Here's a DIY with a sacrificial off-brand wrench - start at 2:16

Just went to do same change on my brand new Topstone. Same exact issue. Are they tightening these cranks with pneumatic tools?

I've never had any luck using a crank puller on crank arms. They always slip off. I've even tried slotting a piece of 1/4 inch steel to hook the puller to rather than the crank arm. Bent the flipping steel.

What I have used is a ball joint pickle fork. Brutal but the vibration from the hammer blows really helps break things free

Surprised no one suggested heat.

What might of worked is getting tension on the joint with the puller, heating the crank arm with a heat gun and using a punch and hammer to wack the side of the crank arm. Effective for tie rod ends, applies to crank arms as well

A cheap angle grinder or cut off wheel in a standard circle saw will save you a fortune in sawsall blades.

So would just cutting the aluminium crank arm and splitting it, saving the spindle and other arm.

I like the cutting the aluminum crank arm and splitting it idea.

Same exact issue on my Topstone.

I have only 300 miles on my Topstone and the BB is creaking like mad. I was going to disassemble, clean and re-grease everything to see if that fixes it. Went to remove the crank arm bolt and wow was that on there tight. Idk what they're installing these crank bolts, but the torque required to break it loose was pretty damn high.Based on the install torque that was used, I wouldn't be surprised to find something else not quite right. So I go to remove the bolt, and I run into the same issue here - break the bolt loose, bolt spins freely a few threads until it starts to try to pull the arm off, which is when it starts to flex the retaining ring. I stopped there as I'm not trying to replace anything at the moment.

So what to do if I'm not replacing the cranks? Seems like every "successful" method I've found requires a hacksaw or destroying the crank arm. Remove the retaining ring and go standard puller?

Heat and vibration.

I'm telling you it works.

The crankset is pure junk anyway. Cut it off like I did and put a Shimano crank on there. My buddy has bent two big rings on his already.

Already solved, obviously, but for future reference you could try loosening all the fasteners and then just riding it until it lets go on its own.

I’m adding to this discussion because I too had an FSA Omega self-extracting cap failure which virtually stripped the crank puller threads. I found the comments above extremely helpful in my moment of ‘what now’ despair. My cap was in tight but split in two. So initially I bought another cap but it wouldn’t hold when the pressure came on from the crank bolt. As I had a small amount of purchase left on the threads I did wonder whether there was a glue/epoxy with strong enough tensile strength(?). However I used a 3 inch two leg / jaw gear/bearing puller with 2mm claw ends after using some penetrating oil. The claw ends wouldn’t grip on the rounded crank top sides so I had to cut in two slots with a hacksaw and also tied the legs together with some wire (just using the wire might have worked). I used a standard M8 hex bolt with a 13mm head that I placed in the spindle bolt hole, being smaller than the crank bolt, the head being small enough to push on the spindle end but not the crank surrounds, that way there was both a ‘pull and push’ action. RJ The Bike Guy has two videos on YouTube where he uses a three arm puller on more traditional self extracting (sic) cranks, note that in one he says he filed down the claw ends in order to fit behind the crank arm. I also found the Park Tools video on self extracting crank removal helpful which has a partially cut away crank so you can see how it all works. Hope this helps others in this predicament who want to try and save the spindle before resorting to the final hacksaw solution.