not allow for roll cages or they just would have done that.

[Borbor]

Originally Posted by Sirbelch

As i understand it, the motion ratio of the wheel/suspension combo goes like this. We will use the RSX example with a ratio (which is just a fraction) of 1.7 to 1. The first number relates to how much the wheel moves and the last number relates to how much the suspension moves. So using the above example, the wheel moves 1.7 inches every time the suspension moves 1 in. So to calculate the spring rate at the wheels, you need to divide the spring rate by the motion ratio. So using a 500 lbs/in spring, to get the spring rate at the wheel we go 500 / 1.7 = 294.11 lbs/in. Hope that helps.

You actually have to divide the spring rate by the square of the motion ratio.

So for a motion ratio of 1.7:1, with a 500lb spring, the wheel rate is actually 173lb/in

[Highrev1]

Are you Wayne?

[Borbor]

I'm not Wayne

Well, at least the last time I checked it wasn't

[Sirbelch]

Originally Posted by Borbor

You actually have to divide the spring rate by the square of the motion ratio.

So for a motion ratio of 1.7:1, with a 500lb spring, the wheel rate is actually 173lb/in

Thanks for clearing that up. Does that mean I should re think spring rates for my car? I'm going to run 450 up front and 525 in the rear. So that makes the motion ratio 450 up front and 433 in the rear? Am i right in assuming that? Or am i just an ass?

[Borbor]

Are you absolutely positive your front is 1:1?

I know it's a Macpherson, but one of the most common fallacy with Mac MRs is that people just assume it's 1:1.

Also, your tires are going to play a big part on the spring rate that you'll end up using.

[Highrev1]

Just an Ass... .97 up front to be exact, I think