There is a newish tyre out there, I do not have an opinion whether they are any good or suitable for Vincents but they are available to suit the smaller diameter wheels, 19 front 18 rear, they are a radial tyre, is that a good thing on a Vincent? Continental Conti Classic Attack, tubeless, but tube can be fitted, anyone tried them yet? There is someone selling a kit to convert a conventional spoked wheel to tubeless using little sticky spoke end caps and gooey tape, does not seem like a good idea to me, I will stick with tubes.