I'm doing a tour to France in a couple of months time and want use my old 1970's Claud Butler Olympic Road bike bike to save on cost of buying some thing more suitable. Even though I'll be touring light, I think I'll sruggle with the AR Apex 50/42
chainset, but it doesn't take a smaller ring, so I'm on the lookout for something else; I can get a stronglight chainset 50/32 or whatever, but would prefer something more vintage if possible - I've looked on ebay and most of the old chainsets are 52/42 - could I swop out the smaller ring for something like a 32 or 28 tooth size on these vintage chainsets? If I can, would my old suntour f derailleur work ok or would I need to buy a new one? cheers, Leo
Lower Gearing
Re: Lower Gearing
the smallest chainring is usually set by the BCD (bolt circle diameter ) of the chainrings. Take a look on Sheldon Brown, then just choose according to your need.
Front mechs vary in capacity, sometimes even when the same mech is fitted on different frames. But you can estimate how much by allowing about 2mm vertical clearance per tooth on the chainring. So if you have 10mm vertical clearance at present (between the chain and the front mech on the small-small gear) then you can have a chainring 5T smaller and it will still work OK. However 6T smaller will invite a rattle in that gear and maybe others.
If you can find double chainset with 28/48 chainrings I'd suggest that would work nicely for touring. However such chainsets are not widely made today! So you are looking at (expensive new or) used chainsets only. If you can find the SR 86mm BCD model used (yes they did make one) then you can probably keep your extant BB, but otherwise a new chainset will almost certainly mean a new BB too.
Alternatively you could get a cheap triple e.g. from Spa cycles.
cheers
Front mechs vary in capacity, sometimes even when the same mech is fitted on different frames. But you can estimate how much by allowing about 2mm vertical clearance per tooth on the chainring. So if you have 10mm vertical clearance at present (between the chain and the front mech on the small-small gear) then you can have a chainring 5T smaller and it will still work OK. However 6T smaller will invite a rattle in that gear and maybe others.
If you can find double chainset with 28/48 chainrings I'd suggest that would work nicely for touring. However such chainsets are not widely made today! So you are looking at (expensive new or) used chainsets only. If you can find the SR 86mm BCD model used (yes they did make one) then you can probably keep your extant BB, but otherwise a new chainset will almost certainly mean a new BB too.
Alternatively you could get a cheap triple e.g. from Spa cycles.
cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~