Random flat tyres.

[Clem Fandango]

First I thought some punk kid was letting them down, but it's happened outside college and work, not just my flat. Is it something to do with the change in weather? An existing slow puncture exasabated by the drop in temperature? As far as I remember, my tyres were fine in the summer, now when I walk out to it on a particularly cold morning, I find the rear tyre has dropped 20 psi, having just filled them the previous day.

Anyone else experienced this? And is there a solution that doesn't involve new tyres? At the moment I'm just glad I bought a double barrel footpump.

[Fozzie]

Mods - Move to pitstop.

Sounds like a slow puncture to me, perhaps made worse by the cold as it causes rubber to shrink, which if it's down to a poor fit of the tyre will be the cause.

Get some hot water and washing up liquid mixed up, paint it on the back tyre with it filled with air. Look for the bubbles to form. Paint it on thin as you may be looking for really small bubbles leaking out of the same place. This will confirm if you have a slow puncture.

[Clem Fandango]

Just found out the rear tyre is actually too big for the rim. Undoubtedly this was done by the previous owner to make it look more like a proper sports bike. Only seems to be a problem when the temperature drops dramatically.

[Fozzie]

Ah so it's the poor fit. Must admit I was dubious as to why it would be poorly fitted but it being too big for the rim stacks up.

Get that one off there, and if you replace both (cheap enough on a 125) make sure you avoid the stock Michelins on there. I believe Pirelli make a really good set for the YZF.