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One leg pedaling drills (subtitle: pedal failure)
 

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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/4/17 7:30 AM

One leg pedaling drills (subtitle: pedal failure)

Yesterday morning, I was 8 miles into a ride when i stood to power spin over a small crest and had the pedal axle on a Keywin Ti shear off right where the axle enters the platform housing. It was similar to having a cleat disengage in a sprint, but fortunately, I kept the bike up through a serpentine wobble and did not veer out into the road or impact any body parts on the bike frame. Phew.

I gave some thought to calling one of my retired friends to come pick me up, but for some reason, elected to pedal home with one leg since I had already climbed the worst hill. I've done one-legged pedaling drills on the indoor trainer before, but never for a substantial length of time or distance. Wow, did that effort exhaust my quad. Even the smallest rise would reduce my pace to a crawl after a while.

I have 4 pairs of Keywin pedals, so I am unsure of the exact age or milage on this pair, but my WAG would be that this pair was well over 10 years old and had at least 25,000 to 30,000 miles on them. Maybe even higher use that that?!.

I am wondering about the longevity of my other pairs. Does anyone on this forum replace pedals just because they have a lot of miles on them? Would like to hear thoughts.

Lee


Last edited by LeeW on 5/4/17 8:08 AM; edited 1 time in total

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/4/17 7:41 AM

Still using a 20 year old pair myself. Glad you did not get hurt seriously..

Still my main pedals, one ti and 2 chromo pairs. Since late 90s I just lost another right cleat. That is the 4th in that time. Which is pretty amazing really. Well, I should say the 4th new cleat put on, which really mean 3 failures in all that time of a lot of rolling. Although from 2006 to 2009 my knee had me being a non cyclist in term of the use my Keywin were enduring..

Here I click in and out a lot more than years past as my main routes have a lot more stops/crossing and crosswalks etc than both NJ and TN.


Last edited by Sparky on 5/4/17 9:38 AM; edited 2 times in total

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KerryIrons
Joined: 12 Jan 2004
Posts: 2816
Location: Midland, MI

5/4/17 8:57 AM

Grain failure

Most likely a grain failure where the metal had large grains form and so became weak. Not likely a design flaw but I would be inspecting my other pedals very carefully at the failure point to see if cracks were forming. I've had pedals last well over 100K miles and absent a serious design failure (stress riser built in, poor metal choice, etc.) there is no reason for such a failure.

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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/4/17 10:12 AM

CORRECTION

I was examining my pedals this morning and a correction is in order.

After weighing the failed pedal & axle, as well as the unbroken pedal, I came to realize the pedal set had the chrome moly axles.

Over the years, I had purchased 2 sets of Keywins with the chrome-moly axles and 2 sets with the ti axles. I thought I had the ti-axle versions installed on this bike, but I was incorrect.

In any case, I'm inspecting my pedals with a magnifying glass (best I can do at the moment).

Lee

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/4/17 10:21 AM

I got a new set last year, from someone here NIB. Excuse my memory, but who here is in the Bahamas. They were mailed from there. ;)

I think I will magnifying glass my two older sets as well. I am petty sure my one Ti pair is my oldest and most used/miles.

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dfcas
Joined: 11 Jan 2004
Posts: 2348
Location: hillbilly heaven

5/4/17 1:20 PM

There's a reason most ti pedals come with a weight limit. I would relegate old ti pedals to trainer duties at most, or more likely throw them out.

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/4/17 2:08 PM

I was surprised he said the Chro-Mo set is the axle that broke and not a Ti one...

FWIW, I do no think Keywin ever put a weight limit in the Ti pedals. These I think where first made for velo as well.
My sets came with the locking pins for track...


Last edited by Sparky on 5/4/17 7:12 PM; edited 2 times in total

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dfcas
Joined: 11 Jan 2004
Posts: 2348
Location: hillbilly heaven

5/4/17 6:04 PM

Yeah, he thought it was ti in his original post, then corrected it later. I still am scared of ti spindles.

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Rickk
Joined: 01 Jun 2004
Posts: 473
Location: Montreal

5/4/17 8:47 PM

I also switched over to Keywin pedals about 7 yrs ago, on my "newer" bike, and kept old-school Look and Ritchey pedals on 2 older, commuter and rain/winter/slush bikes.

Not sure if I have the Ti or ChroMo axles on the Keywins; however I have more than 35K kms on them.

The axles never broke on any of the pedals, but thanks for the headsup Lee and Kerry - will check them closely.

+1 re. dodging the bullet and not crashing.

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dddd
Joined: 11 Jan 2004
Posts: 3084
Location: NorCal

5/4/17 11:15 PM

As with any failure of seriously lightweight parts, my first thought is of the usage and of how big is the rider.

I've seen more than one LOOK pedal that has failed and not the ti ones, but perhaps crashed on at some point?

