Author Topic: Which triple crankset will fit my bike?  (Read 3709 times)

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Offline mamachala

Which triple crankset will fit my bike?
« on: January 04, 2014, 06:46:08 pm »
I am currently running a 9 speed drivetrain with a Shimano Ultegra 6503 triple crankset,52-42-30. I haven't had the bottom bracket apart but will assume it is an Octolink but not sure if it is a V1 orV2. I want to go to smaller chainrings, maybe 44-32-22. What 9 speed cranks will fit my bottom bracket? If they are mountain bike cranks, which I assume they probably will be, are there other considerations to make? Will any mountain bottom bracket s fit a road bike? Is BB width an issue?

Thanks
Jack

Offline waynemyer

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Re: Which triple crankset will fit my bike?
« Reply #1 on: January 05, 2014, 05:26:07 am »
The easiest solution is to switch to the crankset you want*. If you're currently running a triple, you know that your chainstays can run a triple without any issues. The bottom bracket is determined by your crankset.

*I say this because mental effort and fitting gyrations are enormously expensive to me. Pick out, say, a Sugino triple crank (or some other square taper crank) and its appropriate bottom bracket. Bickety-bam. Pick a Shimano 54, Velo-Orange, or Phil Wood BB. All of them have legendary reliability. You'll even probably come out at a total lower price point, even with a Phil BB.
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Offline DaveB

Re: Which triple crankset will fit my bike?
« Reply #2 on: January 05, 2014, 10:06:00 am »
Your Ultegra 6503 triple has an Octalink bb and it's a V-1.  If you are content with just a smaller granny, the Ultegra's 74 mm granny bolt circle can take a 26T or even a 24T chainring as replacement for the stock 30T.  I've done that on two 6503 cranks and it works well.

Due to the 6503's outer 130 mm bolt circle, the smallest middle chainring you can fit is 38T but 39T chainrings are far more common.  So you have the potential of say 48/39/24 using your current crank and bottom bracket. 

If you really want a 22T granny and a 32T middle, you have to go to a MTB crank and it's matching bottom bracket.  Be careful to get a bottom bracket that will work with your 68 mm bottom bracket shell as many MTB's use a 73 mm shell width.  Some MTB bottom brackets come spacers to allow them to be used with either shell width so be sure yours does.

As waynemyer suggested, an alternative is a Suguino or other 110/74 mm bcd crank using a square taper bottom bracket.  A 110 mm bolt circle will accept down to a 33T chainring (34T is far more common) and the 74 mm will take down to a 24T so that gets you close to your desired chainring set.

Offline mamachala

Re: Which triple crankset will fit my bike?
« Reply #3 on: January 05, 2014, 04:53:32 pm »
Thanks for the very useful info Wayne and Dave. I am leaning towards going with MTB cranks at the moment to get the gearing I want. I will probably go the ebay route for some lightly used XTs to keep the cost down. Just have to be sure and get the correct BB. Thanks again,  Jack

Offline TokyoNose

Re: Which triple crankset will fit my bike?
« Reply #4 on: January 05, 2014, 11:03:04 pm »
Be aware that you might also have to swap out your front derailleur to accommodate a different crankset.  This is especially likely if you switch to a 44-32-22 mountain triple.  It is also possible, but unlikely, that to shift into a small ring such as the 22 tooth inner ring on a mountain triple, the derailleur will swing low enough to make contact with the chainstay.

Offline mamachala

Re: Which triple crankset will fit my bike?
« Reply #5 on: January 06, 2014, 08:58:23 am »
I appreciate the input TokyoNose, a valid point to consider. If I have to swap the front derailleur to a MTB one will my current brifters be compatible with it? I currently have about 2 cm. of clearance between the chainstay and my front derailleur, do you think the MTB crankset will drop it more than 2 cm?

Thanks

Jack

Offline TokyoNose

Re: Which triple crankset will fit my bike?
« Reply #6 on: January 06, 2014, 11:45:42 am »
Brifters? No, unfortunately, brifters will not shift a mountain front derailleur.  The levers will not pull enough cable to actuate the front derailleur across all three of the rings. 

I like the idea proposed by waynemyer and DaveB: a Sugino triple.  Something like an XD2/XD600 is available with 24/36/48 or 24/36/46 rings, is 9 speed compatible, and will run on a Shimano UN54 or UN55 bottom bracket.  It might even shift with your current front derailleur.  If not, a Tiagra triple front derailleur, which is more tolerant of smaller rings than the Ultegra, should get the job done.

If you still need lower gearing, your next stop will be the cassette.  A larger range cassette might, however, require a longer cage derailleur.  Something like a 9 speed Deore will probably work just fine and will play nicely with your brifter (same cable-pull ratio).  Shimano rear mechs typically come in three flavors: short cage (road), GS (medium length cage), and SGS (long cage).  If you have the choice, get the long cage.  It will weigh just a bit more and require a very slightly longer chain, but will leave you the flexibility to run just about any gearing that you desire.  In any case, stay clear of 10 speed DynaSys rear derailleurs.  They use a different cable-pull ratio than 9 speed rear derailleurs and will not work with your brifters.

Sorry to take you yet another level down into the rabbit hole.  Changing gearing sometimes opens Shimano's Box; altering one part of the system often leads to a seemingly endless chain of modifications necessary to make the whole mess work properly.  Having a good LBS with whom you can work is a great asset, as, for instance, they might be able to experiment with different spindle length bottom brackets at no extra charge to you (although you will probably end up with either a 110 or 113mm spindle) in order to ensure that your drivetrain is set up with the proper chainline.

