Quote:
jmac wrote:
l18-b110 - I keep squeezing the other things in because it is important. Hell I didn't even mention that the wider the tyre the less camber it tends to 'like' - which can be indicative of things.
you shouldn't have mentioned it, because its completely wrong. the wider tyre will gereate more lateral grip and work better with more camber to optimise its contact patch during cornering. Same goes for if you upgrade from semis to slicks in the same width. More rubber on the road means more surface area interacting with the road and more grip. Again they like more camber as a result.
Quote:
jmac wrote:
Of course f1 (or anyone else) is running the widest tyres they can (or what they must run) - you're mis-interpreting what I'm getting at. The reason to run wider tyres is not because they grip better 'per se' - if that's the case I welcome you to get some bob jane australian all rounder tread put on some 265 width tyres, and I'll bring some toyo ra1s around to compare.
you're not even reading, just arguing your points over and over - as I said last time, "it's obvious that different types, brands and models of tyres offer different amounts of grip. No one's arguing that. But as per my example of the exact same tyre, you get the more grip from the wider widths. Thats removing all those variables"
Quote:
jmac wrote:
What I am saying is the _reason_ for the widest tyre possible in a racing situation is to give the opportunity to run the stickiest compound possible, but still get enough tyre life to finish enouh laps between pitstops (or the sprint race distance or whatever). It's not just the width.
as someone who actually uses slicks and semi slicks over the past 10 years, I like to find out what I'm paying $1600-2000 a set for.
Kumho slicks and semis - come in 3 compounds. You choose which compound you want in whatever size you buy.
Dunlop DZ03 made in 3 compounds. You choose your compound.
Yokohama A048 - made in 3 compounds depending on size. Contrary to your assumption, Australian availability of compounds is such that bigger sizes come in harder compounds to suit larger heavier cars.
Yokohama A050 - made in 2 compounds in each size. you choose.
Bridgestone RE55S - made in 3 compounds. you choose.
Toyo R888 - 2 compounds I know of - GG and GGG. Aus distributor network only has one compound available - GG. Can special order the softer GGG though.
Toyo RA1 came in 2 compunds. Earlier RA1 (which were on the 230rwkw 1200 I had) had a UTQG of 40 and were the gun tyre for hillclimbing and wet conditions when they first appeared on the scene. Later tyres all had a UTQG of 100, which is the same as the R888 GG.
Federal FZ201 make 2 compounds. You choose.
there's more brands available, but you get the idea.
Summary is no tyre manufacturer makes the wider sizes of their performance tyres in softer compounds as you claim. Even in street tyres, the model of tyre has a compound used accross all sizes in its range. EG all Kumho KU36 are 180 UTQG. All Federal 595RSR are 140 UTQG, etc etc. Tyre manufacturers don't waste money making several slightly different compounds getting slightly softer as the tyres get wider as you seem to assume. The production costs would be outrageous!
Quote:
jmac wrote:
If you wouldn't mind (and I ask this sincerely, not as a smartalec) - do you happen to have pyrometer readings for the tread - possibly - outer and inner edges and centre region - for the tyres you ran that had the big difference before and after. It'd be interesting to see the spread of temp - both from before and after different tyres, but also to know what temps they ran across the width of the tread, it might be enlightening (to me, if no-one else)
Like 99.99% of club level racers, I don't have a pyro. I use an infra-red temp gun to get surface temps to see if the camber and pressures are in the ballpark. Admittedly more useful for pressures which don't drop off very quickly, but still better than nothing for checking out camber. My current FZ201 medium compound hit between 55 and 65 degrees across the tyre surface - LF & LR around 65deg, RF about 60 and RR about 55deg at Lakeside IIRC.
Quote:
jmac wrote:
I'm DEFINITELY not advocating running 155 width tyres or anything. I hope I haven't come across like that.
what you came across as saying is that width has absolutely no influence on grip:
Quote:
jmac wrote:
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.
If a 195 has exactly the same grip as a 235, why wouldn't a 155 have the same grip as a 195? Given that tyre companies aren't making different compounds for each size of tyre, we should choose the appropriate brand/model of tyre for our intended purpose and then buy the narrowest size they have in that type of tyre because the wider ones have no more grip...
its just not the case as my example of going from 235 to 255 in the FZ201 Medium compound shows.
Transfer
