I've got a vintage 1982(?) Univega Gran Turismo, w/triple cranks.
Front Gearing: 52/48(maybe 47?)/36.
Friction shifting, 5 cog freewheel. Chain is SRAM PC40.
At one point a few years ago, the bottom bracket needed replacing, and the LBS didn't have the proper cup-and-spindle replacement, so sold me the longest sealed BB available (can't remember for sure now, but I think it's a 127mm Shimano, and I do remember verifying that it was indeed the longest available).
The problem is that, since crank/spindle geometries have changed, this spindle is shorter than the one it replaced, and has thus moved the crankset in a few mm. Current chainline is about 42 mm (center of frame to center of middle chainring), while center of frame to center of small chainring is about 33mm. The result is that the front derailleur (a Suntour 4532) doesn't move in far enough to push the chain onto the small chainring. We've tried tweaking that FD in various ways to try to get it to shift successfully between all 3 chainrings, but with no success.
The inner chainring does clear the frame adequately, and if I manually nudge the chain over onto the inner chainring, it works fine, at least for the rear cogs I'd want to use it with.
I presume that the "proper" way to fix this is to replace the BB with an old-style cup/spindle job, and could probably get the parts from sheldon brown, if i could figure out the right length (unfortunately, I had disposed of the old spindle by the time I knew I should have measured it).
But, I'm hoping to keep the cost/work down, so I'm hoping I can just replace the front derailleur with one that will move in a little farther.
I picked up a Shimano FD-TY22 from a local used bike shop, which would clearly move in far enough, but the mechanism hits the rear tire (didn't realize that until I got it home and took the old FD off).
So, I'm wondering if anyone could point me at one (or a family/line of FD's) that would likely work. There are various inexpensive vintage FD's on ebay, but none of the available specs I can find tell me how far in the shifter cage will go. E.g.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=190167590565&ssPageName=STRK:MEWA:IT&ih=009
Presumably a road triple would be more likely to work, since they tend to have a 45mm chainline instead of 47.5. Needs to handle a 52-tooth chainring, but only a 16-tooth spread from large to small.
I may end up going back to the local used bike shop, but most of what they had was pretty junky, not cheap, and a no-return policy.
Thanks!
Front Gearing: 52/48(maybe 47?)/36.
Friction shifting, 5 cog freewheel. Chain is SRAM PC40.
At one point a few years ago, the bottom bracket needed replacing, and the LBS didn't have the proper cup-and-spindle replacement, so sold me the longest sealed BB available (can't remember for sure now, but I think it's a 127mm Shimano, and I do remember verifying that it was indeed the longest available).
The problem is that, since crank/spindle geometries have changed, this spindle is shorter than the one it replaced, and has thus moved the crankset in a few mm. Current chainline is about 42 mm (center of frame to center of middle chainring), while center of frame to center of small chainring is about 33mm. The result is that the front derailleur (a Suntour 4532) doesn't move in far enough to push the chain onto the small chainring. We've tried tweaking that FD in various ways to try to get it to shift successfully between all 3 chainrings, but with no success.
The inner chainring does clear the frame adequately, and if I manually nudge the chain over onto the inner chainring, it works fine, at least for the rear cogs I'd want to use it with.
I presume that the "proper" way to fix this is to replace the BB with an old-style cup/spindle job, and could probably get the parts from sheldon brown, if i could figure out the right length (unfortunately, I had disposed of the old spindle by the time I knew I should have measured it).
But, I'm hoping to keep the cost/work down, so I'm hoping I can just replace the front derailleur with one that will move in a little farther.
I picked up a Shimano FD-TY22 from a local used bike shop, which would clearly move in far enough, but the mechanism hits the rear tire (didn't realize that until I got it home and took the old FD off).
So, I'm wondering if anyone could point me at one (or a family/line of FD's) that would likely work. There are various inexpensive vintage FD's on ebay, but none of the available specs I can find tell me how far in the shifter cage will go. E.g.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=190167590565&ssPageName=STRK:MEWA:IT&ih=009
Presumably a road triple would be more likely to work, since they tend to have a 45mm chainline instead of 47.5. Needs to handle a 52-tooth chainring, but only a 16-tooth spread from large to small.
I may end up going back to the local used bike shop, but most of what they had was pretty junky, not cheap, and a no-return policy.
Thanks!
