Monday, July 02, 2012

I'm a flip-flopper

In hilly country the two-sided "flip-flop" hub offers the fixed gear rider a relatively quick alternative. Gear range depends on how well you can manage the change in chain length.

In this video I change from low to high before a long, gradual descent with a few steeper drops. Even with the rear fender in the way and the bike's weird dropouts that force me to play around with the quick release adjustment, the change takes about a minute.

On a bike with no fenders and decent forged dropouts I could make the switch in 30 seconds on a good day.

video
My helmet is on the ground, braced up with my water bottle to frame the shot. An earlier attempt when I kept my helmet on and tried to bend my head down far enough to capture the action got some uninspiring shots of my handlebars and the ground.

By the way, it didn't really rain that day even though the forecast sounded certain enough to get me to go with the rain bike. That's okay. Occasional fixed-gear rides really help smooth out your pedaling technique and expand your power range in any given gear.

6 comments:

Matthew Boulanger said...

What cogs are you able to run? 1,2 teeth different? Also, I notice you checking the chain tension around the complete rotation of the cranks- any tips for centering up chainrings or is the Sheldon Brown method the best. I have not had good results yet.

cafiend said...

I'm running 18 and 21, which uses up all the available length of those dropouts. I use a half-link to get that.

I've never fussed with trying to synchronize the irregularities of chainrings and cogs. The deviation has never been so bad that I couldn't find a sweet spot in any combination so the chain tension stays within a manageable range.

Sheldon was a master of detail. Because he wrote such complete articles, nicely archived on the Internet, we can use his memory as our memory when we come across a problem that finally seems worth messing with. Most of the time, fumbling seems to have sufficed for me.

Steve A said...

Interesting contrast between flip flop hubs, a kick shift, and the S3X. Yours is definitely the "weight weenie" approach.

cafiend said...

The least weight and the simplest. My father told me about doing this on his racing bike in the late 1930s, early '40s. It's nicely stone age.

Matthew Boulanger said...

Nice. I picked up a Swobo Crosby for cheap on eBay and the Torpedo hub, while fun, makes the rear wheel a brick and has a LOT of internal resistance in freewheel mode. I'm thinking about setting up a fixed/free wheelset, but for all the versatility of the bike, they didn't design much distance into the sliding dropouts!

cafiend said...

Isn't that weird, Matthew? I looked at a used Jim Redcay track bike years ago, that turned up in a Play It Again Sports store. It had track style rear stay ends, and they were still absurdly short. Beautiful workmanship, but your gear range would have been about one tooth difference.