- A folding fat tire electric bike with very approachable step-thru frame. Adjustable seat and handlebar height improve fit though it only comes in one size. Three colors including black, grey, and pink! Color LCD, powerful motor, clean wires and decals, quality 9-speed SRAM X5 drivetrain.
- Good weight distribution of motor and battery pack, low and even across the frame. Ideal battery location, easy to access for removal and charging. Good lock and charge port positioning, high up on both sides of the main tube. Optional fast charger, trunk bag, pannier bags, suspension seat post, and more.
- Free shipping and availability through 90+ dealers. Powerful hydraulic disc brakes with motor inhibitor and brake light blinking mode. High visibility reflective tires, premium integrated lights with side-cutout, and USB charging at the display. Torque sensing pedal assist is responsive and natural, trigger throttle overrides assist.
- Kickstand mount is fairly close to left crank arm and could get kicked while pedaling. Torque sensor may surge or activate unintentionally on rough terrain. Weighs 59lbs due to large motor, fenders, lights, and integrated rack. No mechanism to keep the bike folded and no derailleur guard.
This review was provided for free using a demo bike. My goal is to be transparent and unbiased with you, this video and writeup are not meant to be an endorsement of Surface 604 products. I welcome your corrections, additions, and feedback in the comments below, and the Surface 604 electric bike forums.
- This is the first folding model from Surface 604 and I think they did an excellent job! The company has been around since 2013 and has a good reputation for making fat tire and light trail bikes. What makes it unique and special are the three colors, super-low approachable frame, and powerful motor battery combination.
- I consider this ebike “feature complete” which means it can be used in a variety of lighting and weather conditions, while also transporting cargo. It comes with fenders, integrated lights, and a sturdy rear rack. Components are nearly all above average.
- One of the most approachable folding electric bikes I’ve tested. The step-thru design is very low and long, so there’s plenty of room to mount and stand over the frame.
- The fat tires provide many benefits including stability and comfort. I like the CST Big Boat model that Surface 604 chose because the hybrid tread is efficient and quiet, they have reflective stripes to increase your visual footprint and safety.
- High quality integrated lights are included. The rear light uses two LEDs and blinks when either brake lever is pulled. The headlight is bright, aimable, points where you steer, is not blocked by the fender, and has side cutouts to improve your visibility from many angles.
- The adjustable height stem and low-rise handlebar go a long way to improve fit for different sized riders. You can adjust them, in tandem with the seat height, to maximize comfort and pedal stroke efficiency.
- The bike is fairly comfortable. They used a name brand Selle Royal gel saddle and ergonomic grips. The fat tires offer a bit of shock absorption and vibration dampening, especially if you lower the pressure a bit. They are taller than non-fat 20″ tires and that lowers the attack angle for a smoother ride over cracks and small obstacles.
- Electric bikes can get pretty heavy, especially with powerful motors, high capacity battery packs, fenders, lights, and racks like this one has! The fact that they chose to skip a suspension fork actually makes the bike feel more steady and significantly reduces weight. I look at this as positive trade-off if you care about reduced weight… this model weighs just under 60lbs while similar products are 5 to 10 pounds heavier.
- I love the battery choice, because it mounts from the top! It’s fairly heavy at 8.2lbs, and it’s just easier to access and remove than ones that mount from the bottom of the frame tube. It’s positioned farther forward, so it balances out the hub motor pretty well.
- I appreciate that the charging port and locking core for the battery pack are both high up on the frame vs. near the crank arms, where the cable or key could get snagged.
- I love that Surface 604 included bottle cage mounts on the seat tube! This is something that often gets skipped on ebikes due to battery positioning.
- The price point is pretty good when you consider all of the parts, such as the 9-speed SRAM X5 drivetrain with cassette vs. freewheel and the wide 11-34 tooth spread. The battery capacity is above average and the Bafang motor is high quality. Surface 604 offers free shipping, sells through some bike shops, and a has decent one year warranty
- The three color options look good and I feel like they were brave to offer a pink one! Apparently it’s popular, and it made me smile to see. I like the light grey blue one because it will be more visible at night and is kind of neutral.
- Many electric bikes opt for cadence sensors because they are affordable and pretty consistent. Surface 604 tends to go with torque sensors to provide more instant power and a dynamic ride feel. It performed well for me, and even though it has some trade-offs with surging and requires more consistent pedal pressure, it’s something a lot of people appreciate.
- Both brake levers have motor inhibitors that cut power and activate the rear light in blinking mode. This is not a feature that all torque sensing ebikes include because motor cutoff is already near-instant when torque is reduced. They went above and beyond.
