E-Cells Dual Star review

Rover Bob

New Member
I recently transitioned from a 7 year old RadRover to the E-Cells “5 Star E-Bike” with the “Dual Star Package” upgrade, similar to what is now sold as the “E-Cells Dual Star E-Bike 1500w 60v 35AH”. The Dual Star’s Hentach rear hub motor (R1200 60V 1500W) can draw 2,100+ watts at the hub (per the dash screen); that’s about triple what the RadRover ran. Where the RadRover’s battery limited my ride distances, the Dual Star offers more miles than I want in the saddle. Yesterday’s 40 miles on steep jeep trails left ¼ of the batteries unused per the dash screen, or a bit more per the individual battery readouts.

Despite my experience riding motorcycles the unrestrained Dual Star can go faster than I am comfortable with on a bicycle, so after testing the waters I programmed in a lower limit. My 156 pound weight, plus a laden saddlebag, do not tax the power train on this speedster.

The hub motor makes a pronounced whirring sound; I don’t find it offensive. The big 7” headlight is fantastic, it’s great for announcing your presence on winding single lane roads, even in daytime. The 7-speeds are sufficient, and the top gearing is high enough to be pleasantly useful (unlike the lesser gear set on the RadRover). I like the raised up position of the handlebar.

After 3 weeks and 371 miles I find that the Dual Star has some limitations, which may be in line with the price:

The E-Cells Dual Crown fork with “125mm travel” helps smooth bumps some, but with the front wheel fender installed the actual travel is limited to 95 mm (else it bangs into the steel fender with a resounding Clang). Also, the fork shock slowly loses its air charge, so plan on carrying a high pressure air pump to top it off. Low air pressure in the Kenda 26x4 tires helps the ride.

The four piston Tektro HD-E3940 brakes with 203mm rotors usually do a great job of slowing down this heavy bike, but on longer downhills they fade to the point you need to stop and let them cool off; I wonder if they could be upsized so they don’t require extra wait times.

Going uphill the limitation is heat, even on a mild day. On a long uphill the dash display starts flashing “MOTT” in red next to the Fahrenheit reading. I’m unsure whether this is controller temp or hub motor temp, but presumably it’s an indication to stop and let things cool off. So the bike is limited for extended uphills too.

The throttle does an excellent job of throwing full power into the rear hub; so much so that I reprogrammed it to give a softer start for better control. But the throttle/controller combination also presents a safety issue: they’re so touchy below full speed that it’s quite difficult to hold a steady speed and avoid jerky off/on pulses. At slower speeds your ride alternates between too quickly accelerating, and then completely off to avoid excessive speed, repeat, repeat.

The version I paid for did arrive with the promised derailleur guard, but the frame is not lugged for it so there’s no way to attach it.

Weight: this is a heavy bike. It feels nicely stable when moving along; but more tippy until it gets rolling and more difficult to lift or load. I use a flatbed trailer (with loading ramp), rather than a hitch mounted rack.

Customer support: These are fairly priced bikes but, in my experience, come with no customer support. My several emails asking about missing parts and the leaky front fork go unanswered. Plan on solving any defect issues on your own.

Conclusion: It’s a lot of bike for the price, and way more capable than the RadRover. It has more than enough power coming out of the rear hub and more battery than I expect to use on one ride. It is limited going uphill because it can overheat, and going downhill because the brakes can fade. The suspension absorbs a lot of the bumps, but the fork has less travel than advertised and leaks, and chain clatter is pronounced during bounces.

My add-ons: water bottle & cage, mirror, tool kit, 2 portable air pumps (high and low pressure), saddle bag, upgraded seat, Slime for the tubes, cordura motorcycle jacket and upgraded e-bike helmet rated for the faster speeds.

I’d probably buy the bike again because of the advantages it does offer, and but consider the issues mentioned above. I’d pay more for better brakes, throttle control and suspension. As an older rider I would have bought the similar step-thru version instead but it was seriously back-ordered at the time.
 

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The four piston Tektro HD-E3940 brakes with 203mm rotors usually do a great job of slowing down this heavy bike, but on longer downhills they fade to the point you need to stop and let them cool off; I wonder if they could be upsized so they don’t require extra wait times.
You can get brake pads with different composition. "Organic" brake pads are prone to brake fade and glazing. "Sintered" brake pads are resistant to that but don't have the same initial bite. "Semi-metallic" is a hybrid which combines some of the strengths and weaknesses. You should be able to get new brake pads for the existing calipers pretty inexpensively, and they're easy to swap.

If the brake calipers are 2 piston, then 4 piston would be a big upgrade. They take larger pads (more area to dissipate heat) and can squeeze a lot harder. They also have more fluid behind them so boiling is less of an issue.

If you are getting so hot you are boiling the fluid, you could flush and put a higher quality DOT fluid in (at least if the mfr allows). Cheap tektro brakes may come with a more basic mineral oil.

Oh, and also: You can increase brake rotor size fairly easily if you have clearance. There are standard spacers that go under the calipers to adjust for larger rotors, and the bolt pattern for the rotors themselves is the same.
 
Ben, Thanks for the helpful advice.
Since these are 4 piston calipers, I'll start by replacing the pads and see if that suffices.
Yes, the brakes are marked "mineral oil", so I'll have to look into whether the manufacturer allows DOT fluid, if boiling rears its head.
 
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