Effect of a squared-off front tyre

Q. I have a Kawasaki ZX-6R G1. When I go round corners my steering wobbles and when I’m going really slow in traffic, I’m fighting to balance, but then it’s fine in a straight line at speed.

I checked the tyre pressures, which are OK. I do a lot of straightline riding on motorways and the front tyre has a bit of a ridge on it. Could that be the problem?
Eggyninja, MCN forums

A. It’s more than likely! Bike tyre profiles are designed as complex curves to give you good steering feel and optimum grip from upright to 40 degrees of lean.

Even though the tyre may still be legal, high motorway mileage will ‘square off’ a tyre profile and ruin the handling, making the bike feel like it’s ‘threpenny-bitting’ around bends or picking up any imperfection in the road.

That’s most noticeable if the rear is worn when you cross a white line, as the bike will track along it for a few metres before hopping over it. Get that tyre changed and keep an eye on rear wear too and you’ll be fine.