When I was a youth (Long time ago) I seem to remember only trials bikes had a bigger wheel at the front than the back. Now, seems like several bikes (My Street Twin) have a bigger front than rear wheel. Speed Twin has both the same diameter. Is there good reason for this, or, any advantage/ disadvantage to have odd diameter wheels? Tia. Ken.
Most of the 1970s 750s had 19" fronts with 18" rears, whilst the trials and trail bikes you remember had 21" - in the main. Good point about the FireBlade's 16 incher. However, many owners have now implemented 17" fronts from other models. My view is that one would have to be a far better than 'average' rider to notice the difference!