Flat tyre help?!

Could be the valve.

Are you using Tubies or clinchers? if the latter chuck the inner and buy a new one. They don't cost much and its not worth the hastle.

Kidney Bean said:

I do a lot of wind trainer'ing during cooler/ wetter months, which has begun again. I seem to have a persistently flat rear tyre (though it doesn't go flat very quickly). Is this likely indicative of a pucture or split, or from putting too much resistance against the tyre on the wind trainer? Any help would be appreciated.

I have ridden about 50 miles per week on a trainer since December and have never had a flat. It is just as important to maintain adequate tire pressure on the trainer as it is on the road. Low pressure might increase the risk of flats. Tires do loose pressure normally, regardless of whether they are ridden on the trainer or on the road (or even sitting in the garage). I have to pump mine up about once per week.

the tyre pressure will go down over time anyway - this will be noticeable inside a week (shorter with latex tubes)

so, you may not have a puncture as such, just need to keep pumping the tyres once a week or so.

I ride at 100psi on the trainer

Kidney Bean said:

I do a lot of wind trainer'ing during cooler/ wetter months, which has begun again. I seem to have a persistently flat rear tyre (though it doesn't go flat very quickly). Is this likely indicative of a pucture or split, or from putting too much resistance against the tyre on the wind trainer? Any help would be appreciated.

Where are the punctures on the tube? Inside / outside?
I've recently been getting punctures on the inside of my tube. I originally thought that I may have been twisting the tube when installing, or there is some foreign body foating around in the tyre.
Turns out, my rim tape was getting old (or maybe it was never installed properly), and it was a bit thin, or moved near some of the spoke holes. What I assme was happening, is that the tube would bulge into the hole, and as the tyre flexes, this would slowly wear the tube out, especially when I kept the tyre pressure up.dfs