I rebuilt a kids bike. I had the wheelset and calliper/U-brake replaced. Parts that I used are not cheap parts, lets say its more of mid range parts for BMX, normally made of alloy. I made sure the calliper is installed properly and brake shoe are aligned with the rims.
Still the brake is weak, even on a road that is 15 degrees it won't stop. For me it looks like the brake shoe is slipping and not having a good hold on the rims even if its perfectly aligned. I tried pouring soda on the rims to make it sticky but still no good. Any ideas?
Update: I already did try to degrease the rims and used more expensive brake shoe(Baradine brake pads) still no good. Brakes did improve but not what I wanted. I have to give so much pressure on the brake lever in order for it to stop, when I say so much pressure I feel like the brake lever and the cable wire is about to snap.