Ideally I would like to keep my original bottom bracket, which I believe is 113mm in length, although I have been advised that a new CS might stick out too far - is this likely? Im fitting a new 7sp cass/8sp chain so would these CSes be compatible?
The rest of the bike will remain original - so is it worth spending more on a better chainset like the M510 - is there much performance difference between them? I plan to replace the bike in a year or two.
Advice on what to go for would be really appreciated!
Kirk Frameworks JKS-C, Serotta Nova, Gazelle AB-Frame, Fuji Team Issue, Schwinn Crosscut, All-City Space Horse
If he's talking about BB length I'm guessing crankset. SheldonBrown has a pretty good database of cranksets and what length BB they are designed to use. Length with also vary a bit if you have an oversized seat tube / front derailleur position. I suggest finding what of your options is designed to work with your current BB and go from there. (Am currently looking at buying a new BB for just this 'over sight')
Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
I'm wondering why you want to replace your old crankset. Frankly, that's kind of a big part so, since the higher priced ones tend to be finished more nicely, it improves the esthetics of your bike. The higher priced ones are also more likely to use aluminum chainrings which are lighter in weight. Relative to performance other than weight, however, I doubt you'll notice any difference.