Tyre confusion.

Please "won't inflate" , as in won't hold the desired pressure or loses pressure?

FYI. I think that most-if-not-all the shorter (i.e., forearm length) "frame" pumps will only inflate to 65PSI ...

So, THAT may-or-may-not be the source of your problem ...

The shorter pumps (if THAT describes your current pump) are intended for MTB tyres where 65PSI would be considered the upper extreme for tyre pressure whereas 80PSI would probably be the lower end of the range for a 700x32 (for example) tyre ...

And, 85PSI would probably be the lower end of the range for a 700x28 tyre, etc.

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Thanks both, the tube holds pressure...it just won't inflate past 40 psi. I'm using a longer version frame pump - which works fine (using it on the front tyre works no problem). The only thing I can think is the tube isn't on right on the back wheel, maybe a pinch is keeping the air from going in after a certain point. Guess I'll have to take it off and get another look....

Are you sure that you've got all the 'junk' out of the tire that caused a prior puncture - such as bits of glass, bits of fine wire, thorns, flint etc etc... ?

If you are useing Presta valve the seal at the bottom may have come lose and worked its way up the stem, if so it wont let air in or out .
I have had this happen on 2 tubes of the 6 I got, thay were made by Michelin size 700 - 25-32 I have not used the outher 4 tubes and am not going to, so I don't know about them.

aha! Thanks wild....the bottom bolt was a little way up the stem, I didn't think this had anything to do with air getting in/out, but after tightening it up and then letting a little pressure out I was able to inflate the tyre normally, its now pretty solid and riding fine. Much obliged!