Jonathan M
New Member
- Location
- Merseyside
Fitted a Joe's No Tube kit to my MTB last week, the rims are Mavic X317 on the front wheel, and the X717 on the rear. Tyres are Panaracer Fire XC Pro 2.1s front and rear, the only difference being the front tyre is a steel bead, the rear a kevlar bead.
Because the tyres were difficult to seal on the rim, as per the tip's on the No Tubes website I ran a couple of extra layers of insulating tape beneath the No Tube rim strip, and this seemed to do the job.
Yesterday the set up got it's baptism of fire, and a mate took me to Llandegla. Checked the tyre pressures were checked on setting off, the front needed a little top up, the rear had held pressure for >24 hours.
On the first section of the black run the rear tyre blew off the rim, but happened in a section that meant I was able to stop, re-seat the tyre, and with a CO2 blow it back up. Got going again, next section of the black run same thing happened. At this point the No Tubes rim strip was removed and a boggo inner tube fitted, which survived the rest of the day.
The front tyre was perfect all day, even being run at a slightly lower pressure than I'd usually use - same with the rear, I'd usually use a pressure around 40PSI, but I'd run the front to about 35PSI, and the rear to 38PSI.
So what are peoples thoughts about why the rear popped off? I'm wondering two things really, one is whether the kevlar bead is just to flexible, the second is whether the extra layers of rim tape beneath the No Tubes rim strip just meant that the beads on the tyre were failing to seat properly - I wasn't paying attention, but IIRC the tyre blew off on the same side of the rim on both occasions.
Because the tyres were difficult to seal on the rim, as per the tip's on the No Tubes website I ran a couple of extra layers of insulating tape beneath the No Tube rim strip, and this seemed to do the job.
Yesterday the set up got it's baptism of fire, and a mate took me to Llandegla. Checked the tyre pressures were checked on setting off, the front needed a little top up, the rear had held pressure for >24 hours.
On the first section of the black run the rear tyre blew off the rim, but happened in a section that meant I was able to stop, re-seat the tyre, and with a CO2 blow it back up. Got going again, next section of the black run same thing happened. At this point the No Tubes rim strip was removed and a boggo inner tube fitted, which survived the rest of the day.
The front tyre was perfect all day, even being run at a slightly lower pressure than I'd usually use - same with the rear, I'd usually use a pressure around 40PSI, but I'd run the front to about 35PSI, and the rear to 38PSI.
So what are peoples thoughts about why the rear popped off? I'm wondering two things really, one is whether the kevlar bead is just to flexible, the second is whether the extra layers of rim tape beneath the No Tubes rim strip just meant that the beads on the tyre were failing to seat properly - I wasn't paying attention, but IIRC the tyre blew off on the same side of the rim on both occasions.
