[InWeldingWeTrust]

Theoretically, just switching to 18" could gain you approx 5mph, so if your only looking to do it for speed, its not really worth it

 

[InWeldingWeTrust]

@cxsture

Thats a very valid point. For additional capacity, look to fit the american MT90-16 tyre size as a lot of 130/90-16 tyres will have a load rating as low as 67 (307kg) wheras MT90-16 will likely be either 74 (375kg) or 80 (450kg)

MT90-16 is near as dammit identical to the metric 130/90-16 so clearance problems should not be an issue. This is in effect a toughened tyre spec intended for old school baggers so is right at home carrying you, your passenger, and luggage

 

[InWeldingWeTrust]

@bikermike

Actually 250's (actual size is 250/40-18) is a very old size, as I conceived this tyre size back in 1998 (as a point of interest this tyre turned the custom industry into a billion dollar business for the first time ever). I think the optimum size to work on these chassis would be 160/80-16. Even though this is not overly wide, it would still require modification to fit, but has the right blend of damping, strength, & load carrying capability. It also has the advantage that it is only marginally larger on diameter than a 130/90-16 and slightly less than a 120/90-18. It would however require swing arm mods and engine relocation. If also used with a 130/90-16 front (the optimal front size pairing) it also keeps all geometry the same