In the end I had to heat it. AFAIK the only way to get a wheel off an axle that is tapered is to belt it but using a drift and hammer not just the hammer...less effective but safer on the gear. Spraying with penetrating stuff did not help, but heat did. Actually heat is very effective here, because I am pretty sure that the wheel itself is Al and therefore will expand even more than steel. On the other hand Al is notorious for seizing. AFAICS a bearing puller would be risky here, and distortion of the wheels could easily result. In the end I used a wedge _inside_ the wheel between the boss and the axle mount.
