Not a happy ending: Losing a crank mid-ride

Generally speaking, in cycling, there’s no good reason for bike grease to ever end up on your left leg.  The right leg, sure, it can brush the chain, chainrings, or any other number of parts related to the chain’s operation that may have small amounts of grease on them.  But the left leg – no, no reason.  There’s nothing on the left side of the bike that’s exposed with grease on it.  Thus, this is the story of how I got bike grease on my left leg.

I’ve been enjoying getting out and exploring my new home by bike, and in particular – meeting up with local triathletes (I’m sorry, there’s a ton of e-mails I haven’t finished responding too yet, I’m trying!).

Tonight I had a cycling date with a handful of local triathletes at the same place that I rode at on Sunday, which is about 5 miles from me.  Of course, getting there does first require navigating rush hour traffic on a time trial bike.  My bike handling skills are definitely improving quickly!


It took me about 30 minutes with traffic to get to the ‘loop’ (Longchamp) where I immediately found it packed with cyclists and triathletes alike.  Easily hundreds of folks, probably 200-300 at the time I first arrived.  Some groups were 30-50 people a pop.  For example, this local triathlon team was doing T2 practices repeatedly (bike a few loops, then run a loop).  I took this photo on my second lap, but the first lap looked like a legit transition area, just a huge lineup of bikes.


After I found the group of folks I was meeting up with (Hi!), we set out.  For the most part, we were just doing loops at varying intensities.  Sometimes we’d push hard, sometimes easier, sometimes jump into a different or larger group for a bit – but in general, just having a good time and keeping it civil.

After about an hour of loops, we were down to our last 1-2 laps. We had latched onto a particularly fast moving group of 15-20 cyclists and were pushing relatively hard.  Due to dodging an errant roller blading person, I ended up falling briefly off the back and into a different group for a few seconds.  The speed of the first group meant that I had to really throw down to bridge back across to them.  Figuring it was my last lap or two – I’d give it all I got and go for it.  Plus, I really enjoy the challenging of trying to bridge up.

At this point, the roadway was flat, straight and wide (oh, and basically no cars on the loop).  All I had to do was apply a bit of wattage and go with it.

So I did.


And about 3-4 seconds later I was solo at 30MPH bridging the gap quite nicely.  Another 10-15 seconds and I’d be back on and in the action.


And then…bang!

In an instant I lost an engine.  Or rather, my left engine – specifically, my left crank.  Gone, behind me (as a side note, when moving at that speed, things end up really far behind you rather quickly!)


ETOPS rules were definitely in effect now.

Astoundingly however, I was not on the pavement.  At the time that the crank broke off, I was pressing 594w.  Yes, a fair bit – but in the grand scheme of cycling and bike parts, not terribly much.  Plus, I had put out nearly 300w more than that earlier in the evening without catastrophe.


Anyway, I eventually one-legged back to go and find my crank.  And, as it turned out, a number of other parts as well.  And, despite all the folks who hate those one-legged drills – they do indeed have value!.

Thankfully, without cars, I didn’t have to worry about a Fiat running over my crank – but, it appears the pavement took care of the damage on behalf of Fiats everywhere.  Here’s what I found:


Note, the crank is in my hand – not on my bike.  My bike looked like this:


With the crank hitting the pavement at speed, it also split the left transmitter pod of the Polar/Look Keo Power System in half.  Straight up as if you took a meat cleaver to it.


The zip tie that attached the two together was also snapped, as was (strangely) the metal plate under the cleat.  It fell off:


Perhaps the understatement of the night came from the Polar CS600x head unit, which simply offered this advice to me:


Yes, good advice indeed.

Ultimately, I have no idea what happened.  But it’s clear that the Polar unit was really just an innocent victim in the whole situation.  I do know from talking to them previously that they can indeed replace just the transmitter units (which are the cheapest parts of the whole unit), similar to how Vector can replace just those pieces.  Ironically, the trial unit was set to go back on Friday. :( Thankfully, the Polar folks are good and were just happy I wasn’t injured

As for the source of the failure, I was present when the crank was installed onto the Power2Max (the bike had three power meters on it tonight; a Power2Max, a PowerTap, and the Polar pedals) – and it was installed per the torque values listed on the instructions sheet.  Plus, that was nearly three weeks ago now – with numerous rides since then.  Usually things that aren’t installed right fail pretty quickly, especially something like a crank which would rotate over 5,400 times in a single hour.

It’s a bit unclear to me as to what exactly broke, but the bolt that tightens the crank is definitely nowhere near as tight as required (since it can now just slip on/off) – almost as if that broke.  Ironically, that particular bolt/screw was an issue and replaced on an earlier installation attempt back in early June.

Now I’ve gotta find a local bike/tri shop here in Paris that can both speak English and be able to fix it – which may just be as simple as a new bolt, or much more complex.  I just don’t want it to happen again.  This time I got super lucky that I didn’t crash (most folks crash with the loss of a pedal/crank).  Thankfully I was seated at the time, which probably made the difference.

So there ya go – an answer as to how exactly I got grease on my left leg:


Thanks for reading – and an even bigger thanks to Seb and his wife who drove me home afterwards.  It would have been a very long walk otherwise.  And of course, thanks to all the other guys for a great night prior to that point – looking forward to the next ride!


