# Cassette compatability: Ultegra 6600 to 6700 or 7800 cassette?



## Firemedic510 (Jan 21, 2009)

Hey everyone,

Looking to upgrade my cassette or at least mix it up a bit for some steeper climbs. 

Currently I have a 11-25 105 cassette on the rear. I want to upgrade to either a 12-27 or 11-28. I cant really seem to find a 6600 12-27, so it leaves me with a 7800 12-27 or the new 6700 11-28 (I guess they decided to not make a 12-27 in the new Ultegra). I don't really want to spend the extra for a 7900.

My question is: Can I use a 6700 11-28 on my 6600 setup? I don't know what size cage my RD is but I hope it works. Thanks.


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## Firemedic510 (Jan 21, 2009)

Well.....just ordered the 6700 11-28. Ill give it a go and let you guys know how it works. Looking forward to a higher cadence on my steep climbs


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## frdfandc (Nov 27, 2007)

Yes you can use the 6700 11-28 cassette with your 6600 RD. You should be able to get away with out any adjustments, however a slight adjustment of the B-screw might be needed.


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## Firemedic510 (Jan 21, 2009)

Thanks, just got it yesterday, after my ride of course. Ill install it tomorrow and let everyuone know how it works. More worried about the jump from a 23/25 to a 24/28. Hope its not too dramatic.


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## ewitz (Sep 11, 2002)

Are you running this with a compact?


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## Firemedic510 (Jan 21, 2009)

Yes, compact. 

Probably going to end up with a 12-27, where I might place the 11 from another to make it a 11-27. 

Just trying to find something that will give me a higher RPM while climbing. Currently on anything around 6% incline or more, I can go up it, just seem to be really mashing it.

Im about 210 lbs right now, and hope to drop under 200. Just need a little extra "help" for the real steep climbs haha.


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## a_avery007 (Jul 1, 2008)

nope, tried this (6600 rear der and 6700 11-28 cass) and could not get it to work even with b-screw adjustments.


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## Doolab (Feb 13, 2008)

The rear derailleur (short cage version) on 6600 Ultegra group is rated for 27T gear max, unlike the 6700 rear derailleur, which obviously can accommodate a 28T gear.

To make your setup work, you'll need to change your rear derailleur to the 6700 and it will shift into the 28T for you.


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## Firemedic510 (Jan 21, 2009)

Thanks for the help guys......I havn't installed the new cassette in case I need to sell it for a 6600 12-27. 

On the other side, Does it matter what size cage I get for a new 6700 RD?? Short cage, long cage? Medium cage? No idea......


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## Doolab (Feb 13, 2008)

The Ultegra 6700 rear derailleur (short cage) is rated to 28T gear, as shown here.
http://bike.shimano.com/publish/con...gra_6700/product.-code-RD-6700-SS.-type-.html

HTH


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## DUCKSRUS (Feb 27, 2013)

*Compatability chart from shimano*

COMPATABILITY CHART FROM SHIMANO

shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50lparsys-0025-downloadFile.html/01%29%20Drivetrain%20Compatability%20Chart.pdf


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