(Check out the April Issue Of MBA for the complete story!)
Yeah, we all know how to repair a tube, but try to glue that same patch to the inside of a tire carcass and it will flake off faster than a bumper sticker on the space shuttle. Tubes are extruded from butyl?a type of synthetic rubber that bonds easily to rubber cement and conventional patches. Most tires are made from butyl rubber, but the compound is polluted by different alloying elements, the presence of moisture, and silicone mold release agents. Any one of these factors will defeat a conventional patch. Even tires made from natural rubber like Continentals and Hutchinsons have a greasy-feeling coating that rejects adhesives. Anyone who has attempted a trailside tubeless repair knows that patching a tire carcass requires stronger mojo than anything we carry in our water packs.
We took a field trip to Mike’s Tire Center to observe how the big boys patch tubeless automotive tires. Mike’s sells and services everything from 29-buck tires for Geo Metros to 5000-pound earth-mover tires that cost as much as a brand-new Geo. Then we asked Stan ?Notubes? Koziatek to cut loose with his tubeless tire patching secrets. Surprisingly, we discovered that the basic patching techniques for a tire carcass (full-sized radial or pint-sized knobby) are the same ones we use for a presta-valve innertube?except for one key ingredient: Liquid Tire Buffer. Here’s how it’s done.
1?Find the holes: Leave the tire on the wheel. Inflate the tire and either submerge it in water or use a water bottle to liberally spread water mixed with a teaspoon of dish washing detergent over the tire. Mark where the bubbles form on the tire with a ball point pen.
2?Remove the tire: Break the bead seal with your foot by working around the edge of the rim with the sole of your shoe. Remove it by hand and clean any sealant from the inside of the tire with water and dish washing detergent?then towel dry.
3?Banish the infidels: Use a pen knife to extract any thorns or spikes that remain in the carcass. Find the marks on the outside of the tire and make large circles at each location on the inside surface where you will be installing the patches.
4?Stan’s trick: Use a hair dryer to heat up the area where you will be installing the patch; this will remove any moisture that has been absorbed into the carcass.
5?Chemical treatment: Use a clean cloth dipped in Liquid Tire Buffer to scrub the patch area in small circular motions until the rubber melts and deposits onto the cloth. Don?t sand the carcass or use a metal scraper because it can destroy the fabric layers.
6?Time for the glue: Heat up the patch area once more with the dryer, then smear the rubber cement from your bicycle patch kit (MBA uses Rema Tip Top patch kits) in a circle 1/4 inch larger than the patch. Let the glue dry and don?t touch it!
7?And now, the patch: Peel the foil off the patch (don?t even think about touching the exposed patch surface) and press it firmly onto the glued area. For best results, you should clamp the patch to the carcass for 15 to 20 minutes. A vice or a C-clamp and a small piece of wood will suffice. Regular bicycle patches will work fine, but you?ll need to locate some longer, oval types to seal substantial sidewall gashes.
SO, IS THAT IT?
Seriously, that is all there is to it. The secret is the harsh chemicals contained inside the tire buffing liquid. You may want to use protective gloves when handling the fluid, because every substance inside the can is potentially cancerous. You could carry a small amount with you, but it would have to be in a metal container?if it eats automotive tires, Liquid Tire Buffer could surely find its way though any type of plastic. Be prudent, bring a tube on the trail and leave the tire buffer at home. Liquid Tire Buffer can be purchased by the quart at professional auto parts stores.