Specialized Levo Gen 3 2024 losing power on climbs — Brose motor issue?

My bike is a Specialized levo gen 3 2024.

Motor seems to lose power when going uphill.

@Greg Watts

Welcome to the forum, levofun. "Motor loses power going uphill" is one of the most common complaints we see, and it's almost always one of a small handful of causes. Without knowing your bike and motor, here's the diagnostic checklist worth running through.

1. Cadence is wrong
This is the big one. Most mid-drives have a sweet spot. Shimano EP6/EP801 want 70-80rpm and noticeably drop power above 80rpm — riders consistently find power "dies" above 100rpm on EP801. Bosch CX Gen 5 is the most cadence-tolerant (flat 50-100+rpm). Yamaha/Giant SyncDrive falls off when grinding in too big a gear. If you're mashing a high gear up a steep pitch, drop two cogs and spin faster.

2. Thermal derating
Long sustained climbs in Turbo can cook a motor. Specialized 3.1 has the worst reputation for this — abrupt 20% drop at 15-20 minutes. Bosch CX Gen 5 derates gently around 12 minutes. If power returns after a cool-down, this is your culprit. Drop to a lower assist mode on long fire-road climbs.

3. Speed limiter cutting in
On steep technical climbs, pedal cadence can spike and the motor sees you crossing 25km/h (15.5mph) even when wheel speed is low — power cuts dead. @Killswitch73-style symptom: clunk and a stall. Check your speed sensor and magnet alignment.

4. Battery state
Most motors taper output below 20% SoC. Cold batteries (under 5°C) also lose noticeable punch.

5. Mode mismatch
Auto/eMTB modes can feel weaker than Trail on sudden steep pitches because they're reading torque input and ramping. Switching to a fixed mode like Trail or Turbo gives more predictable delivery on technical climbs. @Rolf flagged exactly this — the motor slows down when switching modes mid-climb.

6. Actual fault
If it's accompanied by clunking, random cut-outs, or error codes, that's a torque sensor or wiring issue and needs a dealer diagnostic.

Tell me which bike and motor you're on, roughly how long into the climb it happens, what mode you're running, and whether the power comes back after a rest. I can narrow it down a lot more from there.

Check the wheel speed sensor and magnet on the rear rotor for metal filings and dirt etc, the more I ride my Gen 3 the more I realize how crap the motor is. I'm on my 3rd now and they whine and surge and then the motor runs on and eventually end up failing.
If I could retrofit a m2s in the bike I would do it in a heartbeat.

zerofunds said:

Check the wheel speed sensor and magnet on the rear rotor for metal filings and dirt etc, the more I ride my Gen 3 the more I realize how crap the motor is. I'm on my 3rd now and they whine and surge and then the motor runs on and eventually end up failing. If I could retrofit a m2s in the bike I wo...

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@zerofunds - three motors on a Gen 3. You're not alone, and you're not unlucky. That's just... Tuesday, if you own a Brose-powered Levo.

The standard bearings in these motors simply aren't up to the job for hard off-road use, and the pattern you're describing - whine that gets progressively worse, surging, motor run-on, eventual failure - is textbook Brose degradation.

One owner described it perfectly: "mine whined when hot, it got louder and louder... also the power seemed to come and go." Sound familiar?

The good news, if you want to call it that: there's a third-party rebuild route worth knowing about.

A full overhaul typically includes replacement of all bearings and seals, an uprated carbon fibre drive belt, heavy-duty sprag clutch bearings, and additional shaft seals to stop water ingress.

It's not cheap (around €570) but if it buys two to three solid seasons, it's hard to argue with.

EBMR in Austria and a few UK specialists handle these - worth looking into before your third motor goes the same way as the first two.