It's the puncture season, as several have commented. If only there was some way of avoiding this, one of bicycling's great blights. Well, maybe there is ...
As some of you will know, I have been interested in using tubeless tyres on a road bike for some time. The main (and over-riding) reason is that they are claimed to be much less prone to punctures, but a secondary reason is that every other sort of pneumatically-shod transport, from earth-movers to wheelbarrows, uses this system. It has been standard fitting on the family car for about half a century. So what's so special about us?
Some of my Audax UK clubmates have been using tubeless tyres for the last couple of years. These are long-distance riders and their reports are good - tubeless does reduce the incidence of punctures, and is often able to self-seal, so that if a puncture does occur then it is not even noticed until you are home. But there must be some disadvantages, mustn't there? Well, yes, but let's have a look at the system first.
There are four special parts to the system, compared with a standard set-up; the tyre, the rim, the valve and the sealant. Let's start with the rim.
Here's a tubeless rim. If you look carefully at the picture you can see that there is a lip that the tyre engages with. You can also see the rim-tape, which is a sort of super sellotape - these two elements make the rim airtight. To get the air in you need a valve
which screws into the rim. The business end is a sort of fleshy rubber - you do it up finger-tight. Lastly, you need the sealant.
The little bottle is the right size for your tyre, you fill it from the big bottle. The sealant in your tyre lasts for about six to eight months - it evaporates gradually, depending on temperature. You can check the amount in your tyre by unscrewing the valve core and dipping in an allen key or similar - if it has gone down, then a quick squirt tops it up.
Put it all together, and this is what you get:
I've been running mine since July, and so far so good.
But what about these disadvantages, then? Well, some of them are just the way things are, rather than actual disadvantages. It's a different system, so you have to deal differently with it. But here's how it looks to me.
Firstly, the tyres. They are not easy to get. Schwalbe, Mavic, Hutchinson and Vittoria make them, to my knowledge, and they come in in small quantities and get out of stock quickly. I don't know why this is, but I have had to wait for the ones I have and am currently waiting for spares. The best place I have found to get them is www.bike24.de - they seem to have more stock, more often, than anyone else. No idea why this is, or why supplies come and go.
The wheels and rims, on the other hand, seem readily available. Mavic, Shimano, Campagnolo, Trek, Specialized and I have no doubt many others produce rims and wheels that will take tubeless tyres. Many of this year's bikes have them, sometimes with tubeless tyres fitted and sometimes not - the rims will take either. I would guess that this variability of fitting is a supply problem, too.
But physically fitting the tyre is another issue. To seat the bead on the tyre in the groove on the rim needs high pressure. Some say a track pump will do it, some say a workshop compressor is better. If you've ever watched while the chap in the tyre depot puts a tyre on your car, you'll know exactly what I mean. The tyre is put on the rim with a spot of sealant around the edge, a brief hiss with the air-line and 'pop' the bead is seated. This may be the ideal way to fit them - get someone with the right tools to do it for you...
Ahh, I hear you say, what about punctures then? Some Wayfarers may be able to remember repairing a puncture in a car tyre, but most of us have never done it. Tubeless tyres are very much less prone to punctures than tubed tyres, and generally deflate slowly if they pick up a nail or some-such. The system I have outlined above has sealant in the tyre that should seal most punctures - thorns, flints and nails seem to fall in this category. For a larger puncture there is a puncture outfit consisting of sticky rubber plugs - you push one into the hole from the outside. And if you get a truly enormous gash from a broken bottle then you have much the same problem as you have with a tubed tyre - you'll have to use some sort of tyre boot to bridge the gash and put in a new tube to get you home - where you'll have to replace the ruined tyre, tubed or tubeless.
Aha! But I won't have a compressor with me! No, of course you won't. But to inflate a tube you won't need one - it will come up to pressure with a pump in the normal way and, incidentally, seat the bead for you. A spare tube would always get you home, but with any luck you will never need to use it.
So, does it work? Dunno. This year, tubeless tyres were used by pro teams in the Paris-Roubaix. Long distance racers and riders on the Transcontinental and Paris-Brest-Paris also used them, and all reports are either of no punctures or of punctures where the sealant has worked. The manufacturers are making huge claims, as you would expect - 'fastest ever' 'no more flats' and so on. You'd expect that.
For performance, I've tested mine in a roll-out down Root Hill and they seem the same as everything else. My tubeless tyres are Schwalbe One 28s, and I don't have an exact comparator, but they seem a little worse than a 23mm Grand Prix and a little better than a 28mm Gatorskin. A slight difference is possibly greater comfort, as they use a lower pressure - 80 psi is about typical. If there is a difference it's hardly night and day, though.
I'm going to run mine through the Winter, and use them for the cobbles of the Tour of Flanders in the Spring. I'll let you know how I get on.
Mark
