# Ultegra 6750 Compact Crankset Inner Chainring options...



## roadworthy (Nov 11, 2011)

Hello,
I am considering building a bike with an Ultegra 6750 compact crankset. I am a bit fussy about gearing and would like to opt for a 50t outer ring and 38t inner ring. I believe the Ultegra outer ring is proprietary and hollow and good news there is...I am fine with the std 50t outer ring and no need to change. I don't need the short gear inches of the 34t inner ring however and prefer closer spacing...in effect making a baby full size crankset of 50/38 versus a std. 50/34 compact. 

My question is...will any generic 110 BCD inner chainring fit onto an Ultegra 6750 compact crankset?
Many thanks


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## Cut.Aussie (Mar 19, 2011)

I use the 6750 compact on both my Look 566 and the DA version on my Cervelo RS though with the stock chain rings 50/34.

While its true the outer ring is a Shimano special I as far as I can see there is nothing special about the inner ring, its just your basic flat sprocket, you can (iI think) also replace the big ring with a plain ring as well I think but is will look rather odd because the spider has that 3d shape but it should work.


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## roadworthy (Nov 11, 2011)

Thank you Cut Aussie for your response. I was wondering if there were any pins on the inner ring of the 6750 crankset and sounds as though any generic flat ring will work. FWIW, I am a Campy guy and run a generic 38t flat ring on the inner position of my Chorus compact Ultra Torque crank and it works fine. Thanks for the validation as I prefer a bit closer spacing than the 50-34 compact...can't use the gear inches of a full size crank and so makes the most sense to replace the inner ring on a compact.
Cheers.


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## Cut.Aussie (Mar 19, 2011)

If you think about it, any lifting pins must by nature be located on the inside edge of the large outer ring to lift the chain up off the small inner ring.

If your making the change from Campy, maybe consider Ultegra Di2, electronic shifting is just fantastic, I could not go back,

Good luck


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## roadworthy (Nov 11, 2011)

Cut.Aussie said:


> If you think about it, any lifting pins must by nature be located on the inside edge of the large outer ring to lift the chain up off the small inner ring.
> 
> If your making the change from Campy, maybe consider Ultegra Di2, electronic shifting is just fantastic, I could not go back,
> 
> Good luck


Thanks for your explanation about the pins Cut Aussie...appreciate that and what you write makes perfect sense.

I am considering Ultegra Di2...and a quick question if you have already gone there.
Do you know of any substantive changes forthcoming to Ultegra Di2 that should cause me to wait?...i.e. 11 speed?...or perhaps a change to the electronic architecture?

The reason I am considering moving away from Campy which I have ridden for years is...I want to move away from a thumb shifter and I want to try 11-28 rear cassette cog spacing for bit more diversity in gear inches.

Thanks for any further perspective.


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## harmony (Aug 4, 2011)

I also changed my Ultegra compact 34t inner chanring to a 38t.
I could not stand the two gear step going from the large chairing to the small one.
I got a FSA, perfect replacment, no adjustment nessery.
Paid around $30.00.


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## roadworthy (Nov 11, 2011)

harmony said:


> I also changed my Ultegra compact 34t inner chanring to a 38t.
> I could not stand the two gear step going from the large chairing to the small one.
> I got a FSA, perfect replacment, no adjustment nessery.
> Paid around $30.00.


Do you recall where you purchased it? Is it just a generic FSA 38t 110 BCD ring?...or advertised as Ultegra compact specific? Thanks for your input.


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## harmony (Aug 4, 2011)

Just a standard chainring.
Got mine at Amazon, Just search for FSA Super Road Chainring, 38t x 110 bcd.
Price Point has it for $ 29.98.


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## roadworthy (Nov 11, 2011)

harmony said:


> Just a standard chainring.
> Got mine at Amazon, Just search for FSA Super Road Chainring, 38t x 110 bcd.
> Price Point has it for $ 29.98.


Thanks again.


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## Overhill (Oct 7, 2002)

Roadworthy, It has been a few months since the last post, but I am curious as to whether you changed your inner chainring to a 38. I just bought my first road bike with a compact [50-34] and find the 34 too small; also, I am cross chaining too much. If you changed the inner what is your experience? What chainring did you buy? Thank you for any comments.
PS, I have appreciated some of your posts on other threads regarding the Specialized Roubaix bikes. They were helpful to me in making my recent purchase.


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## roadworthy (Nov 11, 2011)

Overhill said:


> Roadworthy, It has been a few months since the last post, but I am curious as to whether you changed your inner chainring to a 38. I just bought my first road bike with a compact [50-34] and find the 34 too small; also, I am cross chaining too much. If you changed the inner what is your experience? What chainring did you buy? Thank you for any comments.
> PS, I have appreciated some of your posts on other threads regarding the Specialized Roubaix bikes. They were helpful to me in making my recent purchase.


Hi Overhill,
Never did pick up an Ultegra crankset as I abandoned my plan of swapping out my Campy groupset with Shimano.

I will tell you what I have learned from years of riding however. Big gaps in gear inches for chainrings up front is no good. Also, most amateur riders don't need the big gear inches of pros with full size 130 BCD crankset. So what's a good plan if you don't need the short inches for climbing or can sprint to 40 mph on the flat? A baby full size crank in front with 110 BCD. I run a converted Campy compact which is 50/38 and its perfect. Like you, I couldn't stand 50/34...because one is always between front rings accelerating up through the 16-20 mph range which happens all the time when riding. With 38-12 I can ride 23mph with average cadence. This makes the small ring very usable over a wide speed range. I would have to shift the 34t front ring at a much lower speed...so I was constantly shifting in front...and further, the front shift is more clumsy with 50/34 because of major chainring size difference with std. compact. 50/34 std. compacts are only good if you do serious climbing. And btw if you are not a CAT3 or better and live in the mountains...a triple is a beautiful thing. 

I hope that helps. Pick up a standard 110 BCD flat replacement chainring for your Ultegra compact crank per Harmony's suggestion. FSA makes good non pinned/ramped rings.
Best Regards.


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