hello. please, pardon my obtuse title. i'm trying to pre-empt the ogres who berate ppl for adding new threads. i searched, i looked around on google, i checked manufacturer's sites. I'm sorry, but i think we can discuss s'more.
here's the hypothetical question:
let's say i'm intrigued by the 2x10 gearing that SRAM is offering for off-road use. but, let's say that i'm disturbed by the expense, i despise all of the proprietary stuff in terms of actuation ratios, and i really don't think i need 10 cogs or a 36t in my cassette. (for the record, shimano is offering a 12-36t 9speed cassette, but i digress.) So, what i'm really saying is, i like the idea of running a 40/28 or 39/26 crankset, with an 11-32t cassette. Which is the best option for Front Derailer?
-road double? all the sites everywhere list only the max ring size for front derailers, not the minimum. Would the typical road double, with a 16t capacity and a 53t max ring size, work for a 39/26 crank? drawbacks i see: would need to keep the chainline tight to the frame, would need to run a frame with cable routing for a bottom-pull f.derailer.
-mtn double, as in the slx? The shimano site lists 36t as the max ring size, but i suspect that it could squeeze in a 39t. fwiw, a buddy of mine is running it on a cross bike, with a 48!-39, but i suspect the shifting is yucky. I'm suspecting this is best, but what do y'all think?
-mtn triple, with the limit screws set up drastically? i'm not too sure with this one, but i'm curious.
Now, again, i'm sorry to waste anyone's time with a hypothetical query, especially when i could conceivably buy some 39/26 rings for my old sugino crank, swap cranks on my old hardtail, try it with the mtn triple that's on there, make notes. then, swap the same crank onto my old road bike, and see how it does with a dura-ace 10 speed front derailer. And make more notes. Finally, i could get that slx double deraqiler from my buddy, and try it on both bikes. But, that'd be a lot of swapping. I thought it would be easier to ask here. 'Twould also be easier than searching google and bikeforums with phrases like "front derailer minimum ring" + suck?", which is what i was doing before i posted this.