Bosch CX gen 4 swap for gen 5?

[nickf]

I'd be interested in swapping out a gen 4 Bosch CX for the new gen 5 in my 2022 Trek Rail. I know that the new Bosch model has different mounting holes so it is not directly interchangeable. However, the old gen 4 was actually fitted into the bike frame by means of intermediate fixing plates that bolted both onto the motor and also into the frame.

It seems to me that it should be possible to create a new set of fixing plates with new bolt patterns that would accept the gen 5 motor. Does anyone know if this has/can be done? I seem to recall that in one of Rob's podcasts they mentioned that the gen 5 motor was presented to the journalists at its launch in a Pivot Shuttle bike that normally ran a gen 4 motor. So the assumption is that Bosch had created precisely the kind of adapter plates that I am thinking of.

Given that it might be possible to mechanically fit the new motor into my old Rail, I am guessing that it would also be necessary to use the latest battery models and controllers which would probably require some additional fettling?

 

[RustyMTB]

Far as I know, the Gen 5 is a Gen four with some refinements. I'm interested in the idea but wonder if an adapter bracket might be the least of your problems if you see what I mean? If they've changed anything in the software, that would likely kill it off but I'm here with popcorn for the experience.

 

[megabobra]

I'm keen for this too!

 

[nickf]

My 2022 Rail was the last of the "non-smart" Bosch models. Bosch now has a range of batteries including the new 400, 600 and 800Wh formats that go with the gen 5 motor. But it looks as if the older format 625 and 750Wh batteries come in both "smart" and "non-smart" versions, so I'm guessing there's some special sauce in the BMS that makes them compatible with the smart system. If that's the case then I would probably also have to swap out my old battery and controller for "smart" versions, but maybe someone with a post-2022 bike wouldn't need to do this.

If it turns out that the gen 5 motor is only compatible with the new format batteries then that would certainly add significant complication because the dimensions and form factor of these batteries are quite different to the previous versions, so quite a lot of cunning fettling would be required to fit them securely into the down tube.

 

[RustyMTB]

Happy to be corrected but I'm fairly sure the 750 is smart system only. I'm also running a 625 non smart & would definitely fit a 750 if I could. If I'm right, then you are into a whole system swap at which point it becomes an exercise in fabrication to fit new stuff to an old frame.

 

[robbydobs]

Bosch do everything they can to stop you doing this. You can't officially even buy the motors, and even if you got one, you'd need a shop/dealer to contact Bosch to download a file to program the motor, unless you get one programmed for a different bike. But should you ever get problems with it, you'd need to visit a dealer and Bosch won't touch it.

You'd also need to buy new charger, display, controller, battery mounts and battery, and then fabricate a way to fit it all.

It's getting more and more difficult to do stuff like this, with encrypted communication protocols and stuff. Maybe they are worried about fires if people mess around with them too much.

It'd be easier to get an open source motor controller, like VESC, and then get a Pi/Arduino thing to control it all and replace all the electronics.

EBike / EScooter modular DIY OpenSource electronics and software

 

[nickf]

Bosch do everything they can to stop you doing this. You can't officially even buy the motors, and even if you got one, you'd need a shop/dealer to contact Bosch to download a file to program the motor, unless you get one programmed for a different bike. But should you ever get problems with it, you'd need to visit a dealer and Bosch won't touch it.

You'd also need to buy new charger, display, controller, battery mounts and battery, and then fabricate a way to fit it all.

It's getting more and more difficult to do stuff like this, with encrypted communication protocols and stuff. Maybe they are worried about fires if people mess around with them too much.

It'd be easier to get an open source motor controller, like VESC, and then get a Pi/Arduino thing to control it all and replace all the electronics.

EBike / EScooter modular DIY OpenSource electronics and software

Some good points. Essentially there are two elements to this project: the "technical solution" and the "Bosch support consequences".

