Bike Repair – Converting wheels to tubeless

A pair of bicycle tubeless wheels.

If you want to go tubeless, you don’t necessarily need special rims or tyres. This is how to convert your standard kit relatively easily.

Strip down wheels

First, take your wheels off your bike’s frame, then strip off the existing tyres and inner tubes. If your wheels are old and a bit greasy or dirty, give them a clean either with some hot soapy water or a bit of alcohol. You need the seal between the rubber rim strip and the rim spoke bed to be clean, tight and free from any residue or debris.

Check rim strip

Take the rim strip, unwrap it and turn it so the valve is on the inside face of the strip. Run your fingers around it to check that it doesn’t have any cuts, nicks, bumps or molding imperfections that could give air a chance to leak out. Even a few psi leaking out each day can be very annoying to keep topping up.

Insert valve

Present the section of the rim strip with the valve into the spoke bed, carefully poking the end of the valve through the valve hole and pulling this into position. The section of strip by the valve may be a bit thicker and awkward to seat, but persevere as it’s worth getting it right now to avoid having to find the source of leaks later on.

Seat rim strip

Next you need to seat the rest of the rubber rim strip to the spoke bed. This is easier said than done, because they’re usually quite a tight fit. One of the easiest ways is to get a screwdriver with a long, thin shaft and place the shaft between the rim and the rim strip, with the screwdriver perpendicular to the rim. Run the screwdriver shaft around the rim circumference slowly and help move the rubber strip evenly into the center of the spoke bed.

Make the valve airtight

You must ensure that the valve itself is airtight. Most brands supply a special threaded locking washer that screws down onto the body of the Presta valve. Normally there’s a rubber O-ring which goes over the valve before the locking washer. The act of squashing the O-ring helps form an external seal, locking the air in.

Check tension

The rubber rim strip is now on and it may look central, but you need to check that the strip has gone on with even tension all the way around the rim. If there are loose and tight spots in the rim strip where it has been stretched, it’s likely that air may be able to escape between the rim and the rim strip. Use the screwdriver (as before) to go around the rim, to even up the tension. It may take a few minutes.

Fit first side of tyre

The first side of the tyre has to go on. Tyres vary in fit, quality and detail between manufacturers, and even between models from the same manufacturer. This means some will fit better than others. If yours have been folded for a while, we recommend that you fit them with tubes, pump them up hard and leave them overnight. They’ll fit and inflate more easily the next day.

Fit second side of tyre

Seat the second side of the tyre. It’s important to stand the wheel at your toes with the valve at the uppermost (12 o’clock) point of the wheel. Take the bead and seat it around the valve, then work your hands around the circumference of the tyre (away from each other), easing the bead over the sidewall of the rim as you go. As you get to the bottom of the wheel, leave an eight-inch section unfitted.

Remove valve core

If you’re fitting sealant through the valve, you’ll need to remove the valve core first. You can get sealants that can be applied with the core in place (Sludge is one), but most won’t. Unscrew the core, take it out and don’t lose it. If you’re doing this in the kitchen and lose the valve core, it’ll be under the fridge, guaranteed.

Inject sealant

With the tyre fully fitted and the valve core removed, you can use your sealant applicator with the narrow pointed nozzle to inject the required amount of sealant directly into the tyre. Before you do this, though, give your bottle of sealant fluid a really good shake.

Refit valve core

With the tyre sealant successfully injected through the valve, it’s time to refit the valve core. We recommend applying a small smear of Vaseline on the threads of the valve core first, before screwing it firmly back into position. This will stop any sealant on the threads inside the valve from jamming the core in the future.

Alternative way to add sealant

If you’re not injecting the sealant through the valve, leave a section of tyre bead off the rim and pour the sealant in before popping the last bit of the bead on. If you’re adding sealant between the tyre and rim, carefully pour or use a nozzle applicator to squirt it in as latex makes a mess. When you’ve got it in, be careful not to let the fluid slop out of the unseated section of tyre.

Fit last section of tyre

To fit the last section of the tyre, you need to carefully move the wheel so the unseated section is at the top of the wheel. As you do this, you will have to allow the liquid to make its way around to the other end of the wheel. Don’t worry if a little bit seeps out of the join between the rim and tyre. Use your thumbs to carefully yet forcefully pop the final section of tyre into position.

Pump up tyre

Attach your track pump, begin to pump and – if you’re lucky – the tyre beads will push to the rim. A useful addition to your tubeless armoury is a dedicated tubeless inflator like the Airshot or Bontrager Flash Charger – they make initial tyre set up a lot easier. When you’ve got the pressure high enough (it can take 80psi or so to fully seat UST and tubeless-ready tyres) the tyre beads will ‘pop’ into place with some loud ‘ping’ sounds.

Shake the wheel

There may still be air escaping between the rim and the tyre. Pick up the wheel, hold it by the tyre and hold it flat out in front of you like a tea tray. Shake the wheel vigorously to get sealant to the sides of the tyre, so that it can react with the air and make a thick, air-tight seal. You may find that time helps, too. Leave the wheel for 15 minutes, come back and repeat the step and you should find the air loss has stopped.

Listen carefully

Lifting the wheel to your ear and having a good listen should help pick up the sound of air escaping. If you detect any leakage, it should only be from pinprick-sized leaks. Repeat stage 15 and/or try adding a little more fluid. You might find that there is a critical volume of sealant required to complete the job.

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