Most traction, heavy or light vehicle?

[HertsBiker]

Always wondered this. Think light, but then....

[miniman]

Depends on tyre width doesn't it? Light car with wide tyres will be worst - least weight per area of contact.

[Slow]

Something weighing 100000 tons would have the most i presume.

[Buff Mchugelarge]

If the weight is over the tyres, heavy.

Hence downforce etc

[Willy Nilly]

My 8 tonne tractor has more traction than your car.

[Matt UK]

Buff Mchugelarge said:

If the weight is over the tyres, heavy.

Hence downforce etc

Agreed - seem to remember somewhere that the designer of the Nissan GT-R wanted a 'heavier' car to aid traction due to a lack of proper down force.

[Ozzie Osmond]

Traction may get you off the line but if you've got too much mass it's then very hard to accelerate.

Best to put up with limited traction and have good acceleration through the range.

[miniman]

Willy Nilly said:

My 8 tonne tractor has more traction than your car.

Interesting, but not sure its as simple as that. My mate's horsebox was stuck in a field and we tried to pull it out with a tractor. All we succeeded in doing was digging a couple of trenches in the ground and snapping a chain. Someone who knew what they were doing pulled it out with a Discovery.

[Raize]

miniman said:

Willy Nilly said:

My 8 tonne tractor has more traction than your car.

Interesting, but not sure its as simple as that. My mate's horsebox was stuck in a field and we tried to pull it out with a tractor. All we succeeded in doing was digging a couple of trenches in the ground and snapping a chain. Someone who knew what they were doing pulled it out with a Discovery.

I have a discovery and a tractor. The discovery is a more competent vehicle for such towing.
The tractor is a grey fergie from the 1950s. Not all tractors are created equal.

Vehicles with more weight will have more traction. Look up "Ballast trucks". If more weight did not cause more traction these would not exist. Therefore weight = traction.

[ging84]

this is the dumbest thing i've ever seen how could anyone thing being lighter would give you more traction ?
you could put wings on car to create enough lift to match the weight of the car and have infinite grip, rather than none

[digger the goat]

[otolith]

To a first approximation - the amount of lateral or longitudinal force you can generate through your tyres is proportional to the weight acting upon them and the amount of force you need to achieve a given acceleration is proportional to the mass of the car. In other words, to a first approximation, the effects of weight on the traction you have and the traction you need cancel each other out and thus weight makes no difference.

This assumes no aero, a reasonable assumption for a road car.

It also assumes that the weight you are accelerating acts proportionately upon the driven wheels - if you are pulling something with a rope, that's a different matter.

Edited by otolith on Monday 18th February 03:19

[R26Andy]

Friction is independant of area. Small or large tyres will generally not change the levels of grip.

[Bill]

R26Andy said:

Friction is independant of area. Small or large tyres will generally not change the levels of grip.

Eh? Which is why cars can brake better than bikes, despite weighing more and the put grooves in F1 tyres to reduce grip.

[98elise]

miniman said:

Depends on tyre width doesn't it? Light car with wide tyres will be worst - least weight per area of contact.

Unless you reduce pressure in the tyres the contact patch area is always the same regardless of tyre width. Ifs just a different shape witha wider tyre.

[Monty Python]

R26Andy said:

Friction is independant of area. Small or large tyres will generally not change the levels of grip.

Partly right - in some instances under ideal conditions it is, but in the real world it's more complicated. A larger tyre has a larger contact area, so you'd think the frictional force would be higher. However, the pressure between the two surfaces is lower (since pressure = force/area), so the extra friction is offset by the reduction in contact pressure. Frictional forces are dependent only on the frictional coefficient of the materials and the force holding them together.

It's complicated with tyres as you have to factor in construction and tread design.

Edited by Monty Python on Monday 18th February 07:52

[Scuffers]

and that tyres don't grip by just friction.

[djdestiny]

The truck drivers at work always ask for a bit more weight over the driven wheels when its snowing

[6fire]

Depends on more than just weight. There is a reason piste bashers, snow mobiles and vehicles like the BV 206 have wide tracks. I'd wager that all have better traction than a heavier 'normal' equivalent vehicle when operating on their usual terrain.

[Liokault]

Scuffers said:

and that tyres don't grip by just friction.

? Really, please expand on this.