Short answer: Choose a hub motor for flat, low-maintenance commuting on a budget. Choose a mid-drive for hills, trails, heavy loads and the most natural pedaling feel. The reason is gearing: a mid-drive drives the chain, so in a low gear the same motor puts more torque on the rear wheel than a hub motor can.

How each motor delivers power

A hub motor is built into the wheel hub and turns the wheel directly. Geared hubs use an internal planetary reduction and freewheel when you coast. Direct-drive hubs have no gears, weigh more, and can do regenerative braking.

A mid-drive motor mounts in place of the bottom bracket and drives the chainring. Its power travels through the chain, cassette and rear derailleur, the same path as your legs.

Torque at the wheel: why gears change everything

Spec sheets list torque in newton-meters (Nm), but they measure it in different places. A hub motor's torque is already at the wheel. A mid-drive's torque is at the crank, and the bike's gears then multiply or divide it.

The formulas:

Wheel torque (Nm) = Crank torque x (rear cog teeth / chainring teeth) Thrust at road (N) = Wheel torque / wheel radius (m)

Worked example. Take a 29 x 2.4 in wheel. Rim diameter is 622 mm and the tire adds about 61 mm on each side, so the radius is (622 + 122) / 2 = 372 mm, or 0.372 m.

• Hub motor (illustrative geared hub, 80 Nm at the axle): 80 / 0.372 = 215 N of thrust, in every gear.
• Mid-drive, low gear: the CYC Photon 2 lists 135 Nm max torque. With a 36T chainring and a 42T cog (illustrative cassette): 135 x 42/36 = 157.5 Nm at the wheel, and 157.5 / 0.372 = 423 N.
• Mid-drive, high gear (36T to 11T): 135 x 11/36 = 41.3 Nm, so 41.3 / 0.372 = 111 N.

The mid-drive does not create energy. In the high gear it trades torque for wheel speed, and there the hub pushes harder. The point is that the mid-drive rider can choose; the hub rider gets one fixed ratio.

Wheel size matters for hubs too. The same 80 Nm hub in a 20 in cargo wheel (radius about 0.258 m) gives 80 / 0.258 = 310 N, which is why small-wheel cargo hubs climb well.

For more on picking ring sizes, see CYC chainring options explained.

Hill climbing and heat

How much thrust does a hill need? The force to hold speed on a grade is:

F = m x g x (sin(theta) + Crr x cos(theta)), theta = arctan(grade)

where m is total mass (rider, bike, cargo), g = 9.81 m/s² and Crr is rolling resistance. Aerodynamic drag is ignored because climbing speeds are low.

The commuter needs 114 N. The 215 N hub covers it easily, so a hub motor is a sound choice here.

The cargo case needs 283 N. That is 283 x 0.372 = 105 Nm at the wheel. The illustrative 29 in hub tops out at 215 N, so the rider must supply the other 68 N. The Photon 2 in the 36/42 gear needs 105 x 36/42 = 90 Nm at the crank, which is 67% of its 135 Nm maximum.

That margin matters for heat. Motor torque is proportional to current, and winding heat is P = I² x R. So any motor running at 67% of peak torque makes about 0.67² = 45% of the copper heat it makes at 100%. A hub on a long, steep climb turns slowly, draws high current and heats up. A mid-drive can downshift and keep its motor spinning in a cooler, more efficient range.

Mid-drives are not immune. One owner on the Electric Bike Review forum reported first-generation Photon output derating to 700 to 800W on sustained climbs above 25 mph (source). CYC moved to an inrunner motor with flat-wire windings and a potted core for the Photon Gen 2.

Efficiency and range

Climbing energy is easy to calculate:

E (Wh) = m x g x h / 3600

A 110 kg rider and bike climbing 100 m stores 110 x 9.81 x 100 / 3600 = 30 Wh of potential energy. What the battery spends depends on system efficiency. Using two illustrative values:

• 80% efficient (motor in its sweet spot): 30 / 0.80 = 37.5 Wh per 100 m climbed
• 65% efficient (motor lugging at low RPM): 30 / 0.65 = 46.1 Wh per 100 m climbed

With a 520 Wh pack such as the CYC A-52, that is about 13.9 versus 11.3 climbs of 100 m. On hilly routes, that is where a mid-drive gains range. On flat ground at steady speed, a hub runs near its sweet spot and the gap shrinks.

Real-world data is scarce. One forum owner reported about 16 Wh/mile for a CYC Photon (Gen 1) and about 18 Wh/mile for a Bafang BBSHD on rolling hills. That is one rider and two mid-drives, not a lab test. For hub motors, Grin Technologies' public motor simulator is a good way to model your own route before you buy.

Ride feel: sensors and throttles

• Torque sensor: measures how hard you push and adds power in proportion. It feels like stronger legs. Every CYC Photon and X1 platform uses torque sensing, according to the CYC conversion kit FAQ.
• Cadence sensor: detects that the cranks are turning and adds a set power level. It is simpler and cheaper, and many budget hub kits use one. It can feel on/off at low speed.

Weight and handling

A mid-drive puts its weight low and centered, on the frame. The Photon 2 lists 3.5 kg total, the Photon Pro 4.5 kg, and the X1 Pro Gen 4 5.6 kg. That mass is sprung on a full-suspension bike.

A rear hub puts its weight in the wheel. An illustrative 6 kg direct-drive hub adds 6 kg of unsprung mass for the rear suspension to control. On pavement this barely matters. On rough trails the wheel tracks the ground less well.

