Suspension Theory/Chat Thread

[Sirbelch]

^^^ For you dyno junkies out there, Spring rate is flywheel hp and wheel rate is whp.

I do believe that the front wheel rate is about 1 to 1. So if the spring compresses one inch , the wheel moves one inch (i don't know for sure but that is my understanding of it, Revy, please, please correct me if I am wrong).
The rear is a little different because of the control arm suspension. Since the damper and the spring are attached further away from the hub, this causes the motion ratio to be smaller. I don't know for sure, but i think Revy told me it was .9 to 1. So the rear needs a stiffer suspension than the front to have the same wheel rate. Here is an extreem example:

The front has a wheel rate of 1 and the rear is 0.5. If the front spring is 500 lbs/in then the rear spring needs to be 1000 lbs/in to keep the same wheel rate.

So, here is my question. What happens if you have different wheel rates front to rear? Like, what would happen in the above example if the rear spring was only 700 lbs/in and the front was still 500 lbs/in.

[Highrev1]

FG Motion Ratio
Front Rear
0.95 0.6 both are estimates

FG Civic Si FGCivic LX
Front spring rate 200 170
Rear spring rate 230 200
Front wheel rate 190 161.5
Rear wheel rate 138 120
Wheel F/R bias 1.38 1.35

I will calculate the Acutal Motion ratios shortly!!!

[Highrev1]

I would rather with a better estimate make the rears .7 BUT I HAVE NO CLUE!!! :)

[Highrev1]

Originally Posted by Sirbelch

The front has a wheel rate of 1 and the rear is 0.5. If the front spring is 500 lbs/in then the rear spring needs to be 1000 lbs/in to keep the same wheel rate.

So, here is my question. What happens if you have different wheel rates front to rear? Like, what would happen in the above example if the rear spring was only 700 lbs/in and the front was still 500 lbs/in.

That extreme example would be the rsx chassis the rear motion ration was about .5 I had an ep3 same dimensional chassis and it was not an ideal Motion ratio

Well "worse" handling would happen....Remember the stiffer end loses traction first...Without taking other items into account if you were to run a lesser spring rear with a FWD car you sould encounter understeer

[Sirbelch]

Originally Posted by Highrev1

Well "worse" handling would happen....Remember the stiffer end loses traction first...Without taking other items into account if you were to run a lesser spring rear with a FWD car you sould encounter understeer

So its the end with the higher total motion ratio for the amount of weight that end has to support that will loose traction, not necessarily the end with the higher spring rate. I.E. on the FWD car. If the motion ratios are even front to rear, then, the rear with the less weight to support, would loose traction first. Is that right? am i getting this? If i am, then thats pretty effing sweet. Finaly getting into the good stuff.

[LucasBlack]

Originally Posted by Sirbelch

So its the end with the higher total motion ratio for the amount of weight that end has to support that will loose traction, not necessarily the end with the higher spring rate. I.E. on the FWD car. If the motion ratios are even front to rear, then, the rear with the less weight to support, would loose traction first. Is that right? am i getting this? If i am, then thats pretty effing sweet. Finaly getting into the good stuff.

as much as my feeble comprehension goes, i believe you are on the right track.

[Highrev1]

Originally Posted by Sirbelch

So its the end with the higher total motion ratio for the amount of weight that end has to support that will loose traction, not necessarily the end with the higher spring rate. I.E. on the FWD car. If the motion ratios are even front to rear, then, the rear with the less weight to support, would loose traction first. Is that right? am i getting this? If i am, then thats pretty effing sweet. Finaly getting into the good stuff.

Its the end with the higher wheel rates, and the wheel rates are determined by the motion ratio and the acutal spring rate utalized... We utalize wheel rates cause they can be compared from car to car.

[Sirbelch]

Originally Posted by Highrev1

Its the end with the higher wheel rates, and the wheel rates are determined by the motion ratio and the acutal spring rate utalized... We utalize wheel rates cause they can be compared from car to car.

Yeah thats what i understood it as, i just mixed up the terms. (i ordered the da koni's )

Ok. When setting up a car that has double adjustability, generally speaking, what will increasing/decreasing compression/rebound front/rear do to our car's over all balance and ride on the streets. This is uncharted waters for me, so any help is gonna rock.

[Highrev1]

Originally Posted by Sirbelch

(i ordered the da koni's )
Ok. When setting up a car that has double adjustability, generally speaking, what will increasing/decreasing compression/rebound front/rear do to our car's over all balance and ride on the streets. This is uncharted waters for me, so any help is gonna rock.

The different speeds in which a damper performs deals with different aspects of handling and ride quality. But since you only have 8 adjuster to mess with thats easier than say 16 THat I will be stuck with
Bump Primiaily deals with ride quality. Rebound Primaily deals with handling
I would start with BUMP set to the lowest setting....ALSO When you adjust rebound if you decide to go full stiff or full firm go to the max then turn it back a 1/4 turn...This is to prevent damper damage...As far as rebound I would say go 1/2 Each front and rear, then adjust from there...Did you specify spring rates or no? IF not we can tweak those as seen fit. Congrats btw I am jealous FOR NOW

[Chevelle]

Originally Posted by Sirbelch

^^^ For you dyno junkies out there, Spring rate is flywheel hp and wheel rate is whp.

