Rod brakes are generally paired with Westwood style rims. These rims do not have a flat sidewall, but rather a a curved edge which provides insufficient contact area for caliper brakes and causes the brake pads to ride either up over or down under the rim, unless the rim is perfectly round and the pad centred exactly on crest of the curved edge. So, typically you'd have to replace the rims/wheels for a rod to caliper brake conversion.
Edit: I echo the previous sentiments regarding the performance of rod brakes. Brake performance is large a function of the coefficient of friction between the rim and pad materials. Chrome plated steel is far inferior to aluminum in this aspect and given that rod brakes are found on inexpensive models, I highly doubt that they would use premium brake pad material.
Last edited by T-Mar; 03-12-20 at 08:58 AM.