Re: [CR]How old is too old?

(Example: Framebuilders:Alberto Masi)

Date: Tue, 14 Sep 2004 13:59:18 -0400
From: "Joe Bender-Zanoni" <joebz@optonline.net>
Subject: Re: [CR]How old is too old?
To: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>, Robert Kaufmann <kaufmann@crsa.bu.edu>, classicrendezvous@bikelist.org
References: <20040914192744.56443.qmail@web81001.mail.yahoo.com>


This has been talked to death before but I'll give my opinion point blank. The sharp edges at the arm/spider transition of Campagnolo Record and Nuevo Record cranks was an engineering error. If you want to ride your cranks, file the radius. If you want to hang your bike on a wall or win a concours - don't. It is shameful that Campy never corrected this problem. Sugino did, more or less, on their copies.

The pedal eye problem is a different story- inspect away, preferably with a dye penetrant.

Joe Bender-Zanoni
Great Notch, NJ


----- Original Message -----
From: Jerome & Elizabeth Moos
To: Robert Kaufmann


<classicrendezvous@bikelist.org> Sent: Tuesday, September 14, 2004 3:27 PM Subject: Re: [CR]How old is too old?


> We've had some extensive threads on this. Campy NR cranks had a transition from crankarm to spider that turned out to be a stress riser. They were also very hard alloy, which made for very long lasting rings, but also meant the alloy was more brittle and cracked more readily. Stronglight cranks, by comparison, were softer, so rings wore out more quickly, but they rarely cracked like Campy. Almost all used Campy cranks have small, sometime almost indiscernible, cracks at the transition from spider to crankarm. Occasionally these propagate and the crank fails. They can also crack and fail at the pedal hole, usually where scratches from curbs, etc. had created stress risers. I don't think this is a simple function of age, its more likely a function of the number and magnitude of stress cycles, which would relate roughly to mileage and maybe the weight and riding style of the rider. But scratches and scrapes probably accelearte failure also.
>
> The bottom line is, inspect Campy cranks regularly, and if there is a serious crack, retire them. I did this on a 1968 Allegro Special, where I found a rather nasty crack in the NR left arm at the pedal hole before it failed on the road.
>
> Regards,
>
> Jerry Moos
>
> Houston, TX
>
> Robert Kaufmann <kaufmann@crsa.bu.edu> wrote:
> All:
>
> I have checked the archives, but could not find a good answer to the
> following issue.
>
> Yesterday, I snapped my second NR Campy crank arm in three years. This
> time, the pedal eye "ripped" on a downstroke. (I fell over, but nothing
> more than road rash--the frame is unscathed). The first time, the arm
> cracked across the arm about a inch below the eye towards the axle. The
> cranks were installed at my LBS, and they are very good. So, I wouldn't
> fault them. I ride 3000-4000 miles per year. Once or twice a week, I ride
> hard (20-22mph) for 1-2 hour "time trials" but I am no monster. I weigh
> about 150 lbs. and am about 6 feet one inch tall. Clearly, I am no
> sprinter. I do climb well and like to get out of the saddle.
>
> Both cranks were from the early 1980's. Are cranks of this vintage too
> old to be ridden on a daily basis? I really like the "look" of the cranks
> and would like to keep riding them. After the most recent fall, I am a bit
> hesitant to go to ebay and look for "lightly used" cranks. Is it best to
> pay my money and take my chances or is it time to "modernize" the cranks
> for my everyday ride.
>
> All suggestions welcome.
>
> Robert Kaufmann
> Newton, Massachusetts