Traction.......the grip issue :)

[Zak33]

Originally posted by Big RICHARD
F1 tyres at working temperature (~100 deg. C) are VERY soft and 'squidgy' this is to improve their 'stickiness' (read: coefficient of friction) and therefore grip. When overheated this squidgyness (coefficient of friction) is reduced.

Big Rich and RocketmanX....I love you guys

Thanks people......I enjoyed that one IMMENSELY

[blockers]

thanks. Also another i have always wondered about....why do F1 cars (and dragsters i suppose) have really large tyre walls. Arent low profile better? more confusion

[Big RICHARD]

Originally posted by blockers
thanks. Also another i have always wondered about....why do F1 cars (and dragsters i suppose) have really large tyre walls. Arent low profile better? more confusion

Maybe low profile tyres don't actually reduce rolling resistance either......

Maybe the barryboys have it wrong! Rubber could be made to weigh less that metal.....

[Zak33]

On a Grandprix car I GUESS (ie I dont KNOW) its to give the tyre some flex and bump absorbtion under acceleration.....with all those horses going down onto dry tarmac, the tyre must "flex" a bit or it would jump straight up in the air (an advanced case of Axle-Tramp, where the tyres spin up into the air to get rid of all the power, cos it wont go forward all in one fluid movement)

F1 cars have next-to-zero suspension movement, so its the tyre walls that do it...PLUS (guess again) you gotta get some air into them....you cant have ultra ultra low profiles or there would be NO air in them

I don't think they are really very tall sidewalls tho. They were long ago tho

Dragsters however......they STRETCH under acceleration..the tyre "grows " like TiG said up there /\ and it changes the gearing automatically....supposed to do it.

[oddytomtom]

what gets me F1 cars huge side walls

touring cars - low profile

they both contadict each other but they carnt be any worse then each other cause they wouldnt use them

[IainB]

Originally posted by Zak33
Dragsters however......they STRETCH under acceleration..the tyre "grows " like TiG said up there /\ and it changes the gearing automatically....supposed to do it.

I was under the impression that it was also to do with loading the tyre at launch - if you get a good pic of a Top Fuel (or any other powerfull car on slicks) on the startline you can see how much the sidewall deforms due to the twisting force. I understood this as a way of getting the power to the ground without breaking traction i.e. the tyre 'stores' (worded badly) the torque then releases when the car is moving - especially as most rail's dont have any suspension apart from the flex in the chassis.
And as an aside the sidwalls on mine ar soooo thin, you can actually fold the tyre in on itself (thus making it half its width - so it fits in the boot easily!!) - was quite suprised about that !!

[Zak33]

Originally posted by Eazieb
I was under the impression that it was also to do with loading the tyre at launch - if you get a good pic of a Top Fuel (or any other powerfull car on slicks) on the startline you can see how much the sidewall deforms due to the twisting force. I understood this as a way of getting the power to the ground without breaking traction i.e. the tyre 'stores' (worded badly) the torque

Good point and well made m8....nice touch

[oddytomtom]

Originally posted by Zak33
PERFECT reply....for slightly the wrong reason

It WAS to slow them down, but not cos the WIDTH gave less grip.....but cos they wanted less power put through them if they were to last the distance and not wear out, or if the compunds were softer to deal with the power, they'd heat badly and blister......it kinda back fired cos the tyre boys were a step ahead and as you say..it didn't work....

BUT.....it was only described to the public as being to reduce grip cos it was easier to explain to Jo Public.

What we are all here trying to understand is that is was deeper reasoning than that......it's wear rates and heat build up , caused by narrower tyres.....and THEN you have less grip. But only after a period of time.

IN A SPRINT EVENT.... an F1 car could use narrower tyres than they already use......monster soft..........and skinny for aerodynamics.

it did reduce grip and slow them down because they had to change the compound of the tyres to make them last better, and it did work to an extent i suppose

[RocketmanX]

I've never understood the goofy looking "balloon" type of tires that F1 cars run either. (I think they look awful on such awesome machines, but looks don't matter in Racing )
In my form of racing, and I would think that F1 would be after the same since we're both overpowered and looking for maximum handling, stiff sidewalls are preferred due to "tire deflection", or sidewall flex. The sidewall flex causes the tires, 'scuse me- uh TYRE , tread to roll over making the tread patch, or camber change in a way that is mostly unpredictable. Weight is another concern. I'm sure with the carbon/carbon brakes and ability to use any waterial they want F1 cars have very light wheels and the rubber from the tire would surely outweigh the wheel. My wheels are 15" x 10" wide, made of aluminum and weigh about 9 lbs. The tire weighs more than 9 pounds.

