I have Avon AM26 Roadriders, 3.25x19 on the GTO. As a rider, just wanted some modern rubber between me and the road. They grip well but are heavier and wider than the original tyres, much tougher and take some wrestling on to the rims.
Had to take the front guard off to get the wheel in. When riding two up, we hit a dip in the road and I thought the rear wheel had bottomed the suspension but on inspection the tyre had hit the guard indent at front by the chain run. Small groove in the tyre, so eased the indent out slightly.
Nysz1b, don't go too big with the tyres or you may find similar issues. Brian.