Schwalbe as discontinued the Stelvio in the 650c size and replaced it with the new Ultremo , sweet tire at 170 grams, http://www.schwalbetires.com
At the Bacchetta/Catrike Rally I received a set of Ultremo’s to test. I have intentions of using these at Sebring 24 hour race Feb. 14th, http://www.bikesebring.org/races.html, and though it would be a good idea to put a few miles on them before. I mounted then up on a RENN 577 rear disc and Zipp 404 front. Went out and did a workout that have a 45 minute tempo workout that gave me good range of speeds and cornering for the tires, all went well, after fifty miles not indication of any road scars/cuts. Next ride was the Tour de Cape Century ride, http://www.bacchettabikes.com/forum2/tm.asp?m=48332, the Ultremo’s did a great job and not a single road cut in them yet after 150 miles.
They handle real well and are a smooth supple ride. I think these high end tires are a winner.