Time for a dumb question, take aim! (snow vs tarmac)
Discussion
After watching that GTR ski video, it reminded me of a question that's had me curious before but that I've just accepted as fact without knowing why.
It's a simple one, and I 'get it', but don't have a satisfactory reason why. So...
We all know that 'drifting' around a corner on tarmac is slow. You scrub off too much speed compared to taking the racing line. Naturally on snow and other slippy surfaces, this isn't the case, as clearly you can carry more speed if you're skimming along sideways with all 4 wheels spinning away merrily.
Now presumably this is because you don't 'scrub off' much speed when the surface is slippery? But what is happening that is allowing you to carry more speed when the car is sideways as opposed to if it was attempting to take a typical racing line? The wheels are spinning so are they not providing less grip than if they were gripping properly? Or is it because of the type of tyre used that the rules are a bit different?
Clearly it couldn't work the other way, you couldn't carry more speed through a hairpin on tarmac by throwing it in sideways and booting it, is it just because of the resistance to sideways motion being so much greater?
I assume there's some sort of relationship with the total grip level available, as early racing on skinny cross ply tyres etc. with much lower ultimate grip levels meant a slight slide was presumably the quickest way, hence why that's how they drove.
I'm rambling now, so somebody please educate me.
It's a simple one, and I 'get it', but don't have a satisfactory reason why. So...
We all know that 'drifting' around a corner on tarmac is slow. You scrub off too much speed compared to taking the racing line. Naturally on snow and other slippy surfaces, this isn't the case, as clearly you can carry more speed if you're skimming along sideways with all 4 wheels spinning away merrily.
Now presumably this is because you don't 'scrub off' much speed when the surface is slippery? But what is happening that is allowing you to carry more speed when the car is sideways as opposed to if it was attempting to take a typical racing line? The wheels are spinning so are they not providing less grip than if they were gripping properly? Or is it because of the type of tyre used that the rules are a bit different?
Clearly it couldn't work the other way, you couldn't carry more speed through a hairpin on tarmac by throwing it in sideways and booting it, is it just because of the resistance to sideways motion being so much greater?
I assume there's some sort of relationship with the total grip level available, as early racing on skinny cross ply tyres etc. with much lower ultimate grip levels meant a slight slide was presumably the quickest way, hence why that's how they drove.
I'm rambling now, so somebody please educate me.
I always presumed it was because you're using traction to pull you in the direction that you want to go. If you're sideways and all four wheels are spinning then they're all clawing away to get you around the bend. On dry tarmac you'd just rip all your speed off with the slip angle.
Could be completely wrong, interesting question.
Could be completely wrong, interesting question.
The principle isn't very different really; you still need to take the racing line. The main difference is that the slip angles are much wider before they become slide angles, so the car moves much more than if on slicks on a dry surface.
You also get the benefit of snow (or gravel/mud/etc) providing a modicum of lateral resistance, so a proportionally greater percentage of the tyre's traction circle can be used for acceleration.
You also get the benefit of snow (or gravel/mud/etc) providing a modicum of lateral resistance, so a proportionally greater percentage of the tyre's traction circle can be used for acceleration.
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