I had this problem as well, with large volume MTB tyres and a tiny pump no less so it was particularly disheartening to see it deflate.
The solution: flip your pump's valve to schrader and then use one of those little brass convertors to turn it back into presta. (Long term solution was getting a bigger pump as the micro ones take too long for big tyres).
I had this problem as well, with large volume MTB tyres and a tiny pump no less so it was particularly disheartening to see it deflate.
The solution: flip your pump's valve to schrader and then use one of those little brass convertors to turn it back into presta. (Long term solution was getting a bigger pump as the micro ones take too long for big tyres).