single speed gearing
 

i'm thinking about getting started in folders by purchasing a dahon boardwalk1. einstein bikes international lists this model as having a 63" gear. is this right, and doesn't it seem to be a little high for a singlespeed? or am i not taking into account the 20" wheels? i thought a 2:1 gearing was the norm for singlespeeds. i'm a little confused and would appreciate your input, as i'm no bike expert. thanks.....tonyg

With the actual diameter of 20 inch wheels being around 19 inches, a 2:1 gearing ratio would give you a 38 inch gear, which is ridiculously low for a single speed.

I haven't owned a single speed in a while, but 63 gear inches seems like a reasonable compromise. You should be able to get up moderate hills without walking, and won't have to spin insanely on the flats just to keep up a decent speed.

I run 63 gear inches on my single-speed bikes. I find that to be a good compromise for riding in and around NYC. I do lose a tiny bit of top-end speed, but I can get started easily from traffic lights, and climb all the hills in the nearby New Jersey suburbs, so the tradeoff is worth it.

I can still motor along with my friends at 18-20 mph, and that's good enough for me.

If you're riding fixed, then you'll probably need a higher gear so you don't spin out when descending. If you use a freewheel (as I do), you can just coast.

I have two bikes with 451 mm wheels, and I run 50 x 16 on one, and 54 x 17 on the other.

If you find 63 inches is too low, you can always gear up later.

i'm thinking about getting started in folders by purchasing a dahon boardwalk1. einstein bikes international lists this model as having a 63" gear. is this right, and doesn't it seem to be a little high for a singlespeed? or am i not taking into account the 20" wheels? i thought a 2:1 gearing was the norm for singlespeeds. i'm a little confused and would appreciate your input, as i'm no bike expert. thanks.....tonyg

I have a 2003 Boardwalk S1. I changed the single speed option into a three speed, leaving the rest of the drivetrain (chainring and single cog) alone and with the stock parts. I live in a very hilly area with streets that tend to start at the bottom of hills with a stop sign to prevent me from doing any head starts of mad pumping. I do not have to honk up (get out of the saddle and pump) up the hill. I just make sure I have it in the right gear and start at a dead stop. So the basic layout is right on for almost anything.

For 20" wheels (406s), my preferred single speed setup is somewhere between 40x18 and 46x20, depends on how much uphill riding i expect to do. 44x19 is my standard.

easy to change
 

A 63 inch gear is easy enough to change just get a larger rear sprocket installed.It may cost 50 bucks total with installation. James

2:1 is the standard ratio for 26" wheeled MTBs off-road (52"). Most fixed wheel road riders end up around 66"-72". Singlespeeders can go a little lower because they don't have to pedal on the downhills.