My brake rotor fell off!

[retroJIM]

I had an interesting mechanical failure today. Seems the bolts on my rear brake rotor had been gradually working loose and had fallen out one by one. I was cycling up a steep hill and suddenly heard a clatter and grinding noise as the last bolt dropped out and the rotor detached completely from the hub. How I hadn’t noticed earlier is beyond me, the only symptom was the brake was starting to squeal a bit.

I had to cycle back with just a front brake as I only had 1 bolt and didn't have a T25 bit. Never happened to me before and a surprise as the bolts all had blue Loctite and I'd used a torque wrench.

More regular mechanical checks required I think and maybe an excuse to upgrade the crappy 160mm Avid rotors

 

[mk one]

Lost rotor bolts too, regular checks as you say are recommended. I seem to have more bolts come loose on full suss bikes for some reason, not sure why though.

 

[mdvineng]

The squealing is vibration and this is what is loosening the bolts.

 

[retroJIM]

The squealing is vibration and this is what is loosening the bolts.

Indeed, another lesson learnt. I'd put it down to the calipers needing a clean.

 

[oliverracing]

Had a front disk detach on a rental bike about 6 years ago - luckily was doing ~10mph across a soft meadow as it locked the front wheel dead and threw me over the bars. Had just been bombing down a steep alpine switchback road and it seemed 5 bolts loosened/disappeared and the final sheered as I touched the brakes gently pulling to a stop to check the map.

Rental company tried to charge us for the damage (Front wheel/Forks/disc/caliper) until we threatened to release the footage my mate had from riding behind me - in the end they agreed to refund the rental on the condition we deleted the footage.

 

[retroJIM]

Had a front disk detach on a rental bike about 6 years ago - luckily was doing ~10mph across a soft meadow as it locked the front wheel dead and threw me over the bars. Had just been bombing down a steep alpine switchback road and it seemed 5 bolts loosened/disappeared and the final sheered as I touched the brakes gently pulling to a stop to check the map.

Rental company tried to charge us for the damage (Front wheel/Forks/disc/caliper) until we threatened to release the footage my mate had from riding behind me - in the end they agreed to refund the rental on the condition we deleted the footage.

I can see how it could be catastrophic if it happened on the front wheel. Sounds like you were very lucky!

 

[oliverracing]

Yeah, at the time I wasn't too concerned, more annoyed as lost a days riding, but looking back it could have been horrific.

To be honest my Uni riding days combined with alpine MTB trips had a fair few very close calls for me or my mates that I try not to think too much about. Top three being..
1) Total and complete brake failure coming down a gravel track into Buchs - was touring heavy so towing a trailer, reached ~65kph on the GPS but managed to find a small branching track heading up to the right that just about managed to take and knocked about half my speed off before I ditched as the path started to go back down. Walked away scratch free and bike only damage was a slightly buckled rear wheel and snapped bar end.
2) Mate ahead completely overcooked a corner on alpine singletrack, flying off to the outside - was a ~150m sheer cliff but luckily he landed in the only bush overhanging the edge in sight. We still get shivers when we talk about that togther.
3) I decided to take a shortcut while doing a section of the GR5 that included a Via Ferrata, at one point had bike strapped to back with 10kg of gear, on a ladder, when foot slipped and was only saved by the fact my bar end got caught in the steel cable of to the right, taking the majority of my body and bike weight while I scrabbled for grip. Was only a 5-6m fall to the ledge below but still hate to think how long I'd have been lying there as was very early season and hadn't seen anyone all day on that route, plus phone had died due to wildcamping without a battery pack (also why a took the shortcut as was going off sight/signs not my pre-planned map).

 

[Misha D]

I’m curious if you remember if your rotor was installed correctly- meaning were the splines pointing forward? I recently had 2 e-bikes come into the shop with ‘brake failure’ both had 6 screw rotors incorrectly mounted. I’m wondering if this can cause the screws to dislodge?

 

[madjh]

The solution:

 

[2manyoranges]

Glad you were OK

Daily:
BOLT CHECK

only I never do it.

what I DO do is jam on the brakes whilst standing in the car park at the START of a ride and rock the bike, and pay attention to any give, creaks, bumps and knocks. That has thrown up on occasion: loose saddle, loose handlebar, loose rotors, loose headset, cream-crackered fork bushings, worn wheel bearings, loose pedal, loose chainring, loose cassette (!), and other things which are loose/knackered.

Why I do not do this at the END of a ride and make a mental note of what I need to do before the next one is beyond me.

New daily check
Wake up. Check for stupidity and prevarication.