Heybike Mars 3.0 Review: A Torque-Sensor Folder With an Unpublished Class

What it is

The Heybike Mars 3.0 is a folding fat-tire e-bike built on the same idea as every Mars before it — 20-inch by 4-inch tires, a hinge in the middle of the frame, a 750 watt rear hub motor — with two additions that are genuinely unusual below $1,500. It has a torque sensor rather than the cadence sensor almost every budget e-bike uses, and it has full suspension rather than a fork on its own. Heybike also publishes 1,400 W peak, 95 N·m of torque, a 624 Wh battery, a 440 lb maximum load, a TFT display with NFC card start-up, both UL 2271 and UL 2849 certification, and an IP65 water-resistance rating.

That is a strong sheet for a bike selling in the low four figures, and it is also the most expensive bike this site regularly recommends. Our ceiling is $1,500, so the Mars 3.0 sits near the top of what we cover rather than in the middle of it. The question worth answering is therefore not whether the hardware is good. It is whether the upgrades are ones you would actually feel, and what to do about the four specifications Heybike declines to print.

The torque sensor is the real upgrade

Almost every e-bike under $1,000 uses a cadence sensor: a ring of magnets that notices the pedals are turning and switches the motor on. It works, and it feels like a switch. Power arrives a beat after you start pedaling, arrives at a fixed level for whichever assist mode you picked, and keeps arriving until you stop. On a 70-pound bike in traffic, that lag is the part you notice, particularly pulling away from a light or easing through a turn.

A torque sensor measures how hard you are actually pushing and scales the motor to match, so the bike amplifies your effort instead of substituting for it. The practical differences are smoother starts, finer control at low speed, and better efficiency, because the motor stops delivering full power in the moments you do not need it. It is the single biggest ride-quality difference between a cheap e-bike and a good one, and below about $1,000 you will almost never find one. Our pedal-assist explainer covers how the two sensor types behave in more detail.

The rest of the drivetrain story is conventional: a 750 W rated hub motor with a claimed 1,400 W peak and 95 N·m of torque. The rated figure is the one that matters legally and the one we rank on, because peak wattage is a marketing number measured over a burst nobody defines. At 750 W rated it sits exactly at the U.S. ceiling for a legal e-bike, which is where every serious bike in this bracket sits.

624 watt-hours, and what the range claims are worth

This bike is a small case study in why we refuse to repeat range claims. Three different numbers are attached to the same battery.

• Heybike’s own product page says up to 65 miles.
• The Amazon listing title says 70-plus miles — the retail listing out-claims the manufacturer.
• Electric Bike Report, testing an actual bike, got 61 miles in the lowest assist level and 34.2 miles at maximum assist.

None of those is a lie, exactly. They are answers to different questions. The one number that does not move is the pack: 624 Wh. At the planning figure we use across this site — roughly 20 watt-hours per mile for throttle-heavy riding on fat tires — that works out to about 31 miles, which lands close to the 34.2 an independent tester measured with the assist turned all the way up. Ride gently and you will get far more; ride it like a scooter and 30-odd miles is the realistic plan. Our range guide shows the arithmetic so you can run it against your own commute.

For context on the bracket: 624 Wh is a solid mid-size pack, not a large one. Several bikes on our long-range page carry more capacity for considerably less money. You are not buying the Mars 3.0 for watt-hours per dollar, and it is worth being clear-eyed that you are not.

Four specs Heybike will not publish

Read the panel beside this article and you will see “Not published” three times. That is not a gap in our research — it is what Heybike states, or rather does not, on its own product page for this bike. The missing figures are top speed, e-bike class, weight and the brake type. For a bike at this price that is an odd set of omissions, and three of the four have real consequences.

Class and top speed. This is the one that can cost you access. A legal U.S. e-bike is capped at 750 W rated with assist to 20 mph (Class 1 and 2) or 28 mph (Class 3). Electric Bike Report found the Mars 3.0 ships limited to 20 mph, offers a 28 mph Class 3 setting, and will run to roughly 32 mph unrestricted — above the Class 3 ceiling, at which point it is arguably not an e-bike at all where you are riding it. They also note that the pedal-assist and throttle speeds are tied together, so raising one raises the other. The safe advice is simple: leave it in the setting it arrives in, and read the class guide before you touch the app.

