Hi Jeff,
What is the proper torque on crank arm's such as Campagnolo, Stronglight or Dura-Ace? I forgot my peanut butter wrench and learned the hard way about crank arm torque in Quinlan, Texas in about 1970 when my left crank arm came loose on me and I was in deep trouble because every shop and home we went to could not help. All around was standard threading and the sockets would not even fit into the crank arm cavity to tighten the crank arms. No 15mm sockets or tools anywhere in that part of Texas and we were 55 miles from home. A fellow ground down a socket to fit the cavity and tighten the arm. What is the proper torque? Foot pounds? This could save the loss of the left arm in the trash. Thank you.
John Proch La Grange, Texas
________________________________ From: Jeff Slotkin <jeffslotkin@comcast.net> To: Jon@FAI.US Cc: classicrendezvous@bikelist.org Sent: Sun, January 3, 2010 12:58:12 PM Subject: [CR] Where Left Arms Go, was: Re: WTB Two Left Arms and Two Right Forks
You've explained where left arms go: into the trash.
That path through the BB is very hard on inadequately tightened left arms. Many (usu. inexpensive) new bikes will shed their left arms in a month of riding if they are not tightened by the dealer. Caloi cruisers in particular I remember seemed merely hand tight out of the box, requiring numerous turns before even considering torque. One large maker seems to be getting theirs tighter this year than in the past.
Mssr. Brandt has asserted, I think, that a properly tightened arm can crawl up the spindle which then allows the bolt to come loose, which can then allow the crank to work loose if the bolts are not checked...and that well-installed metal crank caps can prevent all this. This all seems right, though again if they are never tightened well to begin with I think bolts and arms just fall off together.
Jeff Slotkin, usually at The Bicycle Shoppe, Charleston, SC
On Jan 3, 2010, at 12:00 AM, Jon M. Crate wrote:
> Two Left Arms
>
> It is easier for me to understand where the mates to my sox go than to
> understand where the left crank arms go.
> I can see the load runs (in reverse) from the chain to the chainring, then for
> the right arm directly up the arm to the pedal and for the left side it goes
***
> through the bottom bracket to the arm and them pedal.***