Hi Jochim, I saw your post at the F1 thread:

All about tires my man all about tires... I was on the same boat till few of my buddies lend me a use tires and walla its was freaking dialed. New set of F1 tires don't work for crap as the sidewall is stiff as heck... Key is sand it down enough where the side wall of the tires is rounded. and WD40 the crap out of the tires before race days. It's guarantee you will have traction galore and it does not matter what tires you use follow this break in steps and it will be cherry.

May I know specifically how you sand the side walls? Like how much you sand and if you sand both inside and outside or just the outside? Much appreciated!

Gab