Looks like .3" - .5 " Narrower .. on Tread Width .. Depending on Tire Manufacture . . , but I'd Watch the Over All Dia. - 10X already has 3 Over Drive Gears at Least ..
Extra Dia. say 26.3" would be good for the 6Speed. Setup .. as 5th Gear for them is Starting - OD Gear , but that Setup most like be able to Run Out - 5th Gear .. Where as
10X 6 Gear may be little Short , but 7th Gear is OD may Not be able to Run that Out .. , 8th OD , 9th OD , 10th OD , so that setup might Only be able to Run Out 7th .
Sorry fro getting side Tracked : Important Area Here is to Not Rub the Inner Liner with to Tall a Tire ..
If You Bump +1 to 18" 225x45x18" those stay right around
26" - 26.3" Dia. - stock are 25.7" - 25.9"