Camber V.S. Straight-Line Speed

[marekk]

Know nothing about camber vs rolling resistance (my guess will be slightly increase if we assume no change in pressure), but IMO at high speeds more camber means less drag from the tyres (high pressure area in front and low pressure area behind the tyre are smaller), and this can increase top speed of the car.

[munks]

I always felt camber is used to aid cornering by providing bigger contact patch in roll.

Yep...That's the reason for the short track settings that were mentioned. In the corner that tire that is leaning way over on the straight, is standing straight up mid corner.

I know this is off-topic and xpensive might get mad at me for replying, but this is just not correct in my opinion and it's a disservice to let people think it is.

Red Bull's static camber this weekend at Spa was over 4 degrees on the front tires. Do you honestly think that Red Bull's chassis was leaning over 4 degrees to get their outside front to stand up straight in the corners? I'll give you a hint: Pirelli was only worried about the tire joint on the inner edge.

Also, Supercar V8s and NASCARs have been known to run up to 8 degrees camber, but the cars don't roll anywhere near that amount. (Yes, I'm ignoring small changes in camber due to suspension geometry.)

Look up "camber thrust"; I believe that is the primary reason camber is used.

[Jersey Tom]

Look up "camber thrust"; I believe that is the primary reason camber is used.

I would say camber thrust is attributed incorrectly to giving extra grip.

[munks]

Look up "camber thrust"; I believe that is the primary reason camber is used.

I would say camber thrust is attributed incorrectly to giving extra grip.

Not sure where you're going with this. From the data I've seen, it does seem to increase maximum lateral force somewhat in the direction cambered. Is that not generally true? And there's been suggestions that it generates lateral force "more efficiently" (generates less heat) than a slip angle producing the same lateral force. I have no data to back up the second claim, however.

But yes, there are other positives and negatives to using camber.

[strad]

Red Bull's static camber this weekend at Spa was over 4 degrees on the front tires. Do you honestly think that Red Bull's chassis was leaning over 4 degrees to get their outside front to stand up straight in the corners? I'll give you a hint: Pirelli was only worried about the tire joint on the inner edge.

Do people just pick and choose?
Look, I said that was short track settings,,not road course.
The Red Bulls just went overboard and blistered their tires. Whats hard to understand about that?
Now the question is, does it decrease the rolling resistance. I say it does,,some say it doesn't.
I reason that a two inch by the circumference presents less resistance than the full width of the tire by the circumference.

And I'm sure as hell tired of every question or discussion becoming a full blown arguement.

[Jersey Tom]

Look up "camber thrust"; I believe that is the primary reason camber is used.

I would say camber thrust is attributed incorrectly to giving extra grip.

Not sure where you're going with this. From the data I've seen, it does seem to increase maximum lateral force somewhat in the direction cambered. Is that not generally true? And there's been suggestions that it generates lateral force "more efficiently" (generates less heat) than a slip angle producing the same lateral force. I have no data to back up the second claim, however.

But yes, there are other positives and negatives to using camber.

You will sometimes (or even frequently) get more peak lateral force when you add camber, to an extent.

However, the mechanism for the increased grip is what I would not attribute to "camber thrust" - which is something I associate to a completely different F&M aspect.

[munks]

Red Bull's static camber this weekend at Spa was over 4 degrees on the front tires. Do you honestly think that Red Bull's chassis was leaning over 4 degrees to get their outside front to stand up straight in the corners? I'll give you a hint: Pirelli was only worried about the tire joint on the inner edge.

Do people just pick and choose?
Look, I said that was short track settings,,not road course.

Short track settings are where you'll find NASCARs running the insides at +8 degrees (or at least they did a few years ago). I really don't think those tires are flat on the ground.

Apologies if trying to correct information is a "full blown argument". I thought I was being polite, perhaps it didn't come off as such.

[munks]

However, the mechanism for the increased grip is what I would not attribute to "camber thrust" - which is something I associate to a completely different F&M aspect.

