Quick-Fix Flat Repair

Story by Costa Mouzouris//
December 1 2013

A flat tire can put a big damper on your ride, but if you are well prepared and your bike has tubeless tires – and most motorcycles do these days – you can be back on the road safely in about 10 minutes.

First, however, there are things you can do to reduce the likelihood of a puncture. Your first defence is a properly inflated tire. If it is under-inflated, it will produce lots of heat, which softens the tire and makes it easier for sharp objects to pierce the rubber. There’s also the possibility it will heat enough to cause a catastrophic failure of the carcass that isn’t repairable – in other words, a blowout.

Also, if you’re taking off on a cross-country trip, make sure you start on relatively new tires. Leaving on worn tires is almost begging for trouble, even if they are pumped up to specs.

Avoid riding on the paved shoulder, as it collects masses of tire-wrecking debris. If you have to use the shoulder to pass a turning or stopped vehicle, do so cautiously. Also, be wary of construction sites; if you ride through one and hear a regular ticking sound as you roll slowly away, stop and have a look to make sure it isn’t just a rock you picked up; it could be an unwanted hitchhiker in the form of a piece of metal.

If you do find a nail, screw or other offending piece of metal in your tire, note that air loss will be minimized if you leave it in, so don’t pull it out. Instead, ride carefully to a spot away from traffic, where you can perform a tire-saving operation.

There are several tire repair kits on the market, but after years of riding and repairing countless flats, I’ve found that the cord type is most convenient and easy to use. This kit consists of a few sticky cords, a rasping tool and an installation tool. This type of tire repair kit has several advantages: it is easy to carry, it is inexpensive, you can repair a flat without removing the wheel from the bike, it can be a permanent fix, and it is very effective. I never use that sloppy goop that is injected into the tire to seal a flat; it’s messy and often fails.

Make sure your bike is on level ground. If the tire is still inflated when you begin the repair, you don’t want the bike to fall from its side stand if the tire deflates completely. This is not an issue if your bike is equipped with a centre stand. Before you extract the object from the tire, prepare the tire repair kit by threading a cord halfway through the installation tool and having the rasping tool at hand. This way, you can act quickly before the tire loses too much air, if it isn’t already deflated.

Take note of the angle at which the object has entered the tire, and pull it straight out. You must push the rasping tool into the tire at the same angle as the offending object, and move it back and forth in a sawing motion while twisting it, without pulling it out all the way. The rasping tool is a serrated shaft that enlarges the hole and rounds it out to a more uniform shape. Once it gets easier to tug on the rasping tool, pull it out (don’t be alarmed by the louder whoosh of air that will follow), and push in the installation tool with the cord attached. You’ll have to use some force initially, but don’t push too hard, or you’ll go in too deep and might end up with a stray cord inside your tire, in which case you’ll be using a second one to plug the hole. The force needed will diminish once the cord has passed through the hole to the inside.

Push the cord, which will have folded in the middle, into the tire until there’s about one centimetre sticking out of the hole. Twist the installation tool about half a turn as you pull it out; the tip of the tool is slotted and will slip off the cord, leaving it in the hole. Cut off the excess cord with side cutters until it is flush with the tire tread. As a final touch, I like to momentarily burn the tip of the cord, melting it all together.

Now pump the tire back up to the specified pressure, and you’re on your way. You can use carbon dioxide cartridges to fill the tire, but I prefer to carry a compact bicycle pump; it takes a bit longer to fill a tire, but it has a limitless air supply. If you have the space to carry one, a 12-volt mini-compressor is also very handy.

The glue used on these cords remains tacky, but it combines with the tight-fitting cord to provide a long-lasting seal, though tire manufacturers consider it a temporary fix and recommend professional patching from the inside of the tire. I’ve ridden thousands of kilometres on this type of fix, and if done properly, I consider it to be permanent. I would not recommend this fix for a road-race tire when you intend to use the racetrack, as the repair compromises the tire’s carcass and high-speed running might cause it to fail. Also, if the hole is larger than 6 mm or the sidewall is punctured, the tire is junk.

Technical articles are written purely as reference only and your motorcycle may require different procedures. You should be mechanically inclined to carry out your own maintenance and we recommend you contact your mechanic prior to performing any type of work on your bike.


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