best suspension setup for my m-roadster?

[rf900rkw]

There are forum posts here that dwelve into the math behind the scenes and makes alternate suggestions. Hint, you don't talk spring rates, you talk target suspension frequency, then work backwards to your springs.


What I would like to see is rather than making suspension recommendations purely on the volume of the wallet, they should be made on the volume of the knowledge. If you think adjustable shocks are about ride quality, stick with non-adjustables. If you think you can set up adjustable spring perches with a tape measure, don't. There are many stories in these forums where someone with an "awesome" sharp-handling setup got into a situation that required using more than 80% of the potential, and found themselves suddenly snap-spun off into the ditch/weeds/on-coming. One infamous thread over in the E39 forum the guy ended up hanging the car from a guiwire by the right front wheel. "Must of hit some gravel"

Though I have never driven one hard, I would guess the TCK with it's insane 160+ CPM front and Cadillac-grade 80CPM rear should at least be safe-ish.



Koni's are great. H&R springs on Konis SUCK. Well, the rears do. The fronts are okay.

[JeffPortland]

There are forum posts here that dwelve into the math behind the scenes and makes alternate suggestions. Hint, you don't talk spring rates, you talk target suspension frequency, then work backwards to your springs

[..].

Thank you for your input and sending this conversation in a constructive direction. TC Kline has a nice suspension 101 article here: https://www.tcklineracing.com/webdoc...etails1149.cfm

[MartyBtoo]

Kline's article is a nice primer on the subject, but doesn't even mention what it takes to just get the ride height and cross weight percentages correct. If you don't have access to a 4 corner set of weight scales on a leveled piece of ground with a controller that calculates cross weight for you, you don't have a prayer of actually adjusting spring perches correctly. Not to mention the driver sitting in the drivers seat with the sway bars disconnected and a consistent way of accurately measuring the chassis ride height. It would take me a couple of hours to get it right most of the time, but the results were worth it.

Marty

[Andryuha]

Kline's article is a nice primer on the subject, but doesn't even mention what it takes to just get the ride height and cross weight percentages correct. If you don't have access to a 4 corner set of weight scales on a leveled piece of ground with a controller that calculates cross weight for you, you don't have a prayer of actually adjusting spring perches correctly. Not to mention the driver sitting in the drivers seat with the sway bars disconnected and a consistent way of accurately measuring the chassis ride height. It would take me a couple of hours to get it right most of the time, but the results were worth it.

Marty

That sounds like a complete overkill for a street car.

[JeffPortland]

That sounds like a complete overkill for a street car.

Overkill but I love knowing about it. Would be a blast to have time and resources to get this serious about it. As a street car this also makes me appreciate the stock suspension more and less likely to try "improving" it.

[MartyBtoo]

That sounds like a complete overkill for a street car.

You may think so, but I guess you've never seen how screwed up the handling can become when someone who doesn't understand it installs adjustable spring perches on a car.

Marty

PS I didn't even mention half of the stuff you would do to a real race car, because it has a lot more variables in play.

[ncskier]

i have koni yellows with ground control/eibach ers springs, soon switching to tc kline springs. I should have just bought TCkline from the start.

single adjustable if daily and poor (me)
double adjustable if you have the funds.

I would not go with lowering springs:
1. lowering springs might have the rear sit lower than the front
2. the spring rates are very important for this weird little car, lowering springs tend to not have enough in the rear
3. finally, not being able to adjust height will get under your skin, either it will be too low or too high.

I apologize for the noob question but what is adjustable on a single adjustable shock? Compression? I’m considering the Koni yellows to replace my tired stock setup. I would love something that is height adjustable as there seems to be quite a bit of tire/fender gap in the rear. It’s a coupe, if that matters.


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[Randy Forbes]

I apologize for the noob question but what is adjustable on a single adjustable shock? Compression? I’m considering the Koni yellows to replace my tired stock setup. I would love something that is height adjustable as there seems to be quite a bit of tire/fender gap in the rear. It’s a coupe, if that matters.


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Bump & rebound are a combined adjustment.

Roadsters that were ordered with the hdtp fitted at the factory had taller rear springs/higher ride height, but I am not aware of the differences in the Coupe's springs; you could check the Spring Table in the TIS for variants.

[solimans]

Some info here:

Z3 TCKR Single Adjustable Coilover Kit

https://r.tapatalk.com/shareLink/top...ink_source=app


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[rf900rkw]

Koni single adjustable adjust the slow speed rebound valving only. Since you have to get through the slow speed valve to get into the high speed valve, the adjustment does effect the entire rebound curve. In theory the adjustment should have no effect on the compression side, but more dyno graphs show a slight variation.


Here's a site with dyno graphs of both single and double adjustable.

https://wilhelmraceworks.com/koni-shock-dynos