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12-30 cassette fitment

Posted: Thu Aug 16, 2012 4:59 pm
by plpete
I'm slowly gearing up to ride my first Granfondo (Jeremiah Bishop's Alpine Loop) and I'd like to make any changes to my bike early on to avoid any issues during the ride. The ride will be about 100 miles and have about 11,000 feel of climbing, some of which will take place on compacted dirt roads and etc. Since I'm not a pure climber at 167lbs I'd like to adjust my gearing in order to handle the long and sometimes steep climbs for the ride. FYI I am running a Sram Force drivetrain with the new YAW Red front derailleur. The shifting is perfect. In the front I am running the Rotor Q Rings which I really like for climbing and will be sticking with those. They also help my knee pain. In the back I am running a Shimano 12-27 cassette. Although its fine for local hills, the long and steep at times climbs would be a bit easier with some taller gears on the top range. I know that officially the sram force RD will support up to a 28t sprocket. I have been eyeing the new Ultegra 12-30 cassette which seems like an ideal choice for the ride. The Apex 32t cassette will be a stretch but has anyone run the 12-30t cassette or the Tiagra equivalent on a Sram RD without going to a long cage Apex RD? Technically, the B screw on the RD could be adjusted to clear the RD pulley with the large cog. I've read of guys running the cassette with Ultegra RD which officially support up to a 27t cassettes. Any thoughts are appreciated :thumbup:

Re: 12-30 cassette fitment

Posted: Thu Aug 16, 2012 6:43 pm
by Valbrona
Don't worry, on the day you won't be the only one that didn't fit a triple.

Re: 12-30 cassette fitment

Posted: Thu Aug 16, 2012 6:59 pm
by HillRPete
I'm about to try a Tiagra 12-30 cassette on my training wheels (DA 7900 drivetrain). If you're hard pressed for clearance on the bottom gear seems to be to swap in a 10 tooth upper pulley.

Re: 12-30 cassette fitment

Posted: Thu Aug 16, 2012 8:07 pm
by eric
A 7900 RD ought to clear a 30t cog. But in the end it depends on your frame's derailleur hanger.

I can get a 2012 Red RD to shift on to a 30t cog without even touching the B screw. But you have to try it on your bike to see if it works. If it doesn't and screwing the B screw in doesn't help, then you'll need a different derailleur.