General Discussion Triathlon Talk » crank set- 11-23 or 12-25 on a P2C Rss Feed  
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2009-10-05 3:01 PM

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Extreme Veteran
1996
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Halifax, Nova Scotia
Subject: crank set- 11-23 or 12-25 on a P2C
My training partner/best friend is about to pull a trigger on a P2C  bike. It currently has a 12-25 on  it but he's thinking he wants an 11-23, a swap they didn't want to make at the LBS as its a demo bike. He did his first race in 15 years last month and did a 2:10 with a 1:12 bike split on a old roadbike with cheap (mine, actually) unaero wheels. He even had to borrow a suit from me. Thats the fastest that suit has ever gone.  He'll probably drop 5 minutes on that time by next year with regular training.

He asked me to research this question a bit and suggested asking you folks, so here goes- riding on rolling hills, similar to coastal New England, what do folks feel is best; 11-23 or 12-25 for a pretty quick guy?  

Jorge, I know you pulled a switch this summer- how did that go?

thanks a lot,
   Blair

Edited by blairrob 2009-10-05 3:10 PM


2009-10-05 3:12 PM
in reply to: #2443752

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Sensei
Sin City
Subject: RE: crank set- 11-23 or 12-25 on a P2C
I guess if he has the legs, the 11-23.

However, the difference is minimal, IMO.  How often are they in the 12 and wish for one bigger gear?  Probably not that often, I'm guessing, on a hilly route/course.

I have an 11-25 and a 12-25 and would be hard pressed to tell you which one I had on the bike at any given time.

On a side note, if they are THAT picky about gearing, just get a couple cassettes.  they are cheap and then you have one for every occasion.

I have a 11-25, 12-25, and a 12-27 for the hilly days.
2009-10-05 3:55 PM
in reply to: #2443752

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Master
1927
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Guilford, CT
Subject: RE: crank set- 11-23 or 12-25 on a P2C

I have an 11-23 with a 53/39 up front.  I like it fine. 

I live in coastal New England and I think I benefit more having the 11 than I would having the 25.  I can get up what I need to get up, but when I want to cruise down the other side and keep my momentum, I do sort of like having that 11. 

I don't know what is "best".  It is probably all preference.  What will he be running up front?

If he wants to go nuts, he can get a 11/25 and have the best of both worlds.  He'll just be missing one of the middle gears.

Here's the ultegra 6700 specs...might help:
11-23: 11-12-13-14-15-16-17-19-21-23 T.
11-25: 11-12-13-14-15-17-19-21-23-25 T.
11-28: 11-12-13-14-15-17-19-21-24-28 T.
12-23: 12-13-14-15-16-17-18-19-21-23 T.
12-25: 12-13-14-15-16-17-19-21-23-25 T.

2009-10-05 4:01 PM
in reply to: #2443752

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Extreme Veteran
1996
1000500100100100100252525
Halifax, Nova Scotia
Subject: RE: crank set- 11-23 or 12-25 on a P2C
He will have a 53/39 up front.

Thanks guys.
2009-10-05 4:51 PM
in reply to: #2443872

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Pro
6582
50001000500252525
Melbourne FL
Gold member
Subject: RE: crank set- 11-23 or 12-25 on a P2C
11-25

53/11 is ~39mph at 100rpm, fun on the rollers, and the 39/25 can climb a lot. 
2009-10-05 7:20 PM
in reply to: #2443752

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Expert
1046
100025
Fountain Hills, AZ
Subject: RE: crank set- 11-23 or 12-25 on a P2C
I just switched my training wheels and race wheels to new Ultegra 6700 11-28 rear casettte ... so now I am riding compact 50-34 X 11/28. Only one short ride so far but ...It's awesome. You get more top end on 50X11 than on 53X12, and much, much, much more low end on 34X28 than anything you can get with a 39 front or a 23 rear. 

