Quote:
Originally Posted by V8 Fireworks
At least two cars from the 1968 season already used 15" wheels:
Front rims: 15x8.5"
Rear rims: 15x9.5" (Lotus 43 sizes, 49 may be wider)
Front rims: 15"x9.65"
Rear rims: 15"x11.5" (Honda RA273 rim sizes)
Source: http://srmz.net/index.php?showtopic=4952
Therefore 13" wheels with high profile tyres being regulated in Formula One was surely arbitrary and of no real engineering basis? I think the rear wheels were restricted to 13" first, as teams still had a choice of 15" fronts in the early 80's.
Why stick to 13" when USAC allowed 15" to the present day with no issue? 13" is so arbitrary, adopting 18" is perfectly fine... The only drawback is the FIA increasing the total tyre diameter as well, which is silly.
18" wheels with 680mm tyres (so only +10mm instead of +55mm) look perfectly ok:
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Yes, smaller cars means smaller wheels look equally good. For clarification again, I'm not suggesting to stick with 13-inch. I'm saying use the same tyrewall height as the 18-inch but on a 16-inch wheel for a overall diameter of 670mm.
Here's a picture that compares the 13'' to the 18'' (and this is without the wake deflector):
See how much wider the rears actually look on the smaller diameter?
They would nut be very dissimilar to a 15-inch indycar tyre. Just a slightly larger 16-inch wheel and a slightly lower side wall within roughly the same diameter.
Since 2016 the wheel/tyre combo gained ~16.5kg due to the extra width in 2017 and another 14kg due the larger diameter wheels and tyres in 2022. So in total the wheel/tyre combo got more than 30kg heavier. All rotational unsprung mass.
If in 2026 we drop the MGU-H and we then do get the originally planned addition 20cm reduction in wheelbase on the current 10cm reduction (or perhaps even a bit more), we could go to a smaller diameter again which would still be nicely in proportion to the then smaller car.
I could then imagine the following size:
Front 265/670/16
Rear 365/670/16
For reference:
2016:
Front 245/670/13
Rear 325/670/13
2022:
Front 305/720/18
Rear 405/720/18
That tyre/wheel combo would weight about 15kg more on all corners combined than the 2016 combo, but 15.5kg less than the 2022 combo.
You'd have:
- The same tire wall height of the 2022 cars.
- Proper visibility
- Wheel size still nicely in proportion to the then smaller cars.
- Less aquaplaning
- Less spray
- Less (unsprung) (rotation) mass.
- Less drag
- Less aero interference
- 8cm wider opening leading to the venturi tunnels.