For the former, you may be right that we'd need to replace all the electrical elements along with the new motor. That would be costly and require some ingenuity to mount the new format battery, but the new 600Wh is only a few mm wider/longer than the old 625Wh version, so in principal it should fit into the downtube. But we might just be lucky and find that the new motor is compatible with the previous smart batteries, in which case there would be much less work involved. I am still optimistic that some technical skills and a determined mind could make it work, even if that did indeed require swapping out the whole electrical system.

I am less optimistic regarding your valid points about the consequences for support from Bosch with this modification. And I haven't even addressed the issue of how I'd get my hands on a gen 5 motor in the first place! But many people choose to technically modify their bikes in various ways in order to overide the speed limiter, and they presumably are prepared to live with the hassle in the event that something goes wrong. Moreover, there is also a legal issue with overiding the speed limiter, whereas swapping to a newer model motor is just a commercial inconvenience for Bosch.

The reason why I am even considering this idea is because my high mileage 2022 Trek Rail will soon have effectively zero resale value. But otherwise I am totally happy with it, and the only reason why I'd change it for a newer bike is to have the quieter gen 5 motor. Buying an equivalent new bike is going to cost circa 8K euros, so there are 8000 good reasons to consider swapping the motor system!

 

[Weeksy]

A pair of 22p ear plugs will be £7999.78 cheaper and just as quiet

 

[Doomanic]

The charger/battery uses a different plug/socket so nothing you currently own would be any use. Pre-Smart System bikes are unlikely to have been designed with a bigger batter in mind so the 750 almost certainly won't fit. Better off buying a new bike.

On the flip side of that, there's a Powerfully HT in the Classifieds with Smart System and low miles that's tempting me at the moment, if only the aluminium Rail wasn't such a tank...

 

[BostonDye]

you will not be able to mount a gen 5. But if you have a dealer willing to sell it to you. You could go to a gen 4 cx with the smart system. Using a newer purion and smart system battery. You will spend close to 3000usd and that’s if you can even find someone to sell you a drive unit.

 

[Lee Dove]

Gen 5 has different mounting bolts (2 vs 3 for gen 4) so not physically possible to swap

 

[ValActionT 750]

Bosch do everything they can to stop you doing this. You can't officially even buy the motors, and even if you got one, you'd need a shop/dealer to contact Bosch to download a file to program the motor, unless you get one programmed for a different bike. But should you ever get problems with it, you'd need to visit a dealer and Bosch won't touch it.

You'd also need to buy new charger, display, controller, battery mounts and battery, and then fabricate a way to fit it all.

It's getting more and more difficult to do stuff like this, with encrypted communication protocols and stuff. Maybe they are worried about fires if people mess around with them too much.

In a nutshell, liability I’d say. Reputation too.

 

[Ark]

In a nutshell, liability I’d say. Reputation too.

I'd say the whole thing is a bunch of crap and they don't understand people who own bikes, which is why they think servicing an ebike motor is beyond us...

and locking down motors and making them obsolete on purpose is some weird apple cult think

My next bike definitely won't be Bosch again, and I doubt I'm the only one doing that.

I'm surprised bosch even let users update the firmware

 

[bordim]

I'd be interested in swapping out a gen 4 Bosch CX for the new gen 5 in my 2022 Trek Rail. I know that the new Bosch model has different mounting holes so it is not directly interchangeable. However, the old gen 4 was actually fitted into the bike frame by means of intermediate fixing plates that bolted both onto the motor and also into the frame.

It seems to me that it should be possible to create a new set of fixing plates with new bolt patterns that would accept the gen 5 motor. Does anyone know if this has/can be done? I seem to recall that in one of Rob's podcasts they mentioned that the gen 5 motor was presented to the journalists at its launch in a Pivot Shuttle bike that normally ran a gen 4 motor. So the assumption is that Bosch had created precisely the kind of adapter plates that I am thinking of.

