Mine is too big...
 

My chainring is too big!

Is it possible to go with a chain ring smaller than 39 on a cottered crank?

Were there multiple standards for spacing of mounting holes for 3 armed cottered cranks as there are for cotterless? If so, I will measure...

Thanks for any comments... I am looking for an easy way to have lower gearing without changing the looks too much on my old Sears bike.

What kind of grade are you trying to ride up?

Let's just say that with my girth, a 5% grade for me is about equivalent to a 15% grade for a good climber.

The issue isn't the grade as much as the 300+ pounds of cyclist and bike trying to get up the grade.

Let's put this in real terms... you know those rollers that everyone just powers over and considers it a flat ride... They make me say to myself "When will these hills ever stop!"

:D

My mosty immediate goal is the Covered Bridges metric century in Bucks County in October.

Tom Waits wasn't the first to say that (1979 fernwood tonight ~ before) It's an oldy but a goody though.

We should take a poll to see how many retro-bikers like tom waits though!

He's the only person i've heard say that (on an old tv clip) and so it is his voice i hear when i think of it. In my mind, it will always be his saying.

For the OP, it might be easier to change the cog gearing.

I think I have come to the same conclusion... a 39x34 gear should be low enough for most climbs...

I am just getting by with the 28X30 on my Sedona... But, I think I would have to move to a triple to get close to that... :D

I love Tom Waits!

Have you considered swapping out the freewheel (and possibbly rear derailer)? I don't know if your rear spacing would permit it, but you may be able to find a freewheel with a bailout gear for those hills.

I understand that you like the looks of your cottered crankset, but you might also be able to find a used cotterless crankset and bottom bracket that looks "right" on your bike. If nothing else, see if your LBS has anything in the backroom. Cottered or cotterless, it might be easier to cast a wide net and look into a different crankset, instead of seeking only chainrings for your current crank.

I am not too opposed to changing cranks, but with even a used crank and BB I am quickly into the bike for more than it is worth... But, it has occurrred to me, thanks for the comments.

Of course to get a real low gear, I am probably looking at a triple or compact double, and I don't think compact doubles are too available used yet... and a triple would probably be best (and maybe the compact as well) with a new FD, and then I would probably have to add cable guides...

A megarange freewheel is beginning to sound better, and I already have a 6 speed megarange rear derailleur.