Hi Keith Some Scotts are quite sensitive to tyre sizes. The late Chris Williams, who rode the late Clive Waye’s Scott told me that the handling was good if they used a 3.25″ rear tyre. However, on one occasion, their tyre was very worn and they could not get a 3.25″ rear tyre with an acceptable rounded profile, so they fitted a 3.5″ x 19 Avon GP) tyre instead. The handling deteriorated badly and was only restored when they fitted another 3.25″ tyre. I can vouch for the handling of that bike, as I raced it at Cadwell and it was so much better than mine, that it was like riding in a dream. Recently I have been using a modern Avon front tyre on the back with direction reversed. This is a 90 x 90 x 19″ Roadrider AM26, which I use in an intermediate race compound, but a normal road compound tyre would be fine in the Scott for road use. This tyre has a rounded profile and is an equivalent size to an old 3.25″ tyre but with a much better profile. This improved the handling of my bike considerably. The latest advance is that Avon have made this same tyre in 90 x 90 x 21″ form for a front tyre to replace the old Speedmaster. I always found that a bike handles best with similar profiles front and rear so I am looking forward to testing this at Cadwell. To be fair, I have never had a front end breakaway with a Speedmaster with race compound, but they were designed for the days when road surfaces were much inferior to today, so it was not expected that bikes would corner at any great inclination. This means that we soon wear a big bald patch on the sides, which is OK if it is dry, but if we get rain, then it is like cornering on slicks! This causes me considerable apprehension. On previous experience, this tyre combination should be the best yet. I will let you know how I get on, but from the feedback of others using this new 21″ tyre, I expect a significant improvement.
So that would be my advice as being the best tyre choice for a vintage type Scott with 19″ WM2 rear rim and 21″ WM 1 or 2 at the front. Of course if you are running a 19″ front, then use the same 90 x 90 x 19 AM26 both ends. Roger
