Bulging tyre?

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After discovering my bike had suffered another "unrequested tyre deflation" overnight in the garage this morning I quickly fitted another inner tube.

I set off but about 5-10 minutes later the front wheel (the one I had just fixed) started to judder. I stopped to discover that the tyre was bulging outwards by the tube valve. The tyre itself appeared to be almost coming off the rim in this area too

Does anyone have any idea what may have caused this?? I've never seen it before (and I've been using these tyres for a little while)


Über Member
You didn't seat it properly.
You pushed the valve in, then laid the tyre on top of it so that the bead on the tyre wasn't fully engaged in the wheelrim.

Fit your tune and locate the valve in the opening in the rim. Seat the tyre around it.

Then push the valve 2/3 of the way back through the rim into the tyre and seat the tyre bead properly in the rim. Then pull the valve back through the opening as far as you can.

That probably makes more sense if you imagine what I'm saying as you read it.

Changing tubes and fixing p*nctures is well worth practising before you actually have to.

Elmer Fudd

Miserable Old Bar Steward
Had the same problem myself, to overcome it, push the tyre into the rim and push the valve into the tyre as you do so, make sure the valve is still in and the tyre still seated correctly as you inflate. My theory is that the 'double skin' round the valve area gets trapped under the edges of the tyre beading and as you inflate it pushes the tyre off the rim.
Since I've started doing this I have never had a repeat of this problem.
cheers - yeah I can picture exactly what you mean and now I think about it, it did look like the valve seat was trapped under the beading (first thing in the morning though which is never the best time to work these things out). Believe me, I've had plenty of experience of fixing punctures but have never had this happen which I guess must be through luck as much as anything

Don't think I'm using a particularly weird combo of wheel/tyre Dom, but just thought I'd ask. You know how these things can be - if you don't ask the question you can go for years in complete ignorance of something everyone else knows.
When I have to change a puncture, I fill the tube with a few squirts of air to give it shape before I fit it. Then I start putting the tyre back on the rim at the valve and work my way around from there, letting out a puff of air every now and then when I need to in order to get the tyre on.

I've got Michelin Pro2 Race's which are a right old bugger to fit at the end, and I always have to help it on with a tyre lever, grr, and the tube is totally deflated at this point.

Then I push down on the top of the wheel and roll it through 1 revolution to make sure the tyre has slipped into the rim properly. Then pump away. I've never had any bulging probs doing this method.


New Member
Jacomus-rides-Gen - Iwas about to post the same tip, stops it getting trapped or twised.

I put a 25 tube in a 23 tyre last week and as I inflated it it blew the tyre out of the rim and propmtly exploded. Teach me to do it by sight won't it.

Keith Oates

Penarth, Wales
Once the tyre and tube are in place then carefully check that the tyre rim is insde of the wheel equally all the way around and on both sides. If this looks Ok there shouldn't be any problem when you then pump up the tyre!!!!!!!!!
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