Tubeless tire conversion on a mountain bike
Background
When I started mountain biking, my friends (who are more experienced) suggested that I should convert my wheels to “tubeless”, i.e. removing the tube and adding sealant for plugging small punctures. It was something totally unfamiliar to me and sounded too involved. I reasoned that it’s unnecessary since I hadn’t had a flat by then.
Fast forward a few rides and I do get a flat with 3 pairs of 2 small holes on the tube at the same time. After wasting 2 hours trying to replace the tube, pinching the new tube and breaking 2-3 tire levers in the process due to a super-tight tire-rim fit (granted, I hadn’t replaced a tube before — now it only takes me 10 minutes), I decided it was time to “go tubeless”
This post documents almost everything I’ve learned while going through the process and I hope it saves you some time. It is what I wish I had when I started out.
Pros
- Less weight on each wheel since there’s no tube (duh!)
- Have the tires use lower pressures, providing a better grip (you can’t do that with a tube because the rim will pinch it causing “snake bite” holes)
- Relatively small (or maybe big) punctures are instantly plugged by the sealant, so you don’t get flats
Cons
- You have to spend extra money and time for the conversion (if you do it yourself)
- You can still get a flat if the tire is punctured and the hole is too big for the sealant to plug. So you still have to carry a spare tube, some tire patches and boots.
- In dry climates and high temperatures, if you don’t ride regularly, you have to rotate the wheels every once in a while, so that the sealant does not dry out
- You have to regularly check whether there’s enough sealant in the tires, and if not, refill
What you will need
- Pair of tubeless-compatible/ready/easy rims
- Pair of tubeless-compatible/ready/easy rims tires compatible with your rims
- Puncture repair kit with patches and vulcanizing glue if your tires have been used before (they will have many small holes)
- Pair of tubeless valves, with a removable core, that fit perfectly the channel of your rims (very important!), are long enough for the depth of your rims and have a width that matches the valve hole in your rims
- Valve core tool
- High-pressure, flexible, tubeless rim tape to seal your rims (pick a width 2 mm greater than the width of your rims or read the Troubleshooting section below)
- Sealant liquid
- Sealant bottle (around 60 ml) with narrow cup and a hole to pour the liquid through the valve or a feeding syringe (50-60 ml or bigger)
- Pair of wide, plastic tyre levers (do not use metal ones as they will damage the rim)
- Floor pump
- Bucket with water and dish soap
- Soft brush
- Rubbing alcohol
- Clean rag
- Toothpick
- Pointy knife
- Scissors
Note: Some bikes (mine included) have different front and rear rim widths, so it is important to check your rim dimensions before buying tape, valves and tires.
Instructions
- Remove the wheels from the bike. Watch this, this and this.
- Remove the tires and the tubes from the wheels, using tire levers as necessary, taking care not to pinch a hole in the tube. Keep the tubes as spares.
- Remove any existing tape from the rims
- Clean the rims thoroughly with a soft rag and rubbing alcohol
- Tape the rims to create an airtight seal, starting opposite of the valve, overlapping the tape by 10 cm at the end, and trying to have as few air bubbles as possible. Take your time to do it right.
- Insert a toothpick in the center of the valve hole from below and push gently up until it touches the tape
- Use a knife to make a very small round hole where the toothpick is and then remove the toothpick
- Insert the valve in the hole, gently pushing it down until it sits firmly on the rim channel (center). This will cause the tape hole to grow.
- Use a tire lever to push down the valve with force and screw the nut tightly on the valve with your hand (do not use a tool)
- Install one bead of the tire and seat it on the rim channel, using tire levers as necessary
- Install the other bead of the tire, using tire levers as necessary
- Pour dish soap in a bucket with water and shake with your hand vigorously to create a lot of foam
- Use a soft brush to pick the foam (only the foam, not water!) and briefly brush the tire sidewalls, both sides (some foam will enter the rim — that’s OK)
- Using a floor pump, quickly pump the tire to 50 psi (or lower if this exceeds your tire’s or rim’s maximum pressure). This will cause the tire beads to lock onto the rim sidewalls (you will hear loud popping)
- Check the wheel for any leaks by listening closely for escaping air or, better, immerse and rotate the wheel in a bathtub with water and look for air bubbles
- Assumming the wheel does not leak air (if it does, consult the Troubleshooting section), deflate the tire
- Remove the valve core with a valve core tool
- Pour the sealant liquid into the valve hole (check the recommended amount on the back of the sealant bottle based on your tire width)
- Screw the valve core firmly (but not too much) with a valve core tool
- Pump the tire back to 50 psi (or lower if this exceeds your tire’s or rim’s maximum pressure)
- Shake the tire on a horizontal plane with big wave-like, round motions to ensure the sealant is evenly distributed and covers any holes
- Place the tire vertically and spin it a few times for the sealant to cover any holes
- Leave the wheel horizontally for a while and repeat the shaking process a couple of times more (with a few hours in-between)
- If you know the tire has holes (if it’s used, it has), you can try to leave the wheel vertically so that the holes are at the bottom. This will give the sealant a chance to plug them more effectively. Rotate the wheel slightly from time to time to cover the whole tire surface.
