Re: Cornering - road car v F1 car

The coefficient of grip (cg) is a measure of the adhesion between two
surfaces 'for a given contact force'. The contact force in most situations
is the weight of the object. Contact force x cg = total grip. When just the
weight of an object is pressing it down onto a horizontal surface then
contact force = 1 and lateral grip in g force is the same number as the cg.

Downforce simply increases the contact force and the grip varies directly
with it. The coefficient of grip doesn't actually change much. In fact for
tyres it decreases slightly as contact force increases.

Put a box on a table and ask someone to move it by pressing laterally. Now
put your hand on it and push it down and ask them to try again. What changed
was not the cg but the contact force.

For road tyres in the dry the cg varies between about 0.85 for something
cheap and cheerful and just over 1 for the best rubber with a reasonable
life. In the wet between about 0.6 and 0.85. Very soft compound racing tyres
have a cg of about 1.3. The grooved F1 tyres might be a tad lower than this.

The maximum cornering g force possible is thus the same number as the cg for
road cars with no appreciable downforce and up to three times the cg for F1
cars that generate twice their own weight in additional downforce at top
speed. Downforce varies with the square of speed so at lower speeds it's a
very much smaller number.
--
Dave Baker
Puma Race Engines- Hide quoted text -

I've never understood how a dragster can generate up to 4G in the
split second BEFORE any downforce aero occurs --- the old mantra used
to be that 1G "must" be the limit for grip. Odder still (less so
today), bygone dragsters were exceeding 1G even during massive
wheelspin at the start --- how can this be?

.

Relevant Pages

  • Re: Cornering - road car v F1 car
    ... is the weight of the object. ... Contact force x cg = total grip. ... Downforce simply increases the contact force and the grip varies directly ... For road tyres in the dry the cg varies between about 0.85 for something ...
    (rec.autos.sport.f1)
  • Re: Cornering - road car v F1 car
    ... I think you'll find what he actually said was "coefficient of grip" not ... Downforce simply increases the contact force and the grip varies directly ... For road tyres in the dry the cg varies between about 0.85 for something ...
    (rec.autos.sport.f1)
  • Re: Cornering - road car v F1 car
    ... I think you'll find what he actually said was "coefficient of grip" not ... Downforce simply increases the contact force and the grip varies directly ... For road tyres in the dry the cg varies between about 0.85 for something ...
    (rec.autos.sport.f1)
  • Re: Cornering - road car v F1 car
    ... I think you'll find what he actually said was "coefficient of grip" not ... Downforce simply increases the contact force and the grip varies directly ... For road tyres in the dry the cg varies between about 0.85 for something ...
    (rec.autos.sport.f1)
  • Re: New Tyres
    ... People often forget how much the handling of a car is influenced by ... This is before considering just how much grip you *actually* need ... Some tyres wail their protest at moderate ... tyre is designed for something with another 100 kg of weight on each corner. ...
    (uk.rec.cars.modifications)