# compact crankset



## slotnick (Aug 27, 2009)

Hello,

I'm after a new compact crank to upgrade my 97 Ultegra group

I'm doubting between the following cranksets:

- 6650 Ultegra SL
- R700 compact

Are there (apart from looks) differences between both? I've read somewhere that the R700 is comparable to ultegra quality.

Thank you


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## majura (Apr 21, 2007)

If memory serves me right, you'd looking at basically the same thing. One is series, one is non-series. Both same quality.


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## slotnick (Aug 27, 2009)

would I have to change my bottom bracket when upgrading to one of these 2?


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## DaveT (Feb 12, 2004)

slotnick said:


> would I have to change my bottom bracket when upgrading to one of these 2?


If your current BB/crank is 6500 series 9-speed, and you want to change to the R700/6750 series crank, you will have to get a 5600, 6600 or 7800 bottom bracket. All will work with your new cranks.


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## slotnick (Aug 27, 2009)

thx,

I've searched a bit on the net, and I think mine is called Ultegra 600 (it's from '97)

What's the difference between 5600, 6600 and 7800 BB's?


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## DaveT (Feb 12, 2004)

slotnick said:


> thx,
> 
> I've searched a bit on the net, and I think mine is called Ultegra 600 (it's from '97)
> 
> What's the difference between 5600, 6600 and 7800 BB's?


The differences in the three bottom brackets are relatively small, mainly in finish, functionality being pretty much the same amongst them.

Any of them will fit the new cranksets that you are talking about. The difference in price of the cheapest (105 5600) to the most expensive (Dura Ace 7800) is about $20.


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## slotnick (Aug 27, 2009)

thx a lot Dave 

Will these BB's fit a '97 Merckx steel frame? Or are there differnt standardisations in bottom bracket tubing?


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## DaveT (Feb 12, 2004)

slotnick said:


> thx a lot Dave
> 
> Will these BB's fit a '97 Merckx steel frame? Or are there differnt standardisations in bottom bracket tubing?


There are two different threadings for bottom brackets; English and Italian. I'm not sure what your Merckx takes but the Shimano bottom brackets come in both. You will have to find out what yours takes before you order the correct BB.


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## slotnick (Aug 27, 2009)

mmm, which takes me offcourse to the next question:

How can I find out what thread I have? I have noticed btw that mine is indeed Ultegra 6500

sorry for all the questions: I'm a bit of a newby...


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## DaveT (Feb 12, 2004)

slotnick said:


> mmm, which takes me offcourse to the next question:
> 
> How can I find out what thread I have? I have noticed btw that mine is indeed Ultegra 6500
> 
> sorry for all the questions: I'm a bit of a newby...


When you remove your bottom bracket, it should have a label on it similar those in the pictures. It will say 68 then BC 1.37x24 if it's English and 70 and 36x24T if it's Italian. Be sure that the new bottom bracket that you purchase has the same numbers as the one that is currently on your Merckx.

Your bottom bracket may not look exactly like those in the pics but it's what the label says that is important.

*ENGLISH bottom bracket*


*ITALIAN bottom bracket*


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## slotnick (Aug 27, 2009)

Thanks again Dave,

I'm unable to dismount it at the moment (no tools around), but I noticed 36x24 stamped in small on the side of my BB, so I guess it's Italian.

Does it also matter for the crank itself, or is it just the BB where I have to pay attention to when it come to the thread?

cheers


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## DaveT (Feb 12, 2004)

slotnick said:


> Thanks again Dave,
> 
> I'm unable to dismount it at the moment (no tools around), but I noticed 36x24 stamped in small on the side of my BB, so I guess it's Italian.
> 
> ...


Just the bottom bracket.


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## slotnick (Aug 27, 2009)

DaveT said:


> Just the bottom bracket.


thx for all the info Dave  I know what to get now


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## Indianajim (Apr 8, 2007)

I just replaced my R700, with the new Dura Ace Compact. I was just looking to buy replacement rings, but those cost more than a whole new crankset. Since I got a good price on the Dura Ace I went with that and a new bottom bracket as well. That being said the R700 is a good crank. I never had any issues with it, just a bit heavier than the Dura Ace Crank too.


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## twinkles (Apr 23, 2007)

The 6750 crankset has the rings a teenie bit further apart, in the plane of the chainrings, than earlier models. This was done so the small ring can be used with more small cogs in back, without the chain scraping on the big ring. 10 speed chains are narrower than 8 or 9 speed chains, so the ultegra might give you use of more cogs in back, while in the little chainring.


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## slotnick (Aug 27, 2009)

twinkles said:


> The 6750 crankset has the rings a teenie bit further apart, in the plane of the chainrings, than earlier models. This was done so the small ring can be used with more small cogs in back, without the chain scraping on the big ring. 10 speed chains are narrower than 8 or 9 speed chains, so the ultegra might give you use of more cogs in back, while in the little chainring.



I will upgrade my rear cassette to a ultegra 12-27 (9 speed). I guess I need to opt for a 9-speed ultegra chain then?


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## DaveT (Feb 12, 2004)

slotnick said:


> I will upgrade my rear cassette to a ultegra 12-27 (9 speed). I guess I need to opt for a 9-speed ultegra chain then?


Nope, use any good quality 9-speed chain. I use KMC chains.


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## PSC (Mar 10, 2004)

Good deal here on R700 crankset and BB:

http://www.jensonusa.com/store/product/CR407B13-Shimano+R700+Compact+Crankset+W+Bb.aspx


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## Clevor (Sep 8, 2005)

Indianajim said:


> That being said the R700 is a good crank. I never had any issues with it, just a bit heavier than the Dura Ace Crank too.


More than that! I weighed an R700 crank. This compact crank with two chainrings weighs the same as a Dura Ace triple crank with three rings!!! So for the same weight, you get 10 more speeds with the Dura Ace triple.

Then again, you can pick up an R700 crank from JensenUSA for $94 including BB (albeit it a heavy Ultegra 6600). While just a Dura Ace triple crank will run $350-450 nowadays, if you can find one. They were going for around $270 couple of months ago at CRC, but prices really shot up recently.


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## Len Ciccone (Jan 17, 2008)

*R700 bottom bracket changeover*

I realize this is an old thread,but I am changing from 53x39 to a compact can I use fsa crankset on R700 italian thread torelli frame? thank you


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## slotnick (Aug 27, 2009)

I guess it should work ... I've several shimano equiped bikes with FSA cranks. My friend has a FSA compact on his Ultegra bike aswell, and he's pleased with it


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## sbrinley (Jul 29, 2014)

Do you still have the Colnago C50 with the FLR paint job?


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