My bike weaves with new tyres fitted

If your bike’s bars flap from side to side when you’ve just fitted a new set of tyres, you’re not alone.

We estimate we see this once in every 100 pairs of tyres we fit. It’s our assessment that 90% of the time it happens on a bike with a topbox. Usually that topbox is packed with heavy stuff, too.

When your tyres are new, the profiles are much sharper than your old tyres. It stands to reason; old tyres square off. These sharper-profile tyres are more sensitive and will wander around if there’s not enough weight on them.

From our experience, removing the topbox is the best first step to take. Go and ride your bike again and see if the problem is still there. If the problem isn’t there, then you’ll need to adjust your bike’s suspension until your tyres bed in. We suggest adjusting the rear preload to compensate for the additional weight of the topbox.

You might be thinking the same thing some of our customers say to us: “Why should I do that? I didn’t have to before”. However, these things need adjusting, as the new sharper profile front tyre doesn’t have enough weight on it, so it patters across the road surface and gets into a weave. You need to add more weight over the front (by stopping the rear squatting down too much) in order to solve the problem.

If you don’t have a topbox, it’s worth checking your tyre pressures to start off with. Then if you can, adjust your rear suspension preload. If you still have an issue after 100 miles of riding, you’ll need to take it back to the shop who fitted your tyres for them to investigate.