Offline mamachala

Re: Which triple crankset will fit my bike?
« Reply #7 on: January 06, 2014, 12:50:57 pm »
More helpful info, I wasn't sure if the MTB frt. der. would work with the brifters, oh well. The Tiagra will be my  plan B

I will look into the Sugino cranks, just trying to keep the cost down at first.

I am already running a 34-12 cassette and long cage derailleur so cranks are the next step.

Thanks again,

Jack

Offline TokyoNose

Re: Which triple crankset will fit my bike?
« Reply #8 on: January 06, 2014, 01:36:48 pm »
Yes, swapping out the crankset is indeed your next step.  Apart from that, you could swap the cassette to a Shimano 9sp HG-61 11-36t, but non-Shadow-type Shimano rear derailleurs sometimes require B-screw modifications to clear the 36t cog.

I understand the temptation to run the 22-32-44 mountain crankset.  It definitely offers the low gear ratios that are desirable on a loaded touring bike (I am assuming that this is the issue which you are trying to address).  Unfortunately, Shimano mountain/road component incompatibility bugs could turn a seemingly simple solution down a dead-end path.

The suggested Sugino crankset is, new, quite reasonably priced, at least as cranksets go, and the Shimano bottom bracket is not a terribly expensive piece of kit either.  You might have some luck snooping around on eBay (beware of worn chainrings, the replacement of which could cost you a large percentage of the cost of a brand-new crankset), and there are any number of online retailers and local bike shops from which you can source the Sugino crankset.  Rivendell sells them for $146, and offers them in 4 different arm lengths, which is nice if you are picky about that sort of thing (I am).

FWIW, I am running a Sugino Alpina 2 (24-36-48) crankset with a Shimano Ultegra triple FD (10speed) and 105 brifters, and the front shifting is as good or better than that on any bike that I have ever owned.  YMMV, but it is at least worth taking a shot at running your current Ultegra FD with the Sugino.

Good luck!

Offline mamachala

Re: Which triple crankset will fit my bike?
« Reply #9 on: January 07, 2014, 09:56:37 am »
It does look like the Sugino is the better option, I don't really need to go as small as 22-32-42. This has been a lot of help, Thanks.

Jack

Offline Doug64

Re: Which triple crankset will fit my bike?
« Reply #10 on: January 07, 2014, 10:27:04 pm »


Offline Doug64

Re: Which triple crankset will fit my bike?
« Reply #11 on: January 07, 2014, 10:43:16 pm »
The above post was a test to see if I could attach an image.

The bike is a Bianchi Volpe with mountain drive train:  44/32/22 with an 11-34 cassette.

Tiagra STI shifters work work very well with a 4503 Tiagra front derailleur.  I had to use a shorter bottom bracket (103 mm) to maintain a 46 mm chainline, but this is usually the case when putting mountain bike cranks on a road bike.  Most mountain bike drive lines run with a 50 mm chainline and the shorter BB is required.

Unforunately, the Sugino DX 500 is no longer available, but other cranks with a 104/74 bolt pattern should work.  I've used this setup on 3 bikes and it has performed very well. 

Offline paddleboy17

Re: Which triple crankset will fit my bike?
« Reply #12 on: January 09, 2014, 12:39:07 pm »
Thanks for the very useful info Wayne and Dave. I am leaning towards going with MTB cranks at the moment to get the gearing I want. I will probably go the ebay route for some lightly used XTs to keep the cost down. Just have to be sure and get the correct BB. Thanks again,  Jack

XT is sometimes overrated.  I would seriously look at LX (whatever its currently called since I think Shimano rotated names around). 

I thought I read comments telling you to replace the front derailleur.  My experience has been that sometimes you need a mountain front derailleur to go with a mountain crank, and sometimes you can get the existing road derailleur to work (if you lower the road derailleur down the new proper height).  I would spend the effort tweaking your current front derailleur before I would invest in a new derailleur.
Danno

Offline RussSeaton

Re: Which triple crankset will fit my bike?
« Reply #13 on: January 16, 2014, 04:09:45 pm »
I'd suggest keeping it simple and just changing chainrings on the crankset you own right now.  You can put 48 or 46 outer ring, 38 or 39 middle ring, and 24 tooth inner ring on the current crankset.  That will provide great gearing.  And be easier than changing cranks and bottom bracket.  Use same front derailleur.  Just lower it a few millimeters.  Cost wise it will be about the same price as buying a new mountain crank and bottom bracket.  Chainrings are kind of expensive when bought individually.  High end ones like TA or Stronglight with pins and ramps on the outer and middle rings to help shifting will be best.  But costly.  Cheapest inner ring you can find.  Keep it simple, change chainrings on the crankset you own right now.  46-38-24 crankset will give about the same gearing as the mountain crankset.  Perfect for riding with the 12-34 cassette you have now.  Not quite as low gear but still low enough.  24x34 is a low low gear.  The difference between 22x34 and 24x34 is not enough to worry about.

Offline officerdare

Re: Which triple crankset will fit my bike?
« Reply #14 on: January 17, 2014, 09:56:24 am »
I scanned through the responses and agree, keep it simple and just change out the chainrings.  If your triple is a 130BCD, you can change the rings out to a 50-39-24 combination which will still give you a good top end, and the middle (which I use 98% of the time) is a good compromise.  The 24t mated up to an 11-34 cassette will definitely help on the low end and climbing. 
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