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Dura Ace w/ a 12-27 cassette(18 posts)

Dura Ace w/ a 12-27 cassettetook
Aug 8, 2003 7:20 AM
Anyone used a 9-spd DA derailleur w/ a 12x27 cassette? will it work? I'm doing a six gap century and need a serious bail-out gear for one of the climbs.
I will be installing one in a few days, I'll let you know. (nm)Uprwstsdr
Aug 8, 2003 7:34 AM
re: Dura Ace w/ a 12-27 cassetteRusty Coggs
Aug 8, 2003 7:36 AM
Sure it works.May have to fiddle with the "B' tension, and make sure the chain is long enough if you mess up and get ino the big/big.
Be a man........use an 11-21.......................nmMR_GRUMPY
Aug 8, 2003 7:49 AM
Works w/ Ultegra long cage triplepitt83
Aug 8, 2003 8:15 AM
Again, adjust the "B" screw so the cogs clear the tension sprockets and the chain doesn't rub.
Just try it on your regular DA derailer ...pmf1
Aug 8, 2003 8:48 AM
There is no need to monkey with the "B" screw. I swap from 12-27 to 12-23 all the time. No changing of the derailer settings or chain length required.

And you don't need a long cage triple derailer either. That's only for a triple. If you have a triple, you have it. If you have a double, you don't need it.

If you don't know the answer to a question, its better to keep your mouth shut and be assumed to be a fool, than open it and remove all doubt.
12-27 cassette and A. LincolnIronbutt
Aug 8, 2003 3:10 PM
Good advice on the cassette. Works fine for me too, and my bike has a pretty short chanistay. By the way, the actual quote is: "'Tis better to be silent and be thought a fool than to speak and remove all doubt."

A. Lincoln
Why a long cage??.....Rusty Coggs
Aug 8, 2003 11:55 AM
Every one of the short shimano 9 speed road RD is speced for a 27 cog and will handle more.
re: Works okChen2
Aug 8, 2003 8:38 AM
I've used 12-27, 12-25, 13-25, 13-26, and 13-27 9-speed with my Dura-Ace drive train, all with the same D-A derailleur.
Why wouldn't it work?pmf1
Aug 8, 2003 8:44 AM
If you're really worried, you can also get a 38 tooth small ring (I assume you have a double) from Excel. Works well and gives you a little more gear -- every bit helps on a steep hill. I used on when I did Ride the Rockies and was happy I had it.
re: Dura Ace w/ a 12-27 cassetteBanky
Aug 8, 2003 9:09 AM
I also am doing the Six Gap in September, I changed my rear to a DA 12-27, with no problems, you may have a chain length problem depending on what size rear cassette you had before. I also ordered a 38-52 front chain rings ( TA Hegoa) for a little more help. Everthing works perfect, no special tweaking necessary. From what I here the Gap is pretty serous especially Hogpen which averages a grade of 7% for 7 miles, some grades are 15%. Good luck and see you there.
re: Dura Ace w/ a 12-27 cassetteTarheel71
Aug 8, 2003 10:32 AM
In addition to the chain length, I also turn my B-tension screw in pretty far to keep the upper pulley from running to close to the 27 cog.
Banky, where's you get those rings?pedalAZ
Aug 8, 2003 7:08 PM
I've been looking for those.
Banky, where's you get those rings?Banky
Aug 11, 2003 8:59 AM
Go to and search TA Chainrings. I got mine from Peter White Cycles. Over Priced and not very cooperative, I will get them elsewhere in the future!
Thanks! nmpedalAZ
Aug 11, 2003 12:28 PM
re: Dura Ace w/ a 12-27 cassettemoving up
Aug 8, 2003 12:07 PM
Made this exact change and replaced the Ultegra cassette w/ a DA 12 - 27. Did not change or tweak anything other than the cassette change and it works better than the original setup. As for the "be a man comment" forget that idea and save your knees and strength. Heras rode a 3 ring up L'Angliaru last year in the Vuelta. It's the result that counts, not the misery en route. Good luck on your ride.
Works fine if you don't go big-bigspookyload
Aug 8, 2003 2:31 PM
Then your chain will be way too short. Have fun at six gap. The only thing that saves you there is it isn't at altitude.
I just popped in an Ultegra 12-27 and it's greatlotterypick
Aug 8, 2003 2:34 PM
Works like a charm and my shifting needed no adjustment.

The 27 improved my commute time by 6 minutes! Not killing myself up some hills, just spinning like a spinning fool.