Hi Killa’s Garage fans! Today’s post is a bit more practical than some of my others. In fact it might not be esoteric enough to qualify as an esoteric observation on bicycles and cycling, but I’ve been wanting to talk about this topic for a while now. I will attempt to describe how I change a bicycle tire, without using tire levers.
Watching someone remove and install a tire without tools is a bit like watching a magic trick. You can see it being done, and it looks easy. But it doesn’t work when you try it. I’ll break the magician’s code and tell you how it’s done.
This is not another start-to-finish instructable. If you want to watch a video on changing a tire, Google “bicycle tire change”. What I’ll do is reveal the four key techniques I use that make it look easy.
I know there are a few different ways to approach this problem, and this is just the way I do it. Here are my secrets:
- Talcum Powder, Lots of Talcum Powder
In the garage I keep a large container of talcum powder (Johnson’s baby powder if you must know). I sprinkle it generously on any new tire and tube before assembly. It helps the tube slide into a comfortable position inside the tire, and it helps the tire slide over the rim rather than gripping it and fighting me.
When I pack my spare tubes for the road, I put them in a Ziploc bag with a generous dose of baby powder. It makes the new tube easier to install, and it gives my seatpack a nice fresh scent.
I once made the mistake of using corn starch. Did you know that corn starch makes a pretty good glue when it gets wet?
- A Little Bit of Air in the Tube
It is a lot easier to manipulate a tube into position if you first blow some air into it. Not a lot, just enough to give it shape. You can use a pump, but I just blow in some air with my mouth, then screw the valve stem closed to hold it in. Although I have never tried, I don’t think you can blow into a Schrader valve with your mouth … Hang on, I’ll be right back … I was right, you can’t blow into a Schrader valve tube with your mouth.
This bit of air in the tube will also help ensure that you don’t get the tube caught under the bead.
Open the valve stem and let this air out when you are almost done mounting the tire, for two reasons. First, the air in the tube will make it more difficult to get the last bit of bead over the rim, and second, but no less important, if you forget to open the valve stem and you use CO2 to fill your tire, you’ll be releasing about 900 psi from the cartridge against a closed valve. Your CO2 inflator will likely fly out of your hand and into the weeds, never to be seen again. I know.
- Pinch the Bead into the Middle of the Rim
Rims are deeper in the middle than they are at the edges next to the brake tracks. This deep middle region is your friend in tire mounting. Demonstrate this for yourself by noticing how easy it is to get the first bead onto the rim. This is because the tire naturally falls to the center of the rim.
By the way: Rims are built deeper in the middle and shallower at the edges for a reason. If you could lift the bead over the rim wall with the bead next to the brake track all the way around, air pressure would do the same thing and blow the tire off the rim when you pressure it up.
So, to remove a tire, let all the air out. Then go all the way around pinching the tire to push the beads to the middle. Then you can start pulling the first bead over the wall of the rim. Sometimes you must hold the tire in place with a bit of bead over the wall and go back around with the other hand pinching the beads in again. Eventually you get enough bead over the wall and it gets easier.
To mount a tire, pop the first bead into place, then insert the tube and begin popping the second bead over the wall. Be sure the tube is tucked up inside the tire. This is easy if the tube is powdered well, and contains enough air to give it shape. Continue popping the second bead into place. When you can’t pull any more bead over the wall, stop and pinch the bead to the middle of the rim, starting at the opposite side and working around the rim in both directions to where you are trying to get the bead over the rim. You will then be able to get a little more bead over the rim. With a very tight tire, you may have to cycle (no pun intended) between working bead over the wall and pinching the bead to the middle several times.
- Start and End at the Valve Stem
At the valve stem, it is not possible to push the bead to the middle of the rim, because the valve stem is in the way. So, make the valve stem the place where you start when removing a tire and where you finish when installing a tire.
I have seen lots of videos and instructables on tire changing. Many of them don’t have you start at any specific location for removal, and they have you finish installing the tire opposite the valve stem. I disagree. That’s what makes the world so interesting.
My friend Wes uses a method of tire removal where you force both beads off the rim at once. Obviously you can’t start at the valve stem if you use this technique.
After the last bit of bead has popped over the rim, push the valve stem in (towards the outside of the tire) to allow the beads to settle into place, then pull the valve stem back into position.
Those are the four biggies. But while I was writing this I kept thinking of other little things I have learned about tire-changing over the years, mostly from roadside experience. I’d like to share those with you now.
- After putting about 25-30 psi in the tire, check around the rim to see that the bead is well-centered. There is usually some sort of line from the tire-molding process that will be visible and evenly spaced all the way around. If it isn’t, the cause may be the tube caught under the bead. Let the air out and pinch the beads together to work the tube into the tire.
- When changing a flat, try to find the cause. Run your fingers around the inside of the tire to feel for a bit of wire or a sharp rock, and remove it. Pump some air into the tube to see where the leak is. Inspect the outside of the tire for evidence of the cause.
- Stop with 50-60 psi in the tube and check for a bulge in the tire (usually on the sidewall) that would indicate a cut large enough to allow the tube to protrude through and blow out. If there is a significant cut in the tire, use a boot made from a piece of an old tire or use a Park Tool Emergency Tire Boot. In a pinch an energy bar wrapper makes a fair boot.
- While the tire is off the rim, check that your rim strip is seated properly and is covering all spoke holes completely. A bad rim strip is often the problem when you have recurring flats.
- Get a new patch kit every year and write the date on it. A spare tube is always preferred, but you want to have a back-up plan, and old patches don’t work well. I use Park Tool Glueless Patches if I must use a patch. I have opened up that little green tube of glue too many times and found it dry.
- Try really hard not to use tire tools for assembly. For disassembly, OK, but there is too much chance of pinching and cutting the tube during assembly.
- Make sure the valve stem on your spare tube is long enough for those super duper fancy aero wheels you just bought.
- Check that you can get your tires off and back on before you have a flat out on the road. Some tires are built tighter, and some rims have a shallower center The only time I could not repair a flat successfully, even with tire levers, was on a 650c rim. I forget the tire and rim brands, but the fit was unbelievably tight. Too much rim tape will also make tire changing difficult.
- Pro tip: When mounting new tires, put the major label at the valve stem. Not only does this look cool, it allows you to infer the location of the leak in the tire from the location of the leak in the tube, to help you identify the cause of your flat.
- Finally, know this. CO2 moves through rubber faster than air. If you use CO2 to pressure up a tire on the road, let out the CO2 and refill the tire with air when you get home, or you will think you had another flat when you get on your bike the next morning.