Wheels/Tyres - Advice please

[The Monzta]

First of all, let me say "Hi" to all my new fellow SVXers, I caught 'the bug' a week or two back by buying a black '96 SVX. I live in the good old UK, southern England to be more precise and would like to pick the brains of this esteemed forum.

My question is:

What is the widest tyre that I can comfortably fit that will not adversely affect the ride comfort/road noise/steering lock and wheel bearings? I currently have a motley collection of various unknown makes of the 215/45R17 size but would like to go up to 225 or even 235. I am a fan of Bridgestone and particularly like the SO3 Potenza range. I prefer a firm, sporty ride so a little bump, thump isn't much of a problem.

Any advice would be very appreciated.

Apologies if you've read this question on other forums.