Weight. Electric Bike Report weighed it at 71.7 lb against a 70 lb claim made elsewhere. That is unremarkable for a 20x4 folder with full suspension and a 624 Wh pack, and it is still 71 pounds. Folding means this bike fits in a car trunk, not that you can carry it to a third-floor apartment. Our weight guide is worth five minutes if you do not have ground-floor storage.

Brakes. This omission is the strange one, because the answer is good news. Independent testing reports hydraulic disc brakes with two-piston calipers on 180 mm rotors, and a stop measured at 20 feet 8 inches. Hydraulic brakes need less lever effort and hold their adjustment far better than the cable-pulled discs most budget bikes ship with, and on a machine weighing 70 lb before you sit on it that matters more than it does on a road bike. Heybike should be advertising this. Our brakes guide explains what to look for.

Mars 2.0 versus Mars 3.0

The generation you are probably comparing this against is the Mars 2.0, and that comparison got simpler in September 2026: Heybike rolled its Amazon listing over to the 3.0, so the 2.0 is no longer stocked there. Our review of it stays up because people still search the name and deserve a straight answer, but its buy link is now a search rather than a listing.

For the record, the changes that matter are the three you would feel. The 2.0 used a cadence-style assist and the 3.0 uses a torque sensor. The 2.0 had a suspension fork; the 3.0 adds a Horst-link rear end with about 30 mm of stroke behind a 65 mm fork. And the brakes went hydraulic. The battery grew modestly, from 600 to 624 Wh, which is not a reason to do anything. If you can still find 2.0 stock somewhere at a genuine clearance price, buying the outgoing generation is exactly the trade this site exists to find. At list price, the 3.0 is the better bike.

Certification, and what it is worth

Heybike states that the Mars 3.0 carries both UL 2849, which covers the whole electrical system, and UL 2271, which covers the battery pack, plus an IP65 rating for water and dust resistance. The U.S. Consumer Product Safety Commission is explicit that certified packs are what buyers should look for, and holding both listings rather than one is meaningfully better than the norm in this bracket.

That is not a small point on a bike you will charge indoors. If it lives in an apartment or a shared hallway, certification is the specification to refuse to compromise on, and our battery care guide covers the charging habits that matter just as much as the listing does.

What it costs to run

About 13 cents for a full charge. That is the 624 Wh pack plus roughly 10% charger losses, at the current U.S. average residential electricity rate of 18.44 cents per kilowatt-hour. Charge it every single day for a year and you are still under $50 in electricity. The full arithmetic, and how it compares to making the same trips by car, is in our charging cost guide.

The running costs that actually add up are the ones nobody quotes: tires, brake pads, a charger if the original dies, and eventually the pack itself. Our battery lifespan guide is the honest version of that math.

What to check before you order

Confirm the class in writing. If you plan to ride bike paths or multi-use trails, ask Heybike what class the bike ships as and get the answer in an email before you buy. An unpublished class is not automatically a problem — it becomes one at the exact moment somebody asks you about it.

Plan the storage before the bike arrives. Seventy-one pounds folded is still seventy-one pounds. Measure the space, and if it lives indoors, our storage rack roundup covers what actually holds a bike this heavy.

Budget past the bike. A fat-tire folder at this price is a theft target, and it does not arrive with a lock worth the name. Add a real one from our lock roundup, and if you ride after dark, proper lights.

Read the stock note on the listing. This model has been moving in small quantities and Amazon has been showing single-digit stock counts on it. The price panel on this page is pulled live and dated, so that is the number to trust rather than anything written in this paragraph.

Who should buy it — and who should skip

Buy it if the torque sensor is what you are shopping for. It is the cheapest route we know to a torque-sensing, fully suspended, dual-UL-listed folding fat-tire bike, and the 440 lb maximum load is the highest published figure in our registry — which also makes it a serious option for a heavier rider or anyone carrying real cargo, as our payload roundup explains. Hydraulic brakes on a bike this heavy are the right call, and having them at this price is not typical.

Skip it if range per dollar is your constraint. Around $700 buys folders with substantially larger packs, and our under-$1,000 roundup is where the value curve is genuinely steepest. Skip it too if path access is non-negotiable and you would rather not chase a manufacturer for an answer — the Aipas A2 publishes a switchable Class 1/2/3 setting, so the answer there is a setting rather than a guess.

We have not ridden this bike and we do not claim to have. Everything above is either read from Heybike’s own published specifications, taken from an independent tester we have named and linked, or arithmetic you can repeat. This is exactly what we do instead of pretending.