What is the name of this tool?

A ball joint remover is good for removing cranks.

one like this.

wd40, heating and hitting is not a good idea

wd40 can get in the bb and fuck it up
if the cranks are heat treated then you've ruined the process
and hitting something thats connected to bearings is self explanatory

bb will go into the bin anyway

just out of interest:

• how does wd40 destroy the bb?

• how would 80°C destroy a heat treatment?

this needs to be filled with picture of lfgss members...

bb will go into the bin anyway

just out of interest:

• how does wd40 destroy the bb?

• how would 80°C destroy a heat treatment?

wd40 will break down the lubricant in the bb and you'll be left with a lubricant that is to thin

how do you know it is 80°C?

as soon as you put heat into something that has been treated you start to change its properties
when hardening you heat the metal to the desired temperature then cool the metal down rapidly by quenching it, putting it in water or oil
once its been quenched the metal is extremely hard, but too brittle to use
so the second part of the heat treatment is tempering, taking the metal to a certain °C and letting it cool down slowly, by air or on a warm slab of steel, which softens the metal a little bit to take some of the brittleness away
so putting heat into it and then letting it cool down will temper it even further and effectively make the metal softer/weaker
by how much, who knows, only a rockwell hardness test can tell

Hmm, I usually stick to boiling (or close to boiling water) on ally cranks that I'd like to ride again for this very reason....

Dunno if cranks are usually heat treated, though- I thought decent ally cranks are mostly forged items??

wd40 will break down the lubricant in the bb and you'll be left with a lubricant that is to thin

Okay

how do you know it is 80°C?

as soon as you put heat into something that has been treated you start to change its properties (..)

I normally use a small IR thermometer in conjunction with the heat gun.

I understand your point but actually I know heat treatment only from chainrings and bmx cranks, so mostly cro-mo stuff and not alloy like those Miche cranks I was removing, so I guess I should be fine.

magnus,get 2 hammers support one under the crank and the with other hammer give the top of the stuck crank one good tap(dont bash the fuck out of it)

Its a gear puller Toolstation have a set of three for£15.00

Dunno if cranks are usually heat treated, though- I thought decent ally cranks are mostly forged items??

the op didn't say what type of cranks they are, or i missed it :)
i think its something like ally = forged, hot or cold, mostly cold because of the strength advantage which also means you can make things lighter
and cro-mo = heat treated
dont quote me on it though :)

Okay

I normally use a small IR thermometer in conjunction with the heat gun.

I understand your point but actually I know heat treatment only from chainrings and bmx cranks, so mostly cro-mo stuff and not alloy like those Miche cranks I was removing, so I guess I should be fine.

oh, ok
if you stayed at 80 you should be fine
again, don't quote me on it :)