Cable-pull hydraulic calipers can be a good way to upgrade. Avoid the Catazer calipers on Amazon. I'm still recovering from injuries due to them. The Juintech brakes look good, and I may order a set to try them out. Bolton (now renamed to Area 13) carries full hydraulic brakes for Rad bikes.
I agree! I have two identical RAD Mini 2018 folding ebikes, both with original mechanical brake calipers. To be sure, the mechanical brakes are functional *when properly adjusted*. The proper adjustment is the issue. The mechanical brakes require frequent adjustment, and for many this adjustment is beyond their expertise. The mechanical brakes require an adjustment to the stationary brake pad holder in the back of the caliper, so that the traveling brake pad won't have to move so far (and won't have to bend the disc as much). I consider myself pretty skilled at bike maintenance and adjust frequently, as needed with the mechanical brakes. With almost 5,000mi on the two bikes, I've replaced all pads once, and noticed a significant (2mm) difference in brakes pad wear from one side to the other. The mechanical brake calipers do not provide smooth pressure application, and cause excessive disc wear.
So...I tried two different hybrid-hydraulic caliper upgrades, one from Bolton ebikes/Area 13 ($119), and one from
Amazon/Catazer ($42).
They are functionally similar, but very different.
Price: Unit13 Juintech M1 hydraulic calipers $119 ($149 at time of writing this review) for front and back calipers.
Catazer hydraulic MTB Road HTB-100 $42
Wow - with such a big price difference, I wondered what was different.
Looks: Advantage Catazer. They have a spiffy paint job that is reminiscent of upgraded brake sets on a Porsche or other high end performance car.
Weight: The Unit13 Juintech M1 calipers weigh about 5oz. The Catazer weighs 5.9oz. They have clearly different castings, pistons, and cable adjustment pieces. They are NOT the same calipers.
Performance: Both Catazer and Unit13 brakes improve the braking smoothness by providing a more even pressure distribution to both sides of the brake pads. The smoothness in braking is noticeable over the old mechanical brakes. PLUS, no bending of the disc when applying the brakes, even after many miles. The 3rd adjustment to the back of the mechanical calipers is not needed at all. Both brake calipers apply pressure to both sides of the pads, and self-adjust to the disc.
Braking Force: Unit13 brake calipers are significantly better here. The Catazer brake calipers require 50-75% (my estimate, not measured with a scale) more brake handle pressure to lockup the rear wheel. I have strong enough hands and I could use either effectively. However, my child and girlfriend both struggled to get full braking power from the Catazer calipers.
Fitup: Both Unit13 and Catazer brake calipers bolted on to my 2018 RAD Mini folding bikes easily by using the OEM hardware for the mechanical brake calipers. The manufacturer-provided spacers were not needed. The whole project can be done in 20-30min. However, the Catazer caliper has a different angle to the frame, and causes excess friction to the cable at the bend made by the angle of the mount on the rear wheel. (See pic). The brake handle will still snap back, but slower and you can feel it is rubbing on something when you work the brake handle.
My Conclusion: If you want the best brakes, go with Unit13. Better alignment with the brake cable and less brake pressure is required to lockup the wheel. If you have strong hands and an eye for price-performance, the Catazer functions okay, though I expect you would need a new rear brake cable housing in a year or two from the friction.