# HELP - Ultegra 6800 11-Speed Groupset Config



## rscrant (Jul 15, 2013)

Hi,
I am asking for some help with choosing the correct 6800 groupset as I am not sure which Chainring Set (53-39, 50-34, 52-36, 46-36), Crank Arm Length (165, 170, 172.5, 175) and Rear Derailleur (Short Cage, Medium Cage) to choose.

I am going to put this on a 51cm Cervelo s5 and would like simple guidance on what to select.


Thanks in advance.


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## cantride55 (Sep 19, 2008)

With respect to crank arm length and chain ring options, what are you riding right now? 
Short - medium cage is about cassette options

When in doubt, check what you have now......then inquire with your LBS


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## rscrant (Jul 15, 2013)

cantride55 said:


> With respect to crank arm length and chain ring options, what are you riding right now?
> Short - medium cage is about cassette options
> 
> When in doubt, check what you have now......then inquire with your LBS


Hi cantride55,
Thanks for your help.

I was riding a standard 105 groupset and don't remember the config of it. My height is about 5'5"/165cm and I primarily road ride on flat to small incline/decline terrain for fast-paced leisure and possibly to compete.


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## rscrant (Jul 15, 2013)

Bump anyone???


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## ClayL (Dec 14, 2012)

50/34 compact crankset with 170 crank length, 11-28 or 12-27 cassette.


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## Trek_5200 (Apr 21, 2013)

ClayL said:


> 50/34 compact crankset with 170 crank length, 11-28 or 12-27 cassette.


There must be a lot of cyclists with weak legs. What else explains all the compact cranks with 28 or 32 cogs. If you are in good shape 53-39 and 12-25 works great, even with steep climbs. Plus standard gearing keeps one honest and avoids false senses of accomplishment. i ride 53-39 was talked into an 11-28 recently, and very much thinking of switching to 12-25. i tend not to use either the 11 or the 28 cog.


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## ClayL (Dec 14, 2012)

Trek_5200 said:


> There must be a lot of cyclists with weak legs. What else explains all the compact cranks with 28 or 32 cogs. If you are in good shape 53-39 and 12-25 works great, even with steep climbs. Plus standard gearing keeps one honest and avoids false senses of accomplishment. i ride 53-39 was talked into an 11-28 recently, and very much thinking of switching to 12-25. i tend not to use either the 11 or the 28 cog.


I guess I have weak legs then.... I was just stating my opinion, how you can state standard gearing keeps one honest is beyond me, there must be thousands of us dishonest cyclists out there


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## Trek_5200 (Apr 21, 2013)

ClayL said:


> I guess I have weak legs then.... I was just stating my opinion, how you can state standard gearing keeps one honest is beyond me, there must be thousands of us dishonest cyclists out there


apologize if that came off as cocky, i'm not very fast but i'm good at climbing. the reference to keeping one honest, was about avoiding the temptaton to shift into the easiest gears and force oneself to stay in a more difficult gear combination.


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## gaspasser (Aug 27, 2011)

I got fitted last summer and was recommended to switch to a 170 from a 172.5 (I'm 5'8"/32" inseam). I was in the process of switching to 50/34 anyway (from 53/39)---can't really tell a difference with the new 170. So unless you're more than a serious rec rider, you probably won't notice either. I went with 50/34 to maintain better cadence on our many 6-8% inclines and that has definately made a difference. On a steep downhill you'll spin out faster with a 50/34 but I ride for the uphills---that's where the fitness gain is. We have several 12% plus grades so I added a 12-28 cassette. It's much easier now to maintain 80-85 rpm on a 30 mile ride and knees feel much better. Hope this helps and post what you go with.


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## bubba117 (Aug 20, 2012)

Trek_5200 said:


> There must be a lot of cyclists with weak legs. What else explains all the compact cranks with 28 or 32 cogs. If you are in good shape 53-39 and 12-25 works great, even with steep climbs. Plus standard gearing keeps one honest and avoids false senses of accomplishment. i ride 53-39 was talked into an 11-28 recently, and very much thinking of switching to 12-25. i tend not to use either the 11 or the 28 cog.


Wow, really? I ride and race on a compact. 50x11 is almost the same gearing as 53x12, do the math. Also, compact gearing promotes a higher cadence on climbs, which studies show to be much more efficient.


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## MMsRepBike (Apr 1, 2014)

rscrant said:


> Hi cantride55,
> Thanks for your help.
> 
> I was riding a standard 105 groupset and don't remember the config of it. My height is about 5'5"/165cm and I primarily road ride on flat to small incline/decline terrain for fast-paced leisure and possibly to compete.


Your crank length should be 165mm-170mm I'd go with 165 if I were you.

Chainrings - 52/36 or 53/39 (52/36 if you are weaker)
Cassette - 11-25 or 11-23 (11/25 if you are weaker)
Rear D - SS (short cage)

if you did more climbing it would be a totally different story.


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## sappie66 (Oct 28, 2009)

MMsRepBike said:


> Your crank length should be 165mm-170mm I'd go with 165 if I were you.
> 
> Chainrings - 52/36 or 53/39 (52/36 if you are weaker)
> Cassette - 11-25 or 11-23 (11/25 if you are weaker)
> ...


What's this about being "weaker"? A "proper" gearing range for a given person allows that person to ride at that person's preferred cadence. Also, a gearing range may be selected for a person's most-common terrain. Pro riders use different set-ups depending on the race they will be riding. For example, guys going up the Angliru in the Vuelta may take a 34/28 with them.

So if I destroy a big masher up a climb, and he's using a 53-39 and I'm using a 50-34, he's not going to be telling me (in between gasps) that I am weaker.


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## expatbrit (Oct 16, 2013)

ClayL said:


> I guess I have weak legs then.... I was just stating my opinion, how you can state standard gearing keeps one honest is beyond me, there must be thousands of us dishonest cyclists out there


I'm in that category too -- I'm also a 14 stone plus Clyde. I climb enough that I appreciate my 34; I'm not strong enough to need the 53-11.

OP -- I think this is down to how strong you are, and how much you ride. Plus point with 6800 is its all one BCD.

I'd look at a gearing calculator and how fast you like to ride, set it up in the middl. For me, in the NM 'hills', that's 11-28 and 50/34.


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## jeremy_s (May 6, 2015)

gaspasser said:


> I got fitted last summer and was recommended to switch to a 170 from a 172.5 (I'm 5'8"/32" inseam). I was in the process of switching to 50/34 anyway (from 53/39)---can't really tell a difference with the new 170. So unless you're more than a serious rec rider, you probably won't notice either. I went with 50/34 to maintain better cadence on our many 6-8% inclines and that has definately made a difference. On a steep downhill you'll spin out faster with a 50/34 but I ride for the uphills---that's where the fitness gain is. We have several 12% plus grades so I added a 12-28 cassette. It's much easier now to maintain 80-85 rpm on a 30 mile ride and knees feel much better. Hope this helps and post what you go with.


Everyone states you'll spin out easier, not the case. A compact crankset with 11-28 cassette is moving more mph at 100 rpms in 50/11 that a 53/39 with a 12/28 cassette in 53/12


There is no "false sense of accomplishment". It's technology plain and simple.


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