sideshow wrote: So, that is an XC casing, mated to a DH tread, glued to the rim?
It's a full tubular casing. They're different than a standard clincher casing because they are fully round. The tube is sewed into the tire.
A high TPI cotton sidewall is used on the Dugast mtb tires that I have one of my racers on. Cotton(or silk) sidewalls suck, they're fragile and exposure to wetness helps to destroy the casing. These fuckers are hand made by some French dude in a shed. The tread is in fact glued on. Some of the xc teams send the tires that they are sponsored to ride to the back-yard tubular makers who glue that tread on. The Scott/Swisspower XC team has had Ritchey tread on Dugast casings for a few years now.
The Maxxis mtb tubular xc tires haven't been spotted in the wild yet but they will likely use an Aramid reinforced casing for sidewall protection. An XC casing would be close to 300tpi for teh supple. Tubualrs will continue to gain market share in the $6k plus Olympic-level XC market until the gear used in elite races is nothing at all like tires that are suitable to every day riding.
If there was a Maxxis HD casing I'd imagine they'd be about 125-150tpi with larger cords with a high Aramid content to tune the ride feel and promote somewhat reasonable sidewall durability.
Gary Fisher worked with Vitoria to develop XC tublars in the early '90's but they slowly slipped into obscurity.
Factoid- there were no machines for making tubulars in Taiwan until 3 years ago. Tubular production stayed in the EU, Eastern Bloc and Japan until the market for carbon tubular wheels exploded.
Now most brands are made in Thailand.