Crankset confusion
 

I've recently discovered my drive-side crank arm has a stress fracture. I replaced the left arm for the same reason a few months ago. So, I'll be needing a new crankset.

I was browsing ebay, and came across this:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=220358073864

He says a square taper bb is required, but it appears to be octalink. What's up with that?

Also I have 7 speed, the seller says it works with 8 or 9 speed. Could I make this work?

You should know that My prior crankset was shimano 105. I don't know the BCD, but I'm assuming 130. I also don't know what the bb size is.

thanks

That is not an octalink. Shimano 600 was square taper.

It should work for you.

I'm pretty darn sure those are indeed square taper....You need to measure the spindle on your current cranks to see if the length is compatible. Those cranks listed should work just fine with 7 speed.

Cool, will the chainrings just be a bit thinner?

Most likely square taper, 130 BCD.
The allen bolts screw into the end of the bottom bracket. If you have the type requiring nuts just save your nuts from the old crankset and reuse.
To measure your BCD, look here: http://sheldonbrown.com/gloss_bo-z.html#bcd

Your crank arms should NOT develop stress cracks. If they do, it is certainly a design or (more likely) manufacturing defect. Contact Shimano for a replacement.

I tried get Campy to replace my NR cranks and they told me to f'ck off.

How'd they phrase that exactly?:roflmao2:

Crazy americano. Prendete un cazzo di escursione.

If you are getting cracks at the spindle eyes, your spindle may be too large for your cranks. In the 1970s Shimano used a larger taper (same angle, just larger cut-off end) than everyone else, but many others eventually adopted Shimano's dimensions.

That crank takes square taper BB. I have the same crank on my bike. The owner has replaced the 14mm hex crank bolts with 8mm allen bolts with built in dust cap, probably because the plastic snap-in dust caps get all mangled when you try to remove them.

It will work fine with 7-speed. I don't think there's any difference in thickness. The 9-speed large ring is likely ramped and pinned.

IIRC, my bike has a 68x115 BB axle.

Well the paint/anodizing whatever is chipping off everywhere. Here's an incredibly *****y picture of the left crank arm taken by webcam.

http://i41.photobucket.com/albums/e2...t_20090210.jpg

it's cracked all of the way through.

:eek::twitchy:
-Gene-

My legs are huge.

No but really, what could have caused this do you think?

I don't think it's the spindle issue because the bb and 105 crankset are stock.

Maybe something somehow got stuck in the space between the spindle and crankarm when it was installed and slowly caused a stress fracture which eventually broke. Or maybe a manufacturing defect. You're lucky it wasn't worse, it might have ended badly.
-Gene-

I may try this, but...

I doubt they have old 105 cranksets stockpiled.

And

I'll never find a receipt for a bike my dad bought in the mid 90's.

hmm

More succinct: Vaffunculo. I want a bike with that on the downtube; can't decide whether it should be a French or an English one. Headbadge a photo of Beppe Grillo (Louison Bobet style) giving the V-sign.

Call them up anyway. They're still doing good on a crankset recall that is already 9 years old - call the number listed on those recall forms. A crack like this on both arms is bound to get their attention, and you might get a nice courtesy replacement when all is said and done.

-Kurt

I'd like to see some hi-res pics of the arms and BB.

Interesting.

I dunno......I could maybe see this happening if someone greased the BB spindle and was a ham fisted ultra super duper strong man and really cranked down the crankarm bolts...Maybe coupled with a vicious heat/cold cycle? Yunno dis-similar metals expanding/contracting at different rates? Weird.

I do live in michigan.:thumb:

Here are some higher res photos.

http://i41.photobucket.com/albums/e2...rankfail01.jpg

http://i41.photobucket.com/albums/e2...rankfail02.jpg

http://i41.photobucket.com/albums/e2...rankfail03.jpg

http://i41.photobucket.com/albums/e2...rankfail04.jpg

STOP RIDING THAT IMMEDIATELY.
Wow... yeah... Umm...
I don't even know what to say.
-Gene-

I think it has a few more rides left in it.

I'm sending a letter to Shimano saying I'm still riding on the drive-side crank. Hopefully they'll see the picture and send me a new crankset.

Interesting argument. Theoretically, since the crack (at least on the left crank) has gone all the way through without catastrophically failing it has released the stress in the crank and can't propagate any further. So yes, theoretically you could ride it although it probably wouldn't stay tight on the spindle....

PRACTICALLY, though, a big wedge could suddenly break out of it causing it to fall off the spindle, causing you to fall off the bike and break your neck.

So I hope you are kidding about riding it.