Originally Posted by
twoflats
If that is not the problem, then the the brake pads are just too compressible/spongy, and I'll try to find pads with a harder compound; I've read that ceramic pads are harder than sintered.
Sorry, but I don't think the spongyness of the pads are your problem. You'll be just wasting your money. If these pads can adequately stop a tandem weighing 400 lbs with riders and gear, I think they should be able to stop your bike. You need to work on the adjustment to get the pads parallel.