Question: Can I add a chainring to this crank?
 

Hi everyone,

I had a question for anyone who has more experiencing working on bikes than me. My brother just picked up a nice Soma Double Cross that's set up as a 1x8 with bar end shifters. The current chainring is a 39, but the guy tossed in a 46 as well. Would it be possible to add another chainring to this crank and run it as a double? I think a 46/30 would provide a really nice range for its intended purpose as an all rounder. I attached a photo of the current set-up. Any info on this would be greatly appreciated.

I see what looks like a front derailleur cage keeping the chain from misbehaving. Is it a functional derailleur or just some kind of funky chain keeper? Ideally the bottom bracket axle would be lengthened to push the big ring out a bit to make room for the new ring and so that the chainline with the rear cogs doesn't get crazy for the new ring. Ideally the ring that is the outer ring will have lifting ramps and chain guides and the bonus 46 the dealer gave you probably has neither. Well people shifted their bikes more or less well even before shift ramps. Chainlines are a compromise in the best case scenario. So the main question is: Is it worth it to source a front changer and figure out cable guides, etc. for a 30/46. I dunno.... now if it was a 39/52(3) I'd have less hesitation.

Looks like they left the front derailleur on the bike. Supply a few more pictures of the back side of the crankset, the front derailleur and the 46t chain ring and we can give better advice.

that one flipped over on the other side of the spider, and a larger one where it sits.

longer bolts. and likely a longer BB.

Yes. I could see attachment points peaking from behind the spider arms.