# Compact Crankset questions.



## AlanS (Feb 5, 2003)

I, too, am looking to change cranksets. I have an 'old' Ultegra...53/39...I want to drop some weight, go compact. Are cranksets 'compact specific'? I saw in a post above that a number of cranksets were recommended...can they use 'any' rings...or do I have to look for Compact? If it is Compact Specific, what suggestions for a crankset and BB that would be lighter than the circa 2000 Ultegra crank and BB....
I want (1) as stiff or stiffer (2) lighter (3) cannot break the bank.... I have other things to also spend $$$ on (shifters).


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## Svooterz (Jul 29, 2006)

The most popular road cranks are either "standard" or compact. Basically, the crankarms of a compact crank have a different bolt circle diameter (BCD) and you HAVE to use chainrings with the same BCD as your crankarms. The most common road cranks use either a 130mm BCD (standard cranks) or 110mm BCD (compact). Campagnolo is something of a standalone in that market : their standard cranks use a 135mm BCD and their compact cranks use the 'common' 110mm BCD... But I think the bolt pattern is not the same as other brands, so Campy rings are compatible with nothing else.

So, basically, if you want to change to compact cranks, you have to buy a whole new crankset. You can't just buy crankarms and use your rings, it won't work. You'll have to buy a bottom bracket that fits the crank you buy, but it's easy to find info on BB/cranks compatibility.

Now that all the education part is done, let's go onto the "problem"... Circa 2000 ultegra cranks - I take they're the 9 speed version with octalink BB? Well, if you want the easy way out, buy a Ritchey WCS compact crank... They use the exact same octalink BB as the 9 speed Shimano stuff, and they're pretty light. Starting at 85$ on e-Bay :
http://shop.ebay.ca/?_from=R40&_trksid=m38&_nkw=ritchey+wcs+crank&_sacat=See-All-Categories
There's also BikeSomewhere, but they sell it for 168$. Get 2 on eBay or 1 on BikeSomewhere. Your pick.

Now, if you're using a more recent version of the ultegra cranks, the ones with outboard BB's, you'll have to get an octalink BB too, but even then, it's probably the least expensive way to go compact & to shave weight.


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## MerlinAma (Oct 11, 2005)

Svooterz said:


> ................ The most common road cranks use either a 130mm BCD (standard cranks) or 110mm BCD (compact).............


You see, a chainring smaller than a 39 (38 if you could find one) simply won't work with 130mm BCD cranks as the bolts would be outside the chainring.


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## muscleendurance (Jan 11, 2009)

AlanS said:


> Are cranksets 'compact specific'?...can they use 'any' rings...or do I have to look for Compact...


:lol: so have you asked yourself the question what makes a compact a compact? - the answer should deliver you to answering your own questions ut:


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## Svooterz (Jul 29, 2006)

MerlinAma said:


> You see, a chainring smaller than a 39 (38 if you could find one) simply won't work with 130mm BCD cranks as the bolts would be outside the chainring.


Yeah, I forgot to mention that part...

Hey, now my mind is running : for the same reason that you can't put a smaller ring than 38T on a 130 BCD crank, I suppose that it's technically impossible to fit anything smaller than 39T on Campy's 135 BCD cranks... is it?


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## ctracer01 (Jan 5, 2006)

Svooterz said:


> Yeah, I forgot to mention that part...
> 
> Hey, now my mind is running : for the same reason that you can't put a smaller ring than 38T on a 130 BCD crank, I suppose that it's technically impossible to fit anything smaller than 39T on Campy's 135 BCD cranks... is it?


nope, nothing smaller than a 39 fits on a campy standard


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## fontarin (Mar 28, 2009)

I'm swapping to Compact also from Double. I was wondering the same question as the OP, and I assumed correctly that you can't change them out.

One question I haven't been able to find the answer to specifically, but I think i won't need to - I'm changing out a Ultegra SL double to a Ultegra SL compact - would I need a new BB, or just the crankset?


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## MerlinAma (Oct 11, 2005)

fontarin said:


> .......One question I haven't been able to find the answer to specifically, but I think i won't need to - I'm changing out a Ultegra SL double to a Ultegra SL compact - would I need a new BB, or just the crankset?


Just the crankset. Both are doubles and would have the same chainline.


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## Svooterz (Jul 29, 2006)

MerlinAma said:


> Just the crankset. Both are doubles and would have the same chainline.


In fact, you could have said "both use the same Shimano's external-bearings BB" and you would have had it covered... even for triples. The 5600/6600/7800 series components all use the same BB, whether they are compact, double or triple. That's one advantage of having the spindle stuck in the crank : you don't need to change BB to have the proper spindle length...

I just pointed this out because your post could've been misleading about triples. But your answer was basically correct : fontarin, you don't need a new BB.


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## fontarin (Mar 28, 2009)

Thanks for the help!

Would there be anything else I need to swap out that you can think of? I'm assuming no, but I'm still pretty new at this.


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## Svooterz (Jul 29, 2006)

fontarin said:


> Thanks for the help!
> 
> Would there be anything else I need to swap out that you can think of? I'm assuming no, but I'm still pretty new at this.


One thing I can think of : you'll need to put the pedals on the compact crank 
Seriously, no, you don't have to swap anything else. Everything you have now will work with the compact crank.

Just make sure you lower the front derailleur & readjust the cable tension. Your front derailleur should be a few millimeters lower than it is right now. A front derailleur that is correctly setup sits pretty close to the rings, and since compact rings are smaller, you'll need to lower it like I just said.


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