Bilstein Sport with Coilover question

[z31maniac]

^Yes, but no one actually refers to it's capabilities by the effective wheel rate.

[Stephen]

^Yes, but no one actually refers to it's capabilities by the effective wheel rate.

Yea, for comparisons sake, my rate is 500

[Hellabad]

^Yes, but no one actually refers to it's capabilities by the effective wheel rate.

You need to when you're having Bilsteins revalved. I think thats what that guy was thinking.

Not very long ago, you could call Bilstein, and they would know roughly what to revalve an e30 to. Same for a VW rabbit, or an RX7, or a Dodge motorhome.

Nowadays, almost all of the good Bilstein guys quit when their jobs were moved from San Diego to Mooresville NC, so you need to tell them EXACTLY what you need, including the motion ratio.

So imho it is relevant, in terms of adjustable shocks vs non-adjustable shocks that need revalving.

Jay, who has a Dodge Motorhome with custom valved Bilsteins and sway bars

[z31maniac]

I assumed Bilstein, like you guys, wouldn't need to be told things like that when told what vehicle they were going on.

My bad.

[Stephen]

jay, can i call you about my billys? it seems like 500 should be ok with billys, not bounce like crazy

[z31maniac]

^Just the buy the custom valved Koni's and move on with your life.

[Colorlesss]

500 will be ok. i DD'd a slammed e with 500/700 rates on bilsteins and it was very solid.not revalved or modified in any way. tires never met my fenders except a few times on full turns with buddys in the car


couldnt fit your fingers in there

sportmaxx .. oh god

[fmxomar]

what size tires you running?

[Colorlesss]

what size tires you running?

195/50

[Stephen]

^Just the buy the custom valved Koni's and move on with your life.

Sadly, not in the cards right now. Plus i payed for the billys and would rather deal with warranty if theyre busted or go softer in the rear if necessary. I put the spring pads back in, calmed it down a hair

500 will be ok. i DD'd a slammed e with 500/700 rates on bilsteins and it was very solid.not revalved or modified in any way. tires never met my fenders except a few times on full turns with buddys in the car


couldnt fit your fingers in there

sportmaxx .. oh god

Lol. Well thats good to hear. You didnt bounce in the rear?

[Colorlesss]

Lol. Well thats good to hear. You didnt bounce in the rear?

blew out the boge's the first trip up my street. new bilsteins were in for a little over a month and a half with no issues at all. no bounce. all of it will be going back on my new DD. rears are still perfect.

[Stephen]

Nice, good to know

[njansenv]

Just a quick correction regarding wheel rates vs. spring rates:
Wheel rate = spring rate x motion ratio SQUARED. The motion ratio affects force AND distance travelled.

If the MR = .5
Then: 500 pounds spring force = 250 at the wheel.
Moving the wheel 1" results in 1/2" of spring compression.

A minor point, but an important one! (and a mildly frustrating common mistake often seen by this suspension eng!)

Nathan

[Hellabad]

Just a quick correction regarding wheel rates vs. spring rates:
Wheel rate = spring rate x motion ratio SQUARED. The motion ratio affects force AND distance travelled.

If the MR = .5
Then: 500 pounds spring force = 250 at the wheel.
Moving the wheel 1" results in 1/2" of spring compression.You forgot to square the motion ratio.

Nathan

You forgot to square the motion ratio.

If the "motion ratio" is 0.500, then a 500 pound spring on the arm is 125 at the wheel.

But the spring still only moves 1/2 inch.

A minor point, but an important one! (and a mildly frustrating common mistake often seen by this suspension eng!)

Nathan

Yes. Very Very frustrating (thats very^2)


Jay



OK, Actually, by definition the motion ratio has already been squared. But what was squared? There is no consistent name for the ratio that is squared to get the "Motion Ratio", so I call it the leverage ratio. The distance from the spring to the pivot, and from the center of the tire (on a swingarm car) to the the pivot.

e30 content: The Motion ratio, after squaring, for an e30 is in the low 0.400's

[FredK]

I was wondering what njansenv was trying to get at... haha.