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Rear Cassette choices for an Ultegra Triple???(13 posts)

Rear Cassette choices for an Ultegra Triple???Risky Jim
Jan 9, 2003 11:46 AM
I'm having a Cannondale CAAD5 Ultegra Triple equipped bike built. I was wondering which rear cassette to select (12-23, 12-25 or 12-27). I live in northwest Connecticut and will ride fairly hilly terrain. Any thoughts?
I like the 12-27laffeaux
Jan 9, 2003 2:51 PM
In order to ride as a little as possible in the small ring, I like the 12-27 option. The middle ring on a triple has 42 teeth, so a 42/27 low gear with the granny for bailout when needed works well.
I like the 12-27Chen2
Jan 9, 2003 2:54 PM
We must have posted at the same time. I think your reasoning is good, the 12-27 may be the best choice.
re: Rear Cassette choices for an Ultegra Triple???Chen2
Jan 9, 2003 2:52 PM
No one will really know but you. It will depend a lot on where you ride, how long you ride, and your physical condition. Suggest you start in the middle with the 12-25.
the 16 tooth cog...C-40
Jan 9, 2003 3:04 PM
If you select a 12-23 you get a 16T cog. The others omit this important cog. If you don't have a 16T, don't be surprised if you find yourself hunting back and forth between the 15 and 17, only to find that neither is quite right.

If you've got any experience in riding this area with a double that has the typical 39T small chainring, it's easy to compare gear ratios.

A 30/23 gear ratio, the lowest with the triple, is 11% lower than the 39/27 ratio that you would typically have on a double. The 30/23 is nearly the same as a 39/29.

I would try this combo first. If you can't handle the hills with it, then you might as well move on to the 12-27.
the 16 tooth cog, but with a 39T middle ring...PdxMark
Jan 9, 2003 3:49 PM
I agree with C-40. The 16T cog is wonderful, and you can see it numerically just by calculating the cassette gear ratios with and without a 16T. It's surprising how big the jump is between 15T and 17T relative to the other gear steps.

For that reason, a 12-23 makes great sense, but that raises the issue of which middle ring to use. Many triples have a 42T middle ring, but for me, a 42/23 ratio can be hard on more hills than I thought would be the case. It meant that with a 42T middle ring and 12-23 cassette, I needed to use the small ring more often than with a 39/23 set-up or a 42/25 set-up (which I used to have on another triple) or 39/25 set-up on a double.

The point is, with a 12-23 cassette, I'd recommend a 39T middle ring to reduce the frequency at which you need to use the small ring. For me, I liked having the granny gears of a triple, but the 42/23 set-up meant that I needed my small ring for more than just granny situations. A triple is nice as a refuge, but I really disliked having to use it for some "regular" hills. I found shifting to and from the triple very often to be disruptive.
Opposite experience heredzrider
Jan 10, 2003 5:29 AM
I use a 12-23 most all of the time and put on a 12-27 for loaded touring. The bikes I started riding had nothing easier than a 42x24 and so I still climb easy hills pretty comfortably on the 42x23. I find the gear ratios with a 42 preferable to those I got with a 39 - much less cross over shifting. I don't find using the granny gear to be cumbersome or embarassing.

I live in central CT which is less hilly than Litchfield County so I might need/want more if I lived where you do. My next cassette, I hope, will be custom with the following cogs - 12,13,14,15,16,17,19,22,26. That should take care of my need for a 16, work the way I like it with my 42, and still give me some wall climbing gears.
the 16 tooth cog, but with a 39T middle ring...Chen2
Jan 10, 2003 7:01 AM
Pdx, what kind of 39 ring have you found that works well with the Shimano triples (disregarding the D-A triple)? The double 39 ring is not ramped or pinned for use with a triple, not saying it won't work though.
I totally agree with your reasons for preferring the 39, but my experience with chainging rings on a Shimano triple have not been good.
the 16 tooth cog, but with a 39T middle ring...PdxMark
Jan 10, 2003 10:09 AM
I haven't run a triple with a 39, I just knew that Shimano offers it as an option.

Campy offers a 30-40-50 set-up, but apparently not 30-40-53. In my case, my latest attempt at a triple set-up was Campy 53-42-30 with a 12-23. I hated it. Steep sections on a measly 1000 foot climb would batter me at 42-23.

A 12-25 would have helped some, but i actually just reverted to a 53-39 double with a 12-25 cassette (or a 13-26 on another bike). That's a long way of saying I don't know which particular 39T ring to use.

My bail-out option, if I ever decide I need lower gears, is to replace the Campy 12-25 with a 13-29. With the 13-29 double I lose only the very bottom gear in a triple set-up with a 12-25 cassette.
a shimnao triple 39T...C-40
Jan 10, 2003 10:49 AM
Shimano now offers a standard 53/39/30 crankset, so there must be a triple compatible 39T ring available.
a shimnao triple 39T...CurtSD
Jan 10, 2003 12:42 PM
The DuraAce triple comes in 53/39/30, but DuraAce middle rings aren't compatible with the Ultegra triple crank (on the DuraAce triple the inner chainring bolts to the middle chainring instead of bolting to the crank, so the DA middle rings have an extra tab for this - you might be able to cut the tabs off if you're industrious). TA makes 38 and 40 tooth middle chainrings compatible with Ultegra cranks - see I've never used them so I don't know if they shift as well as the original shimano chainrings. I've got a DuraAce triple on one of my bikes and I really like the 39 tooth middle ring instead of 42 - as mentioned earlier, it's nice to only need to use the granny on 'big' hills.
Agreed. 39 middle is D-A only. (nm)Chen2
Jan 10, 2003 2:12 PM
re: Rear Cassette choices for an Ultegra Triple???Oneheart
Jan 10, 2003 1:21 PM
If you're going to get a triple so you can get up some steep hills then go with the 12-27 rear cassette. Then you have the easiest possible combination of gears if you ever need them. On my double chainring bike I used to use a 12-27 and never missed the magic "16" gear, although I had read testimonials of such.