Given that it might be possible to mechanically fit the new motor into my old Rail, I am guessing that it would also be necessary to use the latest battery models and controllers which would probably require some additional fettling?

Amigo o conseguiu fazer a substituição do motor, estou com essa dúvida também? Acredito que se fizer um flange com os furos para o motor gen 5 encaixaria o quando 2022 minha bike já é a smart sysyem.
E para resolver o problema para emparelhar o novo motor?

 

[Teodor]

I put my gen 4 625W smart system battery paralel on on a friends gen 5 bike, works perfect. Î put a 545 smart powerpack from my gen 4 to gen 5 bike, works perfect. Bateries, dsplays, controllers are the same, only motors are different on the mounting hole for diferent frames. If you can refit the mounting holes, then you can use a Bosch gen 5 on an 2024 smart system bike. ONLY on smart, not older non-smart sytem.
But there are motors for sale, gen 4 smart, 45 km/h.

Bosch Motor Gen4 Performance Line Speed 85Nm 45km/h 0275007072 BDU490P - NEU | eBay UK

Bosch Motor BDU490P Gen4 Performance Line Speed 85Nm 4. Generation 45km/h 0275007072 inkl. Software - NEU. - 1x BOSCH Performance Line Speed 45km/h Gen4 Motor 0275007072. Motorunterstützung: bis 45km/h.

www.ebay.co.uk

 

[bikefisherguy]

I put my gen 4 625W smart system battery paralel on on a friends gen 5 bike, works perfect. Î put a 545 smart powerpack from my gen 4 to gen 5 bike, works perfect. Bateries, dsplays, controllers are the same, only motors are different on the mounting hole for diferent frames. If you can refit the mounting holes, then you can use a Bosch gen 5 on an 2024 smart system bike. ONLY on smart, not older non-smart sytem.
But there are motors for sale, gen 4 smart, 45 km/h.

Bosch Motor Gen4 Performance Line Speed 85Nm 45km/h 0275007072 BDU490P - NEU | eBay UK

Bosch Motor BDU490P Gen4 Performance Line Speed 85Nm 4. Generation 45km/h 0275007072 inkl. Software - NEU. - 1x BOSCH Performance Line Speed 45km/h Gen4 Motor 0275007072. Motorunterstützung: bis 45km/h.

www.ebay.co.uk

I was about to create a post asking this very question but - this answers it! Thanks

 

[sledgy]

so for a 2024 smart bike equipped system it is feasible to swap in a new Cx5 motor if you can fabricate new mounting bracket to accomodate the motors mounting bolt pattern change V4 to V5 but electronically it would work ?

i read somethign about Bosch dealer needing to do some re-programming etc ?

 

[Teodor]

so for a 2024 smart bike equipped system it is feasible to swap in a new Cx5 motor if you can fabricate new mounting bracket to accomodate the motors mounting bolt pattern change V4 to V5 but electronically it would work ?

i read somethign about Bosch dealer needing to do some re-programming etc ?

For start, sorry for my english, I learned it by my own.


On a gen4 or gen5 smart motor you can fit at home all the units you want: displays, battery, controllers, remote. There are the same units. For example, BRC3300 remote works on both motors, is the same remote. Purion displays is the same on both motors. Baterries was tested personal by me, works perfect on gen4 and gen5, I tested my 625w smart and 545 powerpack, they work. Bosch System Controller BRC3100 is the same. In simple words, if is SMART, only mounting hole are different, EVERYTHING else is the same. ALL smart system components are compatible, regardless is gen4 or gen5.
Kiox 300 Display BHU3600 is tha same ALL over the smart system. All others dysplay can be fitted on all bikes on both motors.
Speed sensor is DIFFERENT, on Bosch gen4 is wired on the rear brake disc, on gen5 is wireless on the rim and the magnet is inside the motor. This is the thing I dont know how to replace. I read you can pus a normal wire sensor on the rear but you have to enable a port at the dealer and remove the sensor magnet inside the motor. This must be studied.
So, if my bike is gen4 smart and I want to put a gen5 motor, it works perfect with my actual components. Cables are the same, end termination of the cables are the same, sockets or what is their name, ROUND in smart, OVAL in non-smart. The only problem is mounting holes, but this is a different discution. We are tolking here about components. It is posible you need, at the first use of the motor, if is brand new, to go to a dealer to fit the System Controller BRC3100 on motor. Because, its NEW motor. The rest you can fit at home, remote, display, lights and all the rest of the posible accesories you can put on a Bosch motor. A lot of bikes dont even have displays from store, they cut expenses I have Intuvia 100 on my bike, works with gen5 perfect. Its not about the motor, its the sistem controler that do the job, all components works with that.

