Tyre Bulge

[cochon]

While cleaning my bike earlier today I noticed that when you spin the rear wheel, the tyre bulges out at one point. You can't see it when the wheel is stationary, only when you spin it and see the profile change. Below is a Youtube video of the wheel spinning:

[media]

]View: http://www.youtube.com/watch?v=RV1ykrPFwQ0[/media]


There's nothing obviously wrong when looking at the tyre and deflating/inflating it doesn't make any difference. I haven't had a chance to take off the tyre and inspect the inside.

I don't know how long it's been like this but don't really want to have the tyre blow out so I've not ridden it since I've spotted this.

Is it time to get a new tyre? Or is it something to just keep an eye on?

Thanks

 

[Maz]

I think you'll have to take the tyre off for a close look at the internal walls. Look for any splits or cracks in it.
Let us know what you find there - do what i do and post a picture of it if you can - helps a lot.

 

[Cubist]

Do as Maz suggests, but also check to make sure the tyre is seated properly on the rim

 

[yello]

I've had that on one of my bikes many years ago. I suspected, after advice, that it was a weakness in the tyre wall but - just out of interest - I swapped front and rear tyres around just to see what happened. The bulge disappeared! I figure, as suggested by cubist, that it was how the tyre was seated... but I don't know!

 

[Cubist]

To be fair the video shows a bulge where the tyre seems to bulge out from the rim, rather than a sidewall issue. The treaded surface of the tyre is the least likely to be deformed unless very worn, so my money is on it's not being properly seated.

 

[Smokin Joe]

Almost certainly not seated properly at the valve. Deflate, push the valve up into the tyre and re-inflate.

 

[byegad]

If it is seated properly then it's new tyre time. But I suspect it isn't seated properly.

 

[cochon]

Thanks for the help guys. It is seated correctly and I managed to break 3 tyre levers trying to get the tyre off so took it up to my LBS earlier. They had a look and reckon it's a slight deformity in the tyre and nothing to worry about for now. I'll keep an eye on it to see if it gets worse.

The tyres are the stock ones that came with the bike (a Carrera TDF) so are pretty rubbish anyway.