We might continue riding pedals that have been crashed on, and if anything we might tend to become more trusting of them as time went on, though failures can propagate over time and pedals do not become less prone to failure over time (usage).

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/5/17 8:56 AM

Well, we have had the conversation over the year about how long handlebars should be allowed to stay on before replacement. IIRC, that was for AL bar in those conversations and for the lighter varieties. [Prima 199 etc)

I do not recall any collective opinion(s) regarding carbon bars, seat posts, and never seen anyone here say I toss my pedals after x years/miles. And more inportantly carbon steer tubes.

I have taken to not using my 20 year old bars by justifying new, mainly for the much shorter reach the newer ruff has. Similarly I have replaced seatposts, again mainly for less offset.

2 of my 3 keywin sets are 18 years old probably. Now I am thinking about that. ;) And how I weigh 20 lbs more than then as well..

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Nick Payne
Joined: 10 Jan 2004
Posts: 2258
Location: Canberra, Australia

5/5/17 7:56 PM

@LeeW - I think I still have a spare pair of virtually unused standard length Keywin axles somewhere - I ride heels-in toes-out, and so I would purchase the 6mm longer axles and swap out the standard ones. If I can find them, you're welcome to them to fix your pedals.

E-mail me @ nickDOTpayneATinternodeDOTonDOTnet if you're interested.

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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/6/17 8:59 AM

Ok, rider weighs about 160 pounds in prime cycling season; closer to 165 during the Winter months.

I did initially believe the failed axles were ti, but when I weighed them, they came in at 124 gms per pedal, which corresponds to the spec for the chro-mo axles models. Then, I tried the magnet test and sure enough, the snapped off axle stuck to the magnet.

It is an interesting looking failure. If I knew anything about failure analysis, there is probably a conclusion to be made.

Thanks for the offer Nick. I am still debating what I might do.

Lee

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/6/17 9:28 AM

NM

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KerryIrons
Joined: 12 Jan 2004
Posts: 2816
Location: Midland, MI

5/6/17 11:39 AM

Fear of failure


quote:
I still am scared of ti spindles.


It's all about design and manufacturing quality, not the material. I use Campy ProFit Record pedals with Ti axles. 120K road miles (plus roughly 34K roller miles) on the first set. No issues. Over 50K miles on the second set with no issues. My limited knowledge of metallurgy suggests that steel with poor grain structure is a more likely failure candidate than Ti. Obviously you can under-design anything, so it's more about knowing/trusting the company.

Lee, can you describe the "interesting looking failure"? If you see large crystals in the metal then you are seeing the grain boundary failure I talked about. If you Google the term you will surely see some images that will show you whether this is what happened to you. If that is the case then it was a manufacturing issue such that the forging of the axle resulted in the grain boundary issue.

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/6/17 11:40 AM

"Lee, can you describe the "interesting looking failure"?"


Feel free to send my any pics to host and post in thread if you like...

coupekiss AT gmail

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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/6/17 6:58 PM

Sparky, I'll see what I can capture with a camera. May be hard to discern on a non-professional photo.

Thanks,
Lee

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/6/17 10:20 PM



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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/7/17 5:50 AM

Thanks for posting, Sparky.
I did the best I could with an older i-Phone camera. My Canon with macro capability is dead at the moment. The photo of the pedal body did not come out as sharp as hoped for.

In looking at the snapped off piece of the axel, the left side has a grayish, even texture similar to a very-fine sandpaper, whereas the right portion is shinier, irregular, and sticks up like an irritated wart. The dividing line between the two areas could have been drawn with a straight edge.

Kerry, that's what I mean by "interesting looking".

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Sparky
Joined: 08 Dec 2003
Posts: 15361
Location: Portland, OR

5/7/17 11:35 AM

Inspection in the case of your keywin I doubt could have been fruitful.

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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/7/17 3:10 PM

Sparky, I do believe you are correct.

The fractured surface was essentially flush with the bearing surface, which lies 1/4" or so, inside the cylindrical hollow on the side of the pedal housing. Very doubtful I would have been able to spot any developing crack or failure.

Looks like there may also be a metal sleeve covering the axle material???

Lee

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Rickk
Joined: 01 Jun 2004
Posts: 473
Location: Montreal

5/7/17 7:18 PM

What does Keywin think ?

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LeeW
Joined: 13 Jan 2004
Posts: 325
Location: near Baltimore, MD

5/9/17 6:46 AM

Rick, I have not presented it to Keywin.

I am sure they would need to examine the actual pedals to make any kind of failure determination (if they were even inclined to do that on such an old specimen) and I had not figured to box them up and ship them to NZ. I do not have any real documentation on how old the pedals may be or how many miles were actually logged on them; they could be anywhere from 10 to 16 years old and have anywhere from 25,000 to 40,000 miles on them and I am not making a claim against them.

It would be great to hear what their engineers might conclude though.
I thought I'd see what folks here thought first.

L

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