Sorry for the bandwidth but in all the discussion about wheel sizes and damage to larger wheels from potholes etc, I have to wonder why FIA World Rally cars that run on very rough, potholed and cratered paved roads run very large wheels with low profile tires while the Formula 1 Grand Prix cars, running near 200mph on very smooth tracks run a seemingly "normal" aspect ratio.

Seems it would be the other way around doesn't it?


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Happy Motoring, Erwin in Memphis, '95855t

This one I know, at least the F1 part anyway.

Formula 1 used carbon brake rotors, which can handle EXTREME temperatures and generate tremendous braking force. Therefore F1 has mandated 15" wheels as a way of limiting braking technology. With a 15" rim, you can't have much more than a 13" diameter brake rotor ans still have room for the calipers and enough room to do a quick tire change. As it is F1 cars pull over 3g's of negative acceleration under braking. For comparison that's like being suspended face down in the air, hanging by your seat belts and having a 400 pound person sitting on your back.

Tire diameter is also mandated, as are the 4 grooves you see in modern day F1 tires. Until the rules change (not likely) F1 will stay the same.

Bye the way, I have been to the two F1 races at Indy. Before the races there are Porsche Supercup (racing 911's) and Ferrari 355/360 races. The F1 braking distance from 180 mph is less than 1/2 of the Porsche and Ferrari cars from 150mph.
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Nathan Valles, Black 855R, Tint

I just rechecked the FIA regs for F1. Formula one is limited to using 13" rims not 15" rims as I posted earlier. OOPS.
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Nathan Valles, Black 855R, Tint

F1 cars have no fenders so the air must go over the tires. there is less wind resistance in the smaller tires. (That was one of the reasons for the 6 wheeled elf cars)

You have a pic of a WRC car with low profile tires? I spent 2 campaigns working closely with a WRC Talon back in the mid 90s. I never once saw low profile tires on any of those cars.

Here's a pic of the last race in Spain. On the tarmac they have some pretty low profile tires going, but on gravel and such they get taller.

I've been hooked watching the races on Speed channel!

www.wrc.com

http://content.wrc.com/en_GB/Gallery/Photo/2002_R_E_PanizziAction.htm

http://content.wrc.com/en_GB/Gallery/Photo/2002_R_F_PanizziBreaksdownShakedown.htm

rules is rules.

They mandate the F1 cars' tire dimensions to slow them down so they're not hitting light speed in the corners, for safety reasons. (Just as competitive if everyone is going 170mph as when everyone is doing 200mph...)

-Paul Demeo
1990 780T

Thanks,

I knew the width was regulated but didn't know about the aspect ratio. Rules. Not a real concern in my 855t then. I might drop from the 16s to 15s just for a comfier ride.

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Happy Motoring, Erwin in Memphis, '95855t

most race series based on actual sedans/coupes/wagons, like the british touring car championship, dtm, etc, run fairly low profiles. wrc isn't quite as low as those series. plus, they carry spare tires or some fixit things don't they? they repair anything from tires to engines on the spot...hardcore. on f1, it's 13" rim diameter, with fairly thick tires. as erwin said, it's to slow the drivers down. can u image how hard th ride would be if they'd actually had like almost no rubber =).