Depends on what you are going to put them on and use it for.
Don't buy ag tires like on a farm tractor you will dig your yard up big time the ones they run on the big commercial modes like Dixie Chopper is a Carlisle Chevron tire There great tires for ZTRs but you still have to be careful with them they will dig good luck
Taller the tire faster the mower and yes 1 inch will make it faster. A lot faster no.
But I am thinking with the tires you wanting to use will be closer to 2 inch bigger.
I know the size says it will only be a inch but put a tape on them and bet comes out close to 2 inch more in diameter and I inch and a half wider
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