Swapping Chainrings

[Hiswitsend]

Hi,

Looking at buying an e-bike and after a couple of short rides on a Cannondale with a Bosch motor and an Orbea Vibe I am nearly convinced and have longer test rides planned this weekend.

However am not really struck by the looks of the Cannondale and it's huge motor and really like the Boardman ADV 8.9e, it's just that I could really do with a larger chainring on the front. Fazua tech support said I would need an FSA Spider to change it, has anyone else done this and how easy is it - I've changed drivetrain on a few of my bikes but not able to get a close look at how the chainring is connected on this motor.

Thank

 

[Hiswitsend]

A bit more digging, I think there was a miscommunication and all Fazua bikes will already have the spider for the chainring

 

[PedalUma]

The key is to find the BCD. You are best off not making a dramatic change in the tooth count and keeping thickness identical.

 

[Marci jo]

If you are still considering the Cannondale here is some info on the Bosch motors. Basically, changing the gears may trigger an error code and shut off the motor. Too bad because Cannondale knows how to make a lighter weight ebike.

Going to a larger front chain ring on a gen 4 motor

@stephen-Bosch Team, or anyone else that has a definitive answer to my question: I have a Cannondale topstone Neo Lefty 3 that comes stock with a 42T front ring. I've purchased a 46T front ring and I've been told that the motor will need to be reprogrammed (or something like that) before the...

electricbikereview.com

I found the thread while thinking of changing the chainring on my Trek class one with Bosch gen 3 motor. Turned out to be not so simple. An owner should be able to change the gears on their own bike without the darn motor shutting off.

 

[Hiswitsend]

That's great info, thanks. I wondered how the motors for away with such small chainrings in some applications, it sounds like it's not driven directly by the pedals.

I'm not so sure what motor to go for, would prefer a mid-drive but I like the look and simplicity of the Fazua. It is a simpler design of motor that can be left at home (ideal for build packing trips where charging it would be a problem)

 

[Stefan Mikes]

it sounds like it's not driven directly by the pedals.

It's never driven directly by the pedals in mid-drive motors.

Bosch has started using normal size chainrings for Gen 4 motors. Still, you are not allowed to change the chainring size in Bosch motor e-bikes. Fazua is probably easier. No issue with Ebikemotion X35 in Orbea Vibe, as it is the hub-drive motor.

 

[Hiswitsend]

It's never driven directly by the pedals in mid-drive motors.

Ah, had never really looked into it any detail before, can see now that the chainring sprocket on the Fazua is not attached to the arm shaft.

Thanks for the heads up, much appreciated

 

[Hiswitsend]

The detail in the e-mail from Fazua makes more sense now: "Your bike shop should be able to swap it out for you no software changes are needed."

 

[Marci jo]

The best ebike in the world is the one that fits your needs.
Test rides will help narrow the field and also lots of fun.
Of course a pic of your new bike would be great!

 

[Hiswitsend]

Just a pic, pre chainring change

 

[Hiswitsend]

Speed Rocket mudguards and 50T chainring fitted with no issues. Chain was the right length so didn't need to shorten it at all.

 

[PedalUma]

Speed Rocket mudguards and 50T chainring fitted with no issues. Chain was the right length so didn't need to shorten it at all.

Nice mudguards! I got caught in the rain today riding a bike without fenders. What is your motor? It looks clean. Check this paint job. 120Nm.

 

[Hiswitsend]

Cracking paint job

It's got the Fazua motor in it.

 

[PedalUma]

Cracking paint job

It's got the Fazua motor in it.

THAT is why it is so clean! I love it. Nice bike. Stealthy. How does it like the new chainring?
This green one is one that I made yesterday and delivered today. The outer chainring was intended to merely function as a decorative chainguard. But in the upper register of gears it can be used, it is also 50-t. The motor is 750W with a torque sensor. No throttle. The rack holds 120Kg of cargo. The new owner is a green politician. It is a recycled cycle. What do you think of the battery top idea?

 

[Hiswitsend]

It good with the new chainring, the 42T original was just a little on the small side for the commute.

That is a lovely looking machine, some motor was well - is it mounted under the bottom bracket - a very neat installation indeed!

 

[PedalUma]

Once upon a time I used a 58-t. It was very fast on the top end. But would derail itself from the chainring when in the low gears. That was dumb. This chrome one is 50 to a Nexus 8, 16-t cog. I like 50 a lot but usually stick with 42, so as to not overstress the main bearing. The owner of the paint job Christmas bike is duel citizens with the UK/US so I surprised her with a bell.