Other What's that horrible noise?!?! Did my rebuilt motor die?

RebornRider

Well-known member
May 31, 2019
638
661
NorCal USA
Near the end of a recent ride, my Levo suddenly started making a truly horrible noise when I pedaled. It sounded like metal scraping and it was loud! My first thought was that my recently-rebuilt Brose had a bearing failure. I could feel crunchy vibrations through the pedals. I began to imagine having a bit of an argument with the rebuild shop.

But motor assistance seemed normal, and the noise always stopped as soon as I stopped pedaling.

Cutting to the chase, it turned out to be a small stone REALLY stuck in the crank sprocket chain guide. I rotated the guide halfway around and finished my ride in silence and relief.

After I got home, it took some serious prying with a screwdriver to dislodge that stone.

My lesson is that I need to think of the most likely cause for an issue on the trail, not the most annoying or scariest cause.
 

steve_sordy

Wedding Crasher
Nov 5, 2018
9,033
9,481
Lincolnshire, UK
Easily done to scare ourselves silly with our expensive purchase.

A few weeks after I bought my first emtb (Focus Jam2), it suddenly became really hard to pedal, with heavy vibration. If I put some effort in it would go. So I stopped and walked the bike back to the car. I dropped it off at the Focus dealer. I was convinced it was a problem with the motor.

It turned out to be a loose motor bolt that had wound itself out into the chainring. The bolt was gouging into the arms of the chainring. Maybe another 100 yards and one of the arms would have sheared through! Yep, it was that bad! The chainring was toast and so was the bolt.

The thing is, when did I stop problem solving bikes? I could easily have resolved that and fixed it myself, if I had bothered to look!. But I convinced myself it was "the motor" and stopped thinking. I felt such a fool when the mechanic explained it to me. :(
 

#lazy

E*POWAH BOSS
Oct 1, 2019
1,408
1,537
Surrey
I’ve quit a ride cos of a knocking noise from the motor only to realise the chain guide had dropped and was rubbing the chainring/crank 🤪
 

salko

E*POWAH Elite World Champion
Aug 29, 2019
1,275
867
SLO
Had these stones in chain guide several times, each time I forgot about it and scares shit out of me 😅
 

brigcampbell

Active member
May 30, 2022
184
138
SoCal
Thought I cracked something in the rear hub with all the crazy banging so I rode home hoping to make it.

Oops


20231129_115621.jpg
 

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