Why have those BIG BIG wheels??????

[normski]

Other than looking good, there is totaly NO benefit  to those 13inch wide wheels regards grip! You may just as well have 2CV wheels on your RX7!

Why?  well all to do with the law of friction.

THE laws of static friction are usually described as: (1) F = R, which governs the relation between limiting frictional force F and normal reaction R; and (2) the coefficient of friction  is independent of the apparent area of contact.

Ummmmm!

[shaunwil]

Thats silly. So what you are saying you could get better times drag racing on 2cv wide wheels than drag radials even if the rubber and compound was exactly the same ??

Why do formula 1 cars not just run on bicycle tyres ??

Shaun

[RemarkLima]

Heh heh, that old chestnut!

Yes, the contact patch is the same area on wider tyres (given the same construction, sidewall stiffness, temperature and pressure), F(orce) = M(ass) x A(rea).

However, on a wider tyre there\'s more lateral grip as you have more rubber going sideways.

And the major benefit? Better heat dissapation, sounds bizzare but the wider the rubber the more rest it has between contact with the tarmac, even if it\'s only a small amount it allows the tyre to remain cooler and maintain grip without overheating.

Apparantly

[od404]

The following link might shed some light on the mechanics behind tyre grip.  Needless to say it\'s a complex subject (kinda makes me glad I design engines and not tyres ).

http://reviews.hspn.com/articles/128/1/The-Physics-of-Racing-Part-10-Grip-Angle/Page1.html

[MikeLMR]

thats a good link and shows just how complicated anything is when you try and do anything but a rough estimate.

I remember reading somewhere that they amount of grip given by a proper top fuel style wrinkle wall slick actaully defies some of the formula\'s used to try and estimate grip due to the fact that the tyre deforms and absorbs energy + the fact that it is practically stuck to the track as well!

[RedRummy]

wider = more rubber on ground... period.

[MikeLMR]

wider wheels ... or tyres? oh there\'s another debate narrow tyres on wide rims and wide tyres on narrow rims ... a can of worms on many forums

[BlitzBoy]

Bit confusing this thread
I think as I understand it the diameter of the wheels has an effect on grip as well.
Eg having 18 or 19 inch wheels on the drag strip degrades the amount of traction you have off the line, you better off with 16 inch diameter wheels as you have more of a sidewall of the tyre which will allow flex and less prone to wheel spin.
Thats why a lot of drag tyres have huge sidwalls mounted on 16 or 15 inch diameter wheels to allow flex and deformation of the tyre to gain traction

[RemarkLima]

wider = more rubber on ground... period.

How so? Pressure = Force / Area

So if you get wider tyres, there\'s a wider area for the same weight (add in gravity to you mass), so that same area must be thinner (front to back)

But of course this is all static... Add some movement into the equation and it get\'s weird.

[Paul-Tll]

My thinking is a wider tyre would be more likely to find the \'grip\' point over a larger area.
So if yout tyre was a foot wide and only 1inch of the ground had grip and say the other 11 inchs was pollished metal, Ice or grease you would have at least 1 inch of good contact, where as a Bike wheel may never find that one inch of available grip.
P.

[weejimmy]

why do people get so tecnicall about antsy things. . .
 
once i was listening to a raceing driver at knockhill being interviewd. he was asked why dose he still weav about the track on warm up when its "proven" it dosent heat tyres up any more due to bla bla bla.
answer: if i dont, i crash at 1st corner.
 
easy answer.
 
if you think skinny tyres are good go for it. ill just keep my wide ones thanks,

[dthebuk]

Other than looking good, there is totaly NO benefit  to those 13inch wide wheels regards grip! You may just as well have 2CV wheels on your RX7!

Why?  well all to do with the law of friction.

THE laws of static friction are usually described as: (1) F = R, which governs the relation between limiting frictional force F and normal reaction R; and (2) the coefficient of friction  is independent of the apparent area of contact.

Ummmmm!

its a simple model like assuming theres no air resistance on a falling body

makes its easier to understand a level mechanics apparently :Hammer

[shafster]

i like the look of wide tyres hence having 19x12 rear wheels

[chrisJDM]

i went from standard alloys to 18x8.5j front and 18x9.5j rear, the new ones weigh alot more and i think they have maybe taken a slight bit of acceleration but not alot, i had similar tyres on both sets, on the new ones the handling is alot better and much more grip.

[Timmy]

This makes no sence if F= M x A and you increae A surely you have more force.
 
ie
 
M is 10
A is 10
so F = 10 x 10 so F = 100
and if we increase A to 20 F= 200