Revolve Rough Rider - EBTL Test Report

EBTL

Electric Bike Test Lab Test Report of:


Revolve Rough Rider

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Tested in October of 2019 by

Jason Holmes (Chief Engineer and Owner)

Summary

The Rough Rider excelled at braking and managed the one mile long hill climb extremely well. The large wheels, heavy weight, and long wheel base create a stable, easy to ride bike that encourages confidence when braking and performs well at higher speeds. The Revolve Rough Rider was the best performing ebike tested to date in the braking test.


Summary of Test Results
  • Braking Distance from 20 mph: 31.6 feet
  • Brake Fade: Light
  • Max Speed Throttle Only: 20 mph (non-adjustable)
  • Zero to 20 mph Throttle Only: 15.4 seconds
  • Max Assisted Speed: 22 mph (non-adjustable)
  • Zero to 22 mph with zero effort spinning: 17.8 seconds
  • Zero to 22 mph with moderate pedaling: 14.5 seconds
  • Throttle only hill climb: 0.25 miles before stopping at 1:31 (average speed of 9.7 mph)
  • 100 Watts of pedaling hill climb: One mile long hill completed in 5:32, average speed of 10.7 mph, average pedal power of 99 watts.

Ebike Specs of Note
  • Motor type: Rear wheel mounted geared hub
  • Rated power: 500 watts
  • Battery Details: 48 volts, 10.0 amp-hour = 480 watt-hours
  • Actual Weight: 69.7 lbs
  • Brakes: Mechanical Discs
  • Cadence or Torque: Cadence only
  • Mileage at time of test: 4.0

General Testing Notes

For all of EBTL’s testing of the Rough Rider, the rider and instrumentation equal a total weight of 200 pounds. The weather was 60 to 74 degrees F and the wind speed was near zero (early mornings are the best time to test).

Brake Testing

Brake testing is probably the most important factor, at least when it comes to safety. With the higher speeds that ebikes can achieve, braking becomes critical. And with the advent of ABS systems for ebikes, manufacturers are catching on to the importance of good brakes. This test appears very simple, achieve the desired speed, then simply stop as quickly as you can. For the Ancheer, this means pulling the front lever as hard as possible as it wouldn’t lock the front wheel, nor would it lift the rear wheel. The rear brake is engaged fully as well, which resulted in skidding. It takes practice to get it right! And every ebike rider should practice emergency stopping from top speed on different road conditions when and where they can safely do so.

The Rough Rider stopped at an average distance of 31.6 feet from 20 mph. After each full stop, light to moderate brake fade was noticed with the fifth and sixth stops requiring slightly longer distances as the front brake simply wasn’t applying as much pressure to the rotor. Brake fade can happen to any brake as the friction surface becomes too hot to remain as effective as when cold. Better friction materials can prevent this. However, in real world use, it's unlikely that one would need to use the brakes repeatedly enough to notice brake fade except for perhaps, after braking going down a long hill.

In summary, the Rough Rider was the easiest e-bike tested to date to reach maximum braking. Due to the long wheel base and higher weight, it’s simply impossible to bring the rear wheel off the ground. In addition, the large 26” x 4” Kenda tires create a large friction surface so locking either the front or rear wheel is nearly impossible. The Rough Rider stopped quickly and confidently for all six stops from 20 mph. This was the first e-bike to impress me during the braking evaluation.


Road Load Range Evaluation
For the road load range evaluation, the bike is simply pedaled with zero assist at 5, 10, 15, and 20 . The power required to move the bike at each speed is then determined and an equation is developed to represent that relationship. The Rough Rider results are below:

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Rough Rider Road Load vs. Speed

Once this is determined, one can calculate the power required to maintain the speed of each PAS setting:


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Once the power required is known, the range in miles for each PAS and rider input can be calculated, results for the Rough Rider below assuming 100% of the battery is used:

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This road load range should differ from the real-world range as it assumes a constant steady state speed over level ground with no coasting. In real world usage, many variables can affect road load and range.

As an example of how to use the tables: a 200 pound rider who is contributing 100 watts of pedaling can expect to reach 27.1 miles at 22 mph while using maximum assist. To conserve battery life, one should discharge no lower than 20%, which would leave 80% of the battery capacity. In this instance, with only 80% of the battery capacity, the range in the above example would reduce by 20% to 21.7 miles.


Acceleration Test Results

The acceleration test is straight forward, how fast does it get from zero to the desired speed?

  • Max Speed Throttle Only: 20 mph (non-adjustable)
  • Zero to 20 mph Throttle Only: 15.4 seconds
  • Max Assisted Speed: 22 mph (non-adjustable)
  • Zero to 22 mph with zero effort spinning: 17.8 seconds
  • Zero to 22 mph with moderate pedaling: 14.5 seconds
The Rough Rider was slightly slower with zero effort pedaling vs. throttle only. I attribute this to the battery being slightly more discharged as the throttle only testing was completed first. In addition, their was a slight lag with pedaling until the cadence sensor kicked in the motor. You'll also note that the acceleration to 22 mph is recorded with moderate pedaling effort. The target for this is 150 watts of pedal power, and for this testing, the average was 149.5 watts.

As a comparison, a Magnum Metro+, which also claims a 500 watt geared hub motor achieved 20 mph in 12.4 seconds with throttle only, where the Rough Rider achieved 20 mph in 15.4 seconds. The Rough Rider is heavier and has much larger wheels and tires which explain the slower acceleration rate.


Hill Climb Performance

For the Hill Climb Test, the Rough Rider climbed 0.25 miles up the mile long Ice Pond hill using only the throttle before coming to a stop. It's average speed for this portion was 9.7 mph.

For the 100 watts of pedaling portion, the assist was set to the highest level. The Rough Rider completed entire one mile long hill with an average speed of 10.7 mph in a time of 5:32. The average rider input was 99 watts. Given the weight and tires, the rough rider performed the hill climb nearly as well as the Metro+ (which completed the entire hill in 4:50).