# Convert 7800 with compact rings



## tidi (Jan 11, 2008)

I would like to convert from 53/39 to 50/34 using the current 7800 130pcd cranks. I've found the 7800 compact outer in a 50 tooth but is there a preference to the 34 inner ring i should go for as i haven't found a 7800 compact inner, don't even know if they exist?
regards


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## GDTRFB (Feb 12, 2011)

I found this reference on another forum.

According to Sheldon Brown, the smallest chainring for a 130 BCD crank is 38t


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## tidi (Jan 11, 2008)

Thanx for the info.


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## GDTRFB (Feb 12, 2011)

I should have added this:

There was no compact 50/34 option for DA7800.
The next best crank was the Ultegra SL, which came in a compact, and had a very stiff BB.
You could also go non-series, R700, which gets a lot of positive reviews as well.


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## BCRexer (Dec 1, 2011)

Fulcrum works very well for me. This setup is 50/34.


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## GDTRFB (Feb 12, 2011)

BCRexer said:


> Fulcrum works very well for me. This setup is 50/34.



This is a 110 BCD. 
OP has DA7800, which is 130 BCD


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## mpcbike (May 12, 2009)

BCRexer said:


> Fulcrum works very well for me. This setup is 50/34.


Fulcrum also used 110 "campy" bcd, making rings a pita compared to normal 110. But all for not since indeed 38 is smallest ring you can use on 7800 crank.


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## mpcbike (May 12, 2009)

GDTRFB said:


> I should have added this:
> 
> There was no compact 50/34 option for DA7800.
> The next best crank was the Ultegra SL, which came in a compact, and had a very stiff BB.
> You could also go non-series, R700, which gets a lot of positive reviews as well.



Ultegra SL(just dark grey 6600) uses the same bb as 7800, nothing "stiffer" than any other Shimano Hollowtech.


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