Can I relubricate the bearings?
The bearings in all electric bike (ebike) motors are already greased and should be good for the life of the motor. If the bearing is damaged by water or dirt, it will be permanently damaged and no amount of grease will help. It will only make the inevitable damage go away.

Why are ebike bearings so bad?
Bearings for ebikes are often high-quality, oversized bearings. Much bigger and stronger than they should be. It’s not the bearings fault, it’s usually the environment the bearings are facing.

But what if I just keep driving, loud bearings do last a long time, don’t they?
No, they don’t last long if it’s an e-bike engine that’s been driven in harsh conditions or washed regularly. Let’s look at an example of a crank bearing: As the bearing wears, the balls in the bearing become smaller, which allows the bearing to move and is usually felt as play in the crank. This ‘play’ lifts the bearing seals out of place, allowing water and dirt to enter the bearings, leading to further problems. If you hear the bearings while driving, it’s already too late!

What type/quality of bearings do you use?
We always try to use original or better bearings. There are cases where a manufacturer may prefer to use a bearing with less friction rather than a sealed bearing. For example, if we have noticed that a particular bearing often fails in the field, we will replace it with a better sealed bearing.

How much will it cost to repair my engine?

As a very rough guide for most e-bike engines, the lowest price is around 60 to 80 euros, and the worst case scenario would normally be 250 to 350 euros. (Not usually, but if internal parts need to be replaced, this cost can be exceeded. Again, you will be informed before any work is carried out).

What is the current implementation time?

We are currently working with a timeframe of 10 to 12 working days from the moment your engine arrives with us.

Who should I use to ship my engine?

The courier you choose to send your engine to us is entirely up to you.

What is involved in a comprehensive renovation?

Your engine will first be tested, then all internal parts of the drive train will be removed for ultrasonic cleaning and inspection. All bearings on the drive train will be removed and replaced with original or better ones. New grease will then be applied to all relevant surfaces, and additional specialised lubricants may be used to protect against wear or water ingress. New gaskets, O-rings and clamps will be installed. The engine will then be reassembled. (If any part is worn, you will be informed before we proceed and install the new part).

What is included in the service/repair?

Your engine is disassembled and inspected, then we contact you with a report and price before we proceed with any work. Usually only parts or bearings that have failed are replaced. Often with certain makes of engine we need a complete overhaul.

My engine squeaks, is it the bearings?

Bearings do not usually squeak. When people bring their bikes to us with these sounds, they are the reasons we have so far found for the squeaking or popping of engines of all kinds: loose engine bolts, (causing the engine to squeak against the frame), loose chainring bolts on the spider, loose crank arms, squeaking pedals, squeaking seat stays, squeaking rear suspension links, loose front chainring (usually the wrong type of chainring for a Bosch or worn spider mounts for a Yamaha). Loose spokes in the rear wheel or squeaking rear wheel axle (when we say loose we don’t mean they are not tight, but not tight enough to prevent squeaking).

Is my engine waterproof?

The answer is probably no. At the moment, it would be commercial suicide for e-bike motor manufacturers to seal the motor properly, as this would lead to added friction and reduced battery range. This does not look good on comparison charts when people are deciding on buying an e-bike. Most current bike motors rely on dust seals rather than any special seals against water. This situation is good enough for most road bikes, but bikes used off road will be problematic.

How can I protect my engine from water ingress?

There are customised products for some engines, but not all. There are also some simple steps that can help. Store the bike upright, in a dry place. If you are transporting the bike behind a vehicle, make sure the engine is covered if the roads are wet. Do not direct water spray at the engine, especially at the crankshaft area. Do not cross any water deeper than the bottom of the engine.

If water gets into my engine, will it dry out?

The Yamaha has a small breathing membrane that allows the engine to dry out over time. If there is more than a drop of water, the engine will be in trouble. Most other engines do not have this small membrane, and once the water is inside, it cannot escape. (Engines are certainly not designed for moisture of any kind inside them).

Does my crankset sometimes get stuck when I push my bike out of the garage?

This is because water has entered the bearing during washing or driving. Water will rust the bearing balls on the bearing raceway. This usually means the beginning of the end for the bearing.

Is it OK if I put some oil on the bearings or in the crank?

No! If you think you need to put oil on the bearings, something is already wrong and needs attention. Besides, these engines are not designed to contain oil inside. This can cause problems with the journal bearings, circuits, coatings and lubricants. Above all, it creates a mixture of grease and oil that goes where nothing should be and smears surfaces that should be clean. Even if you only drip a few drops occasionally, it will build up over time.

Does driving in turbo mode cause additional wear or damage to the engine?

Turbo mode adds a little more power through the drivetrain and so the engine may wear out a few kilometres faster than at some of the lower power levels, but in truth we have not seen any difference in any engine that has worn out or failed because it was used at its higher power levels.

Does tuning or chips cause any damage?

We have not yet seen any damage caused by the use of an engine restriction device.

What can cause engine damage or wear besides water and dust?

Slightly higher wear rates are observed for engines used with slow cadence in high gears, so that the engine revs relatively slowly but tries to add full power. Pedalling at higher cadence (rpm) is definitely better and more efficient for the engine. Pedal knocks and bumps can cause damage, but that’s all! As a rule, engines are very resilient if they are well maintained.

When should I have my engine serviced?

Most e-bike engines are not serviced and will last for thousands of kilometres when dry. Yamaha and Impulse engines are the exception to this rule, as they have a special grease that wears off or dries out, which can cause excessive friction and wear. Yamaha and Impulse do not give a recommended distance for this, but in our experience we would service a Yamaha used off road after 2,500 to 3,500 kilometres, and if used on road, 5,000 to 6,500 kilometres. We would recommend servicing the Impulse engine at 2,500 kilometres at the latest.

