Multi-speed Fixed Quickbeam

Quickbeam, originally uploaded by gjtramey.

From one of my Flickr and RBW group friends. I like his gear spread for a go-anywhere fixed gear bike. He’s using the Surly Dingle double-fixed cog and some larger rings than the stock Rivendell setup.

Rings: 39/45
Cog 1: 17/21 Surly Dingle cog
Cog 2: 23
Gears: 46, 50, 58, 62, 71.5

I’ve migrated toward larger rings on road cranks, too, but I like his 23t flip cog better than a 15t cog. That’s a beautiful spread. He can drop from 72″ to 50″ without taking the wheel out of the dropouts. Flipping the wheel, his biggest and smallest gears have the exact same axle position.

39
rings 45
17
61.9″
71.5″
cogs
21
50.1″ 57.9″
23
45.8″ 52.8″

Running the numbers, we can see that he must be using 32mm tires. And, uh, plus we can see them. 38 or 40mm tires will give slightly taller gears.

English Cycles mountain bike

This bike has haunted me, ever since OHBS.
The English Cycles bikes were beautiful, different, super-light and had extremely interesting engineering details.A  belt-driven singlespeed 29er, with internal hydraulic line routing, full-height seatmast, and integrated bar and stem that attach to the fork with a topcap under the fork crown. I saw several belt drives at the show; they’re starting to grow on me.

The seat stays look like bird bones. Rob English assured me they were plenty strong enough, but they’re the lightest-looking I’ve ever seen. The thin wishbone is an English trademark – his 10.5 lb roadbike is even more spare. I like wishbone seatstays – it’s the Bontrager fan in me.

english cycles mountain bike seat stays

The seat mast is dead sexy. The other ones I’ve seen (Gordon, Speedvagen, Tsunehiro) use top caps, I think. Rob English’s design uses an internal wedge seatpost, similar to a quill stem. He says you need to remove the seat to adjust saddle height, “but how often do you change your saddle height anyway?” Mm. Depends. Maybe I’d drill a 9/16″ hole in the seat for access.

Rob English and English Cycles custom mountain bike seatmast and rear triangleThe “one-piece” (two, I guess) bar/stem and fork setup was impressive. I love the fork style, and I’m a big fan of integrated stem-and-bar combos. Kind of like a seatmast, they preclude adjustment, but if you know your size and your setup they look really slick, and can save some weight. This 29er is 18.5 lbs.

The headset top cap is actually under the fork crown, and it’s the stem that has the steerer tube (if I have that correct). The fork has two bolts on the back to clamp it on.

I keep fantasizing about what an English Cycles snow bike would look like, and how light it would be. Perhaps a Schlumpf two-speed carbon Gates belt drive… *sigh* The breakthrough thought I had was that with the massive air cushion of a 4″ tire, you could build a very delicate machine on roadbike lines, instead of the overbuilt machines that snowbikes tend to be.