I realize that elite triathletes can crank a 39X23 up any hills, but here in hilly central Maryland, I cannot. I just switched from 12-27, but I used 34X27 all the time, especially on my training rides and on hilly triathlons like Columbia. And I question how many BT's can even crank 39X25 ... much less 39X23.

Note that Shimano does not spec their "older" 6600 Ultegra, Ultegra SL 105 and DA 7800 rear derailleurs (I never spell that word correctly) for handling the 17 tooth difference in 11-28 cassettes but I personally called Shimano Tech Support last week and they told me there were only a very few and rare frame geometrys that would cause shifting problems with a 17 tooth difference (ie 11-28). Same thing as the shop owner at my LBS told me ... and now I agree. (In fact, my 2008 Specialized Tarmac originally came stock with Shimano RD plus a Sram 11-28 and I switched it to a lighter Ultegra 12-27, so I guess Spesh was OK with 11-28, too). I rode my Ultegra SL drivetrain with 11-28 for first time tonight and it shifts as crisp and clean as the 12-27 I had on before. New DA7900 and Ultegra 6700 is fully spec'd for 11-28, but like I said above, mine works great on my Ultegra SL 50-34 crank and new Ultegra 6700 11-28 cassette.

So, my $0.02 is: If you have to ask, you should be on a compact 50/34 or a 53/39with 12-25. Or 12-27. Or 11-28. Another way of saying this is: If you can spin 80 RPM on your steepest uphill grade on you regular roadie in 39X23, you are a freakin' bike maniac who doesn't need help from an online forum on how to get faster. (All respects and no disrespects intended here, fellahs).

Most of us should be on a compact. We spend so much more time climbing so that 12-25 or 12-27 or 11/28 is much more effective than the extra speed we get on the downhills from 53X11 or 53X12.

Edited by jsselle 2009-10-05 7:21 PM


2009-10-05 8:23 PM
in reply to: #2443752

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Pro
4828
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The Land of Ice and Snow
Subject: RE: crank set- 11-23 or 12-25 on a P2C
I have a 12-25 on my P2........suits me fine. Awesome on the flats and enough wiggle room to climb the monsters.
2009-10-05 10:17 PM
in reply to: #2443752

Master
2460
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Subject: RE: crank set- 11-23 or 12-25 on a P2C
I ride faster than that by a fair margin and the 12-25 is perfectly fine for hammering everything on the tri course, even the big downhills. Plus, it's eminently rideable for even monster uphills.
2009-10-06 6:23 AM
in reply to: #2443752

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Champion
9407
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Montague Gold Mines, Nova Scotia
Subject: RE: crank set- 11-23 or 12-25 on a P2C
Blair,

My average OD bike split is around 1:08 and have lots of hours riding the terrain in the area so hopefully this will help.

For the past few seasons I have been running a 53/42 with a 12-25 on my tribike and am in the process of switching chainrings to a 53/39 (aero rings I got a good deal on) and with the 39, I am going to run a 12-23 on my tribike instead (might actually be an 11-23 - I'll have to check on that).

I would say having two cassettes is probably a great way to go; keep the 12-25 that comes on it and then pick up an 11-23 (or even a corncob) for flatter routes/racing.

Shane
2009-10-06 6:30 AM
in reply to: #2443752

Subject: ...
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2009-10-06 6:43 AM
in reply to: #2443752

Member
1748
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Exton, PA
Subject: RE: crank set- 11-23 or 12-25 on a P2C
I'm assuming that the 1:12 bike split he did was on a 40K?  With that I will say he is close to where I am on the bike. My last split at that distance was a 1:15 on a hilly coarse.  I am on a low end road bike with a 53/39 crank and a 12/25 cassette.  I regularly go up grades from 10% to 22%(not a typo) where I live with this gearing. If it where me I would leave the crank at 53/39 and get an 11/25 in the back.  Most of my rides I wish I had the 11 in the back. I also think I could get up anything with the 39/23 combo but why bust my butt if you can get a cassette with an 11/25.


