Originally Posted by
pccp
I am at my wits end trying to research this stuff and I feel like even more of a noob than before. I rode this bike 20 years ago in college and I tried it again recently and fell in love with it but I'd love to make it more functional. The first problem is that it has 52/42 front and 13/28 back, 12 speeds total and the gearing isn't enough for where I live. I'd like to add a triple front at the very least before I think about changing the wheel and adding a higher count rear set. Also can I change out the brake pads for a modern one? I found koolstop holders for 25 dollars a pair but I'm not sure I can put them on (the brakes are shimano 600) or if it's even worth when I can probably upgrade to a more modern dual pivot for not much more?
The biggest thing I wanna change though again is the gearing, if I add a triple front crankset 52/42/30 which I found on ebay for $67 with shipping, Sugino crown triple 130 74 bcd, would that work with the bb axle that's on there currently or would it need to be longer? Also would the front derailleur and rear derailleur need to be changed? The front derailleur that's on there now has a much wider range with the friction shifter than the double chainring needs and I know similar models of this bike back in the day had a triple front chainring.
I have more questions about front and rear derailleur compatibility for future upgrades but for now I mostly wanna know how to get a triple on the front for the least amount of money and I'm eyeballing that ebay sugino hard. If the derailleurs need to be changed though, I don't know what is compatible...
Without knowing specifics (e.g., make and model numbers of existing components and intended replacements), what follows is speculative. But here goes anyway.
1. My guess is you'd indeed need a different bottom bracket spindle. For square taper, the crankset almost always determines the spindle length required for proper chainline. You might get lucky, but I wouldn't count on it. And since we're talking a Peugeot, there's a fair chance the bottom bracket is French threaded. That introduces another potential complication if you can't find a replacement spindle of correct length and need to replace the bottom bracket.
2. I'd also guess there's a good chance you'll need a new RD (and maybe a new FD as well). FDs designed for double cranksets sometimes don't "play well" with triple cranksets. The late Sheldon Brown's website has a page regarding FDs that explains why. Regarding the RD, there are two factors of importance: min/max sprocket size supported and total capacity. Total capacity required can be calculated: (max rear - min rear) + (max front - min front). Going to a triple, you're going to raise the total capacity required substantially - in the case you posit, from 25 to 37. My guess is that's almost certainly going to require a long-cage RD - and even that may be iffy with period-correct RDs.
3. I've heard great things about Koolstop pads and how they improve braking performance. I've not yet tried them, however, so I can't say anything about them from personal experience.
Posting photos would be a big help, and might get you more accurate answers.
Best of luck.