Compact crank questions...

Discussion in 'Cycling Equipment' started by ArvinC, Apr 15, 2007.

  1. ArvinC

    ArvinC New Member

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    Hello all...it's been a while since I last posted, but glad to be "back"!

    Anyway, I have a 2003 Kestrel Talon with full-spec Ultegra, SPD 9-speed. I want to go to a compact crankset to give me more lower gear options. My question is, do I need to get a new front derailure to use a compact crank or is my current Ultegra derailure compatible? Are there any other considerations/specs I need to be aware of to make sure that the cranset will be compatable with the rest of my drivetrain?

    FWIW, I'm looking at these two cranksets...the Ritchey Logic WCS Carbon Compact and the FSA K-Force MegaExo Compact.

    Thanks for any help or suggestions! :D

    Arvin
     
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  2. Mish

    Mish New Member

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    C, none of the above. Go with the Shimano compact and lower your current derailleur to within 2mm of the 50t chainring and you will be amazed at how well it shifts and how much time you spend in the big ring. Around $200 on e-bay. By the way, what is your current cassette?
     
  3. alfeng

    alfeng Well-Known Member

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    I love the Octalink BB, but I would probably opt for either the FSA MegaExo or Shimano's compact Hollowtech II crankset.

    Try your current front derailleur -- it will either work to your satisfaction, or not -- a lot of people say it should work, and I know that I had a crank with a 48/34 with which an Ultegra 6500 front derailleur worked fine; but, I generally buy the TRIPLE version of a front-and-rear derailleur REGARDLESS (a legacy of my "old" days when maximum drivetrain flexibility rather than optimum was-and-still-is my goal).

    Whether you "need" a long cage rear derailleur depends on the cassette & chainrings you choose to use with a compact crank.

    FWIW. I'm almost sure that the 2008 Shimano ROAD cranks will get a fairily significant change in the way the left arm is attached (as witnessed in their newest MTB cranks) ... you can probably look for something similar with FSA's cranks sometime in the future, too.

    FWIW2. Your Ultegra rear derailleur can probably handle a 30t rear cog (you'd have to cannibalize a 12-34 LX cassette for the 30t cog) ... you can use your Ultegra 9-speed shifters with almost any Shimano MTB rear derailleur and thereby continue to use your current 130BCD crankset with up to an 11-34 cassette (if that is the capacity of the MTB rear derailleur you choose) ... so, if you have a MTB you can "borrow" the parts from (i.e., the rear derailleur & cassette), you can see if the lower ratio is what "works for you" before you spend money on the compact ...

    You never know -- you may end up wanting a triple.
     
  4. ArvinC

    ArvinC New Member

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    Hey guys...thanks for the replies!

    Mish - My current cassette is an Ultegra 9-speed 12-27. I found this on Shimano's website...Shimano FC-4550-S 9-Speed Compact Crankset. It doesn't even require me to swap out my current Ultegra front derailure. I checked on the other two Shimano compact sets, but they both specify 10-speed compatability only.

    It seems like the ideal solution, like you guys have said, but it is impossible to find online...may have to hit my LBS's and see if they can order it for me? Oh well...guess I'll have to pay retail on this one! :p

    Thanks for the suggestions!!

    Arvin
     
  5. ArvinC

    ArvinC New Member

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    Thanks for the reply, Alfeng. Just wondering, since you brought it up...why is the way the left crank arm is attached to the cranks so important? (Noob question) In reading your post, you almost make it sound like waiting to upgrade my driveline (heck, my whole grouppo!) would be smart...

    Oh, and about the triple...it's the hard-headedness in me that will wait for my lungs and legs to explode before I go triple...LOL! :D (Then again, it's not like I go for rides in the Alps, either!)

    Arvin
     
  6. Mish

    Mish New Member

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    Wait a minute. The crankset you want is a model FC-R700. It says 10 speed but it will work on 9 speed and is of the best quality and performance. Because the spacing between the two chainrings are a little tighter than a 9 speed there is the need for fine tuning of the derailleur adjustments. You can get it on e-bay for $200 or so but you may be better served buying it at a good shop and having them do the installation to get it right. Your current cassette is perfect to get you very low and not loose much on the high end.
    Get the FC-R700 and not any other current shimano model.
     
  7. nerdag

    nerdag New Member

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    The 4550 is the Shimano 9s compact. It shifts a bir more cleanly than the R700 does on a 9s drivetrain.

    Its also a good 150 USD cheaper than the R700, with not much of a weight penalty (if thats important to you).

    n
     
  8. nerdag

    nerdag New Member

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    Try 3ringcycles.com - I purchased my set from there.

    n
     
  9. gclark8

    gclark8 New Member

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    I bought the chainrings from this crankset for a customer and fitted to 160mm double crankarms. (have Pix if required) I have yet to fit it to the bike, however I don't see any problems using a Sora Front Derailleur. I will have to fit a 110mm BB, however, as the bike originally had a triple.
     
  10. alfeng

    alfeng Well-Known Member

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    Supposedly, the left arm can loosen ... and, fall off (that can happen with any crank arm).

