jetpackjbd
100 W
I’ve had this bike for about 10 months now which I bought on Amazon for $450, $550 with shipping. I’m not even sure what it is and can’t find it anywhere else, it was listed as a HILAND ROCKSHARK but has no Hiland logos on it. The sticker underneath it says it’s manufactured by JOY KIE TECHNOLOGIES, but even then it’s hard to find my model online. Apparently it’s a “Model: ROCKM007 gy-75A455-350WA”.
Amazon Link
So, even though you probably won’t be buying this model anywhere, this review should apply to a lot of cheap Chinese eBikes:
Quality: It’s fine. The welds are kind of ugly but seem strong, most of the parts are off the shelf from brands I recognize, and nothing major has gone wrong. The shifter arrived with a crack in it but was still functional, and I used it for about 400 miles like this. Their support is terrible though, I tried to message them at one point about the broken shifter and got no response, they likely only deal with Chinese customers. Maybe my email got flagged by The Great Firewall. It’s a $20 part, whatever. Battery is holding up fine and hasn’t even gotten warm. No squeaks yet! (outside of the things I installed on the handlebars myself).
Repairs Done: Most of the repairs are from general usage or my mistakes. I’ve had to adjust the shifting a few times, the brakes need adjustment every hundred miles for some reason, and the tubes have been replaced numerous times. More “major” repairs were my fault; I got my chain all tangled and ending up cutting the shifter cable to fix it while trying to replace the rear tube. The front wheel bearings failed recently which might’ve been my fault, as I had loosened them at one point to reapply grease (they never seemed to move as smooth as a new bearing should) and I don’t think I tightened them enough, causing a bearing to chip and the balls spilling out of the races. My biggest issue has been the brakes. They fail in some way roughly every 100 miles. Currently, they’re both a bit loose and the rear brake spring “skips” and releases if I brake harder than it wants to. One day it’ll be looser and skip, the next day it’s mostly fine. I have to take apart the brake calipers to fix the skipping by reseating the spring and adjusting the screws. There’s a bit of a wear mark inside the caliper from where the spring skips but I don’t know what was causing it to do so in the first place. Replacing the caliper would fix it I’m sure, but it’s still annoying to have to replace something that failed after ~400 miles. The seat ripped too, but it was uncomfortable anyways and I had had the bike upside down on the dirt so it’s mostly my fault.
Advertised vs Reality: The listing claimed a range of 30-50 miles with pedal assist, or a range of 26-40 miles with throttle only. That’s misleading, although I will say the range hasn’t gotten much worse in 1000 miles. It’s more like 20-30 miles with pedal assist if you drive reasonably, and 10-20 miles by throttle only. It’s still more than enough range for me but it’s something to be aware of. I go about 3 days between charges, riding ~6 miles each day. I could squeeze a bit more range out of it but I’m trying to preserve the battery life by not fully cycling it. The speed claims are actually accurate though, if not understated. They claim 21MPH throttle only, and I’ve gotten up to 22MPH throttle only (wow!!). They also claim 25MPH with pedal assist, but that depends on many conditions like the driver’s strength and terrain. I’ve gotten up to 35MPH once going down a steep hill pedaling as hard as possible with full assist (weak numbers to some of the people here, I know), but typically the most I can do on normal land is 23MPH or so. The trails are twisty here so I only choose to go about 17MPH if that.
General Complaints: Besides the brakes that love to fail, I have some other annoyances with the bike. First off, the pedal assist lags by half a second. Maybe it’s normal for it I have a delay for “safety”, but in my experience it’s annoying and a little unsafe. Not only does it take half a second to turn on once you start pedaling, it takes half a second to turn off when you stop pedaling. Luckily the brake sensor cuts it off with very minimal delay, but it’s still a little concerning. I should also mention one of my brake sensors came unsoldered, but since I turned off pedal assist it favor of throttle-only I haven’t bothered fixing it. Controlling the assist manually with the throttle is a more pleasant experience. Another annoyance is that only one color option of the bike came with a headlight, for the same price. I didn’t notice until after I bought it, so I don’t have a headlight (but I still have the ability to turn on the absent headlight by holding the up button). I might be able to add one, but I haven’t needed to open it up and have an excuse to find the connector. I think the controller or display was originally designed for SLA batteries, as the battery display is very misleading. The battery chart decreases with voltage drops and rises when unloaded again. It doesn’t really show until the charge is below 70% or so. Thankfully there’s a voltage readout as one of the menus, otherwise I wouldn’t trust it. 3/5 battery only shows at 36V and below according to the meter, and only goes into 2/5 at around 33V.
Positives: It’s a great first eBike if you’re on a budget and don’t mind doing some work every so often. The other cheap eBike brand at the time was “TotGuard” at a slightly lower price, but the main reason I chose this instead was that I didn’t want a name that means “Toddler Protector” on my bike.
