Let's share some unpleasant mechanical failures we've had

I’m a bit burnt due the constant mechanical failures I’ve had last weeks on the road. I feel like a bit clumsy haha I tought this post would help me at the time we could share tips about this circumstances, maintenance, things to avoid…

I start:
3 weeks ago one of my rear wheel bearings died. I started my z2 ride at 30kph and speed slowly decreased, a big group passed me. I heard shrieking so I stopped, checked the temperature of the hub (hot) and turned around. Maybe I’ll arrive home, I tought… Error. At some point I was moving 350w at 15kph on flat without wind, few seconds after, #CLANK! My quick release skewer dissapeared, my wheel jumped out of the frame, broke my derailleur and derailleur hanger too.

After that I bought a new pair of winter wheels, changed all bearings, chain, casette, derailleur and a couple of cables.

2 weeks ago I go to ride with light rain. Tought it would be a good mentally strengthening session. My 4iiii powermeter dies. After all comprobations support offered to me to do, I saw a little water drop in the button cell housing.

1 week ago I see my brand new Vision aluminium front wheel turns like a drunk man. I stop and see one of the spokes sounds very different when I hit it with my index finger. 15km to home so hopefully I’ll arrive. No, 5km later the nipple finally loosens and the spoke goes free like crazy, hitting the fork.

Today. I have my wheel again revised and trued perfectlly. After 90km, when I finally arrive home I see theres another free spoke without its nipple.

Checked for cracks on the rim, nope, the spoke and nipple thread OK, spoke seems not stretched. I think I’ll buy a spoke tension meter and some blue loctite and repair it for myself… Ideas?

@enric97 sounds like you need to offer that bike up as a sacrifice to the bike gods and get a new one :exploding_head:

I had a screw fall out of my cleat, couldn’t unclip and fell shattering my phone. In the middle of the woods on a bikepacking trip 90 miles from home.

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That scrap of aluminium survived 3 crashes already, and lots of pathholes too haha.
With my record I’m afraid of doing a step to a new bike, a carbon one for sure. Maybe at 4.5w/kg :crossed_fingers:

I had that happen on a mountain bike ride. I fell numerous times that day. No fun not being able to clip out!

I flatted out of the winning breakaway in a road race - that sucked

Was going for a KOM on the ol’ single speed, fairly steep 250m hill with a LH curve near the middle.
As I was approaching the curve going ~30km/hr, my chain snapped.
The road turned, I kept going straight. For about 0.25 seconds until I smashed into the curb and went down.
The single saving grace was that I landed on the only small patch of grass along the entire road. Hit that first and then skidded onto the sidewalk.

I’m quite sure I provided some afternoon entertainment to those in the vicinity. I also had a good chuckle when I pulled up my Strava which recorded me rolling along the ground. :rofl:


I’ve had my computer bounce out of its mount, off of the road, and into a creek.

Also a stick got kicked up by my front wheel, get caught in my chain, and destroyed the rear derailleur- two different times.

Also, if pre-cellphone days- had 5 flats in one ride. No calling for help. Just patch the tubes over and over.

Had my seat tube snap down at the front derailleur. Took a few minutes to figure out where my sudden suspension was coming from. Still had 10 miles to ride.


I’ve been pretty lucky and mostly avoided mechanical issues that caused any injury, but I was about halfway through a 90km ride that needed ~1000m of climbing when my rear derailleur cable snapped and had to slowly grind my way through the second half in my smallest rear cog.

On the bright side, the steepest climb was early in the ride.

I was descending at about 40mph around a right hand corner when my front tire blew. I slid into traffic but luckily didn’t get hit. I broke my wrist, which required surgery. It took ~6 months for my wrist to work correctly again.
Now I run tubeless.

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Years ago I decided to warm up before an outdoor ride. I put my bike on the trainer but didn’t tighten it down properly. One pedal stroke and I’m down on the ground and the rear wheel had several twisted spokes.

So I’m ‘that guy’ who’s crashed on an indoor ride.


Big shout out to Exposure lights. Pre smart trainer, I used to do all my winter traning at night, in the dark, around local hilly routes. The Exposure Toro is so bright I got pretty confident on the back roads around me, even on descents.

On just such a descent, in pitch dark, doing maybe 35mph, not realising that I hadn’t clipped the light on properly (my Garmin was too close to it), it suddenly detached and went bouncing and spinning down the road beside me like a demented lighthouse, while for a few moments I rode at high speed completely blind with a big drop off just to my left (this is Scotland where we ride on the left!). Pretty scary but thankfully short-lived panic!

