Originally Posted by
pdlamb
I think the 20 gear inch target is reasonable. To get there, you're going to need AT LEAST a new crank, cassette, and probably derailer.
Unfortunately, that's going to be difficult to do, unless you're willing to buy used parts. The 2300-series components on the OP's bike are currently the
only 8-speed components made by Shimano or SRAM. Personally, I wouldn't trust components made by anyone else... Capacity for 2300 is fairly limited, according to Shimano's specs.
Without spending a fortune, I think there are only two options:
1) Switch to a triple crank. That means new shifters, a new front derailleur, and a new crank. The smallest chainring moves down to 30-teeth from 34-teeth and the rear derailleur limits you to a 26-tooth cassette. The lowest gear is 31", according to Sheldon Brown's gear calculator, which still isn't great
2) Try to find a used or NOS 8-speed mountain bike rear derailleur and pair it with an 8-speed 11-34 cassette.
If you could make it shift reliably with the 50/34 crank (I didn't check the specs), you'd be able to get down to 27 gear-inches. It doesn't quite make the 18-24" range the OP was targeting, but it's pretty close.
You
could combine 1 and 2, to get down to 24 gear-inches, but you'll also have spent quite a bit of money. At that point, it's probably better to spend a bit more and move up to a 9- or 10-speed component group.
The retrofit will be suspect as far as your ability to mount racks and carry a load without shimmy (heavy load plus lightweight bike = not a good idea).
For me
this would be the biggest reason not to upgrade.
I tried adding 15 pounds of gear to my relaxed-geometry road bike using a Carradice Nelson Longflap saddle bag and Bagman support. I
hated the nervous, twitchy handling that resulted from trying to carry a load on a bike with a relatively short wheelbase...