Bike Tyson
Guest
You need a 3 foot long allen key to get enough force to stop some FSA cranks from falling off
Left Crank Fell Off
- Thread starter Venod
- Start date
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You need a 3 foot long allen key to get enough force to stop some FSA cranks from falling off
Bike Tyson
Guest
My mate pulls out in the road in front of me in his Golf GTi, I am on my winter bike and have just changed the crank from triple to compact, I sprint up the side of him and am just about to overtake and my left crank leg falls off, I think there was a spacer on one side of the BB I had failed to remove, luckily my mate never saw a thing.
Dogtrousers
Kilometre nibbler
My second FNRttC I think.Lol what kind of moron would do such a thing?!
‘twas Friday 3rd Aug 2012, with a forced ride home due to Olympic train issues from Bri to Lon. Hard to believe that was almost 10 years ago!
Well, had this yesterday!
For the first time in my 25 years bicycle no car anymore.
Hobbled slowly between lotsa people (city summer fest), left crank felt loose, then just felt down hanging.
To first storyline my case in order to help pinning the cause:
Last april I discovered cranks showing play near axle.
Dealer diagnosis: bottom bracket replacement needed.
The old was an Octalink 1 type.
Dealer didn't find a spare in his stock, said he had to order them, could take a while due to you know, post lockdowns havoc.
I then asked to order a spare too.
But little over a week later, mail, I could come to replace it.
Apparently however, there was still a problem. I saw him inserting a thread creator/repairer tool in the eccenter module of the travelbike.
I assumed he cleaned the thread first, but when seeing him applying alot force, I started to wonder, and asked what was going on.
He answered that he had to increase the thread size in the eccenter to allow fitting of the new bottom bracket.
I then realized what was happening, but too late, since he already started doing it.
I told him that by doing this, he altered the standard of the bike, which could mean trouble later on, no answer, just looking.
Since it was too late anyway, he proceeded. It looked like a tough job, at some point the eccenter rotated in its frame hole, despite its two fixation bolts. Probably leaving some fat scratches on its outer surface.
Eventually, he got the job done, and I also took the spare with me, now in front of me:
Shimano
bottom bracket BB-5500
70 mm M36
118.5 mm
Numbered checkboxes 1 - 8 with 1 and 8 checked.
BB-5500 118 36 70
Since my experience with dealers so far was nearly entirely negative, meaning, I don't trust them a penny, in april already I decided to add such a big sized allen key to the tools bags I always keep in my bikes luggage.
That saved my ass yesterday from a 20 km walk home, holding a loaded bike at hand, since saterday late, all bicycle shops closed, and lotsa people but surely none with such an allen key.
The bolt didn't fall out, so I pushed the crank inwards, and tensioned gradually the bolt, I think I could give it 4 or 5 full rotations before feeling resistence. I decided to tension it as hard as I could with the short allen key, holding tissue on it to prevent it cutting in my skin. At some point heard a metallic sounding click, I still gave another push, and heard a second click, then I was unable to tension more.
On the way home, I stopped 5 times to try (re)tension the bolt, but couldn't, so it looked good.
I'm now not sure what to do. Fact is, the left crank all of sudden just came loose. That something to worry about, because of the material damage and accident potential. It is possible that splines got damaged yesterday, and that a next fall off is now easier to come by.
It's now just start of vacation. Possibly and likely dealer too. I have a spare bike but it's not as well equipped and I hate to build again over and back things like in april.
I could unscrew that bolt again and inspect the splines (if that is possible without undoing the other side too), but I rather prefer to not touch it.
I will for the moment continu check the bolt along the road now and then, but I have no clue as how many crank rotations it may need to get the splines shifting away from eachother enough to make it fall off again and eventual damage the splines further.
For the record, I have an older bike from this same dealer that replaced the bottom bracket now, that had an Octalink 2 (= Hollowtech 2?) bottom bracket, with external bearings and a pair next to eachother visible bolts towards the axle, where I thus never had this problem, talking about 15 years, it's that current spare bike I talked about here.
Several people in this thread recommend to check the bolts regularly, never had to do that on my old bike, but surely gonna start doing that now. In post 6, Venod stated "the left crank coming off allowed the shaft and crankset to move to the right.." so maybe my chainline has been changed, gonna check. Any other thoughts / advice?
