Tyre bulge

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Tyre bulge

Postby Big_Red » Fri Nov 23, 2012 3:59 pm

I have a set of 700C x 28 Conti Ultrasports on my road bike and near the end of the commute into work this morning, i've had a bulge appear in the rear tyre, which was big enough to rub the brake caliper at the top of the tyre. After stopping to investigate the noise, i found the bulge, but it appeared that the tube had not deflated at all. After managing to limp the remaining kilometre to work, i've taken the rear wheel off the bike, stripped the tyre & tube off and can't find anything wrong with either. Put tube & tyre back on the wheel and start pumping it up and a 2nd bulge appears in the tyre! I've only ridden on these tyres for about 700km and while i've had about 5 flats on the rear wheel, would the bulging occur because the tyre carcass has split? I have a spare pair of vittoria rubino II's to put on in the meantime that are a little worn, there's no way am i putting the Conti tyre back on... How much distance should you expect out of a tyre? < 1000km seems like a bit of a rip!
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by BNA » Fri Nov 23, 2012 5:24 pm


Re: Tyre bulge

Postby master6 » Fri Nov 23, 2012 5:24 pm

Is the bead of the tyre seated evenly on the rim? Check this by comparing the lines around the side of the tyre with the rim. You could have either of two problems:-

1. Tyre is not tight enough to stay seated on rim,


2. A fracture in the tyre case.

When you remove and refit the tyre, does the bulge appear again at the samoe spot on the tyre.
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Re: Tyre bulge

Postby sogood » Fri Nov 23, 2012 5:35 pm

Assuming there's no mounting error, then bin or warranty claim. Never ride an irregularly bulging tyre. The tyre carcass is faulty.
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Re: Tyre bulge

Postby Big_Red » Sat Nov 24, 2012 12:46 am

I've had the tyres only since the start of September, but I would have taken the tyre off/put on the rear wheel a minimum of a dozen times, including swapping from one wheelset to another. I would have have gotten about 6 or so punctures on the rear tyre in that time which was really giving me the irrits as the vittoria rubinos never got punctures. That said, i've done more km this year than the last 3 combined.

The tyre was always mounted correctly and tight enough to stay on the rim (i needed at least one tyre lever to get it on/off the rim) even without inflating the tube. When i pumped up the tyre after pulling the tyre & tube off then putting it back on again, the bulge occured in the same place as it originally had (3 o'clock from the valve stem) and there was an another bulge, near the valve stem.

The vittoria rubinos i have spare are 23mm wide and a far tighter fit than the contis. Looks like i'll just bin the conti it as it was only $19 from CRC, probably not worth the bother of a warranty claim i think. Might try a Schwalbe Lugano in 25mm wide instead.
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Re: Tyre bulge

Postby R12RT » Sat Nov 24, 2012 7:41 am

I had a similar experience with a Continue 4000S. In my case the bulge appeared with in 100km.

The carcass of the tyre appeared thinner at the point of the bulge and the rubber was slightly paler.

I returned the tyre to Ribble. They refunded my postage costs and sent me a replacement tyre.
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Re: Tyre bulge

Postby RonK » Sat Nov 24, 2012 10:05 am

You have what is known as a tread separation. Replace the tyre.
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