Bicycle Mechanics - Changing Crank Arm

Does anybody know if Ultegra crank arms are interchangable?

I'm currently using a triple 170mm crankset, but would like to go down to a 165mm crank arm. The arms are on a double chain ring. Both sets of arms are Ultegras. I'd like to keep my triple, just change the arms. Is this posible or advisable? Or do I have to go to a double to use the 165mm arms?

If it is a double crank, the 165 that is, then there is no place to bolt your small ring(the 30t.) You might also have a chainline problem running the double crank on a spindle for a triple. The spindle for a triple is wider(118mm) than the double(109.5mm) and might put the crank out to far for ideal shifting.

The 165mm is a double. Sounds like it's not advisable. Thanks for your response.

You can use a 165mm triple if that size suits you.
If Shimano can't supply one, then Specialities-TA certainly can.
The high quality TA chainsets use square-taper bottom brackets (not splined) and come with a Shimano sized bolt pattern, or a smaller bolt circle for lower gears.

Thanks. I'll check into it.

Another option is a "triplizer" middle chainring, which has two rows of bolt holes. Yet another option, if you do not need too low a gear, is to mount three chainrings on the same bolt circle, using long bolts and spacers. I ran a great "third-step" 15-speed 49-46-43 / 13-16-19-23-26 combination (check out that ratio progression in an Excel spreadsheet!) for years, before the days of 7+-speed freewheels.

That is an interesting trick but I think the lowest 130 circle chainring isa 38. The best would be 42/38. If you just want a bit lower gear you could try a 38 with a 12/27 cassette.

Yeah, I was think about puting the double on and going with a bigger cassette in the back for those long hill climbs.

We have a couple of rides around here that I use that set up for customers(Not me I'm a hill sissy, going up anyway) They are Triple Mountian Metric, Assault on Mount Mitchell, Bridge to Bridge.

I just did the Skyline Drive (Shenandoah, VA) ride last Sunday and would have been in big trouble without my sissy, granny gear. You can call me sissy or whatever, but when the ride starts with a 5 mile climb up to 1,000 feet, any and all gearings are welcome? :)

No, I am a hill sissy in that I don't like to go up them. What ever gets you to the top is cool. After doing a hill sprint and seeing 203 on my heart monitor I decided to lay off that stuff.

Originally posted by Rev.Chuck
No, I am a hill sissy in that I don't like to go up them. What ever gets you to the top is cool. After doing a hill sprint and seeing 203 on my heart monitor I decided to lay off that stuff.

I'm Grinning here... 203...

I cant wait to get into shape, then I can repeat what you've said!!