Singlespeed & Fixed Gear - Building first fixed gear, couple questions

Hey Everyone,

Alright, so I am in the process of building my first fixed gear from an old mid-1980's schwinn traveller III. I had a rear wheel built and I just installed it, and took it for a tear around town and it works great.

Thing is that I kept the original crank set which gives me the option of 39 or 52 teeth. So right now I am riding at 15/52, like I have been for several weeks while riding the bike like a single gear (only the one gear worked on it so I rode it like that). Anyways I've been reading online and I notice that people generally are riding with a lower gear ratio. I have also read that having a lower gear ratio makes it easier to skid-stop (I still have my front brake on my bike, but I want to learn to skid stop)

Basically what I am asking is what kinda gear ratio is recommended for riding fixed gear. I live in Toronto, there isn't a whole lot of hills here, it is generally pretty flat. 48/15? 46/15?

I should mention that my chainrings are pretty worn and I need to replace them anyways. I should also mention that I don't really know a whole lot about road bikes, I've always been more of a mountain biker, but since moving to the city I've decided to give road bikes a try.

Also I have a 170mm crank right now, which gives me 4" of clearance, I have read that 165mm is recommended for fixed gears so your pedals don't hit the ground when turning. Should I go to 165 or can I stick with 170mm?

Thanks,

Trevor

I'd say something in the neighborhood of 3:1 gearing (mid to high 70's in gear inches) would be about average, with people who prefer spinning higher cadences or who live in hilly areas running something a bit lower. I live in a flat area too, and 48:16 (exactly 3:1) works great for me. Since you're interested in skidding, I wouldn't do exactly that gear since it only has one skid patch, but 52:17 is close gear-wise but it gives you 17 patches.

I would really only switch to 165mm cranks if you're noticing pedal strike with your current setup or if it's too long for you to spin comfortably. That's more of a personal thing than a necessity.

http://www.bikeforums.net/showthread.php?t=510358

Thanks

Please tell me you're using one chainring at a time and have adjusted it for a straight chainline, and not running fixed gear just assuming the two chainrings in their existing locations are going to work?

170mm is fine. 46x15 is fine if it's really flat, I've been happy with 46x16.

Check the chainline. If it's not pretty close to straight, that can be a big problem.

Yeah right now I am running 39/15. This gives me a perfectly straight chain line (15/52 was... pretty straight.....i know). When I took the chain ring off and cleaned it up I noticed the teeth are pretty badly worn, so I think I should replace it soon.
After riding all over town yesterday, including some high winds and a few hills, I realize that I would prefer a gear ratio higher than 39/15 but definitely lower that 52.
Because when I ride with derailleurs I never really put much thought into my gear ratios, its hard to know what gear ratio I am going to like best without being able to ride them. However I feel that around 44/15-46/15 will probably be about right. 170mm seems to be working fine. I think I need to replace the crank arms as well because I have been having a bit of trouble finding a chain ring that fits.

Alright thanks!