inner tube sizing

I've had an inner tube explode, literally like a shotgun, super loud. A few minutes later why I was sat at the side of the road swapping tubes a car pulled up and a husband and wife got out to ask if I was OK.

It turned out they'd been a little ahead of me, and were so startled and then concerned, they drove all the way around the towns one way system to come back and check if I was OK!

The worst thing, it was my old commuter bike which had Slime in the tubes, resulting in one big mess.

I had one "go off" on Friday evening. Any sufferers of constipation in the immediate area were instantly relieved.

I guess we've all used a tube that is 'officially' too small, but I for one have never had it explode. However, being stretched a little more than the optimum amount might make it more likely to puncture?

You'd probably get away with 20-25 in the 28s, but i'd swap them if you can (returns ?). Having detonated a similar tube in a Challenge Strada Bianca (30mm, so rather larger) whilst inflating it, i'd prefer not to think about that happening on a downhill. No point in making them more stretched and brittle if you can avoid it IMO.

Edit : I'm not saying you need to change, i've run 18-23 tubes in 25mm tyres on wide rims (27+mm inflated) and they've been OK - but if you can swap it'll give the tubes an easier life and they'll be less prone to punctures and less likely to let go in a nasty way. Just my 2p worth anyway.

I've just put back in a very skinny inner tube when I fitted a 32mm Gatorskin on the rear wheel. Of my tandem. I'll replace with something bigger when I get my forearms back again.

I've got 18-23 tubes in my 28c tyres mainly cause the other bike runs on 25c tyres and bought a few tubes cheap.