Chainrings - is this correct?

[hobbes748]

Hey,

I contacted my local Haibike dealer this morning regarding doing some work on my bike. Here's what I wrote...

'Hi. I've got a Haibike Sduro Cross electric bike and I'm finding the gearing a little low for my liking (I only ever use gears 7-9) and as it's for commuting from out of town, 99% of the time it's in 9th. I've no wish to go faster but I'm thinking about putting a bigger ring on the front so I'm not always in top to alleviate a bit of wear and tear. Is there a bigger ring I (you) could put on the front to make something like 7th the same as my current 9th?'

A couple of hours later I got a reply....

'Thanks for your email, unfortunately un-like a standard bike changing the gear ratio is not as simple or some times possible on electric bikes, Looking at your bike specifically which has the Yamaha power unit, chaining the front chainring to in-corporate a larger ratio is not possible, as the motor and the torque settings are set for the ratio on the bike and you are not able to re-colaberate the settings I’m afraid. There is room for tolerances but this would be for the cassette on the rear, if you was to change this yourself the motor will either go to-fast and potentially void any warranty or the motor will get confused and go into a error and not work un-till it is put back to the ratio it is set for.'

It sounds like rubbish to me, but could someone confirm/deny/explain?

Many thanks

 

[Gubbins]

I agree. Sounds like someone from a call centre reading a script without understanding what they are saying.

 

[soundwave]

http://adrenalinatv.co.uk/shop/

they have the bits you will need

 

[Izzyekerslike]

http://adrenalinatv.co.uk/shop/

they have the bits you will need

They are a really helpful company and will no doubt talk you through it on the phone.

 

[Danidl]

Hey,

I contacted my local Haibike dealer this morning regarding doing some work on my bike. Here's what I wrote...

'Hi. I've got a Haibike Sduro Cross electric bike and I'm finding the gearing a little low for my liking (I only ever use gears 7-9) and as it's for commuting from out of town, 99% of the time it's in 9th. I've no wish to go faster but I'm thinking about putting a bigger ring on the front so I'm not always in top to alleviate a bit of wear and tear. Is there a bigger ring I (you) could put on the front to make something like 7th the same as my current 9th?'

A couple of hours later I got a reply....

'Thanks for your email, unfortunately un-like a standard bike changing the gear ratio is not as simple or some times possible on electric bikes, Looking at your bike specifically which has the Yamaha power unit, chaining the front chainring to in-corporate a larger ratio is not possible, as the motor and the torque settings are set for the ratio on the bike and you are not able to re-colaberate the settings I’m afraid. There is room for tolerances but this would be for the cassette on the rear, if you was to change this yourself the motor will either go to-fast and potentially void any warranty or the motor will get confused and go into a error and not work un-till it is put back to the ratio it is set for.'

It sounds like rubbish to me, but could someone confirm/deny/explain?

Many thanks

Why assume it's rubbish. Changing and increasing the diameter of the chainring will increase the torque load on the crank shaft. And this will reflect all the way back onto the rotor in the motor. So of course and being anxious to prevent a kalkoff type situation they will be wary. How is road speed calculated on this model? Does it detect the gear it's in and calculate the road speed from the chain speed or does it use a direct measurement of wheel rotation using magnetic pick up?.

 

[Rutland Cycling]

Hey,

I contacted my local Haibike dealer this morning regarding doing some work on my bike. Here's what I wrote...

'Hi. I've got a Haibike Sduro Cross electric bike and I'm finding the gearing a little low for my liking (I only ever use gears 7-9) and as it's for commuting from out of town, 99% of the time it's in 9th. I've no wish to go faster but I'm thinking about putting a bigger ring on the front so I'm not always in top to alleviate a bit of wear and tear. Is there a bigger ring I (you) could put on the front to make something like 7th the same as my current 9th?'

A couple of hours later I got a reply....

'Thanks for your email, unfortunately un-like a standard bike changing the gear ratio is not as simple or some times possible on electric bikes, Looking at your bike specifically which has the Yamaha power unit, chaining the front chainring to in-corporate a larger ratio is not possible, as the motor and the torque settings are set for the ratio on the bike and you are not able to re-colaberate the settings I’m afraid. There is room for tolerances but this would be for the cassette on the rear, if you was to change this yourself the motor will either go to-fast and potentially void any warranty or the motor will get confused and go into a error and not work un-till it is put back to the ratio it is set for.'

It sounds like rubbish to me, but could someone confirm/deny/explain?

Many thanks

Good Afternoon,

That is the exactly the same information that was provided to me by Haibike when I asked the same question a few months ago. There may be a work-around by getting the motor's software changed, but that is currently not able to be done in the UK.

Your best bet would be to change the rear cassette at this point in time.

 

[soundwave]

i can put any size chain ring on my bosch bike from 13t to 25t and no software problems and i guess it is the same for yamaha motors.

problem is some ppl want to put more effort in and go faster esp if it has a dongle so only option is bigger front chain ring.

otherwise you just spin out but going bigger at the front means less climbing ability.

so i got 2 on mine 18t and 15t for climbing

 

[anotherkiwi]

Which chainring do you have, the 44? There is a 48 tooth https://www.e-bikeshop.co.uk/Haibike-sDuro-Outer-Chainring

I wouldn't go to a 48 tooth on a 28" wheel myself and they don't make a 46 but any 104/110 BCD whichever it is, chainring should fit?

