Wanting to fit GSD03 F1s to my P1, the size isnt an exact match, slightly narrower tyre height i believe (width). Will this be ok or should i stick to exact match?

Bloke at black circles reckons 215/45 will affect my gearing and a 205/40 will make my speedo over read by 5% - UGH - much is a speedo recalibration since dont fancy getting caught speeding due to some error!

What does he mean affect my gearing?

You won't get done for speeding if your speedo is overreading - only if it is underreading. This is perfectly legal.

higher sidewalls will give you a better ride, but you will loose crispness on turn-in, more roll and less stability.

Why not try some in the right size?

Only Bridgestone or Pirelli make the correct 'exact' size.

Both of which are to be frank crap - SO3s are a poor cousin of the SO2.

Tyres i rate are the Toyo, new Goodyear F1 GSD03 and the SO2.

Now being told that would be best to go with 215/45/17s instead of the car's actual 205/45/17s.

Anyone confirm this will be fine?

Get the 215/40/17
I put the F1 GSD03 on my P1 and highly rate them. Way better that the Pirelli tyres and i feel as good as the old S02's.

Gav

Chris - I had Pirelli PZero 205/45/17's on mine. Just ordered 215/40/17 Toyo T1-S Proxes - everyone on here recommended them and said they are ok to replace the smaller width tyres and also offer your wheels better protection against kerb scrapes. BTW ordered mine from Scoobyworld at £78 each which was the cheapest I found - usually take 48hrs so should be here tomorrow.

P.S. Did u ask your stepdad about my boot lid? May just get it done on ins. Just had my renewall at £911 no tracker and only a £125 XS!

Simon.