sailorbenjamin 

Someone mentioned this last week. Have you guys heard of it? Am I getting this right? Take a freewheel set up for half step gearing. Let's use 14-17-21-26-32 as an example, with @1.25 difference between the gears. Then instead of taking a chainring pair that's half of that, say a 46-49 with a difference of 1.065, we use a pair that's 1.5 times the difference, like a 36-49 with a 1.36 difference (1.36 being pretty close to 1 1/2 of 1.25, the decimal part representing the difference).
You get a better range but the same close ratios and a wacky shift pattern.
Am I getting this right?

Road Fan

You get a wider range, a wacky shift pattern, and less close ratios. It's also called an Alpine. I think we mis-use that term today.

Frank Berto said in Upgrading your Bicycle, if rats can be taught to run mazes, cyclists can learn to shift Alpines. Not true in my case.

Plot out the gears, you'll see what the pattern is. In your case, 36/50 would be closer to ideal, at least if 1.25 is the mean ratio of that freewheel.

BTW, your half-step example needs a 1.125 ratio in the chainwheel if the freewheel ratio is 1.25.

For a while at least the UO-8 was shipped with a 36/50, at least based on my recollection.

jimmuller 

36/52, with a 14-16-19-22-26 freewheel. It "taught" me to shift on the rear only unless I really needed a low.

Road Fan

ok. I should have looked in Sloan.

Road Fan

Hmm, the numbers don't look right, I'll have to look at this again.

sailorbenjamin 

Ooh. You're right. I haven't had to do decimal math since college.

Road Fan

Actually that's not a by the book Alpine. The correct smaller chainring would be a 42, if it was.

Road Fan

Your ideal chainwheels would be a 39/52, given that freewheel, and that you want the 100 inch top gear. For Jimmuller's freewheel it would be a 42/52.

For half-step in both cases, 47/52 for Sailor's and 48/52 for Jimmuller's old Peugeot.

jimmuller 

I don't know what you mean by "idea", but I rode a lot of miles with that combination. Often I wished I had a lower gear too! I recall seeing it described as "Alpine" but that could mean different things to different people. But I do recall working out the ratios and plotting them on a log scale and they were indeed 1 and a 1/2 step. Which is to say when you shifted chainrings the new values bisected the spacing of the other chainrings, shifted one full gear. I never rode it that way anyway so it didn't matter.

sailorbenjamin 

Ok, I think I got it. Thanks, guys. I'll have to set a bike up like this and see if the shift pattern gives me a headache.
Let's see, that's up one on the right, then back down and up on the left. Down with the left and up two on the right. Down on the right and up on the left. Up two on the right and back down on the left. Down on the right and up on the left till you get to the top and then do it backwards to get back down.
Right?