isinwheel Monster Pro
A 60-volt, 5,000-watt e-moto on 17-inch front and 14-inch rear wheels. isinwheel rates it at 50 mph. It is the same platform as the Nexvey Flash Pro, which we measured at 44 on the GPS with a 195 lb rider aboard.
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The Engineering
Built On Better Technology
From Monster to Monster Pro
Every number on the spec sheet went up.
60 Volts Instead of 48
The battery moves from a 48V 22.5Ah pack to 60V 27Ah, and isinwheel's motor rating goes from 3,000W to a 5,000W peak.
Bigger Wheels, Taller Seat
A 17-inch front and 14-inch rear wheel replace the 14/12 setup on the standard Monster, and the seat sits at 29.9 inches. The larger front wheel rolls over ruts and potholes that swallow a smaller one.
Rated 15 mph Faster
isinwheel's rated top speed goes from 35 mph to 50, with a claimed range of up to 70 miles. The 3A charger in the box takes 7 to 8 hours.
Four Power Modes
Three speed caps and a wheelie mode on top. Test numbers are from the Nexvey Flash Pro.
Modes One Through Three
Mode one cuts power at 15 mph and mode two at 25, which is useful anywhere speed limits apply. Mode three takes the ceiling off. In our acceleration test the Flash Pro pulled 29 mph by the 60-foot mark and held 31 mph up a 15 percent grade.
Hold Plus for Mode Four
Holding the plus button in mode three unlocks the wheelie mode. isinwheel calls it Max Wheelie Mode and rates it to 60 degrees.
Throttle You Can Modulate
The twist throttle is detailed enough to crawl along in the highest mode or open it up, with usable control at the bottom, the middle and the top of its travel.
Brakes and Rubber
DOT-grade stoppers on 4 mm rotors, proper dirt bike tread.
Four-Piston Front, Single-Piston Rear
Thick lines feed a four-piston front caliper and a single-piston rear, both on thick rotors that resist warping. These are DOT brakes rather than the mountain bike parts these little e-motos often ship with.
Stopped With Room to Spare
Our braking test is normally run from 28 mph. The Flash Pro, on the same brakes, came in hot at 30 and still stopped a bike and a half short of the marker.
17/14 Off-Road Tires
Aggressive knobby tread at both ends, on thick motorcycle-style spokes. Quiet enough on pavement and genuinely grippy once you leave it.
Security & Ride Modes
Simple Where It Counts — NFC Ignition and Four Modes
NFC card + park mode + four power modes (no app required)
The Monster Pro will not wake up until you hold the NFC card against the display. It then sits in park mode, so the bike cannot take off before you are on it with a brake covered.
From there the plus and minus buttons step through three speed-capped modes, and holding plus unlocks the fourth. The display stays deliberately basic: battery bars, actual pack voltage, speed, an odometer, and a readout you can cycle through for current, distance, watts and time. Reading real voltage rather than trusting six battery bars is the useful part, and it is not something every bike at this price gives you.
Find Your Fit
Size & Fittings
isinwheel Monster Pro 17″ front · 14″ rear
isinwheel's own photo of a rider with the Monster Pro, for a sense of scale.
Will It Fit You?
- Seat height29.9″ (76 cm)
- Overall height38.2″
- Overall length63.4″
- Width at the bars29.5″
- Wheelbase41.7″
- Wheels17″ front / 14″ rear
- Max rider load330 lbs (150 kg)
- Bike weight122.6 lbs
Ben rode the Nexvey Flash Pro, the same chassis, at 5'9″ and 195 lbs in gear. It fit him comfortably, with room at the bars and no cramping at the knees, but it felt soft under a fully grown adult, and a rider around 100 to 120 lbs is who that bike was sprung for. isinwheel rates the Monster Pro to 330 lbs, which is higher than Nexvey rates the Flash Pro. Between the Yozma IN 10 and the IN 10 Pro on size, in Ben's words: a tighter package with softer suspension, but bigger wheels and more power.
Plan Your Ride
Your Range, Not Mine
No cranks and no second battery bay on this one, so the only questions that matter are how fast you ride it, what the ground looks like and what you weigh. Set those and you get the window to plan a ride inside.
The Numbers
Full Specifications
Source: isinwheel.com →⚡ E-System
🏁 Performance
🔧 Suspension & Brakes
⚙️ Frame & Fit
The Bike Cave Verdict
Ben's Take
The Monster Pro has not had test miles from us yet. It is the same bike as the Nexvey Flash Pro with a different badge, so this is Ben's verdict from that review, word for word.
When I saw they were sending a 60-volt, 5,000-watt bike with a 27 amp-hour battery for fifteen hundred and change, I thought no way. There are 48-volt bikes that go for that. But they did it, and the quality is there. Nothing rattles, there is no speed wobble, and I got 44 mph on the GPS at close to 200 pounds when I honestly did not know we would see 40. The brakes are properly good, the throttle is beautifully detailed, and I wish every e-moto had grips like these. The suspension is the catch. It is tuned around a 265 lb limit and a much lighter rider, so at my weight it is soft and there is almost nothing to adjust. If you are a younger, smaller rider getting into riding these off-road, or you are buying for a teenager, this is the one I would get at this price.
👍 What I loved
- 60V and 5,000W for $1,699, which undercuts every bike with the same spec
- 44 mph measured on the Flash Pro twin with a 195 lb rider, well past what I expected
- DOT four-piston front brake that stopped short from 30 mph
- 17-inch front wheel rolls over what swallows a smaller one
- Throttle modulation and grips are the best I have felt on a little e-moto
👎 What to know
- Suspension is tuned soft for a light rider and has almost no adjustment
- Front end wanders under power at close to 200 lbs
- 70 miles is a gentle-riding number. Ride it hard and expect well under half
- Pegs are cheap and worth replacing before you ride it properly off-road
- Display is dim in daylight, though you will not be looking at it
Frequently asked questions
How fast is the isinwheel Monster Pro?
isinwheel rates it at 50 mph. We have not run it against the GPS yet. The Nexvey Flash Pro is the same platform, and with a 5 foot 9 rider weighing 195 lbs in full gear on flat pavement it reached 44 mph. That is a good deal more than Ben expected at this price, and a lighter rider will see more.
How far does it actually go on a charge?
isinwheel claims up to 70 miles. On the Flash Pro, which runs the same 60V 27Ah pack, Ben covered 18 miles of deliberately hard riding, including top speed runs, hill climbs and acceleration tests, and was just under half battery at 56.2 volts. His estimate for that kind of riding is somewhere in the high twenties, which lines up with the rough rule of a mile per amp-hour on a 27Ah pack. Ride gently and you will do better.
Who is the Monster Pro built for?
It has a 29.9 inch seat height and a 330 lb maximum load, and isinwheel says its power and speed suit riders with some experience. On the Flash Pro twin the suspension felt tuned for a lighter rider. Ben's summary of that bike is that a teenager getting into off-road riding, or a smaller adult, is getting a lot of bike for the money.
What are the downsides?
Going by the Flash Pro, the suspension, mostly. It is soft and there is next to nothing to adjust: preload on the rear spring and nothing at all up front. At close to 200 lbs Ben found the front end wandering under power and would not take it on a track. The pegs are cheap, and the display is dim in daylight, though he pointed out you are not looking at it while you ride.
Monster Pro or the standard Monster?
The Monster Pro is the bigger and faster one. It runs 60V 27Ah against the Monster's 48V 22.5Ah, peaks at 5,000W instead of 3,000W, and moves to a 17-inch front and 14-inch rear wheel from a 14/12 setup. The standard Monster is $999 and suits a smaller or younger rider.