Sunday, June 29, 2008
Sometime after I cross the intersection and haven't had to fight with the shifter, it occurs to me that the bike now accelerates much, much faster. I think the biggest improvement to the acceleration is probably just that the derailleur was pretty badly gunked up, so it had to have been generating a lot of friction. But it can't hurt that the whole bike's a little bit lighter now. Certainly it feels a lot lighter in its acceleration and general handling. I notice a more direct feeling when I start pedaling, and I suspect that the lighter feeling of the bike in general is to do with that, although the rear derailleur certainly weighed a lot.
The big disadvantage to the new setup is hills. This bike has never been that good on hills, I think because of the friction generated by the rear derailleur and that it seems to be a fairly heavy bike in general, and it's a lot worse now that I can't give myself some mechanical advantage. The ratio is have is about 5:2 (actually 52 teeth on the chainwheel and 20 on the freewheel, for people who really want to know) which is a pretty high gear, so it doesn't take much resistance before I have to stand up and really push into the pedals. That applies to starting from a dead stop as well - since I geared the bike to perform best cruising at high speed, starting is a bit difficult. What it comes down to is that the bike has two gears: sprinting and soft-pedaling. On a hill, of course, there is no soft-pedaling, which leaves either charging or going into the anaerobic zone. I have to admit that I do run out of steam before I hit the top of the arc crossing the Brooklyn or Manhattan bridge and I don't necessarily have enough uphill sprints in me to ride all the uphills traveling uptown if I hit the lights wrong, but I stand by my gearing choice. With 22 teeth, I sometimes got too fast to pedal smoothly.
So far, I have to say that I really like my commuter as a single-speed. It has a much more aggressive feel and I think my speeds are a lot higher because it's tuned to be best at about 18 mph. The handling's quicker, the bike feels more agile, and it's more fun. Because of the necessity of sprinting more, I suspect that it's also going to make my speeds creep up on my better bikes. I think a single-speed layout's not for everybody - it really requires an athletic style of riding. It reminds me of switching from a soft, intermediate ski to something bigger, stiffer and heavier - this bike really needs to be pushed in order to ride well, but it gives back much more when I do than it did when it had all the components I've thrown out over the year or so that I've owned it.
Monday, June 23, 2008
This is yesterday's first configuration, using the 20 tooth sprocket and a 3/32 road chain, shortened to have no slack. The smaller hole immediately above the adjusting nut on the quick release skewer was the one used to prevent inadvertent rotation of the derailleur; the other is for mounting a rack or fenders.
Further research suggested that by changing to a cog actually intended for singlespeed use, I might fix the problem. The hyperdrive cluster I was using is designed to shift well, and when used with a derailleur it's a huge improvement over previous systems. However, without a derailleur it still performs as designed - it shifts - but without a derailleur to pick up slack and maintain tension, the chain drops. It turns out that BMX hubs use the same threading as road hubs, which means that a BMX singlespeed freewheel will go onto a road hub with no adapters, etc. required.
On my way to work this morning, I stopped at Gotham Bikes to see if they had a BMX freewheel - I figure this is a really common part, and since I don't have the tool to remove a freewheel, ordering everything for the next phase of the conversion online would probably be more expensive than letting them take care of it. They had the part, but only for a 1/8" chain, the standard singlespeed size, usually used on BMX and track bikes as well as many urban singlespeed rigs and probably cruisers. D'oh! Anyway, I figured that the bike's not working very well for me as it is - I want to be able to accelerate rapidly - so I went ahead and bought a new chain too.
This is the new freewheel, and the new chain.
Finally, here's the new iteration of the drivetrain. The only original parts left are the bottom bracket, crankset and pedals (not including toeclips, which I had the shop throw in when I bought the bike.)
I'd be lying if I said I didn't enjoy the black and silver finish on the chain, or how clean this setup is. The gear ratio is 52/20. According to the gear ratio calculator on Sheldon Brown's web site, this means 69.6 gear inches, whatever that means, or 18.6 mph if I spin at 90 rpm. Which means that my cruising speed on the flats is terrifying by casual cyclist standards and not half bad by mine. If I get strong enough riding this way, I might get an 18-tooth cog, which would bring my speed to over 20mph; I'm concerned that any larger and I wouldn't have the torque to accelerate effectively or cruise comfortably.
Saturday, June 21, 2008
So I've been meaning to give my beater bike, "Skank," a tuneup for a while now. I even bought it a new chain, which I never got around to installing... Until today. I also got some new bar tape. I was about to clean the rear derailleur when I noticed that it has an insane amount of play - like a whole gear's worth. Which explains the ghost shifting I thought was just me having a hard time with the old-school friction shifter. So I went on a bit of a tear removing parts.
Here's everything I took off. In the picture are the chainguard and small chainring from the front (I removed the front derailleur months ago,) the rear derailleur, the old chain, which was badly stretched and the old bar tape and plugs.
And finally, the finished product. It's not going to feel quite as good to blaze past the hipsters now that I've got something "cool" and not antedeluvian, but whatever. I wasn't about to pay money for a new derailleur for this bike.
Friday, June 20, 2008
Wednesday, June 11, 2008
I was buying some cycling stuff online, and one of those Google ads on the right-hand side of the confirmation page I got in my e-mail was for cycling jerseys. I'd been having a frustrating time trying to find something for intermediate weather, so I followed it and found, among other things, Metallica cycling jerseys.
I didn't buy it right then. I tried to resist. But the more the day wore on, the more I knew I had to have one. So I bought one.
Now when I pass yuppies on $8000 bikes, I'll be wearing lightning bolts. So they can feel less bad. I've refused to wear brand names or teams for a long time. But this is Metallica.