Which cassette should I get to help me climb?

Chris Oubre

I found out in Coeur d'Alene that I do not have enough gears for climbing.  In my lowest gear I was mashing a 60 rpm.  I have a Cervelo p2 with a stock Shimano 105 11-25T cassette in the back and a FSA Gossamer 50/34 crankset.

I plan to race Buffalo Springs in a few weeks and I', trying to decide.  Do I want to get an 11-28, 12-27, 11-27???  I'm not really experienced enough to know the pros and cons.

Also what makes on cassette worth $100+ more than another cassette with the same ratios?  And how does that translate to watts?

Dino Sarti

Get an 11-28. It's nice and wide without huge gaps in your cadence. It's also not so big that you need another rear DR. An 28/11 will just easily swap out for the race and then you switch back if you want.

Plus, you can keep your 50/11 big combination you are using for hammer flats and descending. A 12-27 will only allow a 50/12 combination, which will have you spinning out of the gears sooner than your current 50/11

The cost of the cassette is likely a weight thing. A more expensive Dura Ace 28/11 is lighter than a 105 28/11. You can look up the specs on the Shimano website. The list the weights in grams. A gram is about the weight of a paperclip.

Quailman28

I agree with Dino however I found I was spending so little time in 50/11 that I went with a 12-27 for my climbing cassette, the combination of the middle gears were more important to my riding.  You won't go wrong either way as both will get you up the hills but I'm not a huge fan of paying a ton for less weight so I typically stay away from the Dura Ace and stick mostly with Ultegra.

Brad Marcus

@Chris- 100% agree with Dino. In fact, I put that exact cassette on just this morning 11-28 at my LBS. I have the same setup as you too: P2 with a compact up front. I live in an area full of hills and am always climbing. I moved from a 12-27 and wanted an extra gear for climbing and found myself spinning out early on downhills so this seemed like the right move. My ride this morning confirmed it - seems just right. I am racing Quassy next week (super hilly half) and IMMT in Aug (also hilly).

You can certainly find it cheaper online but I bought it at the LBS and had them install it for about $110 total. This way they adjusted everything for me, which I never seem to do right. All they had was the Ultegra 6700, so I went with it.

Mark Hickman

Chris,



+2 for 11-28; I have the same bike. Did CDA in 12 with 11-25 and then switched to 11-28 for Wisconsin last year. What a difference it made, and looking to be able to control watts much better at CDA this year!! Don't think I paid more than $100 and installed myself (need a chain whip and hub wrench-a-thingy).

I have found that I miss that middle gear a little bit...cadence can go from 95 to 80; I might think about trying a 12-27 some day, but I love to gas it on the downhills, and CDA has some long straight descents where I can spin that 11 out in no time...

  

mark

Gordon Cherwoniak

Chris,



Go with the 11-28.  Doing a few calculations  here http://www.bikecalc.com/gear_speed

On a 34-25 at 60 RPM (assuming 700c and 23 wheels) is 6.4MPH.  With a 28 you will get up to 68 RPM so better but not good.  It will make a difference for sure and having more gears is better in my opinion. 

As for what you are losing the 12-15 and 11-28 (10 speed?) have the following cogs I believe:

11-12-13-14-15-17-19-21-23-25

11-12-13-14-15-17-19-21-24-28

So you only notice the gap difference in the last two gears when you are on the steeper hills.  If you have an 11 speed then you get one gap plugged 23 to 25.   

11-12-13-14-15-17-19-21-23-25-28

I use Shimano 105 and never had an issue with durability of the parts.  You may also need a new chain.

Gordon

Chris Oubre

This team is amazing!!!! Thank you so much.

Dino Sarti

FWIW - I used a 32/11 cassette for IMTahoe do to altitude and two trips with sustained climbing over a 7,000 foot mountain pass. It worked great. Cassettes save lives, people.

morpheus

not to hijack...
Dino- did you have to get a long cage on the rear der?


Chris- 27 or 28 will be much better, as you already know. as for the 11 or 12, that's a personal preference. Unfortunately, most of us can't try out parts on a whim like the pros.

Dino Sarti

I did get an Ultegra long cage DR. I don't remember the cost but it was pretty cheap in the IM scheme of things.

Paul Hough

Dino, do you leave the long cage dr and 11-32 on your bike, or switch them out for training?

Dino Sarti

I left it on. It's on my older P3. I have not ridden it since IMTahoe. I have been riding my P5. If I want to go climbing tho, I can take it out. It's a nice cassette. Even without the second TT bike, I would have left it on.