A front hub can spin the front tire on loose climbs and loads the fork dropouts, so torque arms matter.

Maintenance and running costs

A hub motor's power never touches the chain. A mid-drive sends its full torque through the chain and cassette, so those parts wear faster.

Cost per 1,000 miles is simple to estimate:

Cost per 1,000 mi = (chain price / chain life in mi + cassette price / cassette life in mi) x 1,000

These lifespans are assumptions for the arithmetic, not measurements. Measure chain stretch with a checker, replace the chain on time to protect the cassette, and shift with light pedal pressure. For high-power builds, CYC sells a reinforced 5-speed Heavy-Duty Drivetrain at $368.

Hub motors have their own cost: a rear flat means disconnecting the motor cable and undoing axle nuts and torque arms. With a mid-drive, the rear wheel comes out like a normal wheel.

Conversion kits: dropouts vs bottom brackets

Hub motor kit fit: - Dropout spacing must match the hub: common widths are 100 mm front, 135, 142 or 148 mm rear, and about 170 mm or wider on fat bikes. - Axle type: quick release, thru-axle, or bolt-on. Many hubs use bolt-on axles only. - Brake: disc rotor mount or rim brake compatibility. - Torque arms, especially on aluminum dropouts and front forks.

Mid-drive kit fit: - Bottom bracket shell width and type. CYC product pages list BSA 68 to 83 mm, BB92, BSA 100 mm and BSA 120 mm. - The CYC FAQ adds PF30, BB30 and T47 through a press-to-thread adapter sleeve. Trek BB90/BB95 frames are not compatible. - Chainstay and chainline clearance for the chainring.

A mid-drive also keeps your original wheels.

Front hub vs rear hub vs mid-drive

If a hub motor suits you: what to look for in a hub kit

CYC builds mid-drives only, but a hub is the right tool for many riders. When shopping for the best hub motor kit, check:

1. Geared or direct-drive. Geared hubs are lighter and coast freely. Direct-drive hubs are quieter, simpler inside, and can regenerate, but are heavier and drag slightly when unpowered.
2. Dropout and axle match for your frame or fork, as listed above.
3. Torque at the axle and wheel size together. Use Thrust = Torque / radius to compare kits fairly.
4. Sensor type. A torque sensor gives a more natural ride than cadence-only.
5. Freewheel or cassette support, so your gearing still works for pedaling.
6. Controller current and battery voltage that match the motor.
7. Parts availability, since a hub failure takes the wheel with it.

Verdict by rider type

If a mid-drive fits your riding, compare the three CYC platforms in the drive system collection and pair one with a pack from CYC batteries. The Photon 2 kit is $950 without a battery, or $1,338 with the A-52. It can be configured to US Class 1, 2 or 3 limits in the Ride Control app. The Photon Pro (3000W rated, 4000W peak, 180 Nm) and X1 Pro Gen 4 (6000W peak, 280 Nm) exceed US class limits and are intended for private land and off-road use.

If a mid-drive fits your riding

These are the three CYC mid-drive platforms. All use a torque sensor and run on 36 to 72V batteries.

CYC Photon 2

Street-legal commuting, gravel and Class 1 trails

750W nominal, 2000W peak, 135 Nm, 3.5 kg

Kit $950 · Photon 2 + A-52 battery $1,338

Shop Photon 2

CYC Photon Pro

Steep off-road climbs, cargo and private land

3000W rated, 4000W peak, 180 Nm, 4.5 kg

Kit $1,098 · Photon Pro + A-52L battery $1,636

Shop Photon Pro

CYC X1 Pro Gen 4

Maximum power off-road builds

6000W peak, dual-stage reduction, X12 controller

Kit $1,250 · X1 Pro 4 + A-65 battery $2,246

Shop X1 Pro 4

FAQ

Is a mid-drive better than a hub motor? Not for everyone. A mid-drive is better for hills, trails and heavy loads because it uses the bike's gears. A hub motor is better for flat commuting, low maintenance and lower cost.

Which is better for hills, mid-drive or hub motor? A mid-drive. In a low gear it multiplies crank torque at the wheel. In our example, the same 135 Nm motor gave 423 N of thrust in a 36/42 gear, compared with 215 N from an illustrative 80 Nm hub on a 29 in wheel.

Do mid-drive motors wear out chains faster? Yes, because all motor torque passes through the chain and cassette. Check chain stretch regularly and shift under light load.

Which is more efficient, hub or mid-drive? On hilly routes, usually the mid-drive, because downshifting keeps the motor in its efficient speed range. On flat ground at steady speed, the difference is small.

Is a front or rear hub motor better? A rear hub has better traction and handling for most riders. A front hub is easier to install and keeps the rear drivetrain stock, but it can spin on loose climbs and needs torque arms on the fork.

Can I convert my bike with a mid-drive kit? If your bike has a compatible bottom bracket, yes. CYC kits fit BSA 68 to 83 mm, BB92, BSA 100 mm and BSA 120 mm shells, with adapters for PF30, BB30 and T47. Trek BB90/BB95 frames are not compatible.

Which motor type is more reliable? Hub motors do not load the chain, so the drivetrain lasts longer. Mid-drives add chain and cassette wear, which you manage with regular checks. Maintenance habits matter more than motor type.

Are hub motors cheaper than mid-drives? Usually, both upfront and in running costs. The trade-off is less climbing ability and a fixed gear ratio.