square taper bonded to crank arms I have had a terrible time trying to remove crank arms from the square taper spindle. The tool used correctly just was forced out and stripped the threads. The left-hand side was about half off and I managed with some cutting to get it off. The drive side with hammering and cutting and even drilling so far has not yet been removed. On closer inspection inside the interface after some cutting, it seems that the two metals steel spindle and aluminium crank arms have almost been bonded together. What causes such a thing to occur???
Is it dry mounting? overtightening with pneumatics? I have noticed this is a feature on decathlon bikes as even removing the crank arm screws was very difficult and involved power tools. Is this a common flaw of the square taper system or is it an incorrect mounting procedure by the manufacturer? If I am to attempt to stick with this system and replace the crankset do I use anti seize mounting paste in future or grease or abandon such system for the external bottom bracket ie hollowtech.
You just need to use a thin layer of grease to prevent bonding between steel and aluminum. Also if you’re having great difficulty when removing the crank arms, spray some liquid wrench in there and wait. Make sure that the puller is fully screwed onto the external crank arm threads to avoid stripping as opposed to partially screwing them on. Finally, remember that force over time means that applying less force over a greater period of time is equivalent and often greater than a large amount of force applied all at once I.e. strong arming. What that means is that you can set up some tension on the puller and leave it, and just keep applying a little more tension if it still won’t budge. Almost like magic, it will give way eventually.