This morning, while I was making my first coffee of the day I was half-watching a video of Alex Dowsett (previously of Katusha-Alpecin, currently of the slightly cryptically named Israel Start Up Nation) attempting to set up his wheels tubeless.
That is, without an inner tube, and with a sealant fluid sloshing around to, in theory, seal up any punctures in the tyres. It’s something that’s been commonplace in the MTB world for a long time, and is getting traction in the road world, and — most relevantly to me — for mixed surface riding (gravel, though since I don’t live in a place with miles of these tracks I’m loath to describe it as such).
Dowsett had success in his efforts following a bit of faffing following some slightly misplaced advice given to him by other riders, after a call to his MTB riding father, who gave him the advice I’d been muttering sleepily under my breath — “you have to explode it onto the rim”. Dowsett did this with co2 cartridges, his father who has a past in motor racing has an air line, and in my own workshop I’d use a boost pump.
“you have to explode it onto the rim”
I appreciate that pro riders are at the mercy of their sponsors with regards to the kit that they have to ride on (and the particular setups they are encouraged to ride — tubeless over tubed, for example), but frankly I’m not convinced that riding tubeless is the best choice for most road riding.
From a mechanic’s point of view, it’s significantly more time consuming and awkward to set up road wheels tubeless. Low volume high pressure wheel setups lead to a lot of opportunity for air loss (and sealant getting sprayed everywhere) with imperfectly seated tyres, and that’s before you get to the high stress activity of actually seating tyres with incredibly unforgiving beads onto the rim itself.
The performance upgrade is what a lot of salesmen will point to, and — yes — I can see that for the top 1% of riders this might make a difference.
Yes, there is less weight in the same wheel being run tubeless versus tubed even if you assume a lighter latex tube, but we’re talking single digit grams here, and, in my experience as both a rider and a mechanic chatting to riders, most of us have a few café stops worth of grams we could lose before the advantage of a couple of grams at the wheel would make a significant advantage in chasing down town signs.
Rolling resistance is the second factor which gets bandied about when riders are upsold tubeless (or when professional teams are shouting about their )
In MTB wheels, there is a significant advantage, which you can see if you look at the below graph from bicyclerollingresistance.com comparing tubeless, latex tube, and butyl tube rolling resistance in MTB tyres, running between 15 and 55psi. You’ll see that the greatest advantage appears at the lowest pressures, and for riders on big fat wheels this is a big deal, with most riders preferring a lower pressure to allow for better grip on looser terrain. Significantly for road riders, you’ll see that the advantage is essentially nil by the time you hit 55psi — which is far lower than you ought be running your road tyres, frankly.
Delving slightly deeper into the arcana of tubeless, cyclist.co.uk ran an interesting advertorial for the (at the time) new GP5000 tyres. They found, in conjunction with aerocoach, that the lowest rolling resistance was achieved by a latex-tubed GP5000, rather than the tubeless GP5000TL, presumably due to the fact that in order to hold the pressure on their own, the tubeless tyres need to be thicker.
Where I will concede to the salesmen is that tubeless allows lower pressures and therefore better traction in general, and improved control on looser terrain, and slightly improved comfort on rougher roads, and also, that they can save you bother while riding because of their self-sealing nature. But these come with caveats which I can attest to from my own experiences:
- If you’re running skinny road tyres on loose terrain, then you’re either lost, or slightly foolhardy; even with low pressure tubeless setups skinny wheels can be somewhat treacherous on loose surfaces.
- While tubeless wheels do self-seal (unless you really mangle your tyre), there’s not a hard and fast rule for how long it will take to seal. I recently managed to puncture my long-suffering WTB Byway tyre on a farm track, and it took almost half a mile to seal up, losing me a good amount of tyre pressure, and showering myself, and my bike in muc-off sealant. It smelled great, but is an absolute pig to clean off bikes and leg hair.
- As Dowsett showed very ably, fitting tubeless tyres is not a roadside job. If you need to do any maintenance on a tubeless tyre, you need time, space, and in some cases, single-purpose tools. It also doesn’t reduce the mount of kit you might need to carry on a ride. Instead of a spare tube or puncture repair kit, you’ll instead want tyre plugs or boots, (in addition to a backup inner tube just in case you can’t re-seal a nasty hole).
“It smelled great, but is an absolute pig to clean off bikes and leg hair.”
The upshot of all of this is this: Tubeless setups are great, they work well, and have significant advantages in a number of riding applications — but these are (in my experience) pretty much limited to riding situations where the most important things are being able to run tyres at lower pressures, and being able to ride through punctures. Mostly these appear when the bike you’re riding has high volume low(er) pressure tyres and you want good traction, but also where it’s imperative that you don’t stop. For road riders the latter of these situations would, typically, be racing.
For most thin-tyred applications I can’t see significant advantages. I might be fighting progress, and I’m not a mechanical engineer, so I could be wrong about all of the above, but it seems to that if you can achieve better performance, easier repair, and cheaper kit, why would you bother to pay a premium for a setup that appears to be objectively worse in many ways?