deathtokoalas
Member
as stated, the screw is not currently stripped. however, i will keep that concern in mind.
shimano fc-c103 bike arm crank
- Thread starter deathtokoalas
- Start date
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Ajax Bay
Guru
- Location
- East Devon
You have to unscrew the crank bolt (14mm (or 15mm) socket as @Ian H says), and stop whining about how weak you are. Leverage is your friend. Power tool is not the answer. You could lay the bike on its side and dribble some penetrating oil on the bolt head overnight.
The spline tool is not needed till you've got the bolt out and then pulled the crank with a crank puller tool. (I recommend you read through this linked Sheldon Brown article.)
Your BB is a 'closed' cartridge - I can see the splines, on its left end (obviously it's not the right end in OP image).
"There is NO locking screw on the outside of the closed cartridge." A cup screws in (normal hand) the left side of the BB shell to hold the BB in place - see the image @dave r shared.
"NO locking screw is damaged, broken or
Nothing has broken. Do what's recommended and you may well ride away with no expense except tools.
Overtightening may already have wrecked the crank, but whatever it still has to come off if, as you said in the OP, you have a loose crank.
View: https://www.youtube.com/watch?v=yBnYoYVTnlo
I'm "suggesting that, once [you] get the [crank] off with a crank puller, [you] will need another tool to retighten
But I warn you that getting the RH one out ('wrong' thread) will be harder than anything else. Installation takes minutes. Removal may take rather longer.
And one further complication (old Italian bike): the threads might be 'normal' on the RHS (others on here will know more about this). If it's a standard BSA threaded BB shell (the bike frame) then the RH cup unscrews the 'wrong' way (see Sheldon link below).
https://sheldonbrown.com/cribsheet-bottombrackets.html
https://www.sheldonbrown.com/tooltips/cartridge.html
Best of luck (and just in case it makes any difference to you) I probably do this about once a quarter on various bikes including ones older than yours.
Last edited:
T4tomo
Legendary Member
If one looks at the evidence:
- picture of modern Sq BB and alu crank
- no further photos for fear of giving anything away
- claims of exotic italian BB when evidence suggests that's completely incompatible with other evidence
- excessive obfuscation
- the OP quite literally talking bollox
deathtokoalas
Member
ugh.
i have not tightened the crank, so how could i have overtightened it? i attempted to loosen it and could not do so because it wasn't loose and, perhaps more importantly, because i'm not very strong. i was eventually able to unscrew it. the bolt is not damaged and has already been removed with a 14 mm ratchet. the thread is not stripped. as mentioned, i may have to bring it in to the shop just to find somebody strong enough to screw it back together, as i will not be able to do so myself; if i try to screw it back together and can't because i'm not strong enough, then i will have a loose crank arm because i can't tighten it back together.
i believe that this poster realizes he's agreeing with my observation that the issue is in the bracket itself rather than the arm, but wants to be superior and dominant and argue about semantics and technicalities instead of be reasonable and cooperative. i have told him repeatedly that the picture he has provided does not describe the system i actually have and he will not listen, and is instead repeating himself to assert control over the situation; attempting to provide information that is different than that determined by the poster is interpreted as a challenge to his authority on the forum, rather than as an attempt to constructively solve a problem. rather than work at solving a problem together, he wants to present himself as an authority that can provide instructions. i don't accept the concept of authority and am not going to follow instructions, when provided. rather, i will seek information elsewhere.
i think i've collected enough information as i can from this forum. some of it was useful. most of it was not. i do appreciate the responses, even when they have not been helpful.
my conclusion is that i will need to independently determine the type of bottom bracket after i've independently determined the type of crank puller required and succeeded in removing the arm. the reason i came here was to determine what part needed to be replaced and this is still not entirely clear. i was hoping i could just replace a locking mechanism. i suspect that i will determine that the bottom bracket is somewhat unusual, as it is neither similar to the ones being suggested to me (which are a more recent technology than the one used in the bicycle) nor is it exactly the bayliss type that it appears to be more similar to, as it is a little too new for that. i don't know what was intermediate between the bayliss and closed systems. i do think the system is more similar to the bayliss because i do think something fell off of it, perhaps a cap of some sort. the poster vehemently disagrees with that assertion, but i don't think that disagreement is grounded for the reasons i've previously posted - i am quite sure something has in fact fallen off. i will not be able to determine if i can replace it until i get the arm off.
regardless, the poster and i clearly agree that the actual issue that needs to be resolved has to do with the bracket not connecting snugly to the frame. the information about the spindle moving freely in the socket was central to realizing that. the poster has suggested that i may be able to fix this by utilizing a tool that tightens the bracket, so that it fits more snugly into the frame, which is the equivalent idea to inserting a locking mechanism in the appropriate transfer of technology. this discussion has helped me understand and realize the historical evolution of the bottom bracket and helped me better frame (ahem) the way the mechanism might or might not work, depending on what is actually installed. i did not previously have the knowledge base to put those considerations into perspective, so the discussion has been useful in that sense. i will need to verify or debunk the poster's claim once i have removed the arm, but it is a hypothesis i will keep in mind as i remove the arm and learn what the bracket type is. i do hope that that is the case, and that particular and singular insight is indeed of some utility to me.
