Tuesday, July 15, 2008

An email correspondence about breaking bike parts

Hi Maynard!

This morning I took my first ride since returning from The Tree Trek. On the fixie -- 45 miles -- it went pretty well. OK, there was an injury involved but it wasn't mine.

I'd ridden through Palo Alto, picking up a seat bracket (Palo Alto Bicycles) and continued up to Woodside (Robert's Market - yum!) and down Mountain Home Road to Old La Honda when I noted a bicyclist walking, turning from Portola Valley Road onto Old La Honda.

"Need any help," I called.

"Do you have a cell phone?" he responded.

So I stopped, handing over my cell phone before I noted his left foot was drenched in blood.

"What happened?" I asked.

He handed me half of his crank. The left side had, quite literally, shattered where it joined the bottom bracket, flipping up and slicing the crap out of his leg, just behind his left Achilles tendon. The wound was about 1/2 inch deep (really deep Maynard) and blood was seeping out quite heavily.

The rider was about 70 years old. I sat him down, handed him a protein bar, got him water from his bike (which was absolutely unrideable) and dragged out stuff from my kit, starting to clean up the wound. It was a mess.

At that time a car pulled onto Old La Honda and I waved. It stopped and provided more paper towels, some antibiotic wash and ointment and a cotton handkerchief I used to bind up the wound.

MEANWHILE he used the phone to call a taxi. I stayed there until the taxi came -- 45 minutes later!

It definitely was NOT an emergency but this guy had real trouble standing (besides, I kept pushing him back onto the ground -- he had no business putting weight on that foot / ankle -- and I was worried about a chunk being taken out of his Achilles).

So finally we got him bundled into the taxicab, bicycle in the trunk, and he headed for acute care -- it wasn't quite ER level, he seemed fine except for the gash, but definitely needed to be scrubbed, disinfected and stitched up (a bit of super glue would have been enough for me).

Never seen a crank fail like that but, no doubt, it's happened before -- particularly when you put LOTS of stress on them, standing. I'd have thought you might bust a chain instead.

So my ride got a little longer then planned -- fortunately Debra had fresh tunafish waiting when I got home. That and a very, very chilled beer made for a good "recovery."

So watch dem cranks sir, watch out!

more later, Jim

Hiya Jim!

Let me see...

I've had two or maybe three frames crack. Two crank arms and one bottom bracket axle. The one time my bottom bracket axle broke the pedal and crank were still attached to my shoe when I got the bike stopped. Banged the inside of my thigh.

Stuff breaks. I never liked to take cranks off and on because each time it stretched the alloy and shortened the life of the crank arm, I thought. When stuff was pantographed, etched with the maker's logo, it would fail where it was etched. I'm sorry for the dude's injury, sucks, but it does happen, more often than you think. The scariest things are carbon forks... They just break.

We used to break rear axles too, in the Campy six and seven-speed days. Cassettes were a cure for those broken axles. Oh, I broke a pair of handlebars...maybe a seat rail or two.

Good on you for helping that guy out....


Hi Maynard

Obviously you WRECK bikes! I took a good look at the busted portion of the crank and it appeared to have started cracking at one corner, followed by a series of half-moon splits. There were also a few odd gear "marks" where the crank splines intersected with the bottom bracket. We used to investigate this stuff during Aircraft Accident Training at Navy Postgraduate School. If only I had a microscope. . . .

But one thing you mentioned got to me -- Carbon Forks. They just break? Where? How? Reason is -- I've got a front rack on my Filmore which "clamps" onto the front forks about 4 inches above the axle. It seems (?) that the forks are SOLID at that point but . . . . .

. . . . I would love to have steel forks but nobody uses 'em (much) anymore.

Meanwhile I'll take the Zurich out tomorrow (it's got a new rear rack -- Nitto -- a bit of a tight fit -- not what I'd design -- but the Zurich is NOT designed to be a luggage hauler) and climb up to Alice's -- again.
ciao jim

Hi Jim,

If you hit a squirrel on that Zurich, you may snap the forks at about the halfway point. At the races, I've seen a dozen, maybe two dozen, snapped-off carbon forks. They don't bend, as you know. People drive their cars into their garages with their bikes on top. Used to bend steel forks. A good framebuilder could straighten them. Carbon ones? Buy another.

When you looked at the stubs of broken cranks you could see a granular area that looked as if the forging was incomplete, and the area of progressive breakage. The square taper ones were not designed to be put on and taken off serially. But they usually broke at the pedal hole or where the logo was. Stuff breaks.

I was always a spinner, not a bruiser, and even I broke stuff. Never a fork though, and never a stem. Remember George Hincapie breaking a stem or steerer at Paris-Roubaix a few years ago; Trek kept the thing quiet post-crash...

I've never used off-brand stuff, or not since the '70s. Always Campy or Shimano. There was always US or foreign stuff available, but I never trusted it. As I reflect on it, I've never broken much Shimano stuff... Wheelsmith, in Palo Alto, had a show case full of broken bike parts, mostly Camp Granola.

Your friend, Maynard

Oh! Commenters... Is it okay to clamp a front rack onto carbon fiber forks?


blackmountaincycles said...

"Is it okay to clamp a front rack onto carbon fiber forks?"

I wouldn't do it to my wife's bike. I wouldn't do it on my son's bike. I wouldn't do it on my bike. I wouldn't do it on any customer's bike.

There are plenty of steel forks available from lots of folks.

Anonymous said...

I just replaced the 12 year old DA crank set on my road bike. The power side failed, [and apparently had been failing since its initial forging], right in the middle of the arm. It bent across the arm so that it began hitting the chain stay. I'm glad I was not out of the saddle. I broke the left side of another set years ago. That time I was climbing Pig Farm. I did end up on the ground that time.

This is one reason that a clean bike is a ridable bike. I once noticed a crack in a fork crown. The dirt line wouldn't wipe away. I don't think my next bike will be carpet fiber. Maybe I won't have a choice.

b wally