Pinch flats - Grrrrr

[RedBike]

I've just finished building up my new cx bike. Today was it's maiden ride.

I took it down a dissused railway / cycle track. I pinched flatted the rear tyre when I tried to bunny hop a puddle. I then pinch flatted the front when I clipped a rock.

To avoid getting any more I tried to pump my tyres up has hard as I could with my little mini pump. I ripped the sidewall of the rear tyre. - Grrrrrr.

6 mile walk/jog back home. My knees really hurt from jogging in SPD shoes now.

 

[gavintc]

Did you pump them up with a track pump before leaving the house? As hard tyres are less likely to pinch.

 

[RedBike]

I did use a track pump.
I pumped them up to 50psi knowing I was riding mainly on the road / hard terrain.

Obviously this wasn't enough to cope with my lardy ass.

 

[gavintc]

Check your tyres for the recommended PSI. My tyres are typically pumped to 110 psi. 50 sounds terribly low.

 

[halo]

I picked up my new Crosser today - I asked the LBS how much pressure they had put in the tyres as they felt rock solid - they said 100 psi mainly because they are on 700c wheels - so more like a road bike than a MTB - I normally run my Roadie at 120 psi and my MTB at 40 psi.
I did read somewhere that 60 psi is a good starting point for Crossers - then work out from there if you want more or less pressure in them to suit your riding style.

 

[Steve Austin]

Pressure depends on lots of things really. What width tyre also allows for less pressure. A skinny cyclocross tyre needs more pressure.
the schwalbe cx pros i use need a fair bit, over 80 at least or i will pinch flat every ride

 

[RedBike]

50psi does sound terribly low. However, the maximum pressure is only 80psi.

At 50psi the tyres actually felt too hard. They rode significantly better at 35psi. However, 50psi clearly wasn't hard enough for rocky terrain nevermind 35!

 

[jpembroke]

This happened to me on my first outing. I used lightweight tubes and they were useless. Since then I've swapped to either Vredestein or Conti tubes and have had no more problems. I suggest trying a new brand of tube before anything else.

 

[RedBike]

I've used all my tubes up so I've got to try a new brand of tube!
The tubes did seem to be too large for the tyres which probably didn't help.
(You can't patch a big slit in a tube so they've all been binned!)

I've also had to order new tyres as my existing rear tyre is shot. The bead has come away from the side wall on the rear tyre.

I've splashed out on two Mitchelin Mud 2's.

 

[jpembroke]

what tyres were using? I was using those Vittoria XG Pros and they didn't seem up to much. My new Panaracer tyres are a lot more robust.

 

[RedBike]

I was using Hutchinson Pro Gold Elite,
Purchased second-hand off ebay,

 

[jpembroke]

Michelin Muds are a good choice. Sure they won't let you down. Just make sure you get tubes in the right size. I'm using conti touring tubes at the moment which seem to cover a wide range of tyre sizes (28-37 I think).

 

[Gary D]

Maximum recommended pressure for Mud 2's is only 72psi according to the tyre sidewall!

Gary.