Formula One Tyre Diameter Changes in the 90's.

[OO7]

Until this 2017 season, the maximum diameter of dry weather tyres has been 660mm (26") and that maximum diameter had been imposed since the 80's, may be earlier. Goodyear manufactured Formula 1 tyres of 660mm for the rears and 635mm (25") for the fronts at least until after 1994. Does anyone know if Goodyear ever switched to a 660mm front tyre and if so when or did this only happen with Bridgestone?

[Vyssion]

Until this 2017 season, the maximum diameter of dry weather tyres has been 660mm (26") and that maximum diameter had been imposed since the 80's, may be earlier. Goodyear manufactured Formula 1 tyres of 660mm for the rears and 635mm (25") for the fronts at least until after 1994. Does anyone know if Goodyear ever switched to a 660mm front tyre and if so when or did this only happen with Bridgestone?

The rear tyres of the McLaren MP4/7A-8 were manufactured by Goodyear and sized at: 660mm x 381mm R13 whilst the front tyres were 635mm x 254mm R13. In 1992 there was a width reduction in the rear wheels to slow the cars down.

Before that, the 1979 Alfa Romeo Tipo 17 used 635mm x 241mm R15 for the front and 737mm x 330mm R13 at the rear. The 635mm fronts seem to have stayed put over the decade or so Goodyear was supplying tyres, so I am not sure if fronts ever were taken to (or reduced from) 660mm. Before the 1970s, you seem to be moving into the tiny thin wheels with very few aero devices present, and before that, youre in the "slipstreaming" era of F1.

[OO7]

The rear tyres of the McLaren MP4/7A-8 were manufactured by Goodyear and sized at: 660mm x 381mm R13 whilst the front tyres were 635mm x 254mm R13. In 1992 there was a width reduction in the rear wheels to slow the cars down.

Before that, the 1979 Alfa Romeo Tipo 17 used 635mm x 241mm R15 for the front and 737mm x 330mm R13 at the rear. The 635mm fronts seem to have stayed put over the decade or so Goodyear was supplying tyres, so I am not sure if fronts ever were taken to (or reduced from) 660mm. Before the 1970s, you seem to be moving into the tiny thin wheels with very few aero devices present, and before that, youre in the "slipstreaming" era of F1.

Thanks for the reply Vyssion.

Weren't rear tyre widths reduced for 1993?
Also according to this page, https://en.wikipedia.org/wiki/Formula_One_tyres Goodyear were supplying tyres from 1964 to 1998, so 35 years?

I'm trying to find good quality, high res profile pictures of Goodyear runners in 1997 (all cars used Goodyear in 1997) and 1998. That way I should be able to take measurements myself and determine if the diameter of the fronts was always less than the rears.

[Vyssion]

Weren't rear tyre widths reduced for 1993?

Possibly - It may have been set out in 1992 and implemented for the 1993 season.

Also according to this page, https://en.wikipedia.org/wiki/Formula_One_tyres Goodyear were supplying tyres from 1964 to 1998, so 35 years?

I'm trying to find good quality, high res profile pictures of Goodyear runners in 1997 (all cars used Goodyear in 1997) and 1998. That way I should be able to take measurements myself and determine if the diameter of the fronts was always less than the rears.

They were part suppliers for a lot of the 1960s to 1970s with them only being the sole suppliers for the years 1985 to 1997. Again though, a lot of the earlier F1 cars in that era were still skinny tyres with the late 1970-1980s beginning to be the wide tyre types. Regarding fronts ever being the same size as the rears, I would hazard a guess that the answer is no since (at least to my knowledge) all F1 cars are rear wheel driven and so the fronts would ideally like to be minimized to limit the aero drag they impart (e.g. the 6-wheel Tyrrell) because they only need to handle steering. I'm not sure if F1 cars have a 50/50 weight distribution, but if not, then they would most likely be biased rearward, which again, means bigger rears always.

[OO7]

Possibly - It may have been set out in 1992 and implemented for the 1993 season.

Yes, I think that's correct.

They were part suppliers for a lot of the 1960s to 1970s with them only being the sole suppliers for the years 1985 to 1997. Again though, a lot of the earlier F1 cars in that era were still skinny tyres with the late 1970-1980s beginning to be the wide tyre types. Regarding fronts ever being the same size as the rears, I would hazard a guess that the answer is no since (at least to my knowledge) all F1 cars are rear wheel driven and so the fronts would ideally like to be minimized to limit the aero drag they impart (e.g. the 6-wheel Tyrrell) because they only need to handle steering. I'm not sure if F1 cars have a 50/50 weight distribution, but if not, then they would most likely be biased rearward, which again, means bigger rears always.

The weight distribution for F1 cars has more weight at the rear, but I can't remember how much. The weight distribution limits are published in the tech regs. I think there is about a 5% difference in it, with teams able to vary the amount by a tiny margin.

On Bridgestone's website, they explained how the diameter of their front tyre was increased by 10mm for 1998. Looking at pictures and considering a possible desire to accommodate all teams, I think Bridgestone in 1997 may have run a front tyre that was very similar to the Goodyear, that is a diameter of 635mm. If not 635mm, it was a value less than the 660mm of the rear tyres.

I'm not so sure about the Michelin and Bridgestone tyres from 1999 onwards, but since 2011 Pirelli's front tyres have been of the same diameter as the rears, 660mm.

[SuperDrummer]

Weren't rear tyre widths reduced for 1993?

Possibly - It may have been set out in 1992 and implemented for the 1993 season.

Also according to this page, https://en.wikipedia.org/wiki/Formula_One_tyres Goodyear were supplying tyres from 1964 to 1998, so 35 years?

I'm trying to find good quality, high res profile pictures of Goodyear runners in 1997 (all cars used Goodyear in 1997) and 1998. That way I should be able to take measurements myself and determine if the diameter of the fronts was always less than the rears.

They were part suppliers for a lot of the 1960s to 1970s with them only being the sole suppliers for the years 1985 to 1997.

Actually the date range for GoodYear being the only supplier is a bit inaccurate. Pirelli came in 1989 for a 3 year campaign and I believe they were absent only for two years before that (1987, 1988). And in 1997 Bridgestone arrived into F1 after their huge success in CART series in the previous year, and helped Ligier/Prost deliver some great results taking the team budget into account. If Panis didn't crash in Canada he might have finished the season as high as P3.

[gdogg371]

The rear tyres reduced in width from 18 inches to 15 inches for the start of the 1993 season. The rear wing height also reduced from 1000mm to 900mm as measured behind the rear axle. This led to the supremely ugly double rear wings used in 1993 and up to Spain 1994, where a second 1000m rear wing was used in front of the rear axle at high downforce circuits.

[OO7]

The height of the rear wing was reduced from 1000mm to 950mm above the ground.

[gdogg371]

The height of the rear wing was reduced from 1000mm to 950mm above the ground.

Hungary 1993 was an ugly race...

[OO7]

The height of the rear wing was reduced from 1000mm to 950mm above the ground.

Hungary 1993 was an ugly race...

I don't mind the double rear wing look for the high downforce circuits , but yes, ahead of the rear wheel centreline bodywork could be 1000mm above the ground, behind it 950mm.