Monday, August 29, 2016

Flat tires and Defective Inner Tubes

The only responsibility of a tube is to seal air.  If the tube sealed---and later fails---it is not the fault of the tube.  It is either a another puncture or improper installation.  The tire rim interface is designed to hold all the pressure, the tube just seals it.



The classic story---My tube held air for about 10/20 minutes, 3 days, and then it failed, it was a defective tube.  No the installation was improper or the you got a puncture.

The true defective tube failure rate is very close to zero.  All tubes are pressure tested at the factory.  Any true bike professional will tell you the same thing.

The most common causes of tube failure from improper installation come from not getting the valve stem positioned so to not be under stress.  If your stem is coming out at an angle then the base of the stem is not in the right spot and quite likely will go flat.

The second most common problem is not getting all the glass, thorns or whatever penetrated the tire out of the tire.  When brought back up to pressure the tube repunctures.

If you do not get the tire bead to seat properly and the tube squirts out under the bead and goes bang, again this is improper installation, it is also hard on the ears...

Thorn Resistant Tubes
Thorn tubes are very good at resisting flats when properly installed.  These tubes are really thick in the area near the road and thinner near the rim side of the tube.  Thorn tubes are very susceptible to failure at the base of the valve stem.  It is very important to get the stem coming straight out of the rim hole.  I have seen under low inflation the tire and thorn tube can sometimes slip around the rim under hard braking.

Slime Tubes
I prefer Slime tubes to thorn tubes.  Slime tubes will seal back up around a puncture.  With thorns and small penetrations you may need to add a little air but the sealant will usually work great at keeping you from having to patch tubes or replace them.

Base of  the Valve Stem Leaks Especially with Thorn Tubes

It is rarely a tube failure with leaks at the base of the valve stems.  Two potential issues.  The tube is not inflated enough to put pressure on the tire and rim to keep the tire from sliding around the rim when braking .or. the tube was installed and the valve stem was not pointing straight out of the rim putting too much side pressure on the base of the valve stem.

Thanks
Rick

Here is a link to another article on Defective Tubes.

Sunday, February 28, 2016

How to Save Money on Park Tool and Other MAP Priced Items

There are a lot of Map (Minimum Advertised Price) items in the Bicycle industry.  MAP prices are set by Manufacturers that want their items advertised  for a certain price.



The retailer is allowed to sell an items for any price he wants but if he advertises the item it must be at MAP price or above.

This is especially true on Ebay and Amazon, the price must be at MAP or above or the Manufacturer will quit selling the item to the dealer.

Park Tool, Lizard Skin, Serfas, Planet Bike, Kryptonite and several other manufacturers have set MAP pricing rules.  This is why you see every Park Tool Repair Stand on Ebay or Amazon are usually priced exactly the same.

Most of the MAP price agreements do not allow the retailer to put "make offer" in the listing.

How to Save Money on Park Tool etc.


You can email any of the sellers and ask if they will come down on the price. This will probably not work on items that cost under $40 as the shipping is high enough that there is not much margin.  However the $200 to $500 items might be discounted if you ask.

Good luck in your Cycling Adventures

Enjoy the Ride,

Bicycle Rick