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jmac wrote:
I'm simplifying the tech stuff below - it's 'right' there's just a few minor other issues which affect overall grip (tyre hysterisis for one) but relatively speaking it is minor, and the 'main' issues are hte ones I mention below.
believe it or not, tread width isn't the big deal here. It's friction co-efficient of the tyre tread compound (apart from chassis/suspension tweaks to maximise downforce/grip)
Here's the deal - IF (and it's a big if) the tread compound is identical - then a 235 will provide exactly the same grip as a 195 width tyre. The reason is simple enough. Grip is a result of teh combination of 2 things - downforce and friction co-efficient. If you have the same tread compound, but halve the width, then there is double the 'load' on each square cm of tread, so it basically has the same grip.
Obviously you can get to a thin enough tyre where it'll just overheat too quickly. And it'll also wear out quicker (since at half the width, it'll have half as much tread area to wear down). Since thinner tyres will experience that, very generally, the tyre makers run harder compounds in thinner tyres, and can 'get away with' softer compounds on wider tyres and still have acceptable tyre life.
So in general, wider tyres 'might' grip more, but it's only because they were made with softer grippier tread, not just due ot the width all by itself.
that simply is not true in the real world. EG I went from a 235 rear to a 255 rear in the same brand and compound of semi slick and had so much more rear grip that it changed the handling balance entirely. Your theory simply doesn't work in practice beacuse you left out the part about grip coming from the interlocking of the rubber and the road surface. The wider tyre has more interlocking due to the increased surface area, while only margineally less psi pushing it into the surface - they only need so much pressure to grip, and once you get to that point it's the law of diminishing returns - doubling the pressure won't double the grip. Its not a linear relationship. Wider tyres of the same type and compound do provide better grip.
Quote:
jmac wrote:
Now, even people who compete in short sprint races can overcook their tyres, so you have to try and find a balance between tyre life, the traction you need, and how long they will be good for 'thrashing' around before they start to go off a little due to overheating. As a good example - this is why the smaller cars (relatively speaking) tend to do so well compared to the big ones in Improved Production - the tyre sizes are too narrow (relatively) for the bigger cars and they overheat after a couple of laps, so the drivers have to nurse them a lot more. They can't 'really' use grippier compounds, because the tyres/compound are a regulated item.
this is a poor example. the IPRA control yokohama tyres come in softer compounds in the smaller sizes, giving the smaller, lighter cars an advantage.
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