approaching this incrementally means i now need to understand what the right crank puller is, and if a universal crank puller is actually universal and worth the expense, given that i may need to do something similar on other bicycles again in the future.
i have not tightened the crank, so how could i have overtightened it? i attempted to loosen it and could not do so because it wasn't loose and, perhaps more importantly, because i'm not very strong. i was eventually able to unscrew it. the bolt is not damaged and has already been removed with a 14 mm ratchet. the thread is not stripped. as mentioned, i may have to bring it in to the shop just to find somebody strong enough to screw it back together, as i will not be able to do so myself; if i try to screw it back together and can't because i'm not strong enough, then i will have a loose crank arm because i can't tighten it back together.
i believe that this poster realizes he's agreeing with my observation that the issue is in the bracket itself rather than the arm, but wants to be superior and dominant and argue about semantics and technicalities instead of be reasonable and cooperative. i have told him repeatedly that the picture he has provided does not describe the system i actually have and he will not listen, and is instead repeating himself to assert control over the situation; attempting to provide information that is different than that determined by the poster is interpreted as a challenge to his authority on the forum, rather than as an attempt to constructively solve a problem. rather than work at solving a problem together, he wants to present himself as an authority that can provide instructions. i don't accept the concept of authority and am not going to follow instructions, when provided. rather, i will seek information elsewhere.
i think i've collected enough information as i can from this forum. some of it was useful. most of it was not. i do appreciate the responses, even when they have not been helpful.
my conclusion is that i will need to independently determine the type of bottom bracket after i've independently determined the type of crank puller required and succeeded in removing the arm. the reason i came here was to determine what part needed to be replaced and this is still not entirely clear. i was hoping i could just replace a locking mechanism. i suspect that i will determine that the bottom bracket is somewhat unusual, as it is neither similar to the ones being suggested to me (which are a more recent technology than the one used in the bicycle) nor is it exactly the bayliss type that it appears to be more similar to, as it is a little too new for that. i don't know what was intermediate between the bayliss and closed systems. i do think the system is more similar to the bayliss because i do think something fell off of it, perhaps a cap of some sort. the poster vehemently disagrees with that assertion, but i don't think that disagreement is grounded for the reasons i've previously posted - i am quite sure something has in fact fallen off. i will not be able to determine if i can replace it until i get the arm off.
regardless, the poster and i clearly agree that the actual issue that needs to be resolved has to do with the bracket not connecting snugly to the frame. the information about the spindle moving freely in the socket was central to realizing that. the poster has suggested that i may be able to fix this by utilizing a tool that tightens the bracket, so that it fits more snugly into the frame, which is the equivalent idea to inserting a locking mechanism in the appropriate transfer of technology. this discussion has helped me understand and realize the historical evolution of the bottom bracket and helped me better frame (ahem) the way the mechanism might or might not work, depending on what is actually installed. i did not previously have the knowledge base to put those considerations into perspective, so the discussion has been useful in that sense. i will need to verify or debunk the poster's claim once i have removed the arm, but it is a hypothesis i will keep in mind as i remove the arm and learn what the bracket type is. i do hope that that is the case, and that particular and singular insight is indeed of some utility to me.
approaching this incrementally means i now need to understand what the right crank puller is, and if a universal crank puller is actually universal and worth the expense, given that i may need to do something similar on other bicycles again in the future.
Ajax Bay
Guru
- Location
- East Devon
I am intrigued what the OP does in real life and how they leverage the knowledge of others to help them along that windy path. I can't decide whether hutzpah or hubris is the more useful concept.
Approaching this incrementally then:
I've shared a link to "the right crank puller" above. a crank puller,
To all intents and purposes this universal crank puller is universal (thread diameter 21mm) for square taper cranks.
If the OP wants to remove the crank from the BB spindle they'll need that.
Let us know when you managed that (takes seconds) and whether the spindle waggles. Maybe worth counting the number of splines in the BB and letting us know: perhaps it's an esoteric twentieth century Italian design previously never seen.
Approaching this incrementally then:
I've shared a link to "the right crank puller" above. a crank puller,
To all intents and purposes this universal crank puller is universal (thread diameter 21mm) for square taper cranks.
If the OP wants to remove the crank from the BB spindle they'll need that.
Let us know when you managed that (takes seconds) and whether the spindle waggles. Maybe worth counting the number of splines in the BB and letting us know: perhaps it's an esoteric twentieth century Italian design previously never seen.
Smokin Joe
Squire
- Location
- Bare headed cyclist, Smoker
-> definitely a troll on a wind up
Without a doubt.
Fastpedaller
Über Member
Nah - there were previously 2 cotter pins which have also gone AWOL 
