A topic that causes much contention on internet message boards, and is generally pretty interesting to a lot of people is that of tubeless tire setups for cyclocross. I would like to give a detailed look at where we are at with the technology, and where things might be headed.
- UST which is a certified system encompassing a spec for both tires and rims. The rim and tire have matching bead profiles, which are much more square than conventional folding beads to give a secure lock. The tire includes a butyl layer - essentially a tube - so that it will hold air. The system may be used with or without sealant as a preventative measure from punctures.
- Converted setups, which involve a rimstrip (originally Stan's Notubes, but now often simply a split innertube) and the use of sealant to seal both the tire/rim interface and the tire casing itself (if a non-UST tire is used).
- Those who prefer tubeless ready tires and rims (eg. Bontrager TLR setup, Hutchinson tubeless ready tires) with sealant, sometimes on UST rims.
- Those who use Stan's Notubes rims, any clincher tire of their choice and sealant - with the rim being designed to fit standard tires tightly, a secure and reliable setup can be had without the weight penalties associated with UST and tubeless ready tires.
- Those still using converted rims and tires - definitely becoming a minority, and IMO this setup does not have the same level of reliability at the bead interface, since it depends on a rimstrip to make a tight fit, rather than a special bead hook or tighter beads on tubeless ready tires.
This takes me to my inspiration for this post - having installed cross tires on my 29er wheels before, I notice that they have a great profile: wide and high volume, which is sure to increase performance.
- for similar money to a mid-range tubular wheelset (+ good tires), you can have the best tubeless setup currently available
- the Alpha 340 rim is marginally wider than your average road rim - this is good for users who want to be able to use their road wheels or perhaps a set of tubulars they already own on the same bike, but this is not ideal if the goal is the best tubeless performance possible.
- the tubeless setup is still dependent on low tpi tires, so the grip and ride will not be as good as tubulars until this situation changes. Low pressure performance is unknown at this point, with the rims not yet on the market for significant testing.
- tubulars still come out lighter (though not by much, if you put the money into light tubeless wheels) and have inherent advantages (being able to ride them flat, etc.)