Last Saturday I converted my Elephant Bikes National Forest Explorer (NFE) to tubeless. My main motivation was the puncture I had suffered 16 km from the goal of BRM423, a 400 km brevet I rode last month.

While a tubeless setup with sealant will not prevent all punctures, it will handle most of them. Only when a cut is too large will I have to still install a spare tube into the tyre as I also would with a puncture in a non-tubeless (standard) setup.

For the first 2,500+ km I had been running my NFE on Compass Babyshoe Pass Extralight (BSP EL) 650bx42 tyres. They are wonderfully supple, with very low rolling resistance, but their sidewalls are really thin.

The existing BSP EL tyres weren’t showing much wear yet. I am confident they would last well beyond 5,000 km, maybe as much as 10,000 km

Neither the BSP EL nor the standard BSP is certified for tubeless use by Compass. So far only the most recently released Compass tyres are officially tubeless compatible:

• 26″ x 54 – Rat Trap Pass
• 26? x 1.25 – Elk Pass
• 650Bx48 – Switchback Hill Pass
• 700Cx35 – Bon Jon Pass

However, other Compass customers had successfully used the Babyshoe Pass and even the Grand Bois Hetre tubeless, with varying results depending on the sealant used and the type of tyre.

Veteran NFE owner Fred Blasdel reported that even the BSP EL survived for thousands of rough miles off-road for him before he finally shredded a sidewall on some rocks. He found the standard BSP more suitable, as the slightly more robust sidewalls lend the tyre more support during cornering without having to resort to high pressures. In Fred’s opinion, having tubeless-compatible rims is a more critical element than having tubeless compatible tyre. This makes sense: It’s the high shoulders of tubeless-compatible rims that ensure a tyre can not easily come off the rim if deflated. The tubeless specific bead shape of tubeless compatible tyres will help to seal air inside, but if you’re using sealant then ultimately the sealant will take care of that.

In any case, I’m relatively light weight at under 70 kg / 155 lbs, so I will never have to run the tyres at anywhere near 4 bar / 60 psi, the maximum pressures specified for Compass tires when run tubeless. Consequently I’m not particularly worried about blowing the tyres off the rims just because their bead is not tubeless-optimized.

So I went ahead and ordered some tyres from Compass, including two pairs of standard BSP tyres: one to install and one as a spare spare set if the first set gets damaged or wears out. The non-EL version is supposed to be slightly less supple, but losing the tube should compensate for that.

Installing the tyres tubeless

I took the bike to Tim at GS Astuto, my wheel builder here in Tokyo.

First we removed the tyres, tubes (Schwalbe) and rim tape (Tioga). Then Tim installed the Effetto Mariposa Caffélatex tubeless tape and tubeless valve set and mounted the tyres. As expected the beads would not seat with a floor pump alone, the air would simply escape without popping the tyre if there was no sealant.

Tim removed the valve core and injected 50 ml of Caffélatex sealant into the tyre and reinstalled the valve core. After that he hooked up a can of Caffélatex Espresso to the valve and started spraying from the can. These cans rapidly fill the tube with latex foam, providing sealant and gas at the same time. The tyre started bleeding foam around the beads which he smeared around to help seal. After the 75 ml can was used up, I switched to the floor pump and started pumping like mad.

On the first tyre we inflated, the bead popped into place from the spray can alone. While it still foamed it finally sealed after some manual pumping. I inflated the tyre up to 4.1 bar / 60 psi, the maximum permitted for tubeless use. On the second tyre, after we finished spraying I could not keep up with pumping because by then my arms were too exhausted. Tim took over and finished the job. We spun the wheels around vertically and horizontally to distribute the sealant and to expose the sidewalls to it.

I was glad to see that both tyres held their pressure, without leaks. Soon after that I rode home 10 km without any problems. I left the tyres inflated at the maximum pressure over night to help seal the tyres.

As for just getting the tyre on to the rim, it was really much easier to install without tube than with tube. However, for a major puncture or tyre damage that the sealant won’t take care of on its own, I will still have to install a tube since installing a spare tyre tubeless is simply not practical by the roadside i.e. without access to a compressor, pressurized sealant cans or sufficient CO2.

The proof of the pudding

I left the Elephant NFE on the bike rack for 48 hours, just spinning the wheels around once or twice a day. I didn’t ride on Sunday but went out with family.

On Monday, before I took the bike out for a ride I checked the pressure to see how well the tyres are holding air. Pressure had dropped from 4+ bar / 60+ psi to about 3.5 bar / 42 psi, which is more than enough.

I could not see any sealant bleeding through anywhere on the tyres, though the valves were a bit sticky. I opened and closed them a few times to clean them. I also loosened the retaining nut on the valve, so I would be able to remove the valve with my fingers if I ever had to install a tube. Tim had tightened it very well.

I dropped the pressure further to 2.7 bar front / 3.0 bar rear before heading out for a 50+ km ride to Onekansen (tank road), one one my favourite sub-3 hour exercise loops. I came back with a few personal records on Strava and the best times in 3 years on several other climbs.

The Babyshoe Pass tubeless is fantastic! 🙂