I've been in the market to get a new crankset. I have been using the Sugino RD crankset. This set delivers a 45 mm chainline, which works fine with the 3/32 8-speed chain (and this is true even of the Sugino Messengers -- this is just an RD set-up with a higher-quality chainring). But I have been considering getting a crankset that will give me that sought-after 42mm chainline. I just have not been able to find any good reasons to do this. So I am considering just getting some shiny new RDs with good-looking Messenger rings.
I have encountered two sets of opinions on this shift in chainline lenght on fixies: Some say "Wider chainline is fine. It doesn't really make a difference to the performance of the bike. Just keep the right kind of chain on there to keep you from eating a dirt sandwich and you should be fine"; one of my lbs mechanics (who has historically given good advice) says this, see what queerpunk says here So when did RD2's switch to 45mm chainline?
and I know that Eric Sovern thinks this as well (he is one of the head guys at Surly). In short, a good 3/32 chain is all you need to use this kind of crank set-up. And, when you use this chain, you get more chainring options to boot.
The other side thinks that going this far beyond the traditional 42mm is just stupid. Some say that there may be greater wear on the components due to this; others say that this set-up is just not as efficient (due to the deviation from rear cog to chainring). See, e.g., what Landgolier says here Sugino RD2 chainline frustrations
and the discussion with E. Sovern about using Sugino RDs on the Steamroller complete here:
Is a 46mm chainline a problem.
There are some angry people in this last thread. The question is: why?
So, let the mud-slinging begin. Is the 42mm chainline just a rule of thumb to be violated with impunity? Or is it the golden rule to be adhered to with fear and trembling? (I like use big words)