2009-10-06 7:22 AM
in reply to: #2444609

Champion
9407
500020002000100100100100
Montague Gold Mines, Nova Scotia
Subject: RE: crank set- 11-23 or 12-25 on a P2C
PennState - 2009-10-06 8:30 AM

I base this on the fact that most people are geared too aggressively. Shane is an excellent rider with lots of experience and I can understand the 11-23 choice. Your friend is good but just returning to the sport.


While I agree with your assessment of the 12-25, I would not necessarily agree with the bolded statement.  I would say I'm an average rider who uses smart equipment choices to get the most out of a small engine

I appreciate the vote of confidence though

Shane

Edited by gsmacleod 2009-10-06 7:22 AM
2009-10-06 7:31 AM
in reply to: #2443752

Champion
19812
50005000500020002000500100100100
MA
Subject: RE: crank set- 11-23 or 12-25 on a P2C
I agree with Fred, Pennstate, get the 12-25.

Cassettes are relatively cheap he can always get another one or 3-4 if he is like me. I change mine when I race based on the course. Training I use a bigger cassette either 12-27 or 11-28 just so I have options.

Getting a cassette with an extra gear is smart. If he never uses the 25 no harm. I see way to many triathletes grinding up the hills with a cadence of 50-60 on a steep hill as they have no more gears. Maybe they feel manly to have the small cassette like 11-23 but if it burns out there legs so their run is sub par what did they get out of it?

Another factor should be what is his normal cadence? Higher cadence you need more easier gears.

Sounds like it has a 12-25 and bike shop doesn't want to switch it either.
2009-10-06 2:03 PM
in reply to: #2443752

Extreme Veteran
1996
1000500100100100100252525
Halifax, Nova Scotia
Subject: RE: crank set- 11-23 or 12-25 on a P2C
Thanks everybody for the time you spent responding. Its much appreciated. I sent him the responses and he's decided based on them to go with the 12-25, and perhaps buy the 11-23 later when he buys his race wheels. Thanks from both of us.

   Blair  (and Dave)  
2009-10-07 1:56 PM
in reply to: #2444232

Expert
832
50010010010025
Framingham, MA
Subject: RE: crank set- 11-23 or 12-25 on a P2C
jsselle - 2009-10-05 8:20 PM

Note that Shimano does not spec their "older" 6600 Ultegra, Ultegra SL 105 and DA 7800 rear derailleurs (I never spell that word correctly) for handling the 17 tooth difference in 11-28 cassettes but I personally called Shimano Tech Support last week and they told me there were only a very few and rare frame geometrys that would cause shifting problems with a 17 tooth difference (ie 11-28).


Thanks for passing this along, I've been dreaming of an 11-28 to go with my 53-39 crank but I wasn't sure it would work.  I'm currently running a 12-25 but I've often thought it would be great to have a few extra teeth on the low end for the tough hills.

Edited by scott 2009-10-07 2:18 PM
2009-10-07 4:39 PM
in reply to: #2448012

Veteran
110
100
Subject: RE: crank set- 11-23 or 12-25 on a P2C
I have the new 11-18 cassette. 

I wrote about it on ST when someone asked about it.

"If you need the low end, you can get the 6700 in an 11-28 configuration. I have done just this.

While it is nice to pedal up steep hills at 75 rpm for 7 mph, the biggest gain for me was in the low end of the larger ring. Basically, I can get to the 21 easily and the 24 for short stints without worrying too much about chain crossing. I used to run an 11-23 (completely inadequate for me for things like Rev3, Harriman, etc.) and found that I was often grinding gears up small hills as I was avoiding shifting to the small ring. Now with the larger cogs available, I spend more time in the larger ring, and have gotten my cadence up a bit in those situations. Of course, this has nothing to do with the 6600 vs. 6700 per se, only that for $100, if you need a new cassette and have the issues I have discussed, the 6700 is a good option.

Gordon


2009-10-07 5:24 PM
in reply to: #2448400

Veteran
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100
Subject: RE: crank set- 11-23 or 12-25 on a P2C
Of course, I meant the 11-28.

Gordon
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