Clincher Tyre Rolling Off Rim?

[Edwardoka]

Hi guys,

Just a quick question. My partner has a Dolce with Alexrims s480 700c wheels and Specialized Espoir Sport tyres.

Today we were out on a ride when suddenly her rear inner tube blew out and her tyre came partly off the rim. Luckily we weren't going quickly at the time so she was able to bring it to a controlled stop.
When I examined it, the inner tube was half out the tyre, twisted and caught up in the cassette and with a big gash in the side of it.

I couldn't tell whether the tube blew out because the tyre rolled off or vice-versa, but I've never encountered this in my 10 years of fairly regularly cycling.

One thing I noticed was how extremely easily the tyre would go back on or came off the rim - I could take it off with a thumb and a finger and hardly any leverage, compared to every other tyre I've used where tyre levers are required.

We're going to get in touch with the company that sold her the bike because such loose tyres are a safety concern (I checked the front as well and was also able to get it away from the rim without any levers), but I was just wondering whether this is a common phenomenon that other people have experienced?

Thanks in advance
Ed

 

[stephec]

Certain tyre and rim combinations have been known to produce either a tight or loose fit, if these are the originals that were supplied with the bike then your next questions should be aimed at the shop where you bought it.

 

[Edwardoka]

Certain tyre and rim combinations have been known to produce either a tight or loose fit, if these are the originals that were supplied with the bike then your next questions should be aimed at the shop where you bought it.

Thanks for the quick reply!

Yeah I should have added that these are stock components. If they weren't we'd have chalked it up to experience and bought new tyres, it just seems to be an odd thing to happen on a bike that has, to date, done less than 200 miles and still has all its original bits!

Cheers
Ed

 

[mr messy]

Not unknown for me to change a tyre without levers but havn't experienced that! Any other obvious damage Ed?

 

[Edwardoka]

Not unknown for me to change a tyre without levers but havn't experienced that! Any other obvious damage Ed?

Nah, the tyre is fine, otherwise. No flints or anything, no holes in the tread, no sidewall damage, and the bead seems intact. She thinks she might have hit a pothole immediately prior but the inner tube was so badly damaged by its subsequent misadventure that it's impossible to see if it was a pinch flat.

 

[mr messy]

Was going to suggest a possible pinch flat....
It is possible for the tyre to roll off the rim when deflated especially when under load...once had to push bike home with double pinch and was pita!
Wouldn't do any harm getting in contact with the shop though...

 

[Mo1959]

My Specialized Ruby came with the Espoir Elite tyres. Haven't done all that much mileage on it yet but, touch wood, no problems at all. Haven't had a visit yet so don't know how easy they will be to take on/off. They seem to be the standard tyre fitted to a lot of the Specialized bikes so wouldn't imagine there is a problem or they would have stopped fitting them by now you would think.

 

[Shut Up Legs]

She may just have dud tyres. I had a dud pair of Schwalbe Marathon Plus tyres last year, and these are normally virtually bullet-proof. This pair came off the rims on 3 separate occasions, causing the tube to instantly explode with a nasty long gash. I think their beads must have been faulty. I replaced both tyres, and the current pair are spot-on.

 

[Tim Hall]

It's very very likely that the tyre came off the rim allowing the tube to escape, which then burst like an over excited balloon, and not the other way round, so you need to look at the reason for the tyre coming off. When you say you can full the tyre off with thumb and forefinger, I'm presuming this is when it's deflated.

How old are the rims? I had a worn rim once that flexed outwards under tyre pressure such that the tyre unseated. Check also that the tyres are sitting evenly in the bead all the way round.

 

[sidevalve]

As above, many tyres can be changed without using levers when deflated. MTB tyres are even easier but they seem to stand up well to a lot of punishment. No point checking I suppose but I'd be looking towards finding that pothole if I were you.