GMAC Motor System

The basic GMAC system is activated by the hand throttle. When you squeeze the brakes, the system will go into regenerative braking at a set percentage of maximum torque (default: 25%), and in this case the throttle sets the brake level, where depressing the throttle with the brakes activated increased the motor's braking torque up to 100%.

Each system is limited to the road-legal top speed of 28mph. However, with the speed limiting removed (a simple procedure), the top speed varies with wheel size. 20” version = 28mph+; 26" = 32mph+; 700C and 29er = 35mph+. The Phaserunner controller can also increase the top speed beyond these limits (via field weakening) if desired.

The battery life varies based on numerous factors (the power level used, the rider’s weight, the amount of pedal assistance, cargo, terrain, wind, etc). Even a cargo-bike rider using full power can expect at least 20 miles to a charge, and you get 75+ miles on a standard bike using lower power settings, smart regenerative braking, and pedaling normally. Most folks report a battery range between 25 and 45 miles.

The total system weighs 19 lbs, but it replaces your rear wheel, which weighs about 2 lbs. So it will add 17 lbs or so to your bike, but the power it gives you will offset its weight 20 times over!

The GMAC requires a bike with:

1. 135mm rear dropout spacing (almost all mountain bikes, most hybrids, and some road bikes have this)
2. Enough room to mount the battery in the main frame triangle
3. Water bottle mounts on the downtube
4. Disc or rim brakes on the rear

We suggest having this system professionally installed at our Seattle shop, which is included in the retail price. If you're outside of the Seattle area, we can ship it to a local bike shop for professional installation, and will provide $100 in labor credit for that shop and detailed instructions and phone support. If you'd like to install it yourself, please contact us for instructions and a potential discount.

The motor and battery come with a 2-year warranty, and all other parts come with a 3-year warranty. Essentially, that means that any damage not caused by an accident or misuse is covered. See the full warranty here.

It really comes down to how well you, the battery’s owner, care for it. With that said, you can expect a full 500 cycles with the standard charger before the battery life drops to 80% of its original capacity. But with the "Cycle Satiator" charger, you can extend that number to 1,000 cycles or more. We warranty the battery for 2 years with some stipulations (see warranty section for more information).

From completely flat, the standard battery takes 6 hours to charge. However, the Cycle Satiator can recharge the battery in just 2 hours!

Nope. But don’t leave it plugged in for too long (24 hours or more). It keeps the cells from dropping down to their resting voltage and prematurely ages the pack.

No! Actually, it's best to not completely discharge the battery. We suggest you simply recharge the battery overnight after riding, regardless of whether it's completely dead or not.