In the past for stubborn pedals I have removed the crank and placed on the floor with the spanner/Allen key with extender flat to the ground and stood on the crank. Usually gets it off. You might need to bounce a bit on it but body weight is usually enough so long as the tool is in tight and can’t round off.
Heat is also a winner.
Also trying to undo it in the correct direction. Guilty of not doing that a couple times.
In the past for stubborn pedals I have removed the crank and placed on the floor with the spanner/Allen key with extender flat to the ground and stood on the crank. Usually gets it off. You might need to bounce a bit on it but body weight is usually enough so long as the tool is in tight and can’t round off.
Heat is also a winner.
Also trying to undo it in the correct direction. Guilty of not doing that a couple times.