    Supposedly, the problem was more frequent with the earlier FSA cranks ... I don't know if that is true or just a rumor.

    The problem is partially alleviated, I suppose, by leaving the threaded "fixing" cap (whatever it's called) in place ...

    Purely speculaton on my part, but I suspect that if you were to wait until after this year's TdF (when I would expect a new version of the Dura Ace crankset would be introduced), the current Hollotech II cranks will probably be available for a 30% price reduction in all venues (LBS to eBay) ... or, not!?!
     
  11. roadhog

    roadhog New Member

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    So I'm in the same boat as the original poster here. I have a full ultegra 9 double setup and want to switch to compact (50/34).

    So the Shimano R4550 looks fine to me except I can't find it in 172.5 for the life of me - which currently rules it out.

    I'm also looking at the Shimano R600, which also looks fine to me and is about the most I want to spend (ruling out the R700, etc). But I can't tell if it's really made for 9 or not. The following listing says it's 9 speed compatible.
    http://3ringcycles.com/page.cfm?PageID=37&action=details&sku=CR7712

    But everywhere else I've seen it lists it as 10 speed. So is the link I posted a misprint or is it legit for 9 or what's going on with this crankset? I want as little messing with front derailleur, etc, as possible.
     
  12. nerdag

    nerdag New Member

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    I thought the 4550 did come in 172.5?

    Anyway, according the guys at Roadbikerider.com - to get a 9 s rankset from a 10s one, simply sticka 0.6mm spacer between the inner ring and crank spider before you bolt it on for any 10s crankset, and it will turn it into a 9s crankset with the right spacing.

    It was in once of their recent newsletters.

    n
     
  13. roadhog

    roadhog New Member

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    Thanks. I would think the 4550 would come in 172.5, but I haven't been able to find one yet at least.

    The shims option doesn't bother me either for the R600. That's a simple enough procedure.

    Last question though, I'm not real smart on bottom brackets and I'd like to avoid needing a new one of those as well. I currently have a 105 BB in there. I understand the splines on Shimano only work with Shimano or something, so I'm hoping my existing BB would still work with either of these cranksets I'm talking about right (4550 and R600)? Or is there yet another reason I might need to get a new BB?
     
  14. alfeng

    alfeng Well-Known Member

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    The various SHIMANO & FSA External Bottom Brackets are interchangeable ... if you have a Hollowtech II BB, then you don't need to change it when swapping out another Hollowtech II crankset OR a MegaExo crankset, and vice-versa.

    BUT, if you have a Shimano Octalink BB (e.g., Ultegra 6500), then you will need to change it.

    Of course, frames with Italian threaded BB shells need Italian threaded BB cups -- not generally a concern with most frames.

    RITCHEY still markets a "compact" crankset which uses the Shimano Octalink BB ... but, it is expensive (IMO).
     
  15. branded

    branded New Member

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    Firstly, I have a 9 speed Ultegra groupset, and 6 months ago installed 172.5mm R700 cranks. Just readjusted the FD (see earlier post - lower it to about 2mm clear of the 50 tooth (1-3mm tolerance according to Shimano)). It works beautifully. Smooth changes, wouldn't go back.


    Seems to be some confusion about the differences between R700, R600 & R4550. FWIW, a 9 or 10 speed chain will work on all these cranksets, as the difference is in the external width of the chains. Internal chain clearance is the same. Makes a difference on the rear cogs, but not the front.

    Also all 3 cranksets have a quoted chainline = 43.5mm. The FD needs to be adjusted to the new compact crank (height & high/low lateral position), so any minor differences are adjusted out anyway. And rear gear changes are not going to be affected by minor (eg 0.6mm) variations in the lateral crank position.
    So spacers are not needed.

    You do need a Hollowtech bottom bracket though, old Octalinks won't work with these sets. Again (as I had to do this) it is a simple change if you have faced BB housings.

    Lastly, looking at the specs & drawings of the so called 9 & 10 speed Shimano compacts, the differences appear cosmetic. The 4550 & R600 have Ultegra like appearance, while the R700 has the new Durace solid big gear appearance. The finishes of these components also differ (some matt, some shinier etc).

    So roadhog, if you need a 172.5mm set, go with the R700. If you want to save some $$ or prefer a more traditional appearance, go with the R600 or 4550. They should all work equally well.
     
  16. roadhog

    roadhog New Member

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    Thanks to both of you for the replies. They're very helpful.

    So I'm comfortable with the crankset choice now, and I guess I'll just find out about the bottom bracket (Hollowtech vs. Octalink) when I crack it open. I'm not sure how to tell what I've got in there. My bike is stock, and this is the only thing I have to go on from the C-dale archives (2004) for the BB:
    http://www.cannondale.com/bikes/04/cusa/model-4RR1D.html

    So if you can tell about my BB from that (Hollowtech versus Octalink) let me know - otherwise I'll just learn about it as I go. I've got a bit to learn on this relatively simple project but I'm trying to force myself to be a better wrench so it should be fun.

    Thanks again!
     
  17. nerdag

    nerdag New Member

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  18. roadhog

    roadhog New Member

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    Figures. Bummer. One more thing to buy...

    Thanks though!
     
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