- Wait one day and then deflate the tire to your ideal pressure
- Wait one more day and then check the tire pressure with a pump to make sure it hasn’t leaked any air
- Ride!
Troubleshooting
I’m not sure what rim tape width to buy
The general consensus is to go for 2 mm bigger than the rim width. If you want to be absolutely sure, here’s what I came up with, and did:
Cut a small piece of office tape and place it across on the rim, starting from one edge/sidewall, going down the channel and ending on the other edge/sidewall. Press the tape down firmly so that it follows all the rim channel surface. Use a permanent marker to mark the side walls. Remove the tape and stick it on a piece of paper. Use a ruler to measure the width! ;-)
I have a hard time removing the tires from the rims
After deflating the tire, and before using tire levers, grab/pinch the tire and pull with force to the center of the rim. Repeat the process around the tire. Eventually this will break the bead and cause it to sit on the channel, introducing some slack to the tire. Repeat the processes with other bead. Now use tire levers to remove one bead. Remove the other bead towards the same direction! It really helps to have wide and strong tire levers for this.
Watch this.
I’m not sure how to tape the rim
Go slowly. Use a headlamp. Grab the wheel close to you so that working on it is easy. One way to do it is to align one edge of the tape with one rim sidewall and press down, then move to the channel, and press down as well. Leave pressing down the other sidewall for the end. This will make it possible to run through the whole tape at the end to remove any trapped air and set the tape better. The tape should be strong, sticky and flexible.
Watch this.
I have a hard time installing the tires on the rims
Place the bead starting from the valve and work your way around with both hands. When things get tight, go down the valve and pull the tire upwards to create some slack, again working your way around with both hands while pulling. Then go to the middle of the tire where it hasn’t been seated yet and pull and rotate/twist it firmly to the opposite side, holding it down on the rim to secure it. With the other hand, use a tire lever to install the tire on the rim, starting from the edges, alternating between them, and working towards the center.
Watch this.
I’m not sure how to add tire sealant
Before adding the sealant, shake the sealant bottle vigorously and for at least 10 seconds to ensure the latex particles are evenly distributed. Wait a little for the foam to settle before adding it.
Watch this.
I cannot get the tire bead to seat/lock on the rim when pumping
You may have done a poor soap job on the sidewalls so the beads won’t slip. Or you are not pumping hard/fast enough. Or the tire is new and has uneven edges due to folding in storage. Another idea is to use an air compressor or a floor pump with an air chamber that stores and releases pressurized air at once.
The valve is leaking after pumping the tire
Make sure you’ve pressed down the valve very hard so that it sits firmly on the rim channel, creating an airtight seal. Use a tire lever for this and screw the nut with your hand while doing so. If it still leaks there are two possibilities: either your tape job was not perfect or the valve is not a good fit for the rim. For example, I had issues with Stan’s universal (the irony) tubeless valve and had success with Mavic’s UST tubeless valve which has a rectangular, wide rubber on the base that makes for a better seal.
The tire is leaking from a small hole on the tread
You probably have a used tire. Even if you didn’t get a flat tube, tires do get punctured and collect small holes as they are used. If the hole is big enough that leaking air is audible, I suggest removing the tire and patching the hole from the inside with a patch and some vulcanizing glue. Watch this for how to do it.
You could ignore it and try to plug the hole with the sealant, but I don’t recommend it. It may be the case that the tire still leaks from some other point (other hole on the tread, the sidewall or from a poor fit on the rim edge) and in this case, you will have to remove the tire and the whole process will be messy with the sealant inside.
First get an airtight seal using only the tire and the rim, and then proceed with adding the sealant through the valve (the so called “dry fit”). If you have patched the holes and there is still a leak, then trying to fix it with the sealant may indeed be your only hope (with a considerable chance of working)
Generally speaking, the tire will leak air through the point of least resistance. If you fix the valve, it may leak through the tire holes. If you patch the holes, it may then leak through the rim edges.
The tire is leaking from the rim edge
The tire bead is probably not properly seated on the rim. Deflate and refit the tire and pump again. Use soap bubbles to help the bead seat correctly on the rim sidewall. If it still doesn’t work, it may be worth trying to plug the gap with the sealant.
I can’t do it :-(
Don’t give up! Going tubeless is definitely worth it and you will learn a lot while trying to do it. If everything else fails, you still have the option of going to a bike shop.