I do believe that the front wheel rate is about 1 to 1. So if the spring compresses one inch , the wheel moves one inch (i don't know for sure but that is my understanding of it, Revy, please, please correct me if I am wrong).
The rear is a little different because of the control arm suspension. Since the damper and the spring are attached further away from the hub, this causes the motion ratio to be smaller. I don't know for sure, but i think Revy told me it was .9 to 1. So the rear needs a stiffer suspension than the front to have the same wheel rate. Here is an extreem example:

The front has a wheel rate of 1 and the rear is 0.5. If the front spring is 500 lbs/in then the rear spring needs to be 1000 lbs/in to keep the same wheel rate.

So, here is my question. What happens if you have different wheel rates front to rear? Like, what would happen in the above example if the rear spring was only 700 lbs/in and the front was still 500 lbs/in.

Wow, I think I actually understood that, thanks for expaining it in a way someone like me (read not so smart) could understand. This thread is great btw, I'm trying to learn as I read.

[Sirbelch]

Originally Posted by Highrev1

The different speeds in which a damper performs deals with different aspects of handling and ride quality. But since you only have 8 adjuster to mess with thats easier than say 16 THat I will be stuck with
Bump Primiaily deals with ride quality. Rebound Primaily deals with handling
I would start with BUMP set to the lowest setting....ALSO When you adjust rebound if you decide to go full stiff or full firm go to the max then turn it back a 1/4 turn...This is to prevent damper damage...As far as rebound I would say go 1/2 Each front and rear, then adjust from there...Did you specify spring rates or no? IF not we can tweak those as seen fit. Congrats btw I am jealous FOR NOW

I told Chris 450/525 F/R and he thought that might be a little conservitive due to the motion ratio of the rear suspension but thought that it would be good for what i want to do and said i could always change springs. I'll be the first in the country with these. I've never felt so special (sniff sniff *wipes tear away*). You all rock at RSM.

[Sirbelch]

Originally Posted by Chevelle

Wow, I think I actually understood that, thanks for expaining it in a way someone like me (read not so smart) could understand. This thread is great btw, I'm trying to learn as I read.

Its Revy's job to get the good information or point me to where it is, then its my job to make everyone understand it (Its almost a gift to be able to simplify stuff for all to under stand). Thats why Revy and I work so well in this thread. Thanks for the coments. Keep reading because there will always be good stuff in this thread.

[Highrev1]

Originally Posted by Sirbelch

I told Chris 450/525 F/R and he thought that might be a little conservitive due to the motion ratio of the rear suspension but thought that it would be good for what i want to do and said i could always change springs. I'll be the first in the country with these. I've never felt so special (sniff sniff *wipes tear away*). You all rock at RSM.

NAH..THere not conservative...Ours is much closer to a 1 to1 ratio its like .7 I ....I will talk to him about it though

[TPC303]

I just lowered my car with the Skunk2's. I am wondering is it just me? I don't notice any difference?

[Sirbelch]

Originally Posted by TPC303

I just lowered my car with the Skunk2's. I am wondering is it just me? I don't notice any difference?

Any difference in what? The springs are not much stiffer than stock so the ride shouldn't change to much nor should the handling. Your suspension mod was basicly for aesthetics and nothnig more. sorry. Your dampers will blow sooner or later, so start saving for a new set. If you just buy factory relacements to replace the factory dampers, those will blow sooner or later too. You are going to have to get an aftermarket damper with a short body that is designed to work with shorter springs. Read this thread for some more information.

People with lowering springs... How are you stock struts holding up?

Hate to be an ass, but this thread isn't really the place for questions like that. Read the WHOLE thread and you will see the suspension light.

[Highrev1]

Hiro Nakamura AKA Yodums GTFO you know mods are banished from my threads ...Belch your evil...

Whats up anyone want to discuss anything good? Paul how about why your springs rates arent' to soft?

[Yodums]

Originally Posted by Highrev1

Ben GTFO you know mods are banished from my threads ...Belch your evil...

Whats up anyone want to discuss anything good?

Damn, that was cold. I can't even lurk without being told. haha.

[Sirbelch]

Originally Posted by Highrev1

NAH..THere not conservative...Ours is much closer to a 1 to1 ratio its like .7 I ....I will talk to him about it though

The ratio can't be more than 1 (can it?), so .7 isn't very close. With the 525 in the rear, that is 367.5 at the wheel which is less than the front at 450. With a motion ratio of .7, I would need 642.8 lbs/in spring to match the front. If that is the case, could you bump up the rear rate for me. If the motion ratio is .8, then a 562.5 is needed. Which would put my orginal guess of 575-600 in the rear pretty close. (hahahah, had to rub it in, but if i'm wrong, feel free to rub back). Please talk to Chris and see if he knows the rear motion ratio.

[Sirbelch]

Originally Posted by Highrev1

...Belch your evil...

Whhhaaaaaaat? What did i do? Me, evil, you must have the wrong person. An evil person *cough cough Revy cough* wouldn't have answer the question at all.