 

[megabobra]

The only problem is mounting holes, but this is a different discution.

Thanks very much Teodor. Can we talk about mounting holes now too?

 

[Teodor]

Thanks very much Teodor. Can we talk about mounting holes now too?

I cant, I know about that only that gen4 has 3 mounting holes and gen 5 has 2. So, its a plate rebuild, you must find a human to build a plate to fit 3 holes to 2 holes, but this is out of my league This is what a mounting plate looks like on gen4, I never took out my motor because the bike is new. I so some bolts from gen5 and I think they use bolts from one side to another, not like gen4, 3 bolts on one side, 3 on the other side. But, this is just from what I supose from what I so from online sell.

Mounting plate gen4:

Bosch Smart System Motor Mounting Plate | eBike24.com

Bosch mounting plate Smart System &#10003 For Performance Line CX motors | Link between motor & frame | Original Bosch spare part &#9658 Buy now!

www.ebike24.com

Bolts:

Bosch Performance Line CX Gen5 screw set. Drive Unit

Bosch screw set for Performance Line CX motor | original Bosch motor screws | narrow & width version | buy now!

www.ebike24.com

And even different producers has different mounting plate for their framea. Motor are the same, but frames are diferent. So...its hard This must be done by hard work, take down the motor, study the plates, sdudy the frame, all frames are diferent, its complicated

 

[Cyclopathic]

Has anyone managed the Gen 5 retrofit yet? I have a beautiful Pivot Shuttle AM and the rattling Gen 4 motor has died, so want to pop a Gen 5 in there, as the frame is otherwise superb!

 

[ValActionT 750]

Will making a cardboard pattern of oringial mounting plates holes, use as a template for where G5 motor bolts go. Then use you fabrication skills to continue a mockup for you bike. It’d be a lot easier if it was a steel frame. Were there’s a will there is almost always a way.

 

[nickf]

Has anyone managed the Gen 5 retrofit yet? I have a beautiful Pivot Shuttle AM and the rattling Gen 4 motor has died, so want to pop a Gen 5 in there, as the frame is otherwise superb!

Have you read the previous comments in this thread yet? It might help.

In summary there are two issues: 1 - fabricating a new bracket to fix the two bolt Gen 5 motor into the 3 bolt frame mounts, and 2 - replacing the electrical components to be compatible with the different Gen 5 electronic system. If your Gen 4 motor is a pre-smart version then you would also need to replace the battery and the charger.. The biggest challenge however is likely to be convincing the new system that it is a legal configuration that won't just be disabled and throw error codes by the Bosch anti-tampering controls.

You're probably better off just fitting a replacement Gen 4 motor.

 

[Cyclopathic]

Have you read the previous comments in this thread yet? It might help.

In summary there are two issues: 1 - fabricating a new bracket to fix the two bolt Gen 5 motor into the 3 bolt frame mounts, and 2 - replacing the electrical components to be compatible with the different Gen 5 electronic system. If your Gen 4 motor is a pre-smart version then you would also need to replace the battery and the charger.. The biggest challenge however is likely to be convincing the new system that it is a legal configuration that won't just be disabled and throw error codes by the Bosch anti-tampering controls.

