What causes tyre warping?

Agent57

I've had a pair of tyres on my bike for the past year; they came with the bike and I've had no problems with them before.They're Hutchinson Equinox tyres, which got a decent review in Bikeradar. Haven't done a huge number of miles on them, but today I noticed that my wheel wasn't rolling very well.

Upon inspection, I saw that both tyres were pretty badly warped:





I haven't over-inflated them -- pumped them up to the recommended 100psi before my ride this morning.

So my question is just this: what causes tyres to do this? I'm going to buy new tyres (not Hutchinson ones mind), and I don't want the same thing to happen again.

cswebbo

My dad had the same tyres on his bike, same problem on rear tyre. It explded on a descent, fortunately he was braking at the time and going slow so kept it upright. We then had to do a makeshift bodge job with sellotape to get home. You made the right call in getting shot of them. I think its just poor quality control by Hutchinson?

Hugh A

The tyres may be warped, or it is possible that they are not bedded evenly onto the rims - bit difficult to tell from your photos. This can happen with grippy tyre beads, more often if the rim is slightly undersized - if they are not talced before putting them on. Sometimes over-inflating a bit can even them out - or blow them off the rim so be warned!

There is definitely something odd going on there though.

The thing I find most often causes tyre warping - although I've never had one as bad as that - is uneven tyre wall thickness. This is usually in the threaded part where two thicknesses overlap and it causes part of the tyre not to expand as much as the rest when inflated. In fact you can feel it in the tyre by running the tread part carefully between finger and thumb. It will usually get thicker at the affected point, but sits low when mounted.