Originally Posted by
cyccommute
It would be more economical to change the cassette, derailer and chain than to change the crank, depending on the level of components. A new 105 compact is going to cost around $270. A new 10 speed 11-34 or 11-36 cassette can be found for $60, a rear derailer will cost from $50 (LX) to $80 (XT) to $170 (XTR) and a chain costs whatever you want to pay. If you went with the XTR (and not including the chain cost), you'd still have to pay less than the 105 crank.
And you'd have a slightly lower gear (32 gear inches vs 36 gi). If you went with the 11-36 cassette, you'd have a low gear of 29 gear inches for the same price.
Yep, compact crank gets him to 36gi. Cassette option gets him lower for lower cost. Especially if he can switch to a cassette that doesn't require a mtb derailleur. What's the biggest cog on a 10sp road or touring cassette that will work with a short cage derailleur? 30t? 39(ring)-30(cog) would get him to 34.3gi, and if he can do that with only a cassette and chain swap, might be his cheapest option.
@Kimmo, if he went with a compact crank, I don't think he'll need to change FD. I used to ride a compact crank with a standard FD.
Originally Posted by
bradtx
I'd swap in a compact crankset (a compact's chainrings may be transferrable to your present crankset, worth checking on) and ride that before any other changes.
Hmmm. Are compact chainrings compatible with standard cranks? I didn't think they were. But if they are, that would easily be the least expensive option.