Brose Motor Servicing
Both the original Brose S&T (Gen-1) motors and the latest Brose SMag motors are very similar internally, the motor casing material and weight is the big difference. When diagnosing or quoting for service or repair, please refer to the questions and answers below for a guide to what the issues may be.
The Brose motor is currently the best motor to service. This motor can be upgraded with stronger belt, stronger sprag (clutch) bearings and fitted with an additional single lip rotary shaft seal, to stop water ingress into the crankshaft, and additional waterproofing... go to our eBike Motor Upgrades page for more information and full pricing.
Brose Full Bearing Overhaul ($714.50)
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All internal drive train parts removed for thorough cleaning and inspection
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All drive train bearings will be removed and replaced with original or better
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New seals, O-rings and circlips fitted
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Where parts are found corroded, failed or worn beyond acceptable limits, the owner will be contacted to discuss options and pricing
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Specialist greases are applied to all relevant surfaces/parts to maximise protection from water ingress and wear
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No belt replacement is carried out with the Full Bearing Overhaul
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Motor is reassembled and tested
Brose SMag Bearing Overhaul+Upgrade ($942.00)
Full bearing/seal overhaul + Brose Upgrade, price reduced where individual bearings not required to be replaced.
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All internal drive train parts removed for thorough cleaning and inspection
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Main Crankshaft bearings removed and replaced
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Uprated latest OEM Brose carbon fibre drive belt
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Uprated motor and crankshaft drive pulley sprag clutch bearing
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Shaft lip seal added to stop water ingress to crankshaft needle bearing
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Genuine Brose bearing cover seal (r/h crankshaft)
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Specialist long-life waterproof grease packed between outer bearings and motor covers. (helps stop water pooling around outer bearings)
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External X-ring crankshaft seal added
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Compromised ECU cover screws sealed to stop water ingress into ECU, circuit board (Gen-1 T/S/TF only)
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Motor is reassembled and tested
Frequently Asked Questions
Does my Brose motor need regular service?
Brose motor should have its drive belt changed after 15,000kms. The rest of the motor is not designed to be serviced and should only be repaired if it starts to fail.
Motor works on walk assist but will not work when I pedal?
This is usually caused by failure of the torque sensor and should be sent to us for torque sensor replacement.
My crank is stiff to turn backwards?
This is normally the first sign that your motor crankshaft needle roller bearing is failing due to water ingress or dust ingress, or a combination... resulting in corrosion or a build-up of dust or grit.
My Brose motor makes cracking, popping or screeching sounds?
A fairly sure sign that one of the two motor clutch bearings are failing. Definitely worth getting this investigated as it will result in complete loss of drive.
My motor runs on when I stop pedalling?
This can be one of two reasons:
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The crankshaft needle roller bearing is badly seized, breaking up or contaminated. This causes the crankshaft and sprocket carrier (torque sensor) to become one or very stiff to turn independently of each other.
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The clutch bearing is starting to fail and the ‘sprags’ (small feet that lock the bearing) are beginning to jam or stick. Both these scenarios allow the motor to continue to add power because it can only see that the crankshaft is still turning. This may happen right up to the cutoff speed.
Brose S & T (Generation-1)
The first generation Brose motors with the original aluminum casing. This is a very strong motor, very quiet and very reliable with various builds of 50Nm, 70Nm and 90Nm torque deliveries.
Brose SMag (Generation-2)
The second generation Brose motor is recognisable by its smaller black magnesium casing. This is an excellent, powerful yet natural feeling motor with 90Nm of torque, although it did have some earlier issues with the first 2019-2020 motor builds. Since that time, the belts have been upgraded to much stronger material and design, and the firmware has been updated to remove unwanted "torque spikes" that were damaging to both the belt and sprag bearings. It is now a very reliable motor, although water ingress is still an issue, like many eBike motors today.