96DXCivic
96DXCivic Reader
9/8/09 6:00 p.m.

I know you want to gain negative camber in bump. But why is that?

fiat22turbo
fiat22turbo GRM+ Memberand SuperDork
9/8/09 6:17 p.m.

So that as the chassis leans, the outside tire will gain negative camber to keep the contact patch parallel with the surface of the road. Maintaining the contact patch is why most people run some amount of static negative camber, which slows the turn-in speed and increases braking distance slightly but the gain in grip in the middle of the corners usually make it worthwhile. This is especially true with strut equipped or other severely compromised suspension designs.

I may be missing some other advantages, but I'm sure the smarter folks in the board will chime in and help make better sense of it all :)

Nashco
Nashco SuperDork
9/8/09 6:23 p.m.

It's all about maximizing contact patch. If this is related to the bicycle tire-shod moonbuggy, I don't think camber gain is much of an issue...

http://grassrootsmotorsports.com/forum/grm/suspension-questions/13436/page1/

Bryce

fiat22turbo
fiat22turbo GRM+ Memberand SuperDork
9/8/09 10:38 p.m.

I concur, I'd focus on removing bump steer and minimizing tire scrub. The longer the suspension arms, typically the better the camber curve, but the packaging gets a little more difficult in the steering department. the buggy guys have this pretty well figured out, see if there is a local buggy shop in your area that you can visit.

Salanis
Salanis SuperDork
9/8/09 10:45 p.m.

It depends on the car. Not all gain it nearly as much.

The reason's you want it were described.

Most strut cars don't have as much camber gain. A car with inequal length control arms (like a Miata) can gain a lot. The top arm is shorter than the bottom. So, as the suspension compresses the upper arm tracks a smaller circle, and pulls the top of the wheel in, gaining camber.

ReverendDexter
ReverendDexter HalfDork
9/8/09 11:51 p.m.

Yeah, us Mustang guys are boned in the dynamic camber gain department. Best we can do is fake it by dialing in at least 4 degrees of caster.

Guess there's a reason they're not known as handling cars, hahaha.

96DXCivic
96DXCivic Reader
9/9/09 12:15 a.m.

Why focus on minimizing tire scrub?

Salanis
Salanis SuperDork
9/9/09 12:22 a.m.
96DXCivic wrote: Why focus on minimizing tire scrub?

As opposed to?

Tire scrub is bad. Tire scrub wastes energy, usually when you need to maintain it the most. And it wears your tires faster.

If this is for your moon-buggy thing, the energy wasted by scrubbing tires will be even MORE obvious with less power.

96DXCivic
96DXCivic Reader
9/9/09 11:12 a.m.

Ok. I just wanted to hear someone else reason for minimizing tire scrub other then the old team lead since some of his answers don't make any sense. How can we go about doing this? The previous buggy was design around this but it's roll center end up being 14 inches underground and the CG is about 14 inches above the ground. So you can see the problem.

iceracer
iceracer HalfDork
9/9/09 5:43 p.m.

The nice thing about caster, it adds camber to the outside wheel and positive to the inside.

iceracer
iceracer HalfDork
9/9/09 5:44 p.m.

That would be negative camber for the outside.

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