Hope it is the right place to ask this question:

I am looking at data from slick tyre manufacturers (Michelin, Dunlop, Hankook, Avon) trying to figure out if I really need new rims for slicks in size 20/54/13 (front axle, for rear I have have 24/57/13 tyres with reccomended 10" rims, so only issue is front axle) .
I already have spare rims in 7" width which I can use. But all manufacturers above say that for those size of tyres (or similar - 180/55/13 - Hankook) the optimal rim width is 9" (8 - 9 "permitted" ).

example for Michelin sizes : https://samotorsporttyres.com.au/product/michelin-racing-slick/

I wonder if it will be a big difference in driving on 7" instead reccomended 8-9" with 20/54/13 od 18/55/13 slicks on it ? Considering those are going to be for wet tyres (or as spare for dry (already have one pair of 8" x 13" ) - so not so often usage I hope.

Is it true that for wet slicks it is more acceptable to use narrower rims than optimal ?

What are Your experiences on tracks ?

TIA!

[Edited on 21/10/19 by Andrzejsr]

[Edited on 21/10/19 by Andrzejsr]

I essentially use 200/540 13 and 250/570 13 " (standard F3 sizes) and the wheels are 9.5" fr and 10.5" rear. Getting a 200/540 (or equivalent) on a 7" rim isn't going to work, you need 180 or even 160 on 7".

Thank You for sharing Your experience !