Match the size, check the e-bike rating
Before anything else, read the numbers on the sidewall of your current tire — something like 26 x 2.0 or 20 x 4.0— and buy that size. The first number is the wheel diameter, the second the width; a fat-tire bike needs a fat tire and a road bike needs road rubber. Then confirm the tire is approved for e-bike useat your bike’s speed. Faster (Class 3) bikes especially need rubber rated for the heat and load, which is why the premium touring tires state an explicit e-bike speed rating.
Puncture protection vs. rolling speed
More puncture protection means a heavier tire that rolls a fraction slower — a trade almost every commuter should happily make. On an e-bike the motor erases the small speed penalty, so there is little reason not to run a well-protected tire if flats have been your problem. Fat tires are a different story: their job is cushioning and grip, and the value replacements focus there rather than on a puncture belt, so carry a spare tube.
Fitting them, and the flat you have right now
A puncture-protected tire is the cheapest way to stop having flats, and it is also the hardest to mount the first time — which matters more on an e-bike, where the rear wheel has a motor cable attached to it and a specific washer and torque-arm order to reinstall. Our e-bike flat tire repair guide walks through both wheels in order, and our tire pressure guide covers the weekly check that prevents most pinch flats in the first place.
If you are still deciding whether any of this is necessary, start with do e-bikes need special tires. The short answer for a 20 mph bike is no — what an e-bike really changes is how fast you wear tires out and how much work a flat is, which is why a published puncture belt is worth more here than any e-bike badge. Tire choice also shows up on the range ledger: how to increase e-bike range puts it in cost order against the free levers.