Runestone
Well-Known Member
- First Name
- Sten
- Joined
- Mar 14, 2021
- Threads
- 6
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- 58
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- 91
- Location
- Stockholm
- Vehicles
- Cross Turismo 4S
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- #1
I have been agonizing over which wheel size to pick, so I decided to do some calculations (and yes, I have read the other threads on this). Looks are important, but drivability even more son (at least to me). I have been a little worried about the larger tires on less than perfect roads. Things are complicated by the fact that the larger wheel not only has a lower rim but also is wider (which is positive on dry road and negative in rain). So if we start by looking at the wheel sizes we have:
You can use that to calculate the height of the rim in mm.
You can further use that to calculate the volume of the tire. This can give an indication of how much ”unevenness” the tire can swallow. The volume is given in dm^3 (= liter).
It seems that going from 20 to 21 is a bigger step than going from 19 to 20 (especially concerning volume). It is also interesting to compare this to other cars. If you for example compare 20’ on a Taycan and 20’ on a Tesla S you find that the rim height is a little lower on the Tesla. I also checked the tires on my daughter's new Audi A5 (default wheels) and they are 18’ with 245/40, which gives a 98 mm rim height and only 14.3 liter volume. It lighter car, but not an extreme sports car.
So my conclusion is that the Taycan wheels not are as aggressively configured as the rim diameter might suggest. Which I think is a good thing. I feel that 20' will be a good choice for me.
PS
I think that these two videos are good practical tests of rim height and tire width differences:
Front | Rear | |
19' | 225/55 | 275/45 |
20' | 245/45 | 285/40 |
21' | 265/35 | 305/30 |
You can use that to calculate the height of the rim in mm.
Front | Rear | |
19' | 124 | 124 |
20' | 110 | 114 |
21' | 93 | 92 |
You can further use that to calculate the volume of the tire. This can give an indication of how much ”unevenness” the tire can swallow. The volume is given in dm^3 (= liter).
Front | Rear | |
19' | 19.3 | 23.5 |
20' | 18.0 | 22.0 |
21' | 15.4 | 17.4 |
It seems that going from 20 to 21 is a bigger step than going from 19 to 20 (especially concerning volume). It is also interesting to compare this to other cars. If you for example compare 20’ on a Taycan and 20’ on a Tesla S you find that the rim height is a little lower on the Tesla. I also checked the tires on my daughter's new Audi A5 (default wheels) and they are 18’ with 245/40, which gives a 98 mm rim height and only 14.3 liter volume. It lighter car, but not an extreme sports car.
So my conclusion is that the Taycan wheels not are as aggressively configured as the rim diameter might suggest. Which I think is a good thing. I feel that 20' will be a good choice for me.
PS
I think that these two videos are good practical tests of rim height and tire width differences:
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