Loose Cranks

Bocaj1994

Bocaj1994

Likes Dirt
Hey. Lately my cranks have become loose when i ride they start to wobble and sometimes fall off. I'm not sure if it is a problem with the Cranks or the BB anyway i could only get 1 photo before my camera battery ran out.

IMG_3062.jpg

I will take my bike into the shop to get repaired but i would like to know what is wrong with it beforehand.
 
K

kjparker

Likes Dirt
is the bolt / nut that hold them tight?

You may have damaged the square taper inside the crank arm. If that is the case, it's an easy and cheap fix, which you can do yourself.

You just need to remove the offending arm (you said it fell off) and put the new one you bought from the LBS on. Just take the old one down, and ask for one the same length.

Get a new bolt from the lbs while your there, I like the hex ones, and do that mofo up as tight as you can. Your done.

Edit:

is it both sides that fall off?
 
JSPhoto

JSPhoto

Likes Bikes and Dirt
Like has been said above, I would say teh taper on your crank is knackered, this will cause the arm to become loose and wobble the bolt out, to be safe its probably best to get a new bolt. My cranks used to do this as well, they were ISIS cranks but same problem. I found the entire inside of the crank arm was knackered and the taper was gone.
 
K

kjparker

Likes Dirt
without seeing it, i'm only guessing, but yes, probably the bolt and crank arm.

Look inside the taper on the crank arm. If it looks damaged in any way, then it's time for a new one
 
Bocaj1994

Bocaj1994

Likes Dirt
kjparker said:
without seeing it, i'm only guessing, but yes, probably the bolt and crank arm.

Look inside the taper on the crank arm. If it looks damaged in any way, then it's time for a new one
Click to expand...
If i could find my dads socket wrench i will take a pic.
 
K

kjparker

Likes Dirt
Yep. Fubar. Needs to be replaced

Check the bottom bracket as well. Is the spindle damaged at all? Shouldnt be, but you dont want to damage a new arm...

If it isnt damaged, then simply take the damaged crank to the bike shop, and buy a new one and bolt.

Simple and cheap fix.

What kind of bike is that anyway....
 
K

kjparker

Likes Dirt
why replace both when only one is damaged?

Wouldnt expect a generic crank to be more than $20 or so, and a few dollars for a bolt....
 
Bocaj1994

Bocaj1994

Likes Dirt
kjparker said:
why replace both when only one is damaged?

Wouldnt expect a generic crank to be more than $20 or so, and a few dollars for a bolt....
Click to expand...
Because my cranks are to long and when i ride i sometimes kick roots and scrap my shows on the ground

EDIT: They are around the 200mm mark
 
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Tazed

Tazed

Likes Bikes and Dirt
Bocaj1994 said:
Ahhh Sarcasm??
Click to expand...
No, I meant it. I'm really enjoying the posts.

Ok, here's your problem: the crank arms are ruined at the taper.
This is because you let the bolts get loose, not the other way around.
You need new arms and need to keep the bolts torqued up correctly.
Use a mild threadlocking compound (Loctite blue) on the steel crank bolts if you need it, but they should not work loose if installed correctly.
 
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Bocaj1994

Bocaj1994

Likes Dirt
Okk my dad didn't listen to me when i said what was wrong so he tried to put the crank back on and cover the bolt with Loctite. He found out that the reason the bolt was coming loose because the threading in the spindle was stuffed. So he used some tool to re-thread it(hes a mechanic) and the tool tip snapped in spindle. So what do i do now do i get a new BB?? and how much is a BB and what brand??
 
tidlibitz

tidlibitz

Likes Dirt
why dont you just get a set of husifelts(sp) cheap off here they usualy come with a bb
your lbs will be able to fit it for $20 or so
 
R

Rhianna

Cannon Fodder
tidlibitz said:
why dont you just get a set of husifelts(sp) cheap off here they usualy come with a bb
your lbs will be able to fit it for $20 or so
Click to expand...

This is Jacob i CBF turning my computer on and logging in so I'm using my sisters. My dad wouldn't allow me to buy off the internet.
 
mlsred

mlsred

Likes Dirt
you could use a quick dry metal epoxy to fill in the gaps loctite do a really good quick metal, thats only if you dont have enough money for new cranks and bb, new cranks would work much better than my bogan repairs :p
 
K

kjparker

Likes Dirt
you could also get a cheap cartridge bb from your LBS for around $30 (will come with the new bolts)

New crank arm ~$20

Plus labour.....
 
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