Final piece in handling jigsaw

I am surprised that Norman White recommended such a low profile rear tyre. From my limited experience, they just don't suit Nortons. Funnily enough, despite their good reputation, I found BT45s didn't do a lot for my wife's Yamaha - very uncertain handling when pushed on a bit - a pair of Avons restored its ability to kick up sparks on corners with confidence.

To be fair to Norman White, his extensive experience comes from short circuit racing and his recommendation is possibly intended there. 18" wheels will give improved turning rates, and the tyres will be on a lighter machine with considerably harder dampers. All somewhat different from "bumpy Shropshire roads".

18" does work on the rear when shod with a larger tyre, although whether the larger tyre offers any benefit is debatable. When I switched from the 19 to the 18 rear there was no worsening of the 'wobble'. The biggest improvement always comes with the fitting of new tyres, which shows how we gradually get used to the the old ones.

The general view seems to be that 19" wheels (front?) are more stable. I would suggest this is due to greater gyroscopic inertia damping the 'wobble'. Logically, heavier steel rims should be better than alloy ones.

I did like your RH article on isolastic adjustment Simon. Interestingly, you say that the bike still had 'wobble' despite those perfect isolastics. It all suggests that 'wobble' has nothing to do with imperfect shimming but is caused by other frame/fork effects. Years ago I saw a Commando that had some 3/8" movement in the front isolastics as we yanked the rear wheel about while holding the frame. We asked the owner if it rode round corners ok and he said it was fine!

If you get a pencil and paper and work out the contact point of the tyre when leaned over appreciably, you will see that with a low profile tyre it is appreciably different from that of a 'normal' or original high profile tyre. Take a moment to work out how the forces are acting on the bike. Absolutely fine if the bike is designed for it, but as a retro-fit it can alter the handling characteristics appreciably - for better or for worse.

Hi Simon, Iâm pleased to read my advice made the same improvement to your bike, that it did to mine.

The trouble with tucking in the exhaust pipes, you then will need to raise the footrest (or have folding ones) then the centre stand has to go, next the side stand. Before you know it you'll be wearing knee sliders.