Worth adding: the bike is a fixed gear, and I seldom use brakes, instead I resist pedals to slow down, so when I'm hobbling slowly between lotsa people, I push the cranks forward and back frequently, as many times as I need to accelerate and deccelerate, which is alot between lotsa people from lotsa directions / unpredictable. So the crank spindle mating surfaces then get stressed alot in both directions.
For the first time in my 25 years bicycle no car anymore.
Hobbled slowly between lotsa people (city summer fest), left crank felt loose, then just felt down hanging.
To first storyline my case in order to help pinning the cause:
Last april I discovered cranks showing play near axle.
Dealer diagnosis: bottom bracket replacement needed.
The old was an Octalink 1 type.
Dealer didn't find a spare in his stock, said he had to order them, could take a while due to you know, post lockdowns havoc.
I then asked to order a spare too.
But little over a week later, mail, I could come to replace it.
Apparently however, there was still a problem. I saw him inserting a thread creator/repairer tool in the eccenter module of the travelbike.
I assumed he cleaned the thread first, but when seeing him applying alot force, I started to wonder, and asked what was going on.
He answered that he had to increase the thread size in the eccenter to allow fitting of the new bottom bracket.
I then realized what was happening, but too late, since he already started doing it.
I told him that by doing this, he altered the standard of the bike, which could mean trouble later on, no answer, just looking.
Since it was too late anyway, he proceeded. It looked like a tough job, at some point the eccenter rotated in its frame hole, despite its two fixation bolts. Probably leaving some fat scratches on its outer surface.
Eventually, he got the job done, and I also took the spare with me, now in front of me:
Shimano
bottom bracket BB-5500
70 mm M36
118.5 mm
Numbered checkboxes 1 - 8 with 1 and 8 checked.
BB-5500 118 36 70
Since my experience with dealers so far was nearly entirely negative, meaning, I don't trust them a penny, in april already I decided to add such a big sized allen key to the tools bags I always keep in my bikes luggage.
That saved my ass yesterday from a 20 km walk home, holding a loaded bike at hand, since saterday late, all bicycle shops closed, and lotsa people but surely none with such an allen key.
The bolt didn't fall out, so I pushed the crank inwards, and tensioned gradually the bolt, I think I could give it 4 or 5 full rotations before feeling resistence. I decided to tension it as hard as I could with the short allen key, holding tissue on it to prevent it cutting in my skin. At some point heard a metallic sounding click, I still gave another push, and heard a second click, then I was unable to tension more.
On the way home, I stopped 5 times to try (re)tension the bolt, but couldn't, so it looked good.
I'm now not sure what to do. Fact is, the left crank all of sudden just came loose. That something to worry about, because of the material damage and accident potential. It is possible that splines got damaged yesterday, and that a next fall off is now easier to come by.
It's now just start of vacation. Possibly and likely dealer too. I have a spare bike but it's not as well equipped and I hate to build again over and back things like in april.
I could unscrew that bolt again and inspect the splines (if that is possible without undoing the other side too), but I rather prefer to not touch it.
I will for the moment continu check the bolt along the road now and then, but I have no clue as how many crank rotations it may need to get the splines shifting away from eachother enough to make it fall off again and eventual damage the splines further.
For the record, I have an older bike from this same dealer that replaced the bottom bracket now, that had an Octalink 2 (= Hollowtech 2?) bottom bracket, with external bearings and a pair next to eachother visible bolts towards the axle, where I thus never had this problem, talking about 15 years, it's that current spare bike I talked about here.
Several people in this thread recommend to check the bolts regularly, never had to do that on my old bike, but surely gonna start doing that now. In post 6, Venod stated "the left crank coming off allowed the shaft and crankset to move to the right.." so maybe my chainline has been changed, gonna check. Any other thoughts / advice?
Worth adding: the bike is a fixed gear, and I seldom use brakes, instead I resist pedals to slow down, so when I'm hobbling slowly between lotsa people, I push the cranks forward and back frequently, as many times as I need to accelerate and deccelerate, which is alot between lotsa people from lotsa directions / unpredictable. So the crank spindle mating surfaces then get stressed alot in both directions.
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