9. How to Replace Cotterless Crank Arms
Crank removal and installation procedure on a square-spindle, sealed bottom bracket.
This tutorial will demonstrate how to remove and install square-spindled crank arms. I’ve based this tutorial on cranks attached to a sealed cartridge bottom bracket. I’ll cover the loose-bearing style in a future tutorial.
To remove the bolt, you’ll need either an 8mm allen key or 14mm socket wrench. To remove the crank arms, you’ll need a crank puller, a 16mm open-end wrench, and an adjustable wrench. If possible, a torque wrench should also be used for tightening.
In order to safely remove the right side, you’ll have to shift the front derailleur onto the smallest chainring, and then carefully remove the chain and rest it on the bottom bracket, so that it doesn’t interfere with the crank arm removal.
Using the crank arm for leverage, loosen and remove the tightening bolt with your allen key or 14mm socket wrench. Be careful not to skin your knuckles on the chainring teeth.
Before using the crank puller, make sure it is fully extended so that the internal driver does not extend past the external threads.
Note: If crank threads are damaged, there are a few solutions at Park Tools.
Carefully thread the external threads of the crank puller clockwise into the crank arm. Avoid cross-threading, which will damage the crank and prevent future removal.
Once the crank puller is fully threaded, place the adjustable wrench on the external flats and turn the internal driver clockwise until it stops. Turn the driver clockwise using a 16mm wrench, until the crank arm pulls free of the spindle. Repeat the same process to remove the left crank arm.
Before re-installing the cranks wipe both the square spindle and the crank’s spindle fitting to make sure there is no dirt or grease on either surface.
Now slide the right crank’s spindle fitting onto the spindle. Before installing the bolts, grease under the head and along the threads of both bolts. Thread the bolt all the way into the spindle threads and torque the bolt to about 35 foot-pounds, or 420 inch-pounds.
Set the chain back on the chainring and repeat the same installation procedure on the left side, making sure the crank arm is pointing opposite the right side.
First of all, sorry if I need a bit of explaining - first bike I've owned since I was a kid and I've never done repairs. The other day I was biking to work when I took a stroke forward on the right and the pedal just slipped down. The pedals are now at similar levels (instead of opposite as they should be), making my bike unbikeable, sadly.
I have no idea what the problem is, but there were a few symptoms (I think) before this happened. There's been a clicking noise for a while whenever I take a stroke forward, and the other day I had a bit of a wipe out. ... Read more >>
My MTB has a riveted triple ring chainset/crankset and I need to replace it. It is a Suntour SR 180 XR with 24/34/42 teeth. My bike is 21 speed.
1 : Is it in any way feasible to drill out the rivets on the chain rings and replace with discrete chain rings?
2: I have looked online to see what is available in cranksets. The specs of some products indicate that they are suitable for 9 speed. So does the crankset have to match the rear sprockets? Does this have something to do with chain ring spacing?... Read more >>
Need some 1/2inch clipless pedals for a single speed project. Any ideas?... Read more >>
I want to disassemble and rebuild a set of crank brothers pedals. What sort of tool is necessary? I presume a tube spanner would be necessary and the nut looks about 9mm?... Read more >>
I got a bike about a week ago for $15. I was going to use it for parts (for another bike I have), but after examination (and because the rims were the wrong size), I've decided to repair it instead.
Apparently, this specific model crank set has the crank arms separate from the gear assembly. And the left crank arm had stripped out the thread and square peg which it had been fastened to. The entire rest of the bike is in excellent condition, though I'm planning to replace the brake pads.
My idea is to drill a hole through the pe... Read more >>
This is a vintage Raleigh Spirit which i found in a dumpster. The wheels were flat ( I thought they were junk but I guess they're in great almost new condition) the rear break mechanism was missing and the rear break wire was rus[attachment=4548][attachment=4549]ted off. I fix these things and I few other small things. I have the fenders which I have yet to install. My issue is with the pedals, which were loose. I tightened them but they worked loose and after doing this twice, the bolt on the right crank completely broke off with t... Read more >>
Hi, just bought a road bike second hand and needed to change the pedals as I don't have the clip in shoes. I can't for the life of get the right Hand pedal out assume the threads have crossed. S tbeasy to resolve I assume a bike shop can drill out but worried it will damage the existing threads.... Read more >>
Hello to all. We just got those folding bikes and they are great. We love them. Thing is my left pedal clicks now and I can feel the vibration right into the middle of my foot which is quite irritating.The bikes are brand new but bought from a couple that never rode them. Just bought them on a whim. They had them hanging in their garage for two years without using them.
Any help would be appreciated.Thanks
Elle... Read more >>
Just brought a Specialized Rockhopper 2012 (A*) off ebay, only to find that the pedal on the right hand side, attached to the crank, was cross threaded and has completely threaded the Crank arm.
Could someone please tell me if the crank in the link below (B*) would fit my bike or if not, could tell me what would please?
I've been searching for some time but I am getting stumped at not knowing if I need a Square or Octalink fitting.
I hope this makes sense to people, as I am just going around in circles trying to find out.
Thanks for yo... Read more >>
I've been manufacturing my own crankset and have come to pretty much the only thing I can't do easily which is tapping for the pedals. I've been told that the taps from Park Tool are designed only for chasing dinged threads versus full treading which is what I am doing. I cannot think of any other alternatives since 9/16-20 is a special size, especially a left hand.... Read more >>
I was wondering if anybody knows how to install a 1980's model Raleigh crank arm. It fell off of my friends bike while he was riding. The square bolt is still attached to the bottom bracket. Any help is appreciated.
[attachment=4272]... Read more >>
I plan on buying a Schwinn Meridian and changing the front crank/sprocket assembly to a 3 gear and adding a front derailleur (and a rear derailleur - to maintain tension only) The 3 gear sprocket assemblies I have are all from bikes with a 2" diameter X 2-5/8" length sprocket tube. Does anyone know the size of the Schwinn Meridian sprocket tube? Whatever crank set I use I will be using the bearing cups that came from the same set.
I am doing this mod because I want to be able to shift to a smaller drive gear when pedaling uphill (I am 65 years old) and changing the intermediate as... Read more >>
Been trying to remove the cranks in order to replace the bottom bracket, after much effort I managed to remove one side, however despite being careful the thread inside the other one has 'rounded-out', meaning the allen key just spins round. There's not much room to drill a bigger hole or anything like that, but I can't figure out how to remove the darn thing now. Any ideas?
Cheers... Read more >>
Hello guys, I have this problem with my bicycle.
Lately, when i start pedaling and driving, I hear some weird noise coming from my cranks, pedals or somewhere near.
It's not clicking sound, I can't even describe it with words.
If you know what is it, help, if you don't know what sound could it be, I can record it.... Read more >>
I got a Cannondale F900 SL from a friend and it is missing something in the left crank.
I want to get it fixed as soon as possible but don't know what I need to buy or how much it would cost.
It is a hole on where the crank meets the frame, and the crank on that side is loose. You can see through the hole.
I attached a picture, and the area that I am talking about is circled.
Thanks for your help.
-Joshua... Read more >>