Fine tuning a new Thorn Audax Mk4 – living with tubeless tyres (update 2: is prevention better than cure?)

I never really fell in love with my carbon fibre Cannondale Synapse road bike after a very scary speed wobble down a steep hill at 40mph. After much research and checking of spokes, head bearings and geometry, I couldn’t launch the bike with abandon down another hill. My Thorn Sherpa inspired confidence: rock-solid handling, fully loaded down the steepest of hills and ridiculous speeds, even on rough tracks. So the Cannondale, and an unused Brompton, were consigned to eBay to fund a new bike. I wanted something for long day rides and B&B or very light camping tours. After considering a Thorn Club Tour, I settled on a Thorn Audax Mk4. Together with my Sherpa, this would cover a broad spectrum, including all my intended cycling ambitions for years.

The bike was specified with Shimano 105 transmission, a Brookes saddle, carbon fork and TRP Spyre disc brakes – held together with lovely Hope hubs and a bottom bracket. Wheels are DT Swiss RR411 asymmetric rims which can take tubeless tyres. Lastly, the build included mudguards and a light rack, plus a T-bar for a front bar bag and an Alpkit frame bag. This is its light touring configuration, these are removed to turn it into a steel framed conventional road bike.

With the glorious local weather and the pandemic lockdown curtailing any further adventures, I have stripped the bike for a summer exercise routine. The wheels came with tubeless Schwalbe G-One 30-622 tyres for winter use, that roll really well and grip like glue to slippery road surfaces. Now I use Schwalbe Pro-One tubeless, but fitting these has been a challenge.

On delivery, I discovered the tyres had been fitted with tubes, so after a few phone calls, Thorn sent me the tape, sealant and instructions for mounting tubeless. Their literature raved about the performance of tubeless tyres, run at lower pressures. Removing the G-One tyres, cleaning the rims and heating them gently with a hairdryer and applying two loops of rim tape, I added the tubeless valve. I fitted the tyre after pouting in 80ml of sealant. The tyre popped onto the rim with a reassuring click after an energetic use of a track pump. Gosh, I thought, these are easy to fit.

Come summer, I decided to fit the Pro-One tyres, as the G-One’s are not long-lasting and I wanted to start a regime of swapping the tyres each season, replacing the sealant. However, installing the tyres a second time around proved to be painful – I just could not get the tyres to inflate and ‘pop’ on to the rims.

Using inner tubes to keep me on the road, I ordered a Schwalbe air booster and some more tape. After much fiddling, I had to start from the beginning: spotlessly clean rims; new tape; carefully fitted valves and use of the new booster. It worked (eventually), and I can confirm that the results are tremendous – the difference in comfort and speed is noticeable. On the downside, the cost of tape (£25), booster (£45) and sealant (£30/litre) make this an expensive option. I hope the value of comfort and puncture protection (pinch flats and thorns) is worth it. I dare not consider a tubeless repair roadside, so I carry tyre levers, a cloth and an inner tube. It is a messy process but it will get me home.

This rigmarole is worth it. The bike handles brilliantly and is very comfortable – this comfort translates into performance, inspiring confidence and I find the bike is actually faster than the much lighter Cannondale frame (particularly down the long steep hills now :-). Imagine riding on a rough section of road that transitions to freshly laid smooth tarmac. It feels like smooth tarmac all day on tubeless.

So I am happy with the bike, now I have fettled the tyres and adjusted the geometry to perfection. The brakes could be a bit more powerful, but improve as they bed down. A Brooks saddle is curving to my form and is now as comfortable as any seat I know. The gears and bearings are silky smooth and the chain oiled with dry chain oil – which is much easier to clean.

Have I found love again? The Cannondale was a beautiful bike, but I prefer the integrity and function of the Thorn – a durable bike that will keep me happy for a lifetime.

UPDATE 1:

2,000km later and I have a puncture, but not that I knew anything about it until I got home and realised my frame had a respray – a fetching cream white, Jackson Pollock affair.

On closer inspection, a 2mm cut in the centre tread had been sealed by the Stans sealant gloop, with NO noticeable loss of pressure. So I had carried on cycling none the wiser, although anyone following me may have experienced a similar respray too.

I am not sure how long the Schwalbe Pro-One tyres will last, but I am mightily impressed with their performance, comfort and roadholding. This, together with the superb frame geometry and compliant ride, gives me the confidence to push harder – both downhill and uphill.

UPDATE 2:

3,000km in and I have had three punctures. Each time the latex gloup has done its magic and decorated my frame. Each time I have filled the tyre with a little more sealant, but now the rear tyre is looking like a pin-cushion. Another puncture today was more severe, but it got me home after cycling 30km at 25psi! Not bad at all.

It was time to remove the tyre and see what damaged has been done and perhaps consider more permanent repairs to the wider cuts, using a reverse puncture repair patch technique. What I found was a large latex ‘sausage’ (no jokes please) inside the tube and at least 5 discernible holes. The latex had hardened and the tyre no longer had any liquid sealant for future punctures. 3,000km for the rear tyre also suggested it was reaching the end of its useful life, so I ordered a new tyre.

Schwalbe have an annoying habit of renaming tyres. So the original Pro-ONE TLE tubeless tyre (HS462) has been renamed the ONE TLE and a new Pro-ONE TLE introduced (HS493). This appears to have better puncture protection, which had me thinking: why have I had so many punctures? Schwalbe rate the HS462 6/6 for protection and durability, but I score it lower. I am not riding any different roads than when I used my old clincher tubed 700C wheeled bikes and I have never had a puncture before. I conclude that sealant is essential for tubeless and without it I would score 1/6 for protection. The tyres are wearing well, but towards the end of their life, punctures have become more frequent. I am going to try the new HS493 tyres, which have a V-guard protection barrier and see how it goes. If I get punctures I think I am going to revert to tubed configurations. I think the inner tube itself provides a degree of protection too.

I haven’t drawn any final conclusions yet, but these are the pros/cons of tubeless vs tubed tyres:

	Tubeless	Tubed
Rolling resistance	Fast – perhaps 5% more so	Good – adequate
Ride quality	Superb grip and smooth ride	Good grip and good ride
Durability	Performance deteriorates with use, more frequent punctures	Performance more consistent over the life of the tyre
Puncture protection	Punctures easily but seals well. Messy.  Need to carry tube to repair	Less easy to puncture, but easy to fix. Carry spare and patches
Maintenance	Awkward and messy, difficult to master. Not repairable on a ride unless tube carried (unable to reseat bead without booster pump)	Straightforward and easily understood
Costs	Tyre more expensive, the hidden cost with sealant, rim tape and valve, plus a booster pump	Universal standard, cheaper tyre and inner tube

I’ll update this after I have ridden the HS493s. The question will be – “Does the ride quality justify the cost and hassle of a tubeless system?”

For now my answer is “Yes”. But I am not sure this will be the case unless in a few months.