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  1. Sorry to hear about the bad luck but Im t curious how come the pedal/crank didnt stick to your foot?(assuming your foot was clipped in at the time)

  2. BTW:Looks like an awesome place to ride and a good atmosphere too with all those cyclist/triathletes!

  3. The same happened to me. The root cause was a mis aligned crankset. It slowly push out the crank as it is turning sideways. Slightly. I had a cervelo r3 and the rotor crank was born mis aligned. The bike shop replaced mine with sram red for free.

  4. Hi Ray,

    I’ve had almost the same thing happen to me with a Power2Max on a Rotor crank. Mine was a Rotor Agilis. It turned out that the bolt on the left side crank turned a bit difficult (out of the factory). I used a torque wrench to tighten it. It indicated that I had used to right amount of torque. However, and this is the important part, I should have turned it more, because when I did that after having lost it during the ride, it started turning easier after a few turns, before going tight again. I’ve never had this problem since.

    I was lucky that the crank fell off while climbing Mont Ventoux at about 12km/h :-). The unluck part was that it happened while I was on vacation about 1000km from home, and the crank cap was nowhere to be found. Luckily my wife had told me to also bring my old standard crankset, so I was able to continue cycling after having changed cranks.


  5. That has happened to me before… I wasn’t to far from home, so I rode with with one leg… Not easy

  6. Not a crank but I did lose a pedal at speed out of the saddle that resualted in some summer ice skating on pavement. Glad that you stayed right side up.

  7. Parisians don’t shave their legs?

  8. Mark J. in Dallas

    You’re just too powerful for modern technology Ray…

    Lucky you didn’t eat asphalt. Nice save.

  9. It looks in one fo the pictures as there is a gap in teh crank, meaning the crank cracked?

  10. Had same thing happen in the middle of Ironman Pocono 70.3 last year. Must be an FSA, they have known issues with that. link to

    Upgraded to a DuraAce and no issues since.

  11. Maybe the Power2Max power meter was offended by your Quarq water bottle.

  12. So did the crack actually snap or just come off its mount on account of a bolt that was incorrectly tensioned?

  13. I’m not entirely sure to be honest. As others above have pointed out, it seems like this is a semi-common issue with the Rotor cranks. In looking carefully at the bolt, I can’t see any obvious cracking, however – it’s hard to tell.

    I’m headed back to the states Friday, so I’m bringing the crank-arm with me to try and see if a good bike shop can figure it out. My primary concern is that it doesn’t happen again. If you tighten to the spec, yet you have to tigthen beyond it and then again (as others imply above) – that seems fraught with failure potential. But maybe that’s just me. Personally, my only dog in this fight is ensuring that I don’t end up face-first on the pavement next time.

  14. When standing and coasting (if you do such a thing), do you have your right foot forward? If so, this will cause the left crank to loosen and fall off over time. This is a known defect of all the splined type 3 piece crank/bottom brackets. See link to

  15. @quindazzi: Interesting! I won’t necessarily stand and coast, but going over rough terrain I do partially unweight the saddle, and then the foot that’s forward depends on both habit and whether or not there’s a right or left bend ahead.
    Checked the crank nut on my GXP crank, and it needed about 1/4 turn to tighten… maybe a dot of blue or purple Loctite will fix this?

  16. Just to be clear- this effects only 3 the older style 3 piece cranks (separate left and right crank, bottom bracket with splines.) Looking at Ray’s pics a little more closely it looks like he may have the newer 2 piece style where the chain ring side is part of the spindle and the bottom bracket bearing are outboard. Hard to tell. I notice you didn;t post a pic of the interface between the crank arm and bottom bracket- do you have one.
    Also, forgot to say sorry you had a failure, and i’m glad you are okay

  17. Dennis

    Hi Ray,

    Sad news. The crank and other stuff can be easily replaced. Not the same with road rash and fractured or broken bones. Good to know you’re ok.

  18. HI Ray,

    I also use the 3d+ with a Power2Max. What’s strange about your failure is that the non-drive side came off. The NDS is already bonded to the axle from the factory. The bolt that secures it shouldn’t be opened at all according to the manual, so I would suspect there was something wrong from the beginning. The crank installation is done through the drive side.

    Good luck in sorting it out, I would reach out to Rotor directly.


  19. Hmm, in my case the drive side came bonded, not the NDS.

    I was hoping to sort it out this week in Seattle with some local bike shops – but none of them know what to do. So, back to France I go, will have to ring up Rotor. I believe they’re in Germany, so perhaps it won’t be too bad.

    Here’s a few more photos:

    link to

    link to

    link to

    I believe at this juncture I’m missing the “o-ring” that goes between the crank arm and the bottom bracket area. I have an extra cap. And of course, the nut on the crank-arm itself is questionable at this point in my opinion.

    Any thoughts are appreciated! In general, I’m putting this in the ‘pain in the butt’ category.

  20. Greg Caldwell

    Lost Rotor Crankarm – Had this same thing happen to me last night. Can you tell me what you did to keep it from happening again? The powermeter was a gift from my kids for father’s day and I hate not to keep using it, but I don’t want to end up face down on the pavement either. Thanks in advance.

    • Allan Urquhart

      This has happened to me on my last 3 x rides during long ascents where the NDS crank has come off.

      I was in Switzerland earlier this week so ended up having to buy a Shimano crank to get me going again – not a happy boy at all :-(