SF Cyclotouring

Ride reports and other ramblings from a San Francisco cyclist.


2007.07.27 - Marin Headlands Night Ride

30 mile night-time mixed-terrain loop w/Carlos. We rode up Conzelman through the Marin Headlands to Tennessee Valley and then back home through Sausalito. 9pm to 12:15am. My DIY dual-CREE XR-E LED headlamp worked fabulously, running for over 3 hours on a non-topped-off battery, and never getting the slightest bit warm. I cranked up the max current on the bFlex driver to 1000mA before the ride to get some extra lumens -- turns out I barely needed it, the mid-beam level was plenty bright to ride off-road by, and the high beam lit up the entire parking lot at Tennessee Valley! I didn't expect the fog (silly me) and that mixed with the Headlands trail dust coated bike+self with a layer of wet grit that made brakes and chains somewhat unhappy.

Also, this was the first ride on new tires for my bike -- I got another set of WTB All Terrainasaurus tires, this time in 700x35C, to replace the 700x38s previously on the bike. Mounted on Mavic CXP21 rims, the 38s measured 37mm wide and the 35s measure about 34mm in width. Not much difference, but this swap gains me another millimeter or so of clearance at the chainstays on the bike. The narrower tires are also somewhat rounder in profile, with less aggressive side knobs on the tread. Somewhat curiously, both tires have the same maximum pressure rating of 75psi (usually fatter tires have a lower max pressure rating). Unsurprisingly, the narrower tires seem to roll slightly better on the road, and perhaps have a teensy bit less grip off-pavement. I might go back to the 38mm width on the front for more cush and steering traction, and leave the 35mm on the rear for the increased chain stay clearance.

I now have three sets of these tires: a pair each in 700x35, 700x38, and 700x40! Unfortunately, the 700x40s won't fit on the rear of my bike, but I might try running one on the front to see what that's like. I'm expecting that the 700x35s might also fit on my Vent Noir, so I might install those tires on that bike and see how it behaves for a little light mixed-terrain riding.


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