-As an eBike, it’s somewhat discreet as the battery isn’t sticking out, it’s inside the frame. The thick frame, wheel motor, and controls give it away, but it’s not obvious at a glance to someone looking for e-bikes to steal (I hope)
-In my case, I think 350W is the sweet spot, as I don’t need to go fast on our twisty roads and I don’t need more power for gravel or dirt roads. It can keep its speed up hills too, peaking at around 17MPH. It doesn’t like going up hills; I can hear the motor strain and see the battery voltage drop, but it’ll do it.
-It’s surprisingly quiet, motor noise is audible but the tire noise is louder. Even so, my dad’s new-ish road bike is louder to the driver than this bike is with a motor and fatter tires.
-Even if it was just a normal bike, this would still be the fanciest bike I’ve ever owned. It’s got an easily adjustable suspension, disc brakes, and a thumb shifter, which is a step up from my previous 4 bikes.
-It’s reasonably comfortable. It only has basic front shocks but it still manages to absorb the feeling of cracks in the sidewalks. You still feel big bumps like a 2 inch gap in the sidewalk or going over a curb, but I think that’s standard with almost any suspension. The big tires alone do a lot of shock absorption, especially at lower pressure.
-It’s built pretty well. Nothing stands out to me as a design flaw, just some cheap parts. They cheaped out on the right things to save money without affecting much of the user experience (except brakes, grrr…).
UPDATE: At ~1200 the throttle started cutting out and giving me an E08 code each time. I tried replacing it twice and neither worked, giving the E08 code the entire time as if they weren’t hooked up, or they were giving lower values than the original one. I broke the original one trying to look for loose wires inside, so now I don’t have a working eBike. The manual says it’s a hall sensor error, but I’m pretty sure that’s because the throttle uses a hall sensor. At least I hope that’s the reason. So I’ve been stuck with my eScooter and normal bike for a few weeks. I’ll fix it at some point, hopefully.
Update 2: I eventually got around to fixing it, the issue was the cable connecting the throttle connector to the motor controller, but unfortunately I already bought a new motor controller before figuring it out. I made a new cable for it and got it working again, but it came undone. New motor controller has more features but doesn’t have a wheel speed readout and feels slower. I’ll try the old one again.
I also got some free hydraulic brakes which I’ll try installing onto this POS. Should hopefully be more reliable than the broken mechanical ones, although the hydraulic ones are broken too (I have the repair kit)
Amazon Link
So, even though you probably won’t be buying this model anywhere, this review should apply to a lot of cheap Chinese eBikes:
Quality: It’s fine. The welds are kind of ugly but seem strong, most of the parts are off the shelf from brands I recognize, and nothing major has gone wrong. The shifter arrived with a crack in it but was still functional, and I used it for about 400 miles like this. Their support is terrible though, I tried to message them at one point about the broken shifter and got no response, they likely only deal with Chinese customers. Maybe my email got flagged by The Great Firewall. It’s a $20 part, whatever. Battery is holding up fine and hasn’t even gotten warm. No squeaks yet! (outside of the things I installed on the handlebars myself).
Repairs Done: Most of the repairs are from general usage or my mistakes. I’ve had to adjust the shifting a few times, the brakes need adjustment every hundred miles for some reason, and the tubes have been replaced numerous times. More “major” repairs were my fault; I got my chain all tangled and ending up cutting the shifter cable to fix it while trying to replace the rear tube. The front wheel bearings failed recently which might’ve been my fault, as I had loosened them at one point to reapply grease (they never seemed to move as smooth as a new bearing should) and I don’t think I tightened them enough, causing a bearing to chip and the balls spilling out of the races. My biggest issue has been the brakes. They fail in some way roughly every 100 miles. Currently, they’re both a bit loose and the rear brake spring “skips” and releases if I brake harder than it wants to. One day it’ll be looser and skip, the next day it’s mostly fine. I have to take apart the brake calipers to fix the skipping by reseating the spring and adjusting the screws. There’s a bit of a wear mark inside the caliper from where the spring skips but I don’t know what was causing it to do so in the first place. Replacing the caliper would fix it I’m sure, but it’s still annoying to have to replace something that failed after ~400 miles. The seat ripped too, but it was uncomfortable anyways and I had had the bike upside down on the dirt so it’s mostly my fault.