- Hydraulic disc brakes are wonderful, because they require less hand effort and have more adjustable levers. These ones are very good because of the motor inhibitors and large 180mm rotors that cool faster and provide an excellent mechanical advantage over the small wheel size. Nice to have with the heavier bike and powerful hub motor.
- Great display panel because of the large size and color readout. You can adjust the angle to reduce glare, and there’s a full sized USB Type A port built into the bottom to power your portable electronics on the go! This checks all of my boxes, and also has some nice settings where you can adjust top speed (lower or higher).
- I appreciate the trigger throttle, because it allows for instant help when starting and overrides lower levels of assist so you can temporarily boost up hills or catch a friend. It’s setup exactly how I like, but you could easily unplug and remove it if you wanted to convert the bike to Class 1 or just didn’t like it.
- Excellent pedal choice! They went with the large aluminum alloy Wellgo folding pedals vs. cheaper plastic ones that flex and aren’t as wide. Great job!
- I appreciate the kickstand choice here, because it offers adjustable length. It’s mounted using a standard 40mm bolt spacing, which makes it easy to replace. They positioned it far enough back that it won’t cause pedal lock when backing the bike up, and it should support a loaded rear rack well.
- There’s an emphasis on ease of use and modular repairs with these ebikes. For example, the controller uses standard XT60 connectors and is much easier to reach for diagnostics and repairs than some of the older ones. Notice the quick disconnect for the motor, headlight, display, brake motor inhibitors, and trigger throttle.
- Folding electric bikes can appear to be small and easy to lift, but they usually aren’t very light. The fat tires, high powered motor, and high capacity battery pack add significant weight to the Twist, in addition to fenders, lights, and integrated rear rack. I would definitely remove the 8.2lb battery before lifting. Perhaps they could use punched out rims on future models to further reduce weight?
- The folding design of the bike works pretty well, but there are no mechanisms to keep it from coming unfolded such as a magnetic clasp (which don’t always work well) or rubber strap. I would use a towel between the frame to prevent chips and scratches, then connect the loose parts using bungee straps.
- The SRAM X5 derailleur is pretty nice, and I love that they chose a short-cage version that won’t get bumped by obstacles in off-road conditions.
- I love the reflective stripes and hybrid tread of the tires, but I wish they had a pressure rating range instead of just “inflate to 30 PSI”. In my own experience with similar tires, they usually say 5-30 PSI which allows for lower pressure to ride on sand and soft loamy terrain. I would also love some puncture protection on the tires, since fat bikes are good candidates for gravel and light trail riding.
- No suspension fork or seat post suspension is included. It’s not such a big issue for people who ride on paved surfaces, but this is where knowing the tire pressure range would be helpful, lower pressure could greatly improve comfort.
- The torque sensor works fairly well, and activates much faster than a cadence sensor. However, it can cause some surge feelings based on the uneven pressure of pedal downstrokes. It can also get activated if the chain bounces a lot while riding on rough terrain. I feel that it requires a bit of extra care when removing and re-attaching the rear wheel too, so things aren’t over-tightened. On the upside, this sensor plate might double as a torque arm because it adds more surface area for the axle to push against vs. just the alloy frame dropouts.
- A couple of times, the heel of my left shoe caught on the kickstand while pedaling. It’s positioned fairly close to the bottom bracket and while it does not cause pedal lock, it’s just a little exposed and could get in the way for people with big feet or shoes.
- The charger for this ebike is pretty basic and a bit slow for the high 672 watt hour capacity of the battery. It’s fairly compact, has a removable wall-side cord to reduce length, and it only weighs ~1.5lbs, but it only puts out 2 amps. Thankfully, they do sell an optional 4 amp fast charger if you’re willing to pay a bit extra.
- The rear rack is welded to the frame, which means it cannot be removed and adds weight to the overall build. The upside is that it won’t rattle loose over time, it’s color matched and has bungee loops, flat slats on top, and is rated to 50lbs (22.6kg). This rack would probably work well with child seats like the Thule Yepp Nexxt Maxi, and is a sturdy mounting point for the included rear light.
- The ergonomic grips are not locking, which means that if you bear down on them you can twist them forward and back (or even slip them off the ends if you really go for it). Fortunately, the relaxed position of the riser handlebar means that you won’t be bearing down on the grips the way you might with a mountain bike. Grips are pretty affordable to upgrade if you want locking, consider the Ergon GP1 for example.
- I was surprised to see that there was no slap guard sticker on the right chain stay. This is a minor annoyance, but it does mean that the paint could get chipped off if the chain is bouncing up and down a lot while riding off-road. Consider using piece of clear box tape or aftermarket velcro slap guard like this if you plan to ride fast and on bumpy terrain.