cassette alternative - difficult century - suggestions ?

There's two issues… first, you're definitely going to need a long cage derailleur, which will affect shifting. Yes, it will work, but don't expect it to be as crisp as a short cage derailleur. Second, you will have some major steps in your cassette, which basically means that you will have either a gear that's slightly too large or slightly too small at any given time. In a century, this tends to sap a lot of energy.

I can't remember the max chain wrap for a medium cage derailleur, but you basically calculate large chainring minus the small chainring, plus the large cog minus the smallest cog, that number is your total chain wrap, which must be less than max capacity for a given derailleur.

If the climb is truly that bad, you may want to consider a triple, which again, won't shift as crisp, but at least that way you can use a more compact cassette

I bought Nashbar brand mountain rear derailleur for a cheap wind trainer solution. The quality was horrible.

Use the same brand of derailleur as the shifter.
I use a Shimano LX 9 speed mtn bike rear derailleur. Too bad it's no longer available. You might have luck with the Shimano Sora family. Technology trickledown has made its way to the lower end bikes. Tiagra might have one that handles a 32 tooth cog.

Another idea is to visit websites dedicated to cyclocross or mountain bikes.

Thank you for responses. It's truly a tough century, Six gap in Ga.

Ride more, lose weight !

Edited by tri42 2014-08-21 7:58 AM

So these should work ?

http://www.ebay.com/itm/300561471235?_trksid=p2055119.m1438.l2649&s...

http://www.ebay.com/itm/231308609931?_trksid=p2055119.m1438.l2649&s...

Good Combination