Originally Posted by
VT_Speed_TR
I have a 2011 Salsa Casseroll with a Shimano Tiagra-GS cage rear derailleur.
I'm wondering if anyone has pushed the rear to a 11-30 cluster? If I don't cross shift the gearing will the rear derailleur handle it? Or should I look to change the front to a 24,36-46 set? Still not as low as I'd want though unless I get a rear derailleur that has the max 27.
Thanx's
I used a Sram 11-32 cassette with a Shimano "GS" (long arm-road) rear derailleur last year and had no issues with a 32 size cog. Fitting a 12-30 should not be a problem.
Also, the Shimano "GS" (long arm-road) rear derailleur also has huge chain wrap and cog size capacity that is much greater than stated on the Specifications.
The chain-wrap limit of the Tiagra/105/Ultegra GS, according to Shimano, is 37. I'm operating safely, with every gear combination, using a chain-wrap value of 42. It is also possible to exceed the 27t Cog size capacity and use a 32t. I've combined a 50, 39 & 26 Crankset with the 10 speed Tiagra 12-30 cassette.
The practical chain-wrap capacity, with a correct length chain, of the road "GS" RD allows the big-big combination of 50t front Chainring & 30t rear cog with a little safety margin and also allows the small-small combination of 26t & 12t without any slack in the chain.
I'm also using a Shimano "GS" (long arm-road) rear derailleur with a 48, 36 & 22t triple with a 12-27 cassette with no problems. I'm sure a the 12-30 Century special from Harris would also work on this drivetrain.
