Shimano Dura Ace 10 Crank Question

[05Fierte TI]

The other night I could not sleep and was on this forum. Somebody posted a link to a site with lots of broken bike parts - Scary! Well, that got me looking at my crank and there are some spots which I cannot tell if they are old scratches or cracks. I am thinking that a new crank might be the safer alternative

Here is the question, is there any problem running the Dura Ace 10 crank on a 9 speed system? Will the wider chain cause any issues with the 10 speed rings? I am currently running an 8 speed square taper Dura Ace crank with the rest of the system being 9 speed Dura Ace.

I really do not want to go to 10 speed as there is plenty of life in current components and do not want to use the 9 speed crank as I do not want the bottom bracket issues.

Thanks for the help

[dirtdigger88]

why not get a 9 speed DA crank

what BB issues are you worried about-

the crank should work- I have a 9 speed crank on my otherwise 10 speed set up-

Jason

[Serotta PETE]

some spots which I cannot tell if they are old scratches or cracks. I am thinking that a new crank might be the safer alternative.

Thanks for the help

It is VERY rare for a crank to break - - especially in recereational use. With 10 speed you will need to replace BB also. Unless you want the 10 speed, you should be able ot get a good deal on 9 speed and there is no reason for recreational or club race user to switch. Need and WANT are different - - just ask SPOKES and ME.....

[05Fierte TI]

I know if I went with the 10 speed crank, I would need a new bb. I really do not want to deal with the octalink bb as I have seen too many of these die an early death.

The current 8 speed crank has quite a few miles and a fair bit of racing. never crashed, but ridden hard for a number of years. Maybe I am being too paranoid, a couple of the scratches look alot like cracks.

So 8 speed is quite old, I really do not want to do the octalink think, that leaves a 10 speed crank with a 9 speed chain, does it work ok or is the clearance too narrow on the crank?

[Serotta PETE]

I beleive it will work. SPOKES where are you MR KNOWLEDGE>

I agree if 8 speed has MILES and races, a change is not bad. Some one on the forum, I am willing to bet has a 9 speed for sale. I just sold my 9 speed to one of SPOKES friends. ( I actually like the looks of 9 speed over 10 BUT then I am old.....

[11.4]

The Dura Ace 7700 (Octalink) bottom bracket got a bad rep because it was designed for optimum performance but required incessant care. Without the care, it died quite quickly. However, the Ultegra 6500 bottom bracket was completely bulletproof and worked just as well -- even pro teams substituted it. All the Octalink bottom brackets, road and track (excepting triples), are fully interchangeable. You can buy a brand new 9-speed 7700 crankset with rings for around $130-140 these days and there are plenty around in almost all sizes, and an Ultegra bottom bracket is about $55-60.

Before you do any of this, however, I agree that these days, crank fractures are pretty much nonexistent. Unless you've hit it hard and possibly already bent it, you're unlikely to crack it. Old Campy Nuovo Record cranks had a way of breaking, but that was before modern forging and assembly techniques. Some close-up photos might help, or you could show it to a good shop that you trust. Criticize Dura Ace however one may, their stuff really doesn't break, so I suspect you had scratches only. I'm not one to take risks with equipment (I take all the risks I want to take in racing) so I'd be looking hard at it and asking questions too. But I doubt you have something to worry about.

[05Fierte TI]

Thanks for the help and clarification

[Ray]

I was the guy who broke his crank and started that whole thread that ended up with pictures of horribly mangled bike parts. I don't know whether you need to replace your crank or not - might want to have an LBS take a look if you have concerns. But if you do...

I just bought one of the new Shimano compact cranks, that of the 10 speed configuration and the hollowtechII bottom bracket. It's pretty much identical to the Ultegra 10 speed crank (which is pretty functionally equivalent to the DA version) except for the smaller bolt pattern and chainrings. Everything else on the bike is 9-speed, including chain. Works brilliantly. Stiff as a mofo too - not sure if I care and I'm quite sure it doesn't change the way I ride, but I do notice it and I'm ANYTHING but a powerful rider.

So, to answer your original question, yeah, it'll work just fine.

-Ray