Tubes Keep Bursting?

[Eugbug]

My tubes keep bursting (either deflating rapidly soon after inflation ,or after a few hours, or overnight). I inflate them to maximum pressure and they always seem to burst on the inner side, closest to the rim. So am I just getting cheap tubes or is something else doing this? The holes seem to occur on the "seam". There's nothing sharp in the tyre and no sharp edges on the rim tape. The spoke nipples aren't sticking through the tape either. I have a theory that I am inflating tubes too rapidly with my air compressor and this could be overstraining the tubes, especially when they are cold 10 C (50 F). The holes seem to be either pin holes and once  a rip on the seam.

PS: Maybe if the criss-cross ridges on the rim tape are somehow puncturing the tubes, it would be a good idea to use fine sandpaper to smooth the surface?

[nfmisso]

First my tire installation method:

* put a little air in the tube, just enough to get the kinks out and make it round; not enough to stretch it.
* put tube in tire, I line up the valve stem with the pressure rating on the sidewall.  Work the tube in all the way around, taking care to remove any kinks, and to fully seat the tube in the tire.
* Push the valve stem thru the hole, and line up one side of the tire inside the rim and the valve stem.  
* working in both directions from the valve stem get one side of the tire inside the rim all the way around.
* restarting from the valve stem, get the other side of the tire inside the rim, continue in both directions away from the valve seating the tire inside the rim.
* let a little air out if needed.
* make sure the tire is properly seated and not pinching the tube all the way around by squeezing the tire inwards.  Go around twice.
* inflate tube to 15 to 20 psi, repeat squeezing all the way around twice.
* inflate to normal riding pressure.

I have never lost a tube using this method.

I do recommend thorn resistant (TR) tubes, and use them because of a large amount of glass on our streets.  TR tubes are several times thicker than normal tubes, and extremely resistant to pinching, in addition to resistance to outside attack (glass, thorns, etc).

[Eugbug]

Thanks for the suggestions Nigel!

That's pretty much exactly what I do except the second last step - inflating to 15 to 20 psi and repeat squeezing. I reckon though on closer examination of the tube, what may be happening is that the tubes are squeezing into the narrow < 1mm gap between rim tape and rim. There is a mark all around the failed tube corresponding to this and evidence of shorts splits developing. The tube in addition to deflating from pin holes also split along this line. If the tape is any way sharp at the edges, any movement of the tube relative to the tape, or simply it being pushed against the edge could be enough to cause failure, especially at the 65 psi I inflate tubes to. The strange thing is that a tube can last for hundreds of hours of riding over bumpy terrain over the year, then all of a sudden I get multiple spontaneous failures (5 this week on the inner side of tubes), even with new tubes.
I find that if I have to blow up a tube with a patch on the inner side I have to do it quick with the air compressor. Do it slowly, and the patch blows off before it seats into the narrow gap between the two walls of the rim. Possibly this could be because the patches are a bit thick and rigid. I usually bend them before inflating. This never happens with patches on the outside of the tube because they are against the flat inner side of the tyre.
As regards punctures from stuff picked up on trails and roads, haven't got any this year since I got a set of Schwalbe Land Cruiser tyres which have a Kevlar lining. Last year I got regular punctures from thorns from whitethorn hedges (which end up on the road when hedges are cut).

[Eugbug]

A new theory on whats causing this:
When tyre is pumped up to 65 psi, walls of rim push out a small bit and surface of tube squeezes slightly into tiny gap between tape and rim wall. Once pressure drops, the walls come back in again and nip the tube. There are marks on tubes, so it's definitely the edge of the tape/rim which is causing damage. Either that or hitting bumps and potholes on road is ramming the tube into the gap. I think I'll resort to wrapping PVC insulating tape around the edge of the tape as they suggested in my local cycle store.

[bobtravers]

Or change your rim tape for new ones...