MiG wrote:Phil wrote:as far as road use goes 17 is better than 16 or 16.5. race bikes are addressing different issues to road bikes.
It doesn't seem right that 17" would be the perfect size for bikes ranging from <140 kg to 220 kg (no idea about cruisers that weigh more). Remember that both larger and smaller sizes have been "normal" before. Looks to me like it's more about what is fashionable and hence available.
Phil is right - 16" and 16.5" tyres are only good for racetracks. Back when motorcycles put out 20bhp, well they could get away with 21" wheels front and rear, without any issues.
Having followed the 'fashionable' trends in tyre sizes since the early 70's, the fact that most manufacturers have settled on 17" is nothing to do with fashion, and everything to do with performance. Those early attempts at 16" front wheels on Jap bikes (GpZ600R for example) have shown that the tyre technology at the time did not match the bike performance, and the tendency of smaller-tyred front ends to 'drop' into corners far more quickly than most normal riders were comfortable with.
16" rears ? pfffft, they used to call them 'Hog' rims, and were fitted to every bodgy CB750 single-cammer *chopper* you ever saw.
17" rims provide the best compromise for handling and feedback for almost every road bike out there. Not all, just most of them. They are here to stay. The laws of physics dictate that. You may see the odd rare factory bike with 16.5" wheels, one of *these* is almost sure to be made, just to cater to the fashionista....
I can absolutely guarantee you that you will never see a new sportsbike with 19" front and 18" rear wheels ever again !!
