jont wrote:I've got a set of old tyres on rims that will shortly be discarded to fit winters, so I might have a go on one of those while I've got a tyre I can afford to destroy
Just been out to try this. Biggest problem - making the hole big enough to get the reamer into (gave up hammering a nail in, started with 3mm drill, moved to 4mm drill, and that did the trick in terms of making a hole big enough to put the reamer through with some effort). Sticky stuff in, tyre returned to 30psi. Will check tomorrow evening to see if it's still holding pressure, but given it was pumped up fairly quickly with a footpump, if it is leaking, it ain't much.
Useful bits to add to the kit- pliers for actually removing a nail/screw, and disposable gloves, 'cos the odds are a used tyre will be manky and the sticky stuff certainly is. Obviously you'll also need a footpump/compressor. I suspect it could even be done on the car without removing the wheel if you had to (but you'll probably still want a jack to help with access). You /may/ want a stanley knife to cut the sticky stuff flush to the tyre - otherwise I suspect it will wear off fairly quickly.
Upside it obviously that it doesn't leave gunk all over the alloy, so when it does come to changing it should be a simpler job for the tyre fitter.