continental ultra sport 25mm 8.5 bar / 120 psi what size inner tube

I am anything but an expert, but 120 sounds a bit high. How much do you weigh?

Additionally, popping 2 tubes sounds like a possible operator error
Did you check that there is nothing inside the tire that might produce a sharp point?
Was the tube properly installed/tire seated prior to inflation? Sometimes the tube is not correctly installed prior to inflation, and the tube sort of 'leaks' outside of the tire and then, BAM !

Did you take the time to ensure that the tube was completely inside the tire and the tire bead was seated properly on the rim (with a small amount of air in the tube) , then inflate fully?

this link to a chart might help

http://oaksandspokes.com/wp-content/uploads/2013/09/pressurechart12...

That's max pressure not recommended pressure. More than likely you should be around 95-105 psi

Here is a link to a current thread on psi - some good info.


http://www.beginnertriathlete.com/discussion/forums/thread-view.asp...

HOLY...!!!!

Okay, I used to run my race tires at 120, but those were 19-21mm skinnies. I can't imagine riding on 25s at that pressure. Maybe I'm just getting old...

But if you're blowing the tire off the rim before you hit the imprinted pressure on the tire, then there's something else going on -- maybe the tube isn't all the way inside the tire before you're airing it up, or there's some tolerance issue between the rim and tire (rim is on the low side, tire is on the high side), or maybe the tire bead has been damaged somehow.

Edited by briderdt 2015-04-06 3:14 PM