You're probably better off just fitting a replacement Gen 4 motor.

Thanks. Yes, I've read the thread, this why asking my question, as it's all doable, it's just noone had yet completed it.
Nothing is impossible, and someone will be figuring it out I'm sure.

 

[monty1991]

Ther is gen5 motors forsale on ebay. if ther was and adopter to fit it to a gen4 smart frame it would be a no brainer for some people, me being one of them

 

[bikefisherguy]

Ther is gen5 motors forsale on ebay. if ther was and adopter to fit it to a gen4 smart frame it would be a no brainer for some people, me being one of them

Same here.. Or even a bafang or avinox adapter to replace the Bosch system entirely

 

[Teodor]

The difference on the bolts. Its hard to fit one into the other motor frame. Event the frames are totally different. gen 4 has 2 bolt down on the right, under the motor.

 

[Kiwimike]

What few to no-one realises is that an ebike is sold as a ‘vehicle’. It’s certified by the manufacturer to comply with various standards. Any modification can invalidate that verification, and likely land the shop that did it or the brand / Bosch in serious trouble. That’s why when I swap a motor there’s a load of paperwork, and the software package that comes from Bosch once approved, specifically set up for that bike. For example, if they provide a replacement motor package designed for a 27.5 bike and I install it on a 29’er, the bike will provide pedal assist well beyond 25kph.

That’s why as a shop, I don’t modify anything beyond repair or simple upgrades.

 

[Cyclopathic]

What few to no-one realises is that an ebike is sold as a ‘vehicle’. It’s certified by the manufacturer to comply with various standards. Any modification can invalidate that verification, and likely land the shop that did it or the brand / Bosch in serious trouble. That’s why when I swap a motor there’s a load of paperwork, and the software package that comes from Bosch once approved, specifically set up for that bike. For example, if they provide a replacement motor package designed for a 27.5 bike and I install it on a 29’er, the bike will provide pedal assist well beyond 25kph.

That’s why as a shop, I don’t modify anything beyond repair or simple upgrades.

Thanks Mike, you're very right.
Sadly, my more cynical side knows (doing what I do for a living also), that Bosch do this to enable lifecycle management, and ensure people mainly keep buying brand new bikes, rather than up cycling their old ones with newer motors. Sadly the same in most modern industries as we all know.
So this upgrade can totally be done, but as you say, Bosch will do all they can to stop it being done, instead welcoming buying a new system for £££/$$$ more.
Personally, I wish more motor companies to the model of Polini, where motors are built to last, be upcyclable, and all parts are available for years and years, and software is open source.

 

[Kiwimike]

Thanks Mike, you're very right.
Sadly, my more cynical side knows (doing what I do for a living also), that Bosch do this to enable lifecycle management, and ensure people mainly keep buying brand new bikes, rather than up cycling their old ones with newer motors. Sadly the same in most modern industries as we all know.
So this upgrade can totally be done, but as you say, Bosch will do all they can to stop it being done, instead welcoming buying a new system for £££/$$$ more.
Personally, I wish more motor companies to the model of Polini, where motors are built to last, be upcyclable, and all parts are available for years and years, and software is open source.

The thing is, Bosch didn’t make your bike. Say Cube did. They certified it with Bosch being just one of many components. If they (or Bosch) actively help you modify the bike beyond its certified state, the bike is then potentially illegal. No company law dept is going to take on that risk.

It’s the same with cars - I can’t drop a 1000hp V12 into our Volvo, without it being certified by a specialist mechanical engineer who will give me a an IVA certificate saying it’s safe to be driven on public roads.

The difference being, ebike mfrs and motor brands are required to ensure the bike can’t break the law, and the liability lies with the mfr. A car IVA is about mechanical safety, because all cars are designed to be able to break the law all the time with no mfr liability.