Gearing for a San Francisco Commuter
 

I have a bike I'm building up... it's a lovely original (1984) Cannondale frame that's i've stripped and refinished. New Campy NR hubset, Sugino BB, Alesa and Ambrosio wheels (two sets).

However, I have to gear it up, and would love some help setting the gearing for this bike... it's been a while since I've ridden so don't really have a starting reference.

The bike will be a daily commuter in San Francisco, from the Mission District to the Exploratorium, so I'll be crossing a major hill, minimum grade is 10%. I'm a strong cyclist, don't mind a bit of sweat, but my left knee can't take to much strain.

It has 170mm cranks (Sugino AT double, 110/74 BCD), and the wheelsets are two diff diameters, (27" and 700c) so I can use two different rear gear sets... but the front I'd like to keep the same. Anybody have any recommendations for front chain rings to go along with freewheels? The freewheels, cassettes would theoretically be gear differently for daily, vs. special riding.

I was thinking about a 38/46 front, with something like a 12-28 in the back.... does that sounds like a good place to start?

What's your route? Are you carrying anything? I've ridden singlespeed 42x16 for a year (I live in North Beach and bike everywhere), and switched to 42x17 last week.

I gotta say that 42x17 is quite a bit nicer in SF. I recommend that you just try your commute, and made adjustments if necessary.

I don't live in SF but given 10% and up grades to deal with, I'd go for a triple. Especially if you often commute with loads.

My route is prolly somthing like this:
Up Valencia St, cross Market, (flat)
Up Octavia St to Fulton St to Steiner St, (ascend Alamo Heights)
Steiner St to Greenwich (up over the Lafayette Hts-Pacific Heights saddle),
Up Greenwich St to Lyon (up Pac Heights),
then dowwwwnnnn hill thru the western part of the Marina to the Exploratorium, Palace of Fine arts.

Thanks... tho I need some gears to try the commute on, before I can make any adjustments ;)

What sortsa up and down hills do you normally ride, and how do you feel about that gearing?

-dodger

That's basically what I am running:

FSA Cyclocross Crankset - 46/36
12-27 Cassette

Sometimes I wish for a little lower gear on super-steep climbs, so I think I'm going to change the small ring on my crankset to a 34.

I'd be tempted to just go all the way around the embarcadero to the marina. You could then use basically any gearing you wanted and it would be a safer ride with a nicer view, too. According to google it'd be about 6 miles instead of 4 miles for the route above, but maybe about the same in time?

I'd recommend going straight up Polk, which is not nearly as steep as the poster's route.

over hill and dale
 

If you have a bad knee, are overweight, out of shape, older or simply not used to climbing, do yourself a favor and use a triple 24x36x46 or perhaps a 34x44 if you have a (110bcd) double crank. I'd use a 11-32 or 34 tooth rear. This will give you somewhere around a 20 inch low with the triple and a 28 inch low with the double. It may not look racy but its what smart cyclists ride when they have big hills. I am a 49 year old cyclist with a bad knee and I live in an area (foothills of Mt. Rainier) where there are major climbs. When I was younger and weighed 168 pounds I could climb most of them in a 40 inch gear. Now that I am old and feeble, I need a 20 inch. Most of my rides are between 10 and 40 miles in this terrain and what I can do at the beginning of a ride is different than at the end.
Moral of the story.........you can always use a lower gear. I don't think high gears are very necessary since you can often coast down hills at up to 60 mph depending on the grade. Its easy to spin out a 120 inch gear around 35 mph +/- and most realistic riding is in the low to mid range.:50:

Seconding this. Polk St. makes a lot more sense.

The trick, of course, is getting onto it from the Mission, given the impossibility of making (most) left turns off of Market.

North on Valencia, right on Market, immediate left merge into the (dual) left turn lanes for Franklin, left turn onto Franklin, right on Grove, left on Polk...

Polk to Vallejo, Vallejo to Franklin, Franklin all the way down to Greenwich/Chestnut/Whatever,and onwards to the Palace of Fine Arts.

The reason I have you take Franklin that last bit instead of Polk is it's synchronized green lights timed for 35-40mph traffic, and you can step into your tall gear and scream down into the Marina at the speed of the cars.

Polk is downhill and filled with stop signs. Recipe for pain.

+1 to Charles Vail's advice. When you're dealing with steep hills, it's hard to have gearing that is too low.