We're ready to learn here! But just so you know where I'm coming from:

The picture of camber thrust in my head has to do with the path that a piece of rubber wants to travel when spinning around a cambered tire (an oval when viewed from above) vs. where it is forced to be (basically in a straight line) on the ground. This creates a force from shearing the tread in between the two paths, which I thought was called camber thrust. And I guess I just figured that camber was shearing the tread more in the front (non-sliding) part of the footprint than it would have sheared with just slip angle and no camber. In other words, the force builds up linearly at the front of the footprint with pure slip angle, but builds up in a curve with camber. Hence, using the tire a bit more effectively.

Now, there's also deformation in the carcass which I assume has some effect on the F&M as well, but to the best of my knowledge this isn't called camber thrust. Please correct me if I'm wrong.

[Jersey Tom]

Consider this:

I think of this almost in a "method of sections" manner of isolation. Regardless of what happens in the carcass... the maximum amount of force you can generate is limited by the amount of, and way the rubber is against the ground.

[munks]

You're a mysterious man, JT.

Well we know that the footprint on a cambered tire is distorted from the "usual" rectangular shape, so the inner edge is longer than the outer edge (assuming negative camber). That doesn't make it immediately clear whether the footprint size would increase, decrease, or stay the same. But since the empirical evidence says that tire spring rate typically decreases with camber, I suppose that means you'd probably get more rubber overall on the ground. That might be counteracted slightly by a more uneven load distribution, but I couldn't say for sure.

I'd still maintain that camber utilizes the front of the contact patch more effectively, and I think this is borne out by the fact that the net camber thrust tends toward the front. And this, in turn, creates a more useful aligning moment on the front tires, which is probably why more camber is used there (although I imagine the reduced thrust capabilities of a cambered rear tire have an influence in the front-to-rear ratio as well).

[xpensive]

You're a mysterious man, JT.
...
But since the empirical evidence says that tire spring rate typically decreases with camber, I suppose that means you'd probably get more rubber overall on the ground. That might be counteracted slightly by a more uneven load distribution, but I couldn't say for sure.
...

We were through the Italic on another thread, long before you became a member munks, where one scool of thought (mine incitentally) was that contact-patch area is simply vertical load over tyre-pressure, which in that case would suggest the same for a cambered vs non-cambered wheel.

As I recall, the debate was over the influence of the tyre-wall's stffness.

[MrBlacky]

You're only talking about camber on the front tires? More camber on the rear wheels is very crucial to the straight line speed.

[marekk]

You're a mysterious man, JT.
...
But since the empirical evidence says that tire spring rate typically decreases with camber, I suppose that means you'd probably get more rubber overall on the ground. That might be counteracted slightly by a more uneven load distribution, but I couldn't say for sure.
...

We were through the Italic on another thread, long before you became a member munks, where one scool of thought (mine incitentally) was that contact-patch area is simply vertical load over tyre-pressure, which in that case would suggest the same for a cambered vs non-cambered wheel.

As I recall, the debate was over the influence of the tyre-wall's stffness.

Must be before i become a member either. Did you discuss details of tyre-pressure in respect to geometry/volume change of the tyre under load for different camber angles ?

[silente]

I read this topic and found it very interesting.

To be honest i didn't have time to read with care last posts, but i can add my pennny here.

After i read this topic, i re-analyzed the best source i have of tyre data and studied a radial tyre behaviour which was phisically tested on a tyre rig.

It is quite clear that:

1) Increasing camber you can see rolling resistance increasing very very slightly (but actually increasing); the tendency is not completely clear, because seems to be affected by temperature and pressure as well, but anyway present. The effect is anyway a very small.

2)Incrasing camber (till a certain value is reached) produce higher cornering forces. After this value is reached, cornering forces decrease a little bit. Also here, this phisical data shows something very strange, cause you can see the tendency of cornering force to increase with camber, but sometimes for higher value of camber you see a lower cornering force. To be clear something like this (numbers are just there to give an idea, but are completely random):

0°--->1000
1°--->900
2°--->1100
3°--->1200
4°--->1100

One thing that must be said is that tyre temperature was not exactly costant during the test and i suspect some of the strange tendencies are connected to temperature changes between one camber value and another.