The tread wrap, or, torque wrap from the sidewall flex as was stated that Top Fuelies use to aid traction would also cause a loss of braking and handling on entering the corner. It would seem to me that any sidewall twist might cause the tire to actualy "chatter" (skip up and down) under the extreme braking that F1 cars are capable of. Sidewall flex would also cause the tire to not turn quickly with the steering input due to the flex under load causing the tire to "twist" on the wheel.

This is all specualtion and I've never heard it mentioned in any talks about F1 technology but I'm guessing that it may have something to do with the rules in F1. I'd read their rule book to find out but it's WAY to extensive.

[badass]

Zak, while I agree that the vast majority of your points are true, I disagree with using GCSE/A level physics to explain the incredibly complex interaction between tyre and road.

The coefficient of friction is used a lot to prove that wider tyres do not equal more grip, but the coefficient of friction only applies to pretty hard, flat surfaces rubbing against each other.
An experiment to prove that coefficient of friction is a vast oversimplification (read cobblers)
take a newton meter. Attach it to a 1 KG block of something, with a tyre compound as the base. Pull the Newton meter at a constant velocity. Based on the coefficient of friction being constant, the meter will stretch up to the required force to break traction, and then remain there.
But that does not happen!
The meter moves out so far, then all of a sudden the block moves and the newton meter contracts a fair bit.
So we conveniently bolt on another bit of physics to explain it, without remotely trying to work out whats actually going on. The static coefficient of friction, and the kinetic coeficient of friction.


Reminds me of the pre copernicus ways of believing that the earth was the centre of the universe. problem was, due to planets not taking a constant path across the sky as you would expect if they were orbiting us, they would ovvasionally go back and forth. I cant remember the word they used for this but they just made up another term for it that "explained" why they would change direction back and forth again.
Of course it was all a load of Bull defacation

Just to prove the point further, try once the block is moving to change the velocity. Even though its still moving, the force changes depending on velocity.
There is no mention of velocity if the formula cF=F/N
cF being the coefficient, F being the force required to get it moving/keep the velocity constant and N being the force forcing the 2 surfaces together (the normal force)
Also note that there is no mention of surface area in that formula.
Everyone uses the surface area argument, but according to the coeficient of friction principles surfqace area has no effect.

The coefficient(s) of friction are simply to approximate the forces required to move 2 hard, smooth surfaces, nothing more.

[Shad]

Holy thread revival batman

[Zak33]

Zak, while I agree that the vast majority of your points are true, I disagree with using GCSE/A level physics to explain the incredibly complex interaction between tyre and road.

my man..if I HAD more than an A level in maths, I'd try again.

But I don't. So I can't.

However in taking all of those relatively valid points, you might as well open up the whole issue of road camber, tyre pressure changes across the tread surface, camber and caster change of the suspension under varying loads and a zillion other things.

I'm trying (I've ALWAYS been trying...ask my mum) to get it across to the majority of reader.

Cheers for your input. I'm open for a new thread if you're brave

[Moby-Dick]

sorry - my bad the issue croppe dup on the SXOC and I remebered we've covered it here !

there are so many variables to consider , I dont think you can come up with a definitive yes or know without looking at full FEA type simulation ?

what about some form of control experiment.

take a car - take 2 sets of wheels , with the same tyres and same tread pattern except that one is on an 8 in ch wide tyre , and one is on a 6 inch wide tyre. Ensure that the rolling radius is the same and that the tyres are not streached accross the wheel.
Then find an open are and start driving round in cirles untill you break traction ?

or again am I over simplifying ?

[badass]

my man..if I HAD more than an A level in maths, I'd try again.

But I don't. So I can't.

You and me both

However in taking all of those relatively valid points, you might as well open up the whole issue of road camber, tyre pressure changes across the tread surface, camber and caster change of the suspension under varying loads and a zillion other things.

Very true. Rather than doing that I think Moby dick answer is the best TBH. Experimental data is the easiest way of answering

I'm trying (I've ALWAYS been trying...ask my mum) to get it across to the majority of reader.

Cheers for your input. I'm open for a new thread if you're brave

And you do a good job of it

[Zak33]

cheers :blush: but I do need people to keep me on my toes.

Rocket Man X (who I miss frm him not being here) is really good at keeping me straight n true

as is Moby /\

[Moby-Dick]

I try

so how can we do some hexus/brainiac tests to see which is right ?