| Inexpensive Tubeless Mountain Bike Tire Conversion
Mark Steinebach |
You can convert virtually any mountain bike tire to tubeless using this system regardless of the tire being new or used. The lighter the tire casing, the easier it will be to mount, but the more it will leak initially and the more frequently you will need to top up the air pressure. Tires with large holes or cuts in the casing should be repaired first or not used.
1. First, assemble all of the supplies you will need including:
- Liquid latex (mold builder)
- PVC (electricians) tape
- 20 inch Schrader bicycle tube
- Scissors
- Tire levers
- Screwdriver
- Spray bottle with soap/water mixture
- Tire
- Air compressor
- Small squeeze bottle with narrow spout
- Valve-stem core remover tool
2. Ensure that the inner rim surface is clean (remove any old rim strips or tape). Apply PVC tape to cover and seal spoke holes.
3. Poke a hole in the PVC tape over the valve hole with a screwdriver to allow access for the valve stem.
4. Stretch a 20 inch tube over the rim (this is a very tight fit so don't be afraid to use a little muscle).
5. Inflate the tube and centre it over the rim.
6. Puncture the tube over the center line and cut completely around. "Flap" the loose ends open until they lay over the rim edges.
7. Spray this exposed edge liberally with the soapy water mix - this will really help get the tire onto the rim.
8. Spray the tire liberally with the soapy water, again to lubricate it.
9. Mount the tire using care not to damage the tube's rim-strip.
10. Once the tire is mounted, remove the valve-stem core.
11. Mix your liquid latex (most Mold Builder will be far too thick…..dilute it with warm water so that the end product looks like Creamo, Half-and-Half or Light Cream.
12. Place the diluted mixture in the squeeze bottle and squeeze this directly into the valve-stem…..for 2.5 or larger tires, you will probably want to use about 120ml initially as you will probably lose some during the inflation process. You will likely only need about 60-80ml to keep the tire nicely sealed and flat-proof. Smaller volume tires can use about 50% this initial amount.
13. Replace the valve-stem core.
14. Visually inspect the tire bead. Ensure that it is in contact with the tube's rim-strip all the way around on both sides. You can manipulate the tire to make this happen.
For brand new wire-beaded tires (or any brand new tire) you can improve this initial contact by first mounting the tire with a regular tube, pumping up the pressure to about 60 psi and letting it sit this way for a couple of days - when you remove the tire from this conventional mount, the bead will no longer be deformed in any way and will usually mount up on the tubeless tire much easier.
15. Completely soak the side wall of the tire on both sides just prior to inflation.
16. Hang the tire from a hook during inflation (do not put it on the floor as pressure and the weight of the tire/rim will deform the part of the tire that is in contact with floor and make it difficult to seat).
17. Inflate with an air compressor.
18. Once inflated, you will see lots of soapy bubbles near the bead. These are from small air leaks. Tip the wheel on edge such that the latex inside will come into contact with the area where the air leak is located. By rocking the wheel back and forth and then flipping it and repeating on the other side, you will ensure a good coating of latex and thus a good seal of these leaks.
19. Cut the excess rubber from the tube rimstrip (about 1/8 inch will likely remain visible)
20. **IMPORTANT STEP** - Mount up the tire right away and go ride around your neighbourhood for 20-30 minutes…..this ensures a good seating in of the tire and good distribution of latex to all areas where its needed.
Congratulate yourself….you're done with the conversion and with flat tires. You will need to check your air pressure and add air over the next few days until all the pores in the tire sidewalls seal. Check air pressure weekly and add more latex about every 6-8 weeks as needed.
