, welcome to the forums!
Those Allterrainasaurus tires are a nice design, Marin deserves a pat on the back for spec'ing those
I used to be a weight weenie and tried to save weight by using... *twitches involuntarily*
... 700 x 19 tubes in 26" x 1.7" Smoke Lite mountain-bike tires
. The moral of the story is that tubes can stretch a bit to fit bigger tires, if they have to. However, this stretches them thinner, making them more prone to seam failure, puncture and impact flats ("pinch flats"). If possible, look for tubes designed for 700 x 32-35 tires, they will not have to do so much stretching. If you needed to use a 700 x 28 on a temporary basis, it would get the job done.
The Presta valve's center pin is held shut by the little knurled guy. You can back it off until it reaches the end of the pin... usually it won't come off because the end of the pin is crimped to prevent this. After it's backed off, you can use a Presta-type pump to pump it up directly, or use a Presta-to-Schrader adapter to convert it to an automotive-style valve. When using an adapter, screw it on until the O-ring begins to make contact with the larger-diameter part of the stem, then give it another 1/2 turn. If you screw it on too far, the valve's center pin may stick out far enough to prevent good sealing with an air chuck on a hose. I'd recommend taking the adapter off and closing the knurled cap down snug when you're done, to seal the valve.
As for brands of tubes, even cheap ones from Taiwan and China will get the job done. Continental and Michelin would be a couple of "premium" brands that come to mind, if you want something that's "brand-name."
The 700C x 35 designation... 35 is the nominal width of the tire in millimeters. 700C is a wheel-size standard. As I understand it, there was a 700, 700B and 700C. Originally, the outside of the tire was the size being measured, and different sizes of 700 tires therefore had to have different rim sizes to achieve the same outside "rolling" diameter. Now we are using a 700C rim, based on 622mm bead-seat diameter, and the outside diameter of the tire is what varies when different tire sizes are fitted to the rim. Hope that sort of makes sense.
Last edited by mechBgon; 07-22-02 at 11:26 AM.