Originally Posted by Kabir
When should I apply the patch on the tube? When it is inflated or deflated? I just applied one when it is deflated. When I pumped the air in, I noticed that the tube underneath the patch stretch out. The patch seems to do its work well. I still wonder what is the right way to apply patch. The instruction on my patch kit doesn't say anything about it.
Thanks
As most others have suggested, it's better to patch the tube UNINFLATED so that the patch won't get scrunched up and deformed when the tube is later deflated.
The rubber of the tube and patch is designed to be very stretchy, so no worry about that. The interesting thing is that when the tube is actually inside a tire, it does NOT stretch very much. It stretches until it's completely pressed up against the tire and rim, then stops expanding. This is a good thing: if you were to pump a tube up to 120 psi outside of a tire, it would explode! But inside a high-pressure road tire, no problem. It's sort of like blowing up a balloon inside a jar... the balloon will flatten itself out against the sides of the jar and then can't expand further.