Tuesday, September 27, 2005

Cult of the Fixed Gear Revisited

John asked:
"Does converting a road bike to a single speed (with freewheel) count as halfway to fixed gear? That's as far as I've been brave enough to go. I'm a little afraid of fixed gear because I've had some knee problems."

Believe me, I know about knee problems. I have trouble with my right knee due to a type of arthritis. Cleat alignment is absolutely critical to pain-free cycling. For that matter, middle age brought myriad aches and pains. It's a rare day when something doesn't hurt, but then, I've broken a lot of bones along the way too. They make excellent barometers!

A single-speed is akin to a fixed gear, but it doesn't work the muscles the same way. When I first start riding fixed, the muscles at the top outside of my thighs hurt. I'm sorry, but I don't know their names. I think a short ride on a fixed is a more intensive workout. Oddly, I feel 'loose' after a fast spinning ride, something that doesn't happen with a geared bike.

Sheldon offers this: http://www.sheldonbrown.com/fixed.html His knowledge far exceeds mine, and this page is a primer in doing a fixed gear conversion.

There's a quick and dirty way to discover if you'll like riding a fixed gear. It's cheap too! If you have an old freewheel-equipped bike with horizontal frame ends, simply remove the freewheel and spin on a cog. I highly recommend a lockring over the cog for safety's sake. If you get a 3/32" cog, you can use a regular derailleur chain, otherwise, with a 1/8" cog, you'll need a 1/8" chain too. Remove the derailleurs and controls. Install the chain on the inner chainring. This will give an adequate chain line, though it's unlikely to be perfect, it will work. Do not remove the rear brake. It's better practice to keep it for safety in the event that the cog spins off as you try to slow down. Total cost for all of this should be around thirty to forty dollars (assuming you already have an old bike to modify!) Some of the guys on the fixed gear list go dumpster diving for suitable bikes.

If you decide you like the set up, you can substitute BMX chainring bolts. They're shorter, so you can use just one chainring. You'll probably mount it on the inner surface of the crank arm. Change the spacers on rear wheel, making them even side-to-side, and re-dish the wheel. Your chainline should be fairly close to perfect. See a copy of Barnett's manual for an in-depth discussion of chainline.

Gearing is a personal choice. I have 2 fixed gears at present, one set up with a 42x20 for bad weather commuting, complete with rack, fenders, and lights, and another set up with 47x18 for faster rides and fun. In fact, I rode the 47x18 to work today since I only needed to carry my lunch and a few work clothes. I've gone as high as a 52 or 49x18 on that bike for time trials, but I wouldn't ride a bigger gear like that regularly. I value my knees too, so I'd recommend using a small gear at first. Something between 60 and 70 inches should do fine. Because there are no 'dead spots' at top dead center and bottom dead center, you can climb in a much larger gear than you would on a freewheel equipped bike. In other words, you can climb with less effort on a fixed gear for an equivalent gear size. My knees are acutely aware of this!

I rode a Paris Sport track bike back when I lived in Pittsburgh. It had a 62" gear, if I recall right, and that worked out OK for the hills. But I was also a lot younger then and about 40 pounds lighter. That 42x20 on my current commuter may seem small to some, but it's perfect for getting into the ever-present Oklahoma headwind while carrying baggage.

It takes some time to adapt to riding a fixie. You may be a bit anxious and fearful for the first couple of rides, and I suggest you stay away from traffic until you feel comfortable. Practice someplace quiet, away from traffic. Clipping into the pedals, or getting into toe clips may be a little problematic at first. Double-sided clipless pedals are a real plus on a fixed gear. Stopping and slowing take a little more planning too. I approach intersections cautiously. Long, steep down hills are another place to be cautious. You'll find that the pedals can spin well above your ability to slow down by holding them back. There are two solutions for this. Use the brakes or avoid going that fast in the first place.

Starting is easiest if you bring one pedal around to give you a good down stroke. I do this by lifting the saddle with one hand while bringing the pedal around with my clipped in foot. Some people can apply the front brake, push forward with their hands lifting the rear wheel slightly, and bring the pedal around, but I've never done this well. Do whatever works best for you.

You'll discover very quickly that you cannot stop pedaling and coast. The bike will remind you of this quite forcefully! I found that I stopped pedaling whenever I went to sit down on the saddle after standing. I learned to keep pedaling when I crossed railroad tracks. And since I'm riding a road conversion rather than a track bike, I've learned to slow down a lot for corners. I do not want to snag a pedal! Track bikes usually have higher bottom brackets and shorter crank arms, making for less chance of a pedal strike.

6 Comments:

Blogger hereNT said...

If you're doing the bum-bike suicide hub, I really recommend that you not only put a lockring on (bottom bracket kind, not a track lockring) and tons of red loctite. Exen with brakes, I think it's a pretty dangerous setup...

8:24 PM  
Blogger Ed W said...

I've had my Centurion set up that way for a couple of years now. It's my bad weather commuter. There's a right-hand threaded bottom bracket lockring over the cog, but it's been on so long I don't remember if I used Loctite. Regardless, it's been solid. I don't do skid stops or anything else to abuse the equipment. I weigh about 210, and that's abuse enough!

9:47 PM  
Blogger Fritz said...

I think the most abuse to knees comes from applying backpressure to slow or stop the bike. If you keep the brakes on your conversion (or add brakes to a track bike) then your knees will be fine.

FWIW, I've put about 600 miles on my fixie this year and about 4000 miles on my geared road bike. Fixie mileage includes some 30 to 40 mile rides, but it's mostly in-town errand running.

10:03 PM  
Blogger Mikhail Capone said...

A bit off-topic, but I figured you might be interested by this:

http://www.treehugger.com/files/2005/09/umbra_on_the_he_1.php

10:47 AM  
Blogger John said...

Thanks for the thoughtful and thorough response to my question.

I was recently given an old frame that was a tiny bit to large for me, so I passed it on to a friend. He's setting it up as a fixed gear and promises to let me take it for a spin once he's finished. That should allow me to get me feet wet before I dive in completely.

8:46 PM  
Blogger mindfrieze said...

In response to hereNT's concerns, my first fixie used a freewheel hub with a cog, B/B lockring, and a generous amount of red Loctite. I also used a lot of torque to tighten down both the cog and the lockring. The bike was eventually involved in a crash (not a result of being a fixed gear). When I tried to recover the cog from the damaged wheel, it was so difficult to remove that I actually stripped some of the aluminum threads off the hub.

I would definitely recommend this setup for a cheap, first-time fixie with the caveat that you take your time to install the cog/lockring well, and you keep at least a front brake for emergencies.

4:40 PM  

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