i had this problem on one spoke hole,so i used some emery paper to remove the sharp edge,problem solved.................Have you got adequate rim tape or substitute covering the inside of the rim and/or is there anywhere where a spoke hole cover has caved in leaving a sharpish edge or is there a sharpened edge of the valve hole exposed?
Change the tape try this..http://www.wiggle.co.uk/ritchey-rim..._campaign=uk&gclid=CION2Oi95LECFYUmtAod624AJwjust had a look, the problem is the spoke holes, a I have deep rims it seems the holes are very rough in side, I have tape, came with wheel, tyre etc, just checked one of the other punctured tubes same problem but different place....
so do I just change the tape or just put more tape over old tape, does tape come in different thickness because if not, then the problem will persist...
I hope this is understandable, running out the door, thanks for the help...
One more thing. Mark the inner tube so you know where it was in relation to the tyre and the rim. That means marking the tube next to some kind of radial datum and also marking a side. When you find the hole in the tube, you will know where on the tyre or wheel the fairy enters. Some tiny shard fragments in a tyre are mighty difficult to feel or see.
This is also why it is a good idea to line up the logo etc on the tyre with the valve hole. Once you have determined where the hole is in the tube you can line up the tube with the tyre and get a good indication of where the problem is/has been. Even if you haven't marked the tube and you are careless removing it you know that the cause can only be a certain distance from the valve hole, either to left or right. Flexing the tyre tread will help show up deeply embeded tiny flints/glass.One more thing. Mark the inner tube so you know where it was in relation to the tyre and the rim. That means marking the tube next to some kind of radial datum and also marking a side. When you find the hole in the tube, you will know where on the tyre or wheel the fairy enters. Some tiny shard fragments in a tyre are mighty difficult to feel or see.