Wide Wheels & Physics

Submitted by Anonymous User (not verified) on

Forum: 

Please could somebody explain to me whether & how wide wheels give more grip upon the road surface?

In my head - wider wheels would give more traction, better handling etc.. because there is more surface in contact with the road - therefore more friction etc...

*BUT*

my physics lessions at school always stated that pressure was = force / area.
So, if the wheels are wider and therefore there is more area for the same weight of the the car, the pressure becomes less.
So does this result in less grip / traction / etc... ?????

Can anyone help me!?
(please Smile

Tyre Grip

Submitted by evansthesheep on

Your basic assumptions are more or less right, the wider the tyre, the more area there is in contact with the road surface, so the forces transmitted to the road by the tyre is dispersed over the footprint of the tyre increasing traction. There are other things that affect this, such as the coefficient of friction of the tyre, tread depth,tyre aspect ratio (the height of the sidewall in relation to the width of the tread)temperature, the list goes on!
When there is reduced friction between the tyre and the road surface there are two ways to deal with it, the most common is to use large wheels and tyres and to reduce the pressure inside the tyre to increase the contact patch and spread the load, effectively trying to float over the surface.
The other method, and lets face it one of the most effective 4x4's are the early Landrovers, is to use narrow tyres with a high pressure to force the tyre through the mud or snow until it can grip on a firmer surface underneath.
Not the most technical answer I know, but hopefully of some help.

So, what you're essentially s

Submitted by Anonymous User (not verified) on

So, what you're essentially saying, is that (given a wider wheel & therefore greater surface area) although the down-pressure at any given point on the surface is lesser, there is more grip due to the increased friction between the wheel and road - due to there being more of it (in contact) Unknw

big is best

Submitted by evansthesheep on

yes, basically, if you think about it when a 4x4 gets stuck in a field what pulls it out? a tractor with two wheel drive but huge wheels and tyres which transmit the torque over a larger area. The friction doesn't increase, because there is a larger contact patch the effort needed to overcome the resistance is less, and is proportional to the area available to transmit the power.
I think that makes sense, but I've had a lager or two now, so will check what I've said tomorrow!