Going tubeless offers many benefits, especially if you ride hard or tackle rocky, loose or slippery trails. In rough terrain, or under a hard-charging rider, pinch flats are by far the most common form of puncture.
That’s when you hit a rock and the impact bruises the tube against the rim. The typical solution is to increase the tyre pressure to prevent the tyre-to-rim contact, but this compromises both traction and comfort. So for many, the best answer is to remove the inner tube completely.
Going tubeless virtually eliminates pinch flat punctures (yes, it is possible to pinch flat the casing of a tubeless tyre but it’s relatively unlikely). With the risk of pinch flats removed, you can lower your tyre pressures and enjoy the benefits; smoother ride, less bouncing and ricocheting off rocks and enhanced traction.
Early on, the UST system (introduced by Mavic) was the most popular tubeless system. It doesn’t require any sealant, instead relying on special UST tubeless tyres and a matching inner rim profile.
In recent years, sealant based tubeless systems have become the more popular choice. The requirements are far less stringent and you can often get away with using a non-tubeless tyre combined with a regular rim. Of course this flexibility in component choice does come with a catch; in some cases the initial setup will be finicky. There are so many variables between rims, tyres and even rim strips that you may wind up in a frustrated, latex-covered mess trying to get your tubeless system to seal.
So here’s our sure-fire list of tips and pointers that will get you out onto the trail and running tube-free. We’ve split the process in two; first there’s a general checklist of things that will improve your success rate, followed by the step-by-step mounting procedure for tough to fit tyres.
Preparation
While it’s possible to use just about any rim in a homemade tubeless system, your success rate will be highest with a ‘tubeless friendly’ inner rim profile. Even though a rim mightn’t brandish a ‘tubeless ready’ sticker, it could still work well without a tube. Look for a deep central channel with relatively wide raised shoulders or fl at sections on both sides (right). The U-shaped channel helps with tyre mounting while the raised shoulders secure the bead once infl ated. If your rim has a smoothly radiused curve that continues right up to the bead hook (left), it may prove more difficult to work with. Even if you can achieve a seal, the lack of a secure shoulder can make the tyre more prone to ‘burping’ under heavy cornering loads.
If your rims have a good tubeless-ready inner profile, you’ll still need to tape over the spoke holes. Use a strong reinforced tape for this—electrical won’t last with the air pressure behind it and you’ll eventually puncture as a result. Thoroughly clean the inner rim cavity with alcohol and tightly wrap a layer or two of tape around the rim. We generally start the tape opposite the valve hole and generously overlap the ends to ensure an airtight seal. Make a small hole for the valve and push it through to form a snug fit.
If your rims have an inner profile that wasn’t designed with tubeless applications in mind, you may need to get some purpose built rim strips. These ones from Stan’s are rubber (which helps to form a seal with the tyre bead) and have built-up sides; this gives an otherwise flat inner rim profile the shape required to hold the bead in place. If the tyre is still too loose once the tubeless rim strips are fitted, use an extra wrap or two of adhesive tape under the rubber strip to build up the inner diameter of the rim cavity.
Valve choice can be important too. The shape of the rubber grommet at the base of the stem can vary quite a bit. Where possible, get a valve stem that matches the inner profile of your rim. It’s also best to get a valve with a removable inner core. This will prove helpful on hard to inflate tyres and allows you to remove dried up sealant if it gets clogged.
Tyre choice is always an important factor and some tyres will just happen to work better. Many manufacturers used to advise against tubeless conversions with their regular non-UST models. Now most brands realise that people will attempt to convert them anyway, so they are equipping them with stronger beads and casing that won’t degrade with sealant swishing around inside. To play it safe, look for tyres that are marked as ‘tubeless ready’ (or some acronym to that effect). Otherwise look to newer models that have stronger sidewalls.
If you’re mounting a brand new tyre that’s spent its life scrunched up like this, do yourself a favour and mount it with an inner tube first. Inflate it to around 30psi and leave it overnight. This will help the tyre assume the desired shape and make your job much easier.
Equip yourself with the right tools. When everything goes well, it’s certainly possible to mount the tyres with a regular floor pump. However, if you’re doing this regularly – or dealing with problem cases – a decent sized air compressor will make life so much easier. You’ll pay a bit over $100 for a basic model, which should be fi ne for home workshop use. Most are set up with a schrader valve fitting, so you’ll either need an adaptor or an attachment like the Prestaflator (pictured). If you don’t have space for a noisy compressor, a high-volume floor pump is the next best bet. Most floor pumps are made with narrow barrels for high-pressure road tyres. Look for a model with a big fat barrel instead; it won’t pump to 100psi but it will deliver lots of air fast, and that’s exactly what you’ll need.
The Process
Once you’ve ticked all the boxes in preparation, you can start with the actual tyre mounting.
Start by fitting an inner tube just as you would with a regular setup. Inflate the tyre until the bead seats itself evenly and fully around the rim (with a proper tubeless ready rim the bead will snap loudly into place).
Deflate and pop one bead off the rim being careful not to dislodge the bead on the opposite side. Remove the inner tube and insert the tubeless valve.
If the valve core is removable, take it out. This is especially important if you’re using a floor pump, as it will maximise the airflow and minimise your pumping. You can get a little plastic tool that unscrews the valve core; otherwise a small shifting spanner will suffice.
With one bead loose, hang the wheel up and tip a scoop or two of sealant into the tyre—between 50 and 100ml depending on the tyre volume.
Now refit the loose bead, starting at the bottom (so you don’t spill the sealant) and finishing at the valve. Once it’s in place, do one last check around the tyre to make sure it’s sitting evenly on the rim without any obvious gaps near the valve.
Lather the sidewalls with soapsuds (mix some dishwashing liquid in with a little bit of water), hook the compressor up and pump away. The suds serve a two-part role; they slow the air loss at the bead and also make it easier for the bead to pop into place. With one bead already in place, a quick blast of air should quickly seat the opposite side.
Remove the compressor hose and pop your finger over the valve to limit the air loss. Quickly refit the valve core and reinflate to 35psi. Look and listen for any leaks and swish the sealant around to stop the air loss. Allow the sealant to pool in one spot, place the wheel on its side and bounce it to splash the sealant against the sidewall. Do this right around the wheel on both sides. Now get out and ride!