Advertised vs Reality: The listing claimed a range of 30-50 miles with pedal assist, or a range of 26-40 miles with throttle only. That’s misleading, although I will say the range hasn’t gotten much worse in 1000 miles. It’s more like 20-30 miles with pedal assist if you drive reasonably, and 10-20 miles by throttle only. It’s still more than enough range for me but it’s something to be aware of. I go about 3 days between charges, riding ~6 miles each day. I could squeeze a bit more range out of it but I’m trying to preserve the battery life by not fully cycling it. The speed claims are actually accurate though, if not understated. They claim 21MPH throttle only, and I’ve gotten up to 22MPH throttle only (wow!!). They also claim 25MPH with pedal assist, but that depends on many conditions like the driver’s strength and terrain. I’ve gotten up to 35MPH once going down a steep hill pedaling as hard as possible with full assist (weak numbers to some of the people here, I know), but typically the most I can do on normal land is 23MPH or so. The trails are twisty here so I only choose to go about 17MPH if that.
General Complaints: Besides the brakes that love to fail, I have some other annoyances with the bike. First off, the pedal assist lags by half a second. Maybe it’s normal for it I have a delay for “safety”, but in my experience it’s annoying and a little unsafe. Not only does it take half a second to turn on once you start pedaling, it takes half a second to turn off when you stop pedaling. Luckily the brake sensor cuts it off with very minimal delay, but it’s still a little concerning. I should also mention one of my brake sensors came unsoldered, but since I turned off pedal assist it favor of throttle-only I haven’t bothered fixing it. Controlling the assist manually with the throttle is a more pleasant experience. Another annoyance is that only one color option of the bike came with a headlight, for the same price. I didn’t notice until after I bought it, so I don’t have a headlight (but I still have the ability to turn on the absent headlight by holding the up button). I might be able to add one, but I haven’t needed to open it up and have an excuse to find the connector. I think the controller or display was originally designed for SLA batteries, as the battery display is very misleading. The battery chart decreases with voltage drops and rises when unloaded again. It doesn’t really show until the charge is below 70% or so. Thankfully there’s a voltage readout as one of the menus, otherwise I wouldn’t trust it. 3/5 battery only shows at 36V and below according to the meter, and only goes into 2/5 at around 33V.
Positives: It’s a great first eBike if you’re on a budget and don’t mind doing some work every so often. The other cheap eBike brand at the time was “TotGuard” at a slightly lower price, but the main reason I chose this instead was that I didn’t want a name that means “Toddler Protector” on my bike.
-As an eBike, it’s somewhat discreet as the battery isn’t sticking out, it’s inside the frame. The thick frame, wheel motor, and controls give it away, but it’s not obvious at a glance to someone looking for e-bikes to steal (I hope)
-In my case, I think 350W is the sweet spot, as I don’t need to go fast on our twisty roads and I don’t need more power for gravel or dirt roads. It can keep its speed up hills too, peaking at around 17MPH. It doesn’t like going up hills; I can hear the motor strain and see the battery voltage drop, but it’ll do it.
-It’s surprisingly quiet, motor noise is audible but the tire noise is louder. Even so, my dad’s new-ish road bike is louder to the driver than this bike is with a motor and fatter tires.
-Even if it was just a normal bike, this would still be the fanciest bike I’ve ever owned. It’s got an easily adjustable suspension, disc brakes, and a thumb shifter, which is a step up from my previous 4 bikes.
-It’s reasonably comfortable. It only has basic front shocks but it still manages to absorb the feeling of cracks in the sidewalks. You still feel big bumps like a 2 inch gap in the sidewalk or going over a curb, but I think that’s standard with almost any suspension. The big tires alone do a lot of shock absorption, especially at lower pressure.
-It’s built pretty well. Nothing stands out to me as a design flaw, just some cheap parts. They cheaped out on the right things to save money without affecting much of the user experience (except brakes, grrr…).
UPDATE: At ~1200 the throttle started cutting out and giving me an E08 code each time. I tried replacing it twice and neither worked, giving the E08 code the entire time as if they weren’t hooked up, or they were giving lower values than the original one. I broke the original one trying to look for loose wires inside, so now I don’t have a working eBike. The manual says it’s a hall sensor error, but I’m pretty sure that’s because the throttle uses a hall sensor. At least I hope that’s the reason. So I’ve been stuck with my eScooter and normal bike for a few weeks. I’ll fix it at some point, hopefully.
Update 2: I eventually got around to fixing it, the issue was the cable connecting the throttle connector to the motor controller, but unfortunately I already bought a new motor controller before figuring it out. I made a new cable for it and got it working again, but it came undone. New motor controller has more features but doesn’t have a wheel speed readout and feels slower. I’ll try the old one again.
I also got some free hydraulic brakes which I’ll try installing onto this POS. Should hopefully be more reliable than the broken mechanical ones, although the hydraulic ones are broken too (I have the repair kit)
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Oftentimes, lower quality hub bearings can be impossible to adjust correctly for the required free-running/minimal play. Or, once adjusted correctly, will not stay in adjustment.
