bicycle problem - any bike mechanics here? - Tilted Forum Project Discussion Community

Sion · 07-22-2003, 09:21 AM

ok, so some how my daughter has managed to bend the left side pedal crank on her bicycle. anyone know how to take one of these things off? it seems to be pressed on, so it looks like I'll need a gear puller type of tool, which I can borrow from work, but given the shape of the crank, its going to be a bit of a pain to use.

advice?

nowthen · 07-22-2003, 09:40 AM

A gear puller may work, they usually destroy the crank but I guess since it is bent this will not be issue, unless you are going to try and straighten it?

To get the crank off in one piece, you need a proper crank extractor. This screws in to the threads on the crank, and then pushes it of the axle. Here is the park version - http://www.parktool.com/tools/CWP_6.shtml,
but you can probably get a much cheaper unbranded version from your friendly local bike shop.

Hope that helps

Edit: Unless you are going to be using a crank extractor regularly (not very likely I would guess), probably your best option is just take the bike to a local bike shop and get them to take it off. They will probably only charge you a few bucks, might even do it for free if you buy a new part from them!

numist · 07-22-2003, 02:20 PM

seeing that the crank puller doesn not come with instructions (I used to sell them) another bit that may help is:

first, take off the cover that protects the inners of the crank. This is either a bolt requiring an 8mm allen or a set of holes that require a pin spanner, or a plastic cap that requires a flathead screwdriver that has a bolt underneath that needs a socket wrench (I forget the size).

That done, take your crank puller (make sure you bought the right one, they come in versions for square-taper (older than ~3 years for the expensive components, and most common components today use this) or splined (youll probably know this is you because your wallet probably stil hurts from buying the bike), and unscrew the nut on the handle until it is at the end of the tip. Make sure all the threads are greased well and thread the nut into the crank, handle still attached until it is finger tight (and at least 8 threads in to prevent stripping). Then twist the handle clockwise until you hit pressure, and push harder. The crank will come right off, generally without any sudden motions, so dont worry about your hand getting stuck.

To get them back on, just put the crank arm back on (make sure its on the right way) and tighten the crank bolt - a lot.

voila!

btw, the crank puller costs ~$15, and having a crank pulled at a shop costs $25 or so, so if your going to do it more than once, buy the tool, your already saving money

[edit] forgot to add this - if the crank is really that bent that you dont have the clearance to pull it with the correct tool, then take it to a shop, because if you try using a crowbar youll just damage the frame. The arm will need replacing and depending on how bad a shape its in, the bottom bracket may need help too....
[/edit]

theguyondacouch · 07-22-2003, 02:55 PM

Do you have a pic? is it a one piece or a 3 piece crank? If its a 1 piece crank, take off the rear wheel, take the chain off the sprocket. Then, take off the large nut with a pair of water pump pliers. There should be a washer, thats keyed into a slot on the crank. pull that off. ther should be another nut with 2 slots in it. Spin that a few turns with a screwdriver. take it off the rest of the way with your fingers. take out the bearings, and the crank should just slide out. Oh, and the nuts are all left hand threads.

Sion · 07-22-2003, 09:54 PM

I think some of you are confusing the crank arm (which is what is bent) with the sprocket.

In any case, I borrowed a three jaw gear puller from work today and was able to remove the crank arm very easily with it. Tomorrow I will take it in and get it straightened out (its only bent abot 5 degrees, just enough to smack the frame and kickstand when trying to pedal).

Oh and it was the kind with just a plastic cover over a 14mm nut that secures the crank arm to the axle shaft.

thanks for the attempted help anyways.

icy_ca · 07-23-2003, 08:37 AM

Oh and tell your daughter to stop dropping her bike.

theguyondacouch · 07-23-2003, 09:28 AM

Oh, it was a 3 piece then? I don't know much bout dem, sorry.

07-22-2003, 09:21 AM	#1 (permalink)
Sion Dumb all over...a little ugly on the side Location: In the room where the giant fire puffer works, and the torture never stops.	bicycle problem - any bike mechanics here? ok, so some how my daughter has managed to bend the left side pedal crank on her bicycle. anyone know how to take one of these things off? it seems to be pressed on, so it looks like I'll need a gear puller type of tool, which I can borrow from work, but given the shape of the crank, its going to be a bit of a pain to use. advice? __________________ He's the best, of course, of all the worst. Some wrong been done, he done it first. -fz I jus' want ta thank you...falettinme...be mice elf...agin...