Can I get more power from my engine?

At the moment, this cannot be achieved in a straightforward way.

Can I exchange my engine for a newer model?

In some cases it might be possible, but not as easy as it sounds. Motors can vary greatly from one model to another; size, type of driver, size and position of mounting screws, type and position of plug for wire connection, etc. All of this can change, along with compatibility with older batteries and controllers. If you are experiencing these problems, then it is usually cheaper and easier to buy a new bike.

All Bosch engines are very different inside. When diagnosing or estimating the cost of a repair, it is very important to know exactly which engine you have. Very often you believe you have a 3rd generation engine when you actually have a 2nd generation engine. I hope this page will help you to correctly identify your engine.

Which generation is my Bosch engine?

Gen 1

Gen 1 Bosch “Classic” Line 50 Nm (2011 – 2014) Mostly fitted to road bikes, but also used on some early electric mountain bikes such as the Moustache and Haibike.
Bosch Gen 1 “Classic”

Generation 2

• Gen 2 Active Line 48 Nm 2014 – 2018 Mostly fitted to road bikes. Early engines were silver, later ones black.
• Gen 2 Performance Line 50 Nm for gear drives, 63 Nm for gearboxes 2014 – 2019 Installed on road bikes and some early electric mountain bikes. Early motors were silver, later motors black.
• Gen 2 Performance Line CX 75 Nm 2017 – 2019 Mostly fitted to Bosch-powered electric mountain bikes and some road bikes. As this motor was installed until 2019 and directly replaced by the Bosch Gen 4 motor, it is often confused with the Gen 3 road bike motor.
  Bosch Gen2 Perfomance Line
  Bosch Performance Line CX
  
  Generation 3
• Gen 3 Active Line 40 Nm 2018 – Still relevant. The road bike engine for flat, city riding and long battery life.
• Gen 3 Active Line Plus 50 Nm 2018 – Still relevant. The road bike engine for city riding with slopes. Same engine, slightly more power, but still better battery consumption.
• Gen 3 Performance Line (not available on CX) 65 Nm 2018 – Still valid. Road bike engine for touring, i.e. longer, higher climbs. (NOT FOR MOUNTAIN BIKES) NOTE: Large chainring not used on the Gen 2 engine.
  Bosch Gen3 Active Line
  Bosch Gen3 Active Line(watch out for the big sprocket)
  Generation 4
• Gen 4 Performance Line CX 75 Nm Mountain Bike Engine. Later upgraded to 85 Nm 2020 – Still current
• Gen 4 Speed Line and Cargo Line motors are also available, but all motors are designed specifically for the task and battery consumption.
  Bosch Gen4 Perfomance Line CX

Does my Bosch engine require regular maintenance?

Bosch motors are not designed to be serviced and should only be repaired if they start to fail. They are sealed for life and will run trouble-free for more than 80,000 km when dry.

My Bosch engine sounds a bit rough, should I keep driving until it stops?

No! If you hear your engine making noise while driving, it’s already too late! Bearings have failed, the balls in the bearing will wear out quickly; as they wear they become smaller, causing the bearing seals to lift out of place, allowing water or dirt to enter the engine directly! All e-bike engines fail in this way when the bearings are worn, and it’s a domino effect. Don’t ignore any change in the volume of your motor, there are limits to what can be fixed.

Why do bearings fail, are they of poor quality?

The bearings fitted in most Bosch engines are of extremely high quality and well sealed, but although the bearing is classified as “sealed”, it is not watertight! Most are water and dust resistant. This is true for 99% of e-bike motors on the market.

Why aren’t ebike engines sealed against water and dirt?

It would be very easy to seal the motor during the design phase, but seals cause friction and friction means battery consumption. It would be commercial suicide for a manufacturer to release a motor that could achieve 10km less than its competitor.

Is my engine squeaking, or are the bearings failing?

Bearings do not usually squeak. Bearings usually rattle, grind, occasionally crunch or jam. They do not normally squeak. Squeaks are usually caused by one of the following:

• Loose engine screws. This causes the aluminium motor casing to squeak against the aluminium frame.
• Creaking of the seat support in the frame (most of the noise is transmitted through the frame and originates in the engine area).
• Loose driver
• If a sprocket spider is fitted (Gen 3 and 4), check the sprocket bolts
• Pedal squeaks
• If a spring link is fitted, check for squeaks in the spring links
• Loose rear wheel axle

Can I get extra seals for my Gen 4 engine?

There is currently no additional protection for the Gen 4 engine, but some pretty good seals are already fitted on this engine. It will depend on your off-road driving, cleaning habits, weather conditions etc how often they need to be removed and re-lubricated.

Will installing the chip damage or wear out my Bosch engine?

We have not seen any damage caused by the use of the device to remove restrictions on the engine.

What can cause damage or wear to my engine other than water and dust?

Slightly higher wear rates are observed for engines used at low cadence in high gears, so that the engine revs relatively slowly but tries to add full power. Higher cadence revolutions (rpm) are certainly better and more efficient for the engine. Pedal knocks and falls can cause damage, but that’s it! Engines are usually very durable if they are looked after properly.

When should I have my engine serviced?

Bosch engines are not meant to be serviced, if kept dry they will last for thousands of kilometres.

Can I get more power from my engine?

Not at the moment.

Can I exchange my engine for a newer model?

In some cases, it might be possible, but not as easy as it sounds. Motors can vary greatly from model to model; size, type of driver, size and position of support screws, type and position of wire connector, etc. All of this can change, along with compatibility with older batteries and controllers. If you are struggling with these issues, then also with chain alignment, crank height, crank position forwards and backwards, etc. Then you have sprocket size, gearing, etc. At the end of the day, it is usually cheaper and easier to buy a new bike at the moment.