## Confusion over 2022 Rim Sizes

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1
Joined: Sun Sep 18, 2022 7:05 pm

### Confusion over 2022 Rim Sizes

Hello, I recently developed an interest in F1 technology and modern suspension components, but have some confusion about the "18 inch wheels" on the 2022 cars.

As stated in the 2022 FIA F1 Technical Regulations section 10.7.2 Wheel Rim Dimensions:

The front wheel rim key dimensions are:
- Tyre mounting width = 335.3mm +/-0.5mm.
- Outer lip diameter = 490,6mm +/-1mm.
The rear wheel rim key dimensions are:
- Tyre mounting width = 429.3mm +/-0.5mm.
- Outer lip diameter = 490,6mm +/-1mm.

I am confused because the outer lip diameter of 490.6mm = ~19.3in, not 18in.

Any clarification would be much appreciated. Thanks!

Tommy Cookers
Tommy Cookers
592
Joined: Fri Feb 17, 2012 3:55 pm

### Re: Confusion over 2022 Rim Sizes

afaik
what the FIA presumably would call tyre mounting diameter will be 18"
the correct name of this in English is bead seat diameter

too many rubbish translations come from the FIA - and accepted by the rubbish english-language press

jjn9128
752
Joined: Tue May 02, 2017 10:53 pm

### Re: Confusion over 2022 Rim Sizes

There's an overlap or the tyre bead and the wheel rim lip so the tyre is held in place. They're wheels for 18"tyres. The 13" tyres had 358mm rims.
#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

RGAEDA
RGAEDA
0
Joined: Thu Jul 23, 2020 3:32 pm

### Re: Confusion over 2022 Rim Sizes

What a coincidence! I was thinking about this a few hours ago. Can anyone provide a diagrammatic representation putting this into perspective?

jjn9128
752
Joined: Tue May 02, 2017 10:53 pm

### Re: Confusion over 2022 Rim Sizes

#aerogandalf
"There is one big friend. It is downforce. And once you have this it’s a big mate and it’s helping a lot." Robert Kubica

chrisc90
10
Joined: Wed Feb 23, 2022 8:22 pm

### Re: Confusion over 2022 Rim Sizes

As above, the mounting width of the tyre where the bead sits will be narrower than the actual lip of the wheel.

If the bead/mounting was the same as the rim diameter the tyre wouldnt seal against the bead and would just slide off.
No Mikey Noo! No! Nooo Mikey! That was sooo not riiight!!

RGAEDA
RGAEDA
0
Joined: Thu Jul 23, 2020 3:32 pm

Thanks guys.