Wheel rates with coilover kits = excess pitch motion over bumps?

[//steve\\]

Originally Posted by IamFODI

Aren't they also running some custom suspension geometry, or do I have them confused with someone else?

I hear this a lot but I'm rather confused as to whether they really have highly modified anything or not. I think in some cases it's both. I guess that does all play into but just generally curious of the ballpark. I've seen some pictures that look like a very modified rear subframe and others where it looks completely stock.

[Obioban]

Originally Posted by IamFODI

Aren't they also running some custom suspension geometry, or do I have them confused with someone else?

The moment you change your wheel offsets, you've altered your motion ratios-- so unlikely they haven't

[bbnks2]

Originally Posted by IamFODI

Aren't they also running some custom suspension geometry, or do I have them confused with someone else?

yeah when I saw that name I looked them up and they run all custom suspension pickup points to induce rear-steer. Something I believe the E92 M3 spindles and sub-frame pickup points do over the stock 135i/335i spindles to some degree but is likely still heavily oriented around being a street car. Once lowered you mess all that up and it needs to be corrected for. A car that is set up to TOE-OUT during its first 1" of travel for better turn-in can easily turn into less desirable toe-in.

That's where suspension modeling comes into play to get the suspension curve back in-line with what might be more ideal for a race-car.

This is kind of what FSAE suspension design is largely oriented around. Lots of good information there on how they get judged based on the curve that the inner and outer wheel follows throughout the cars range of motion. Put the pickup point in the wrong place and the wheel might do something undesirable in roll.

[gmx]

Originally Posted by //steve\\

I've found reading all of this interesting but I sure hope some n00b doesn't stumble across this because they will be thoroughly confused.

All this info is interesting to me but it seems like you're down to details that are chasing after those last tenths.

The hard part is that bad setups can still often be driven very quickly in the right hands so it's easy for someone to come in and say hey I have some of the fastest lap times at track X and this is what I run. Maybe they are just a better driver who could be even faster on a proper setup.

It is quite interesting to me to see that rates are all over the place. I was just chatting with someone I following in Europe who recently upgraded his KW Clubsports to the same rate front and rear. Maybe it's a bandaid to a poor setup, maybe not.

I'd really love to know what rates the Team Schirmer cars run. It's hard to argue their success.

Definitely. Kind of the converse too. Lots of people complain about the OE suspension. It's not that bad. I came to the conclusion they just don't have confidence in it and like a car that doesn't pitch/roll as much to provide them that confidence.
KW CS changed to 110/120 N/mm rates out of the box. He is probably just running it off-the-shelf.
Schirmer run Nitrons, maybe ask them Nitron about it. Or ask them indirectly, what's the rates / valving for a stripped e92 ringtool?

[tdott]

I can't say I understand everything, but Im trying to learn as I figure out my next move suspension wise.

I did find Flat Ride driver's feedback on a race car at NASA 25hr race.
Granted it was on a Lexus IS250.

"I was highly impressed. You guys nailed it on suspension setup - the alignment, everything was just perfect. That's the one thing we haven't really played with is any suspension settings, honestly. The tire wear, mechanical grip, the way it turns. It has a really friendly understeer is what I call it. It turned in with just a little bit of understeer that allowed me to get on the gas real really early for mid-corner exit. So I can't thank you guys enough - 110% in my opinion, for sure." - Kai Goddard

"I 100% agree. I've never driven a car on a race track where we didn't spend all this time messing with rebound and compression and spring rates - all this stuff. We haven't done any of that." - Alan McCallum

"We were so confident with the tuning of the shocks they're not adjustable. We could have made them adjustable but we knew we wouldn't need to." - Nik Romano

"You know there's 5 of us and you've heard from two. The other three guys will say the exact same thing. We've got people with a lot of sports car experience, 4,000 pound stock car experience, open wheel experience." - Kai Goddard

"So everyone is essentially of the same opinion - that this car right out of the gate just handled absolutely phenomenally. It was a breath of fresh air, to be honest with you. So we ran the car yesterday for a few laps. I drove it for three laps in practice and the handling was just - perfect. I mean no complaints, it was awesome." - Kai Goddard