Tyres - 156 17s - anyone run on 55s ?

I realise that the standard tyre for the 156 gta on 17s, is 225/45/17.

In order to help a little with speed bumps and general grounding, has anyone tried fitting 225/50/17s - or even 225/55/17 ?

That would increase your rolling radius though, knocking your speedo out (you will be going faster than it says) and meaning your engine is doing less revs per mile, might be good for fuel economy but bad for acceleration..

Why don't you consider upgrading your shocks or go for a shocks/springs combo?

IMO you will not be able to fit tyres with a significantly larger diameter as they will not fit. The tyres will catch the front and rear wheel arch liners - I know my 225/45 tyres occasionally touch at the front at parking speeds. The rear liners also run very close to the tyres.

Is there room between the suspension and the tyre? - it is already very tight at the front. At the rear I think there is about 5-10mm clearance between the tyre and the spring pan

I remember there were some people with GTAs that tried 205/50R17.

225/50R17 or 225/55R17 would be far too big

I think it would spoil the look of the car.

You could probably get away with a small increase in tyre diameter but would it be worth the cost?

Better to spend the money to raise the front suspension by 10mm to give more ground clearance - you could check with Autodelta if the -25mm V6 springs they supply would actually raise the ride height of a GTA