This is my winter for new technology I’ve decided. After building my disk brake bike (previously documented in the Gallery section) I thought I’d have a go at converting my carbon clincher wheels to tubeless. Some worries about this: tubeless tyres cost a bloody fortune, concerns about mounting, concerns about sealing, but curiousity won out.
Ultremo tyres are a favourite and hosts Starbike are offering the Ultremo Tubeless kit for €75.90, a discounted price because I think the Ultremo tubeless has been discontinued in favour of the Schwalbe One. With €15 of carriage and then another £27 in my LBS for Stans’ tape and valves the outlay was about £108. Ouch. This had better work.
The Ultremo kit contains two 23mm ZX tyres plus sealant fluid plus easy mount fluid. Here’s a tyre, quite weighty at 290-300g ish. The bead is rather pronounced.
Here are the fluids. I had decided I would definitely be using the sealant.
The Gigantex 20mm rim is narrow and not advertised as tubeless ready. It has a profile like an Open Pro.
Now with two layers of Stan’s tape. I’d wondered how 21mm tape would fit into a rim that externally is 20mm wide. The tape is thin and quite rigid, you have to wiggle it side to side under tension to make it sit into the rim. It does fit, completely filling the rim well.
Next, poke a hole through the tape at the valve hole and insert the valve. It was immediately obvious that there was not much space either side of the valve base for the tyre beads. This was an accurate assessment and to get the beads to sit into the rim I had to loosen the valve and let it slide up, then once the tyre was fitted, press hard from the outside and screw up the collar to hold the valve in place.
Getting the tyre on was a struggle though not worse than other tight tyres I’ve come across. The easy mount fluid wiped along the beads was a big help. Before completely fitting the second bead I poured in about 30ml of Doc Blue at the side of the tyre then rotated it into the already seated tyre area. I did use a tyre lever to get the last section of bead across the rim.
Then the big moment, could I inflate the tyre? I attached the track pump and pumped furiously. Air hissed out at the valve. Damn. I tightened the valve collar more and shook the wheel to make sure the interior was coated with sealant, then tried again. Suddenly the indicated pressure was climbing! I whacked it up to 120psi. Some sealant leaked at the valve then... silence.
For the second wheel I trimmed the base of the valve slightly in the hope it would be easier to seat the tyre. This did seem to help. On a wider rim this would not be an issue.
The second wheel went up to pressure straight away. One thing though, it is sensitive to the force of the valve head on the valve, any movement here can provoke air loss. However an hour later both tyres are sitting silently at full pressure.
The inflated Ultremo tubeless runs out at a narrow 21mm width on these rims despite being nominally a 23mm. The tyre plus tape plus valve plus sealant adds 330g to the weight of the wheel. If it ever stops raining in Southern England I’ll take the bike out for a ride and see what the ride quality is like. So check back here in about May?