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Discussion Starter · #1 ·
Hey guys, this is the situation:

I'm dusting off an old trusty Lemond Nevada City road bike for heavy use as I get back into serious riding (was gonna build up a Surly LHT frame into a 'country bike', but am likely going to hold off until next spring... I'm curious as to what Interbike will bring).

I'm pretty heavy right now (hope to become less so, soon), and therefore need some low gears for 'da hills'. The Nev City comes with a cheapie Sora road triple crank and Sora long cage rear derailleur. My options:

1) Go with the stock road triple gearing. Kinda leaning against this, as the Q-factor is not great (yes, Q-factor does have a significant impact on my pedalling, I ran into this back when I was seriously cycling in the '90s), and the crank is, frankly, quite fugly.

2) Get a mountain triple. Nice, because I can then run a tighter cassette with smaller jumps between gears, and still get a nice low low. But I've been pretty much stumped in finding a mountain triple at a non-insane price that has good Q-factor and comes in 172.5mm.

3) The option I'm leaning towards: Compact crank (50-34) and a custom Harris Cyclery 13-30 8-spd cassette. Gearing is nearly as low as a road triple, with a nice low Q and good looks.

My question with regards to option #3: Will the long-cage Sora road derailleur clear the 30t cog? Chain wrap doesn't seem to be an issue, as it's a long-cage model, but Shimano seems to have this thing where their biggest road cog can't dare to be bigger than 27t, and their road derailleurs are rated 27t for the max cog. :frown2:

I've read on Sheldon Brown's site that even short cage road derailleurs will clear a 30t cog, depending on the derailleur hanger's design, but I was curious as to what ppl's personal experiences were here.

I also am wondering what this setup will do to the shifting performance. Obviously, the front derailleur is a triple crank derailleur, and might not function so great on a compact double (though the curve/shape difference between the road triple's 52t outer ring and a compact crank's 50t would seem to be very little).

Ditto the left Sora brifter, which was designed to shift a triple not a double.

Any advice and personal experience is welcome.


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Other Shimano road triple rear derailleurs can handle a 30t cog so I expect a Sora one can too. I've used a 30t cog with Dura-ace 7800 triple RD, works fine.

The front shifter should work on a double if you use the outer two positions. 9sp ultegra shifters were all triple, the cable throw is the same.

I am not so sure that the triple FD will work ok on a double.
 

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I've used short cage Shimano road derailleurs with a 30t no problem so I'm sure the long cage will work fine.

The front derailleur and shifter should work fine...you can use the high (h) setscrew to stop it from shifting to the third gear. The main problem I see is that you won't have a "trim" adjustment that keeps the chain from rubbing the derailleur cage in certain combinations.
 

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Discussion Starter · #4 ·
hayduke1972 said:
I've used short cage Shimano road derailleurs with a 30t no problem so I'm sure the long cage will work fine.

The front derailleur and shifter should work fine...you can use the high (h) setscrew to stop it from shifting to the third gear. The main problem I see is that you won't have a "trim" adjustment that keeps the chain from rubbing the derailleur cage in certain combinations.
Which almost makes me think I should go with bar-end shifters, which I have no prob with, especially if I swap out to a rapid-rise rear derailleur (I likes me some logical shifting).

Though finding good 8-spd bar-ends might be a bit hard these days?...


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