Motors · Shimano

Shimano · EP8 series (DU-EP801)

EP801

Shimano's EP801 — the firmware-evolved EP8 — remains the lightweight benchmark of the mid-power class: 85 Nm of torque from just 2.65 kg, tuned for riders who like to spin rather than grind.

Full power from low rider input under the race firmware, flat and strong through the mid cadences, then a steep, early roll-off above 90 rpm.

The verdict

Shimano EP801 is the firmware-evolved DU-EP8: the unit that rewrote the weight column for full-power Shimano e-MTBs at 2.65 kg for 85 Nm, lighter than almost everything else making real torque. The catch was always character. The early EP8 was a high-cadence motor that asked the rider to keep their legs moving and faded if the revs dropped on a steep, low-gear grind.

The EP801 closed most of that gap. The motor is rated at the legal 250 W of continuous power but Shimano claims up to 600 W peak, and on the dyno Velomotion recorded around 562 W at the wheel across the useful 60–110 rpm band — enough, in their words, for it to "play in the same league as Bosch CX & Co." How readily it releases that power now depends on firmware: at launch in 2022 the EP801 hit full assist from a fairly low rider input, and the free Race-Specific Firmware Update of October 2024 lifts maximum support to 400% so roughly 150 W of rider input unlocks everything the motor has — light-legged riders get the lot without standing on the pedals. That 400% figure is the race tune, not the launch baseline.

What hasn't changed is the personality: sporty, lively, efficient on the flat and happiest at a brisk spin. Push past 90 rpm and power tails off sharply — by 110 rpm it has effectively quit — and the descents still bring Shimano's signature coast-clutch rattle. But for its weight it remains one of the most usable, range-friendly trail motors you can buy.

“Featherweight for the torque it makes — just keep your legs spinning and it never runs out of breath.”

Sustained power & heat

How long the headline number actually lasts under sustained climbing load.

any

Holds 85% for 13 min

ebike-lab.de: ~85% retained for ~13 min of hard climbing, then an abrupt ~15% drop and a fast recovery. For the class that 13-min window is mid-pack — better than the old Bosch CX Gen 4 (fades from ~8 min) but the EP801 derates more abruptly and deeply than the Bosch CX Gen 5, which tapers gently and settles around 80% rather than cutting in a step.

Character

Rider input

With the race firmware, roughly 150 W of rider input unlocks full output (mbr); at 2022 launch the EP801 reached full assist from a lower input but at a lower maximum support level. The motor names its modes Eco / Trail / Boost (renamable to High / Normal / Eco in E-TUBE).

On the trail

Sporty and dynamic with a lively, natural-feeling response that comes very close to unassisted riding — but it rewards a high cadence and pushes the rider to keep spinning.

Noise

No reliable dB(A) figure exists — reviewers deliberately skip the meter here because it's the pitch, not the volume, that defines this motor. Under load the EP801 sits roughly mid-pack on loudness, but its tone is a fairly high-pitched whirr that rises with cadence, and on descents the well-known coast-clutch rattle is far more noticeable than the smoother, lower hum of a Bosch Performance CX or near-silent Brose.

Efficiency

A genuine efficiency king on flat ground, edging the Bosch Performance CX; only slightly thirstier than rivals on sustained steep climbs (≈34 Wh/km uphill vs ≈4.8 Wh/km on the flat, per Velomotion).

The case for and against

Strengths

Outstanding power-to-weight — 85 Nm at just 2.65 kg
Full assist from low rider input (~150 W under the race firmware)
Class-leading efficiency on flat terrain
Lively, natural, sporty support feel
Free Race-Specific firmware lifts response and assist to 400%

Compromises

Power drops off sharply above 90 rpm, dead by 110 rpm
High-pitched tone and notorious coast-clutch descent rattle
Slightly thirstier than rivals on long steep climbs
Outright peak/torque now bettered by full-power rivals (Bosch CX Gen 5, DJI Avinox)

How it stacks up

For its 2.65 kg it makes power on par with the heavier ~2.9 kg Bosch Performance CX in the mid-cadence band, and the EP801 finally matches CX-class peak output. It can't sustain assistance at the very high cadences where Bosch and Brose keep pulling, and the newer full-power crowd — DJI Avinox and Bosch's CX Gen 5 (100 Nm) — now exceed it on outright peak watts and torque. But few match its weight or flat-ground efficiency. Note: there is no separate "EP801-RS" hardware — the race tune is firmware on the same EP801 drive unit, so a standard EP801 and a "race" EP801 are physically identical.

OWNER INTELLIGENCE

Most owners report no problems · 7,087 posts from 848 members analysed.

75Clutch rattle / clack when coasting over rough ground · typical onset: From new.

29Random cutouts / system shutdown mid-ride (no error logged) · typical onset: ~1,000 miles is the repeated figure; some cases from 500 miles or after a motor service.

26Water / wet-climate sensitivity (connector corrosion and internal moisture) · typical onset: Seasonal - failures cluster after winter or wet trips rather than at a mileage.

✓37,500 km on one EP8 (Orbea Rise) - owner repaired the roller clutch himself at 24,300 km with donor parts and kept going

Read the full owner report →

Sources: Velomotion — Shimano EP801 motor test · ebike-lab.de — Shimano EP801 dyno · BIKE Magazin — EP801 lab + practical test · Shimano — Race-Specific Firmware Update for EP801 · mbr — EP801 race-winning firmware tune (400% / ~150 W) · Shimano MTB — EP801 series.