Going tubeless

This guide shows how to fit tubeless tyres and goes into advantages and disadvantages of them. This is based on 3 years experience riding with them, not something I read on the internet. There's two guides to fitting them, a "kosher" guide if you're running UST rims and a ghetto guide for a DIY conversion. You need different garage tools depending on the rims/tyres.

How to fit tubeless tyres to a UST rim

How to make any tyre tubeless on a non UST rim

Advantages/Disadvantages

There's no disputing the fact that fitting tubeless tyres is more difficult than fitting tubed tyres. That said, although it turned out to be fairly easy, that was in my garage. Re-fitting on the trail is possible but it depends on your rim and tyre combination and Lady Luck.

Tubeless tyres are currently a lot more expensive than tubed tyres, however, factor in a tube and they come a lot closer but tubeless is still slightly more expensive. Then add sealant. This is a must. A bottle of Stan's costs £15 in 2009 (£23 in 2011) but I used less than a quarter of it to fit two tyres.

Weight. As you will see below from my own measurements, there's nothing in it.

Lower pressures. I ride cross country not downhill and pinch punctures aren't a problem. In muddy conditions I'll run 15 psi in the front and 20 psi in the rear just to get traction. I can't go lower than this as the bike handles like a complete dog on the road with the tyres that soft. So, for me, being able to run lower pressures isn't an issue.

Lower rolling resistance is often claimed as a tubeless advantage. I can't comment on this, however, any advantage will be small and will be completely swamped by a dragging brake pad.

Puncture resistance. As I've already said, I run slimed tubes as thorn punctures are a big problem for me. I also find that slimed tubes are far from perfect and some brands are better than others. Personally I find the kosher "Slime" brand by far the best and Bontrager self sealing tubes to be pretty poor. Theoretically it should be much easier to seal a punctured tyre than a punctured tube as the rubber is much thicker and the membrane stresses correspondingly lower. It is for this reason alone that I've gone down the tubeless route. Only time will tell if tubeless does indeed live up to the hype.

Punctures

There's no disputing the fact that tubeless tyres puncture less than non-tubeless tyres. They are not immune to punctures though and some tyres puncture a lot more than others. Specialized fastrack LK 2bliss S-works 26x2.0 tyres puncture a lot simply because they're so thin (they weigh only 515g). Regardless of tyre, if you get a 4mm or bigger cut in a tubeless tyre, its going to go flat, period.

There are three ways to fix a puncture in a tubeless tyre.

The first and most reliable method is to fit a tube.

The second method is to take the tyre off, patch the hole by sticking a puncture patch on the inner surface, then re-fit. This is the method I use back home in the garage. I would say you've got to be desperate to do this on the trail. Note that finding the hole in a tubeless tyre is not easy and you may have to inflate it on the rim and find the hole that way. The reason this method is not recommended on the trail is the mess inside the tyre. You've got to dry and clean all the latex off before you can get a patch to stick, then you've got to refit the tyre.

The third method is to plug the hole. I used a Genuine Innovations repair kit twice.

The first time I got a puncture I took the tyre off and refitted on the trail. I stuck one of these plugs in the hole, added more sealant (shampoo/shower gel bottles from hotels are just the right size for taking sealant with you on the trail), then refitted the tyre using a CO2 cannister. This worked initially but after about 1km, the was a bit of a bang and the the tyre went down.

The second time I used a plug the tyre was going down slowly. It sealed itself before it went totally down but leaked when I pumped it up again. Jamming one of these plugs in fixed it (without removing tyre) and it lasted the 5km to home and kept pressure in the garage for the couple of days it took me to getting round to fixing it.

I'm not overly impressed with these plugs, 50% success is not good. I'm confident that a bit of string soaked in rubber solution (the stuff you stick patches on with) will work just as well at a fraction of the cost, however, I haven't had chance to test this theory. The bottom line is you cannot rely on them.

A 4mm cut (silver line) will not seal. You can see how the latex sticks to the inside of the tyre. This has to be cleaned off before you can stick a patch on.

Weight

One of the oft cited advantages of tubeless tyres is a reduction in weight and if there's one component of a bike that can use a weight reduction its rims and tyres. If you have extra weight on say the bike's frame then you have to put in extra effort when pedalling up hill. However, because the wheels rotate, as well as their mass, there is also inertia to consider. Inertia is the product of mass and the radius squared (from the centre of rotation). The worst possible place you can add extra mass to a wheel is the rim/tyre as its at the greatest radius from the axle. A 1kg increase in hub mass won't have any where near the same effect on a bike's responsiveness as a 1kg increase in weight on the tyre/rim. So any weight reduction offered by going tubeless is a great advantage.

Here's some actual masses of a somewhat random collection of wheels, tyres and tubes.

Cheap wheel + Kenda tyre+ slimed tube - front	2.5 kg
Cheap wheel + Kenda tyre+ slimed tube - rear	3.2 kg
Bontrager wheel + Jones ACX tyre + slimed tube - front	2.0 kg
Bontrager wheel + Jones ACX tyre + slimed tube - rear	2.6 kg
Bontrager wheel + Jones Mud X tubeless tyre and sealant - front	1.9 kg
Bontrager wheel + Jones Mud X tubeless tyre and sealant - rear	2.4 kg
2x Kenda tyres	1.75 kg
2x Bontrager Jones ACX tyres (actual weight)	1.25 kg
2 x Bontrager Mud X tubeless tyres (claimed weight)	1.1 kg
Bontrager race disc wheels (no tyres)	2.75 kg
Cheap wheels (no tyres)	3.4 kg
4 x slimed tubes	1.5 kg
2 x non-slimed tubes	0.4 kg
2x Bontrager Satellite elite 26x1.5 hardcase semi-slicks	1.4 kg

As you can see, the tubeless set up is lighter than a slimed tube set up but heavier than a normal tube set up. Where I live in the south of England, slimed tubes are a big bonus as you tend to get lots of thorn punctures. In this situation there is a small weight saving in going tubeless. What is obvious though is that if weight is important then bin the wheels that came with a £700 bike and get lighter ones, the weight saving is far far greater than you'll ever get by going tubeless.

Note that there is no discernable difference between the Bontrager Jones ACX tyre and the Bontrager Jones Mud X tyre.

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