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Cambered Tires Can Improve Fuel Economy
thecarchik writes with an excerpt from Green Car Reports: "We already know that it's possible to curb your fuel consumption just by having your tires properly inflated, or better yet, installing a set of low rolling-resistance tires, however, soon there may be an additional avenue to look at when picking the most fuel efficient rubber for your ride. The answer is the camber of your tires, more specifically, the negative camber. This is when the tops of your car's tires are angled inwards towards the chassis. Of course, there are negative effects too — namely increased tire wear and impaired ride quality — which is why production cars almost always have zero camber." The linked article, as well as the New York Times article from which it draws, describe a new tire which is designed to minimize those negative effects.
Perhaps you should get your shocks replaced....
In a pure theory aspect, less tire on the road, less rolling resistance.
The summary and the article it was taken from are misleading and poorly written. They only use the term 'fuel efficiency' to describe one possible effect of mucking around with your tires in general, probably by increasing their pressure or using harder tires. However, the CamberTire appears to have nothing to do with tire rigidity - and hence fuel economy - whatsoever. What the article appears to describe is a tire which is optimized by shape for negative camber, in order to improve handling of the vehicle, without the faster tire wear that putting negative camber on regular symmetrical tires produces.
WIth negative camber, the tire will be able to withstand more lateral force since it is angled out at the bottom, 'into' the turns. Thus it will be able to corner harder without losing grip.
A hero is someone who knows when to run away. I am a hero. -Trent the Uncatchable
Sigh, go and learn something you retard.
They dont, any competent and not class limited suspension design dynamically adjusts camers in corners to develop the desired cornering camber, while not causing issues in strange line.
A lot of moronic 'boy racers' like to think a ton of negative camber is the sign of a race car, mainly because some suspensions designs develop a lot of un-adjustable negative camber when cars are over-lowerd.. This of course is terrible for handling (but they like to think it is not.) but since those cars cannot have it adjusted out with spending real money....
And F1 most certainly does NOT run static negative camber, it would be a disaster for straight-line handling. They run DYANMIC camber in corners due to the uneven A arm suspension geometries.
I suggest you start here.
http://www.amazon.com/Competition-Car-Suspension-Construction-Motoring/dp/085429645X
http://books.sae.org/book-pt-90
I have a BMW, not a mini, but my car's tires (645ci) are completely different front-to-back, plus the tires are designed for single-direction turning only (i.e. grip works one way, not the other). Put those together and my car's tires can't rotate. They stay where installed until they wear out, which the rear tires already have done once in less than a year.
Then again, there's these really nice, sharp corners on the freeway that I can take at posted speed (though never higher, of course) when most people slow down to 45... $350 tires (each) is part of what I bought when I picked the car.
My rear tires have a static negative camber. I have no idea if it helps the abysmal fuel economy or not, nor does it really matter. I offset the carbon in other ways and I don't care about the cost.
It doesn't hurt to be nice.
Also I wish that people would stop looking at how race cars do things and assume that it is good.
No one said a negative camber is good in all circumstances just because most sports cars use it. Heck, on Indy cars, they often have positive camber on one side of the car because they always turn one direction. Even among racers, they adjust the amount of camber by what type of course they are going to be racing on. In many cases for every day personal cars, 0 or close to 0 camber is the best setting, for others a slight negative camber is going to work best. The point was not that every car should use negative camber. It's that saying "negative camber is a a design defect" is moronic.
have to take it to the logical extreme:
http://www.youtube.com/watch?v=_r6ltUgtFWI
Pretty soon, all stock Toyotas and Hondas will look like this! XD
The coefficient of friction is dimensionless; it's the ratio of the maximum frictional force (opposing motion) to the force pressing the two objects together (such as the upper object's weight).
Aside: What is the unit of measure for friction?
Friction itself a force; therefore, you can measure it in Newtons (or poundals or your unit of choice). However, most non-physicists (that's me! ...so correct me if I'm wrong, by the way) run into the coefficient of friction far more frequently. This number (usually represented by the Greek letter mu) is just a ratio, so there are no units. (This probably explains the confusion in the first place.)
R.Mo
Whether he needed it or not is debatable, but the points about different front/back tires and unidirectional tread are not snake oil.
Particularly in rear-wheel drive cars, it is not uncommon for the drive wheels (which need to apply torque) to be wider, while the steering wheels (which may need to cut through water/snow) are narrower.
Unidirectional tread is less common, but it does help reduce hydroplaning.
If you have just one of these, you can still move your tires in one direction (not full rotation, but front/back or side/side). If you have both, you have to keep your tires in the same location.
I was a mech for many years and grew up in Detroit. Just about ewveryone I knew worked in the auto industry, and I myself worked in the auto industry as an engineer.
And just about every car I have ever worked on or known about specifies some amount of negative camber right from the factory. You can call this anedote if you like, but the fact is I've worked on LOTS of cars and seen a LOT of specs and have seen zero or positive camber specified on a car so few times I could probably count them all on one hand.
Because it's NOT just about how the car grips in the corners, but how it handles in a straight line; Too much negative camber will make the car twitchy as it bump steers over every wave or truck rut, but NO negative camber also makes the steering feel lighter, which is also not a good thing when it means the car has absolutely no "return to center" correction. Any rear wheel drive car will try (to some degree) to straighten itself out, but half a degree to two degrees (depends on car) negative camber is pretty much standard. Part of this is also because cars tend to get knocked out of alignment because of neglect, and POSITIVE camber is really no fun - it tends to make the car even more vague in steering. So a little negative camber is built in just to help make certain things don't go positive.Of course too much is also no fun, since it will make the car try to steer away from the crown in the road and heavily crowned roads will make you feel like the front end is badly out of alignment (because it is).
The same holds true for caster: toe the front wheels out a bit and the thing will wander all over the place; toe them in and the car will tend to center itself. Both of these also will tend to increase friction as well, which also it seems would negatively affect mileage. Given many cars nowdays run on low profile tires inflated to 40psi or more I have a hard time believing it's going to make much difference on a properly tuned and aligned vehicle, however.
I think you may mean Toe? Most cars have zero camber, or very close to it. Toe at zero or toe out is what causes a very twitchy car.