Thursday, 18 October 2012

Punctures between Cottenham and Histon

I recently punctured yet again on the Cottenham to Histon cyclepath.  A lot of other people have too and finger is being pointed at the stones scattered on the cyclepath opposite Cottenham Skips. It is theee worst location I have known for getting punctures (excluding an offroad location near Aldreth I've nicknamed Thorn Alley), and for some inexplicable reason it has been worse since the path was widened.

This short section of cyclepath has a bad track record for me.

Previously, I've tried my road bike on the Cottenham to Histon cyclepath but after puncturing twice in four journeys I decided it wasn't worth the risk. The stock Bontrager (Trek) 23mm tyres are fine on the road but no match for this cyclepath.

I normally commute on a touring bike, and for the summer I changed its tyres to 25mm Continental GP4000s to see how fast my tourer could go - surprisingly quick on the flat is the answer.  I had one slow puncture early on, I think after using them on the C2H cyclepath but otherwise fine all summer until my first night time commute, puncturing again on the C2H cyclepath. I paid the price walking the final 2km home in the rain.  I know I watch carefully for sharp stones in the light and dodge round them, but once dark you end up running over the sharp stones.

So, as much as I love the fast rolling 25's, I am hanging them up for winter and going back to my more heavy weight but more puncture resistant 32mm tyres for dark winter commutes.

My touring bike came with 32mm 700c Schwalbe Marathon (not plus) tyres and they have seen action for two winters, mostly on journeys between Cottenham and Cambridge, mixing roads and cyclepaths. This is what they look like now:

Splits after two and a half years of use.

This is the worst section of the tyre but all round there are splits of various sizes in the tyre.  Occasional  inspection reveals small sharp stones and glass embedded in the smaller splits which would cause lesser tyres to puncture. I recall how one of the larger splits happened: it was whilst cycling along White Fen Drove listening to music I became aware of an out-of-time beat. Removing my headphones I realised the sound was coming from my front wheel and with each revolution an arrowhead flint was being hammered into the tyre. My tyre was soft 10 minutes later in Stow-cum-Quy.

The Marathons have punctured on average every 1000 miles, but I discovered the root cause of most of them was a split that reached the inside of the tyre and would pinch the tube. I have since glued a patch inside the tyre.  Once my tyres are truly worn out, I might be tempted by the Plus version as a winter commute tyre despite the heavier weight.

If you don't like punctures, puncture resistant tyres can be worth the investment especially if you get a bike shop to repair your punctures.  One tyre that always gets consistently good reports is the Schwalbe Marathon Plus (£40+ per pair), with enthusiastic users quoting how many years they go without puncturing.  Recently I've also been told about years of puncture free life from Continental Contact tyres. (It is not one I heard of before but always like manufacturers to have competition or they get lazy and drop quality).

Friends at work also get saved by tyre sealants like Slime. It used to be dismissed by purists like myself but the use of sealants is spreading, as used in tubeless mountain bike tyre systems, and by pros on their winter training road bikes. I've not tried any sealants myself, worrying about potential mess and sealant lifetime I just prefer to fix a flat so long as it is not too often.

And finally, if you've ever had a fight with a bicycle tyre, you need to watch How to Fit a Schwalbe Marathon Plus Tyre. This video has saved my knuckles from losing blood countless times and I've not snapped a tyre level since watching it.

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