Most riders don’t like changing flat tires in the comfort of a well-equipped garage with a cold-beverage-packed mini fridge and a cheering section of able and supportive friends. So what does that say about the poor sap swapping out a tube on the side of the trail with only the tools and supplies that he had carried on the ride? As inconvenient as that is with a lightweight dirt bike that you can easily lay on its side, magnify that several times for the rider on a larger and heavier adventure bike. If the machine is a glossy and expensive model like the KTM 990 or another model with pricey, painted body parts, the task is formidable. In some ways, the actual task of changing a flat is basically the same. But, there are a few key differences, and we discovered some major ones while on a recent adventure ride. Tom Webb flatted both tires on his KTM 990 (the only flats on the entire trip). Naturally, it was all for the benefit of Dirt Bike’s readers. One thing we did right was lay out our tools before the trip. We used them to change the tires on a bike. For that reason, we were confident that we had the tools we needed.

  • img_8554281webOn a normal dirt bike, you could simply throw it on its side and remove the offending wheel. Try that with a bike like the KTM 990 and you risk tearing up the bodywork at a bare minimum. On the KTM 990, there is a center stand, and that is a big advantage. But we found that you can remove the rear wheel easily enough with the bike on the stand. When we changed the front tire, though, it took two good-sized men to hold down the back of the bike and keep the front end in the air.
  • If you don’t have a center stand, you will need to find a rock, low wall or a log to use as a makeshift stand while you change the tire. Our front flat was on a Mexican beach area, and there was nothing large enough to support the front end; hence the two “volunteers” we pressed into service.
  • The KTM 990 and some other high-end adventure bikes have a very wide rear rim. That means that the bead is extremely hard to break. Stepping on it is a waste of time. Fortunately, another 990 sidestand gives you all the muscle you need.
  • We had a shop towel in the tool kit, and we put it on the ground to keep dirt out of the wheel bearings. After we broke the bead down on one side, we flipped the wheel over and broke the bead on the second side.
  • img_8555282webAfter the bead was broken, getting the side of the tire off was a simple matter since the tire was warm and had been ridden a short distance while flat. With one side of the tire off, we were able to pull the tube out and replace it with a new one. First, we wiped the shop towel around the inside of the tire. That turned out to be a good plan, since a needle we couldn’t easily see in the tire snagged on the cloth.
  • With the new tube in, we were able to work the tire back on pretty easily. We made sure to carry high-quality tire irons. One plus is that most adventure bikes do not use rim locks. That makes things easier.
  • img_8563284webThe real secret to changing a tire is to get the beads of the tire down in the well of the rim opposite of the side you are working on. That is fairly easy with an off-road, normal 2.25 to 2.50 rim. Note how short the shoulders of the rim are on this rim. The 990’s rear rim has much wider flat areas of the rim between the well of the rim and the flanges.
  • As you work the tire off the rim, get the dip of the tire iron under the bead. Work the tire off the rim using small bites and working a little off at a time.
  • You want to start with a little air in the tube to keep it round. You want to minimize the chances of catching the tube between the tip of the tire iron and the rim. This is how you pinch a tube.
  • The area around the valve stem is reinforced, so it will want to hang up under the edges of the tire like this one has. If you air up the tire with the valve stem caught like this, and the tube is pinched, you will never get the bead to seat.
  • If the tube gets caught under the bead like this, it will pinch the tube when you air up the tire. Sometimes the tube will pull loose, but many times this will pinch the tube.
  • If the tube gets caught under the rim lock, it will either pop the tube when you air up the tire or when you tighten the rim lock. Make sure before you start that the tube is on top of the rim lock.
  • We used a small hand pump to inflate the tube a little. We did that to minimize the chance of pinching the tube. As it turned out, the pump had no chance of putting enough air into the tube to seat the beads on the wide tire.
  • When we finally had the tire mounted, these were the dead soldiers. We used one tube before we discovered the needle in the tire. Once the second tube was in, we used the pump, every CO2 cartridge the whole group of riders were carrying and even broke a small compressor that a well-equipped rider had along. But we got it done…finally.

If you are prepared, test the tools and equipment you plan to use; you can have a full adventure and a flat.

Comments are closed, but trackbacks and pingbacks are open.