Posted By Thomas Bahde on November 22, 2010

by Robert Leone of the Knickerbikers, San Diego’s bicycle touring club.

If you’d like to read great flat tire repair advice, the place to start, as with so many bicycle maintenance and repair issues, is www.sheldonbrown.com (link goes directly to flat tire article). The clear-writing Mr. Brown details one type of flat that keeps on giving – the flat caused by a fault in a tire. Here I’m presenting an illustrated guide to tire boots.

Sometimes tires get worn through, pierced, or slashed in spots. It could be caused by a beer bottle neck, a twig sticking up from a branch on the ground, or even wear caused by a slipping brake pad. To the left is an example from a recent ride. That faint little full crescent? Something cut or punched through both the rubber and the fabric casing of the tire. This caused repeated flats before the rider figured out what was going on.

Let’s digress here: Inner tubes are mostly rubber. They are elastic and flexible. They hold air, but they don’t hold their shape very sell. On the one hand, this is a good thing. One tube can stretch to fit many tire sizes. In a pinch, even a tube built for a different rim size can be squeezed or stretched into a tire. One consequence is that unconstrained tubes can simply bulge loose and burst. The shape and size of the whole rubber assembly is held in place by the tire, or more properly, by the fabric casing of the tire. This is flexible, but not very elastic. When there’s a gap or fault in the tire casing, whether caused by damage, a manufacturing error, or bad installation, the tube under pressure can leak out. It’s both vulnerable to external damage and able to blow out like an overinflated balloon.

My riding companion had a cut-out section of old, worn out bicycle tire with him (see picture on left). He simply slipped that into place before installing the tire on the rim (see picture below). A section of used tire isn’t the only thing you can use as a tire boot. I’ve seen folded currency and candy wrappers inserted between a tire and tube. Iron-on clothing patches have been mentioned – they are thin, tough, and resist bulging. Tyvek ™ and similar fabrics as used in some FedEx and USPS “Priority Mail” envelopes are also thin, flexible, and inelastic. Park Tools markets a rubber, adhesive-backed tire boot.

If you’re lucky, you will rarely — if ever — have to boot tires to protect your inner tubes from bursting. However, you shouldn’t count on being lucky. If you’ve understood this article, you’ll be a bit more prepared for a bad tire problem.

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