What is the rear spacing on the Sanchez and what is the largest size tire that fits?
The Sanchez is designed to accept track hubs and adhere to a track chainline, so it is standard track dimensions. The rear hub over-locknut dimension (OLD) is 120mm and the chainline is 42.5mm. Considering these parameters, the chainstays are narrower than a road bike. Tires sizes vary by manufacturer and one brand’s 700 x 25C will measure the same as another company’s 700 x 28C and vice versa, so it’s possible some will fit and some will be tight. But if the rear wheel is far enough back in the dropouts, you can probably fit a 700 x 28C. If you want a 700C bike that accepts a 700 x 32C tire, you should consider a Novak, which is a new 3-speed model that will be out in fall 2007.
