Classic & Vintage - what gear ratio's?
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12-11-07, 05:17 PM
I have 52,42,32 chainrings for my TA cranks and I was not sure what I should be looking for as a cassette. I do like to ride fast, but I will also do some light touring...
the reason I am posting in CV is because I am also considering half step plus granny gearing... (which would involve changing atleast one chainring)
and to make things more interesting I need a french threaded freewheel for my maxi car hubs...
I was looking at either of these.. or I can wait for something else If you guyes think I should.
-Regina Extra ORO BX 6-Speed 14-21
-Maillard Course 6-speed 14-25
*One thing for certain I must settle my Large chainring size fairly soon if I decide to get a brazed on chainguard mount hehe
any thoughts would be helpful
12-11-07, 08:17 PM
11/12 to 28 should get you almost anywhere. Roger
12-11-07, 09:14 PM
Have you tried playing around with the gear calculator at Sheldon Brown's site? It's a nice little toy. If you do go 1/2 step granny, get the 47 tooth ring - that would let you go half step with either the 47 as the large, or as the middle ring (if BCDs let you).
I would vote for the 14-25 6-speed freewheel. Post again with the exact cog progression (eg. 14-16-18-20-22-25, 14-15-17-19-22-25, etc.), and I can advise you regarding gear ratios. You may want to consider what I use on my mountain bike, 1.5-step-plus granny, which would probably work out to 52-44-32 or 50-42-32, in your case.
A few winning gear combinations, with few gaps and not too many redundancies:
50-42 / 14-16-18-20-23-26 (my Bianchi, 1.5-step)
48-45-34 / 13-15-17-19-21-24 (on my PKN-10, half-step-plus-granny, before I gave it to my son)
48-40-28 / 13-15-17-19-22-24-26 (my Schwinn mountain bike, 1.5-step-plus-granny)
52-42 / 14-16-18-21-24 (popular 1970s 1.5-step gearing)
49-46 / 14-16-18-21-24-26 (my 1960 Capo project bike, cheating with an ultra-6 freewheel)
One caution regarding half-step gearing: many of today's spiders are so thick that the chain can hang up on the second-largest chainring. The older the crankset, the more likely it is to be a good half-step candidate.
Half step works best with five or six cogs. If you use a narrow range cogset that means you need to have an even smaller tooth difference between your two big chainrings which is why I would go with the 14-25 with a slightly wider chainwheel difference.
I would start with identifying which cog/chainwheel combo you spend the most time in on your present bike. Go to Sheldon's gear calculator and see what gear inch that is. You want a cog and ring combination that will give you that gear inch number when you are in the center cog and middle chainring. You already have the freewheel so this will determine the chainwheel. Sheldon's calculator shows the % difference between cogs do you want the chainwheel difference to be half that percentage. That determines your large ring. The granny gear should be as low as your derailleurs can handle.
No matter what, with half step and the freewheels you propose using, you are not going to have a wide range with the two half step chainwheels. If you set up with largish chainwheels you will be a masher and if you go with smaller chainrings you will learn to be a spinner. I would recommend the latter.
I rode for fifteen years with a half step and a five cog freewheel 44-41 x 14-28 and liked it very much. My highest gear was low by most folks standards but you can sustain 25 mph in a 44x14.
12-12-07, 05:42 PM
cool ok I just played around with the gear calculator... I kinda like the 52 48, 32 which I feel would work well in anything but a crazy headwind (and I would only need to buy one chainring). The idea of shifting the front as often as the rear seems really cool...
the maillard is spaced
I am about to go to via bikes (some of you I am sure have heard of) to see what they have
*im new to this gear calculator so if this doesnt look right feel free to tell me. Also I plan on using 32mm tires and the cranks are 180mm
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