5 replies to this topic

[mclarenmerc]

This may have been discussed before, but I cant seem to find it in the archives anywhere.
What is the concept of a camber, and how is it useful in the design and running of a racecar?
I heard a broad definition on Speedvision last week, which stated it as the angle of the tyre to the 90 degree vertical plane. But that doesnt give any indication as to what it does and how.
Can anyone explain this, and how teams use this. What are the approach of different teams in terms of the use of this?
Also whats the meaning of the term off-camber, or similar sounding terms.

[mtl'78]

well I'm far from being one of the more technically aware members, but here goes:

F1 cars always use negative camber, which means that the top of the tyres point inwards. This is so that when they go into a corner, the outside tyre is at a better angle, and more of it is actually in contact with the road. This obviously gives them better grip, but it also wears out the inside of the tyres faster, so it's always a trade off.

The other settings that blow MY mind is toe-in and toe-out. Thats where the wheels either point "out" or "in" along the horizontal axis. It supposedly helps handling, but I still have difficulty accepting that cars going THAT fast actually have misaligned wheels!!!

[Pioneer]

What'll really blow your mind is the steering geometry... you'd think logically that the front wheels would always steer at the same angle... not so!

The outside wheel steers at a greater angle than the inside wheel.

[MattPete]

[QUOTEWhat'll really blow your mind is the steering geometry... you'd think logically that the front wheels would always steer at the same angle... not so!

The outside wheel steers at a greater angle than the inside wheel.

[/QUOTE]

Yep, pretty weird. On road cars, you have Ackerman steering, in which the inside wheel is at a greater angle than the outside wheel (i.e. the outside is closer to straight ahead). In F1, they use reverse-Ackerman. I don't know why, but apparently it works.

Camber is the degree of tilt from the upright. With negative camber, the wheels are tilted inward. For racing, the tires will be from 0 degrees camber to some amount of negative camber -- whatver works best according to the tire pyrometer (you want even heat across the tread surface). I think I've seen CART cars run negative camber on the right side and positive camber on the inside for ovals.

Toe affects turning and straight line stability. For street cars, you want toe-in (although I think toe might be different for front wheel drivers because of thrust, but I could be wrong). I bought a used RX-7 once that had some toe-out before I got it realigned. It was a handful on the highway.

For F1 cars, I here there is usually a bit of toe-out. It makes the car a handful in a straight line but makes it turn in quicker.

I'm no racing engineer, so I might have some facts wrong, but I think I'm on the right path.

[Ross Stonefeld]

down here in Junior Formula Whatever you'd run toe-out on say a street course, gives you some awesome braking and wicked turn in, and since the straights are so brief it doesnt affect you that much.

Last year in one of the support races at Road America/Elkhart Lake for the CART event a coupe guys tried zero toe to reduce tire scrub down the straight (its a 4 mile track with three massive straights) but that only lasted a few laps because they were scared to death when they turned into the fast corners


That steering angle thing seems really weird

[Whatever]

I'm not sure if it's toe-out or negative camber or both that affect straight line stability, but you will definitely notice that a race car tends to wonder a bit under heavy breaking. It's a trade off to get better cornering.