My all-around commuting road bike is a Salsa Casseroll, geared right now at 39/53 and 12-25 in the back, both of which are too high for my purposes. I'm working on replacing the drivetrain and am hung up on the crankset. I'd like to keep it a double, but it's very hard to find doubles with low gearing. I was looking at some mountain doubles but I'm wary of the width that they would place the pedals. Yes, the 'q-factor', I can in fact feel it.

So then I looked at the Velo Orange Polyvalent 30/46 crankset, which is close, but I'd want to go even a little lower. With a 11-28 cassette and 26/40 chainrings I can get 25 to 98 gear inches, which sounds about right to me. My first thought was to replace the Polyvalent's chainrings because it's hard to find cranks with 110/74 BCD, but I did find some:

http://harriscyclery.net/product/dim...r2330-qc49.htm

They're both square taper, take the same length BB, and are 110/74 triples. But I trust more the Polyvalent because they're sold as a set. If I throw some chainrings on the middle and inner spots on the Dimension cranks, will it shift well? I'd use nice TA chainrings because I can get them in the exact size I want.

As far as the chainrings themselves go, I'd use http://harriscyclery.net/itemdetails.cfm?ID=1427 for the larger of the two. Says it fits the middle position of a triple so no problem right? And for the inner ring, I'd use a sugino ring: http://harriscyclery.net/product/sug...r1151-qc49.htm Logic tells me that this setup would be fine, but I've done some questionable things with bike parts with not the best results. And of course we see parts marketed as sets that are 'supposed' to go only with each other. In short, it's hard to separate the cases where you can be flexible with bike mechanics from the cases where you can't.

I trust that the unmodified Polyvalent works fine, can I do the same with my Dimension/TA/Sugino setup?

And the last issue is chainline. Shouldn't I move the cranks outward a bit in order to make a perfect chainline? I'd rather not do that, so how much does this matter? Obviously the Polyvalent and the Dimension cranks aren't the same, but can I extrapolate that using a 113mm BB will result in a viable setup because the Polyvalent, a similar 110/74 bcd triple also uses a 113mm BB?

Or lastly, what are other options for a very compact double? I suppose if I spent 100 bucks more I could get a White Industries VBC road cranks. That would probably have a better chainline than a inner/mid triple-to-double conversion.

Whew, thanks for reading. I hope was clear, and thanks in advance.