Bicycle Mechanics - Crankset upgrade question: Is a triple a triple?

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cetuximab
04-01-09, 10:26 PM
I have an older road bike that I use to commute to work. I broke the crank today. I was thinking about upgrading to a newer triple crankset. Perhaps with the external bearings. Most of the cranksets are for 9 or 10 speeds. My bike has an 8 speed cassette and shifters. I did not want to upgrade my shifters yet. Can I keep my current front derailer work with new triple crankset (even though the crankset says 9/10 speed)?

Are the external bearing better than my older style square taper BB? I could just buy a new left crankarm?

Thanks


johnknappcc
04-01-09, 10:44 PM
Whoa, hold up fella, how did you break the crank? Anyway, you probably could go to a triple and still use the shifters and fd, but your chainline might be a bit off depending on your preferred chainring. I would look at getting just the new crankarm . . . probably the cheapest way to go anyway.

As for the external BB, yes, probably better (but I'm not sure you would notice it that much).

1) Stiffer because the bearings are closer to the point at which you are applying pedal force
2) Larger bearings (I think) and they can probably handle more weight
3) Serviceable, much less complicated to service and adjust than the sqare taper (like mine).

http://gallery.a-symmetric.com/main.php?g2_view=core.DownloadItem&g2_itemId=169&g2_serialNumber=2

Regardless, my wife's bike has an external BB, and I can't tell anything different. Again, I would just replace the crankarm(s). Keep your chainline (you would probably get more annoyed with a crooked chainline that would cancel any improvements with an external BB).

Seriously though, how did you break your crank?

bikinfool
04-01-09, 10:45 PM
The newer cranks would work fine with your present gear. Whether external bearings are better is a whole 'nother thread (and there have been a few), it's pretty subjective. How did you break the left arm? What is your old crankset?


Panthers007
04-01-09, 11:52 PM
I have Hollowtech II on my hybrid that I installed. It had a cheap Octalink before. And I have a Campagnolo Record bottom~bracket with Super Record crankset on my vintage Puch. The Campy is just a bit better than the Hollowtech II BB. The hybrid has Ultegra cranks - and hey remind me of the Campy's ease of shifting and smooth running.

I'd imagine the Hollowtech II would be better than many square-taper cups & cones BB.

DieselDan
04-02-09, 06:45 AM
Question 1: yes

Question 2: yes, but not necessary, but may be required to use a new crankset.

cetuximab
04-06-09, 09:41 PM
Sorry I did not reply sooner. I have had a lot of call the last several days.

I have never been in a wreck with that bike. The crank broke when I got out of the saddle to climb a hill. They are inexpensive FSA cranks that came with my Giant OCR3.

Thanks for the advice on upgrading the bottom bracket. As this bike is not worth very much, I will leave the current bottom bracket. I found a FSA square taper crankset online, and I bought a crank remover tool.

Thanks again.

DieselDan
04-07-09, 12:30 AM
Sorry I did not reply sooner. I have had a lot of call the last several days.

I have never been in a wreck with that bike. The crank broke when I got out of the saddle to climb a hill. They are inexpensive FSA cranks that came with my Giant OCR3.

Thanks for the advice on upgrading the bottom bracket. As this bike is not worth very much, I will leave the current bottom bracket. I found a FSA square taper crankset online, and I bought a crank remover tool.

Thanks again.

Do you have a bottom bracket tool?

cetuximab
04-07-09, 09:02 PM
No. I thought I would leave the bottom bracket.

Thanks