Mastodawn

Today I had my first flat in over a year. I quickly spotted the cause (a shard of glass) and changed the tube, less than 15 minutes off the bike.
BUT I've had very difficult flats and have been stranded more than once when the repair didn't work or I had a second flat & ran out of spares.

Q5: What was the worst you have experienced with a flat or a breakdown that left you stranded, or otherwise unable to repair on the spot?

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Marty Cormack 1d ago

@ascentale @bikenite
#BikeNite A5d:
Another roadside lesson: I was group riding on an excessively hot day. Back then I was inflating tires to the max value to maximize speed, or so I thought. Sure enough I got a pinch flat from over inflating for the heat conditions. The experienced riders explained that to me. I now inflate at most 10 psi less than the max.

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Kim 1d ago

@MartyCormack @ascentale @bikenite A pinch flat from overinflating? How does that work?

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Marty Cormack 1d ago

@kim @ascentale @bikenite
When it's overinflated, hitting a bump pinches the tube and pop!
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Kim

@MartyCormack @ascentale @bikenite That's certainly what happens when it's under-inflated: The tyre bottoms out and pinches the tube so you get the distinctive 'snakebite' double puncture. (One of the main benefits of running tubeless off-road is that you can have the pressure super-low for lots of grip without it happening.)

I can see how over-inflation leads to the tyre bead popping off the rim, or the rim failing if it's been heavily worn by rim brakes, or the tube working its way past the rim tape and bursting in the spoke hole. (I've certainly had the latter happen - cloth rim tape is much better than plastic in this respect.) And of course there's always the possibility of the tube failing under high pressure. But I don't see how the tube gets pinched if it's rock hard...

Personally, the main reason I avoid over-inflating is that unless the road surface is extremely smooth (eg. a racing circuit) ratting your brains out doesn't actually make you go any faster.

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