24th May 2016 - Punctures & Irresponsible Bike Mechanic / Bike Fit People
People think sorting out a puncture is really easy and just a case of shoving in a new inner tube. Most of the time this is fine, but over the last few months, I’ve had several customers bring me wheels to sort out because they’ve had more than 3 punctures in a row and can’t figure out what’s going on.
DON’T THROW AWAY YOUR PUNCTURED INNER TUBE – IT WILL TELL YOU EVERYTHING !!!!!!
IMPORTANT: WHEN YOU REMOVE THE INNER TUBE, NOTE WHERE THE PUNCTURE HOLE IN THE INNER TUBE APPEARS IN RELATION TO THE TYRE AND THE WHEEL.
INSPECT THE HOLE IN THE INNER TUBE.
There are three main types of inner tube holes (punctures):
1) The Snake Bite. Two small holes next two each other on the inner face of the inner tube. These are caused when the tube is nipped against the wheel when you go over a bump or hit a pot hole. Not much you can do about these type of punctures apart from ensuring you always have your tyres pumped up to a suitable pressure for you and your riding style and the riding conditions (9 times out of 10 this is around 100psi).
2) Foreign Object Puncture. Usually one hole on the outer face of the inner tube. Usually caused by small pieces of flint, glass, nail or thorn. The corresponding offending foreign object is also still usually embedded in your tyre – compare where the hole is in the inner tube to the position it was in when it was in the tyre – you should find the foreign object quite easily then and be able to remove it.
3) Spoke Hole Puncture. Usually one hole on the inner face of the inner tube. Caused by worn rim tape (the plastic protective strip around the centre of your wheel that covers the holes the spokes go through). Sometimes, the rim tape gets worn and a slight tear appears in it where it covers a spoke hole. As you ride along, your inner tube gets pushed through the tear into the spoke hole and gets nipped and punctured. Solution – new rim tape (it’s dead cheap) or even insulation tape will do.
When fitting your new inner tube, before inflating, work your way around the wheel with your thumbs on both sides (starting at the valve) pushing the tyre away from the wheel so that you can see the rim tape, ensuring that no inner tube is visible / trapped under the edge of the tyre. If you can see the inner tube, take off the tyre and start again – if you don’t, as soon as you pump up the inner tube, you will get a snake bike puncture.
Once inflated, before fitting the wheel back to your bike, check that the tyre is central on the wheel. Look for the tyre alignment line and check that it is equal all the way around on both sides of the wheel. If it isn’t, remove the tyre and start again. It’s all good practice anyway.
Irresponsible Bike Mechanic / Bike Fit People
It’s a sad (and dangerous) world where anyone thinks they can be a bike mechanic and / or administer bike fits without proper training or proper tools.
In the last six months, I’ve had to write off two sets of carbon forks, a carbon seat post, some carbon handlebars, a brand new pair of carbon tri bars and an expensive carbon frame – all cracked by people who don’t use a torque wrench, or know anything about tightening up bolts, especially where carbon is concerned.
I know one bloke who’s carbon handlebars had been overtightened (no torque wrench used) and as he was coming down a hill, his handlebars snapped in half. As he fell, the jagged edge went straight through his cheek.
Carbon is fragile where clamped and can be easily crushed or cracked without the use of a torque wrench.
People are also fragile (especially when crushed).
I’ve seen some so called “bike fitters” try and fit people to bikes who have no biomechanical training or understand kinetic chains and (as above) don’t know what a torque wrench is or how to tighten up bolts.
Getting a bad fit by someone who “thinks” they know what they are doing can potentially really mess up your back or your knees, or your bike amongst other things.
In essence, be very careful who you let play with yourself or your nice bike.