07-22-2003, 09:40 AM	#2 (permalink)
nowthen Insane Location: Republic of Panama	A gear puller may work, they usually destroy the crank but I guess since it is bent this will not be issue, unless you are going to try and straighten it? To get the crank off in one piece, you need a proper crank extractor. This screws in to the threads on the crank, and then pushes it of the axle. Here is the park version - http://www.parktool.com/tools/CWP_6.shtml, but you can probably get a much cheaper unbranded version from your friendly local bike shop. Hope that helps Edit: Unless you are going to be using a crank extractor regularly (not very likely I would guess), probably your best option is just take the bike to a local bike shop and get them to take it off. They will probably only charge you a few bucks, might even do it for free if you buy a new part from them! __________________ "People are always blaming their circumstances for what they are. I don't believe in circumstances. The people who get on in this world are the people who get up and look for the circumstances they want, and, if they can't find them, make them." George Bernard Shaw Last edited by nowthen; 07-22-2003 at 09:43 AM..

07-22-2003, 02:20 PM	#3 (permalink)
numist Banned Location: UCSD, 510.49 miles from my love	seeing that the crank puller doesn not come with instructions (I used to sell them) another bit that may help is: first, take off the cover that protects the inners of the crank. This is either a bolt requiring an 8mm allen or a set of holes that require a pin spanner, or a plastic cap that requires a flathead screwdriver that has a bolt underneath that needs a socket wrench (I forget the size). That done, take your crank puller (make sure you bought the right one, they come in versions for square-taper (older than ~3 years for the expensive components, and most common components today use this) or splined (youll probably know this is you because your wallet probably stil hurts from buying the bike), and unscrew the nut on the handle until it is at the end of the tip. Make sure all the threads are greased well and thread the nut into the crank, handle still attached until it is finger tight (and at least 8 threads in to prevent stripping). Then twist the handle clockwise until you hit pressure, and push harder. The crank will come right off, generally without any sudden motions, so dont worry about your hand getting stuck. To get them back on, just put the crank arm back on (make sure its on the right way) and tighten the crank bolt - a lot. voila! btw, the crank puller costs ~$15, and having a crank pulled at a shop costs $25 or so, so if your going to do it more than once, buy the tool, your already saving money [edit] forgot to add this - if the crank is really that bent that you dont have the clearance to pull it with the correct tool, then take it to a shop, because if you try using a crowbar youll just damage the frame. The arm will need replacing and depending on how bad a shape its in, the bottom bracket may need help too.... [/edit] Last edited by numist; 07-22-2003 at 02:23 PM..

07-22-2003, 02:55 PM	#4 (permalink)
theguyondacouch salmon? Location: Outside Providence	Do you have a pic? is it a one piece or a 3 piece crank? If its a 1 piece crank, take off the rear wheel, take the chain off the sprocket. Then, take off the large nut with a pair of water pump pliers. There should be a washer, thats keyed into a slot on the crank. pull that off. ther should be another nut with 2 slots in it. Spin that a few turns with a screwdriver. take it off the rest of the way with your fingers. take out the bearings, and the crank should just slide out. Oh, and the nuts are all left hand threads. __________________ "Lick my frozen metal ass!"

07-22-2003, 09:54 PM	#5 (permalink)
Sion Dumb all over...a little ugly on the side Location: In the room where the giant fire puffer works, and the torture never stops.	I think some of you are confusing the crank arm (which is what is bent) with the sprocket. In any case, I borrowed a three jaw gear puller from work today and was able to remove the crank arm very easily with it. Tomorrow I will take it in and get it straightened out (its only bent abot 5 degrees, just enough to smack the frame and kickstand when trying to pedal). Oh and it was the kind with just a plastic cover over a 14mm nut that secures the crank arm to the axle shaft. thanks for the attempted help anyways. __________________ He's the best, of course, of all the worst. Some wrong been done, he done it first. -fz I jus' want ta thank you...falettinme...be mice elf...agin...

07-23-2003, 08:37 AM	#6 (permalink)
icy_ca Insane Location: Steel Town, Ontario	Oh and tell your daughter to stop dropping her bike. __________________ After all is said and done, more is said than done.

07-23-2003, 09:28 AM	#7 (permalink)
theguyondacouch salmon? Location: Outside Providence	Oh, it was a 3 piece then? I don't know much bout dem, sorry. __________________ "Lick my frozen metal ass!"