The light was pretty easy to find as it was still pumping out 1200 lumens, on the opposite verge. That was a few years ago. It has some pretty impressive chips in its CNC alloy body but has never missed a beat since. Quality product!


My most unexpected mechanical was my rear derailleur snapping, right in the middle of the alloy casting, while just spinning along on the flat, no gear changing, nothing. Just riding along, and…BANG!!

Thankfully I was riding a Ti frame and had a 32 spoke rear wheel. The damage was zero to the frame and the spokes were not too bad really. The mech hanger was obviously fine since it was the mech that snapped off half way up!

I was about 25 miles from home with no hope of rescue, so I split and shortened the chain, tied the mech onto the chain stay with a zip tie and rode home single speed.

I had intended to write to Shimano but I couldn’t be bothered with the irritation of most likely being told it was just normal wear and tear/user error/wrong set up or some such excuse.

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End of a group ride, last descent. Descent has two switchbacks, start sprinting out of the last switchback…


I thought it was my rear tire (I was worried it was getting old). It was not my rear tire. Luckily it only cost me skin, a helmet, and a derailleur hanger.

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Heh. My six-month old Ultegra FD failed on me last week: the input link to hold the cable had sheared off which lost all cable tension. At least I got stuck in the little ring. Again thought of seeing if I could claim a replacement, but assumed the above would be true.

There’s an easier way out of that one, involving tying a knot in the remaining part of the cable close to the derailleur, to set it somewhere else than the smallest cog. Using the limit screw is an alternative but less effective method.

In the old days of screwed-on freewheels. Up a steep climb (it’s the steep part of the Quebec UCI race), freewheel stripped clear off the hub. I was standing up, pushing up that hill… same effect as @Captain_Doughnutman‘s broken chain, except my family jewels had a brutal encounter with my top tube.

I managed to remove the freewheel, remove the spacer that was there, and use the couple of mm of unbroken threads on the hub to mount the freewheel back on, and slowly crawl back home.

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I was noodling about on a route I’ve ridden hundreds of times when a plastic bag caught my eye. It was a fall day and the wind was blowing in such a way that I found myself having my very own American Beauty moment, watching the bag float around aimlessly while pondering life’s existential quandaries.

Twenty seconds later, I find myself pulling said plastic bag out of my rear wheel and assessing the damage…one rear GP4000 was shot, an exploded rear HED Ardennes, an Ultegra rear derailleur, and worst of all a cracked rear triangle on my carbon frame…

The pleasant fall wind that was artfully blowing the plastic bag around decided to shoot said plastic bag into my rear wheel like a heat seeking missile, there was nothing I could do to avoid it.

The bag locked up my rear wheel and put me into a skid, catching my rear derailleur and simultaneously wrapping the cable around the triangle and cracking the frame.

Moral of the story, don’t ponder life’s existential questions. Just focus on riding your bike and all will be well with the world.


Road: I bought my whole Ultegra 8050 Di2 groupies, and the day before I had my appt to have it installed at the LBS, my mechanical shift cable had snapped for the rear, leaving me either with 52x11 or 36x11. I guess the cables somehow knew they were no longer needed and decided to give me a big parting “FU”. Aside from that I’ve only cursed roadside a few times when my GP4000sii tire sidewalls decided to succumb to small rocks on the road, and when I ran over a nice piece of glass with my brand new GP4000 a few months ago and ruined it beyond repair (the center moulding mark wasn’t even worn off yet!!!)

MTB: Bent RD hanger 3x, bent Eagle GX Derailleur Body and had to replace the entire thing, the air piston or whatnot in the fork was defective and was warranty replaced, Eagle GX chain snapped leaving me walking back to the car, and when the chain snapped it also bent some of my cassette cogs which had to be bent back in with a hammer and punch.

I was in a hilly 192-mile ultra race back in the old days of freewheels. Well, we were at about mile 120 when my "free"wheel froze, compelling me to ride the rest of the way pedaling, no matter what. That doesn’t sound like much but, when you’re used to coasting down hills and in packs, that extra energy adds up!

Still won it, though - first and only thing I ever got an outright first place in!


Warm up on the trainer for the State TT Title (20k)
Speedplay Pedal came apart… lots of swearing dam near threw the bike. Wife told me jam it on and ride anyway we are here.

Got on the bike, jammed my foot in, focused on my left leg pedalling. Finished with a Silver. Sometimes you have to put it all behind you and get on with it.