11 May 2008

bikefix Review Update: Specialized Eskar Control 2Bliss tire

When I first wrote about the Specialized's new Eskar, I expressed some concern over the thin sidewalls of the the company's Tubeless Ready format. Unlike UST standard tubeless tires, Tubeless Ready tires' casings lack a sealing rubber layer- relying instead on a sealant such as Stans' or Specialized's own AirLock liquid. While they certainly are lighter (at 700g) and quite possibly less expensive to make, I’m afraid to report that the thinner sidewalls have proved to be a bit of an Achilles heel. At lower pressures, they have been “burping” (releasing air at the bead:rim interface) quite often. On one recent ride, at 32psi, the front tire “burped” in a downhill corner and the unexpected deflation and threw me over the handlebars. There was no damage to the tire and fortunately, we were able to re-seat it using a hand pump and careful manipulation. For the record, I should note that Specialized lists 35psi as the minimum pressure for these tires. However, requiring high pressures defeats much of what makes tubeless great. Many of us have been riding below the manufacturer’s stated minimum psi. on all sorts of tires for quite a while now, and this will be the first time we have had a problem of this magnitude.

Besides all that, I have noticed more tire roll when cornering (at any speed), and when getting jostled about in rock gardens. Despite all of this there has not been any noticeable damage to the tires' cut-resistant "420/D1" sidewalls. Ultimately, though, I believe that this tire would be improved with the impermeable inner layer that seems to give UST tires more rigidity, albeit with more weight. It is a trade-off I am willing to make- especially in a 'trail' or 'all-mountain' tire. I will ride this tire until I find a comparable replacement to install and review- but will be riding it at 38-40psi. I will update this review again if I see anything else new.

No comments: