Two Homebrew MTB Tubeless Conversions.

There are several ways of converting your mountain bike so that it rides on tubeless tyres. Tubeless setups are attractive in that they don’t suffer pinch-flats (a.k.a. snakebites) and that with a good sealant in there, they repair punctures on the fly. So effectively do they repair punctures that you don’t have to worry about thorns at all. In fact, you can show off by going through patches of thorns and brag about your porcupine tyres without fear of getting a flat.

This document deals with two ways of converting your existing, standard MTB wheels to tubeless, at very little cost. There are other, more expensive ways too.

At the top of the commercial list is to buy brand new UST (Universal Standard Tubeless – a Mavic/Michelin/Hutchinson collaboration) wheels which have no spoke holes in the rim and only one hole for the special sealed valve. They require UST tyres which are just like normal tyres but with much more rubber so that they are airtight and seal tightly at the bead. These resemble car or motorcycle tubeless wheels.

The second commercial option is to convert your existing non-UST wheels to tubeless, using one of the conversion kits from the likes of Stans NoTubes. This is an excellent system, but a bit pricey and not as much fun as the McGyver methods described below.

Doing it the homebrew way also offers two options.

Both these methods use standard rims and standard tyres.

But first, the challenges of tubeless conversion.

The success of a tubeless conversion is primarily determined by the tyres you use. Old, cracking, extra-lightweight and skinwall tyres are just too porous for a successful conversion. Also, some tyres with otherwise perfectly thick sidewalls hang very loose on the rim, which makes it impossible to get the tyre to seat, no matter how strong your compressor.

Tyres that I’ve managed to make work are:

Tyres which definitely won’t work.

The list on both sides is obviously bigger than this, but this is from personal experience. If you have success with tyres other than these, let me know and I’ll add them to the list.

Now that you have the right tyre, decide which of the two homebrew methods you’ll use.

Both methods require the use of a liquid sealant. You can either make your own latex concoction or buy commercial sealant.

Method 1: The Sliced-Open 20 inch tube method.

Stuff you need.

Recipe for latex sealing concoction.

Mix it all up.

The Operation:

This method is a workaround for the expensive Stans rim strip and uses a butchered 20-inch tube to mimic a Stans strip. Stans strips work by giving the tyre an additional layer of rubber between it and the rim and helps to seal the bead and rim sidewall area. They look like a soft rubber rim tape with a built-in valve.

Step 1: Remove your existing tyre and tube, but leave the rim tape in place.

Step 2: Flay open the 20-inch bicycle tube by cutting along the extreme outside seam. In other words, make a circumferential incision all along the outer perimeter. The tube will now flop open like one wide, floppy rim strip with a valve exactly in the middle of the strip. Wash it thoroughly so that the chalk is removed. Leave it wet.

Step 3: Now stretch the tube onto your rim and insert the valve through the hole in the rim. Screw on all the valve retention hardware.

Step 4. Install the tyre so that it sits over the tube, with the tube’s edges flapping out the side between the rim and tyre. This is where your buddy and lots of soapy water has its uses. It is a job for an octopus, but four hands will get it done, just twice as slow. Be patient and ensure that the oversized rim strip (your open tube) protrudes equally on all sides and you have a neat installation.

Step 5: Inflation: Now take your bucket of soapy water, sponge, buddy and the wheel to your garage or wheel out your compressor. Attempt to inflate the tyre by simultaneously pumping air, manipulating the bead and applying soapy water to help it seat and seal. It may help to attempt the inflation with the valve core removed so that air can go in faster. Inflate to about 60 PSI or until the tyre is properly seated right around.

Step 6: Deflate the tyre and pour a half cupful of sealing concoction inside the tyre, using your syringe or squeeze bottle.

Step 7: Re-inflate the tyre, this time with the valve core in place. Inflate to riding pressure. Slosh the latex cocktail around inside the tyre with a motion nicely demonstrated on the Stans website at www.notubes.com Look for leaks using the soapy solution and if you find any, slosh the solution so that it covers the leak. Eventually all leaks will seal.

Step 8: Now get rid of that flappy bit if tube on either side by neatly slicing it off with the utility knife. Need I say, do not cut the sidewall?
Go for a ride and slosh the wheel’s content around until all leaks stop. In hot weather you’ll have to top up the wheel’s latex reservoir. It’s best to top it up before it dries out completely. Each time you wash the bike, shake the wheel and see if there is still enough latex in there. If not, top it up. Shake the solution before topping up so that you get fibers in there as well, they help plug bigger holes.

Method  2: The sticky tape method.

This method works like the one described above, but instead of using a rim strip and tube to seal, you use packaging tape, insulation tape, a trashed tube and some luck.

Stuff you need.

 Step 1: Remove your existing tyre, tube and rim strip.
 
Step 2: Clean the rim bed thoroughly, removing all glue, bits of rim strip, rotten tube and dirt. It must be smooth, shiny and oil-free. Use fine sandpaper if necessary.

Step 3: Now seal off the spoke holes with a layer or two of the fiber tape. The idea is to make it airtight, so ensure that you don’t take shortcuts over the spoke holes.

Step 4. Cover the fiber tape with a layer of insulation tape. Don’t stretch the tape. Use moderate tension otherwise it will separate from its glue later on.

Step 5: Now punch a neat hole through the tape where the valve goes through the rim and neatly trim away any ragged edges of the remaining tape. Put the valve with piece of tube around it through the valve stem hole and see that everything fits flush. Trim the tube so that it doesn’t extend into the bead area of the rim. It is OK to make it slightly oval or rectangular, which will make for a more secure union. Now smear some liquid latex with the paint brush onto the rim and tube dot, install the valve in the hole and tighten its retaining bolt on the other side of the rim. Smooth it all out so that the latex can create a firm bond. Wait 20 minutes or so until the latex has dried.

Step 6: Now install your tyre, taking care not to rip the valve dot loose. Use plenty of soapy water and smear the tyre liberally with it.

Step 7: Inflation: Now take your bucket of soapy water, sponge, buddy and the wheel to your garage or wheel out your compressor. Attempt to inflate the tyre by simultaneously pumping air, manipulating the bead and applying soapy water to help it seat and seal. It may help to attempt the inflation with the valve core removed so that air can go in faster. Inflate to about 60 PSI or until the tyre is properly seated right around.

Step 6: Deflate the tyre and pour a half cupful of sealing concoction inside the tyre, using your syringe or squeeze bottle. Don’t forget to remove the valve core first.

Step 7: Re-inflate the tyre, this time with the valve core in place. Inflate to riding pressure. Slosh the latex cocktail around inside the tyre with a motion nicely demonstrated on the Stans website at www.notubes.com Look for leaks using the soapy solution and if you find any, slosh the solution so that it covers the leak. Eventually all leaks will seal.

Step 8: Go for a test ride and top up the wheel as and when necessary, as described in Method 1.