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I noticed after mounting some new tyres that part of the side wall, just above the bead, seems to have been damaged while I was fitting them (see photos below).

These tyres were especially difficult to mount, even with the bead seated in the rim's bead well all the way around. So tight, in fact, that the only way to get the bead out of the well and seated under the bead hook was to pump it up to a much higher pressure than I would ride it with and wait for it to "ping" into place.

I think it's this process that ended up causing the damage you can see in the photos. The tyres in question are these (folding version).

Have I compromised my tyres, or should I not worry about it?

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  • Some soap on the rim is sometimes helpful in getting the bead to seat properly. – Daniel R Hicks Jun 5 '16 at 3:59
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Those strings are quite common with continental tires and seem to be a part of their manufacturing process. Every continental tire I have owned seem to have some of those threads, even ones that mounted relatively easily. I just cut them off and have never had an issue with them. Continental tires are also well known for their tight beads.

The high-pressure technique is a common technique to get a bead to seat. To speed it up you can also put the tire in a vice and pull on the top of the wheel to try and force the bead to seat.

As an aside, many recommend against running fenders with knobby tires, as the knobs can pick up debris (e.g., small sticks) that can jam in the fenders causing a crash.

  • Close fitting mudguards certainly can do that. – Criggie Jun 5 '16 at 6:01
  • Thanks, this reassures me. I hadn't considered the fender problem! I didn't have any problems with the last set of these tyres that I had (the centre of the tyre is smooth), but I might re-consider the next time I change the tyres. – Will Vousden Jun 6 '16 at 11:06
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It turns out the tyre wasn't fine; here it is 2000km later. The tyre has split in two places on one side, and the bond between the bead and the sidewall looks pretty compromised all the way around. Thankfully it didn't blow out while I was on the bike!

Dead tyre

  • Thank you for the followup and closure - you should accept this answer as correct (the little tick/check box below the up/down vote arrows) Sorry to hear about your tyre's demise. – Criggie Aug 4 '16 at 2:59
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    I suspect that damage was caused by a tire iron. – Daniel R Hicks Aug 4 '16 at 11:47
  • @DanielRHicks You could be right, although when mounting the tyre the hook was pointing the other way. The only time the hook would've dug into the sidewall like is when taking the tyre off (I think I only did this once), which involved much less force. Like I said, the bead/sidewall bond looks in pretty bad shape all the way around the tyre. – Will Vousden Aug 4 '16 at 15:01
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The hardest to fit tyres I've ever dealt with were continental comfort contact (and I run marathon plus which are reputed to be difficult). Like yours they needed serious overpressure to seat, even after wetting the rim.

After several years fitted they're still going strong. I had to change a tube in one recently and it was much easier but still hard to seat.

I seem to recall some strings but removed them before mounting the tyre.

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