 

[RobF]

Which chainring do you have, the 44? There is a 48 tooth https://www.e-bikeshop.co.uk/Haibike-sDuro-Outer-Chainring

I wouldn't go to a 48 tooth on a 28" wheel myself and they don't make a 46 but any 104/110 BCD whichever it is, chainring should fit?

That link is for an outer of two rings.

I don'r know if the OP's bike has one or two rings.

E-bikeshop won't supply unless the OP bought the bike from them.

Spa is a good supplier of this type of stuff, but the OP will have to do some measuring.

https://www.spacycles.co.uk/m2b0s149p0/Parts-and-Accessories/Components-Gears-Chainrings-Stronglight

 

[chris_n]

What a load of rubbish, it has no idea what gear you are in, the motor only delivers power proportional to your input. It doesn't know what gradient you are on or how heavy you are both of which have a far greater impact on what the motor is doing. If it is possible to get a narrow/wide single chainring in the tooth count you want then that is the one to go for, if you can't get a single chainring then fit an outer ring and modify/replace the chainguide.
It is a standard 104mm bcd spider on the crank.

 

[Danidl]

What a load of rubbish, it has no idea what gear you are in, the motor only delivers power proportional to your input. It doesn't know what gradient you are on or how heavy you are both of which have a far greater impact on what the motor is doing. If it is possible to get a narrow/wide single chainring in the tooth count you want then that is the one to go for, if you can't get a single chainring then fit an outer ring and modify/replace the chainguide.
It is a standard 104mm bcd spider on the crank.

Maybe! Without access to the algorithm, we are both speculating. The software could be using chain speed as measured by revs of the chain wheel and road speed by a magnetic sensor to infer rear gear.

 

[Trevormonty]

Hey,

I contacted my local Haibike dealer this morning regarding doing some work on my bike. Here's what I wrote...

'Hi. I've got a Haibike Sduro Cross electric bike and I'm finding the gearing a little low for my liking (I only ever use gears 7-9) and as it's for commuting from out of town, 99% of the time it's in 9th. I've no wish to go faster but I'm thinking about putting a bigger ring on the front so I'm not always in top to alleviate a bit of wear and tear. Is there a bigger ring I (you) could put on the front to make something like 7th the same as my current 9th?'

A couple of hours later I got a reply....

'Thanks for your email, unfortunately un-like a standard bike changing the gear ratio is not as simple or some times possible on electric bikes, Looking at your bike specifically which has the Yamaha power unit, chaining the front chainring to in-corporate a larger ratio is not possible, as the motor and the torque settings are set for the ratio on the bike and you are not able to re-colaberate the settings I’m afraid. There is room for tolerances but this would be for the cassette on the rear, if you was to change this yourself the motor will either go to-fast and potentially void any warranty or the motor will get confused and go into a error and not work un-till it is put back to the ratio it is set for.'

It sounds like rubbish to me, but could someone confirm/deny/explain?

Many thanks

Most ebikes are geared so there is 2-4 gears available above the 15mph cutoff. Either you are going lot faster than 15mph, which is impressive without assist or pedally very slowly.

 

[chris_n]

Maybe! Without access to the algorithm, we are both speculating. The software could be using chain speed as measured by revs of the chain wheel and road speed by a magnetic sensor to infer rear gear.

Well mine must wonder what the hell is going on as I never do more than 7mph! It didn't die when I increased my chainring size from 38 single to 44 outer and 32 inner.
Bosch may use such algorithms but Yamaha certainly don't.

 

[argoose]

I have a Yamaha sync drive and I change the front chain ring every two minutes. It has a double chainring set up, 28/38. I have had no problem with the motor in either setting

 

[anotherkiwi]

OK so if you have a single chainring any 104 BCD chainring will fit. A narrow/wide might be the best choice to keep the chain on. My choice on a 28 (27.5, 29)" wheel would be a 46 tooth for mixed riding, 48 on the flat and 44 even 42 for hills. You have to have a cadence of about 70 with a Yamaha motor IIRC so if you feel comfortable pulling one of those chain wheels at that cadence on your typical terrain it is the one to choose.

You can mount a spider and have a double chainring on the Yamaha motor. That makes choosing much easier, big one for fast and easy and small one for steep and lazy...

 

[chris_n]

OK so if you have a single chainring any 104 BCD chainring will fit. A narrow/wide might be the best choice to keep the chain on. My choice on a 28 (27.5, 29)" wheel would be a 46 tooth for mixed riding, 48 on the flat and 44 even 42 for hills. You have to have a cadence of about 70 with a Yamaha motor IIRC so if you feel comfortable pulling one of those chain wheels at that cadence on your typical terrain it is the one to choose.

You can mount a spider and have a double chainring on the Yamaha motor. That makes choosing much easier, big one for fast and easy and small one for steep and lazy...

You don't need to mount a spider, the Yamaha motor has a spider capable of taking 2 chainrings as standard although iirc the chainring is on the inside of the spider and the chainguard on the outside. When I changed mine back in the mists of time I had to use different bolts but I was making it a dual as the original bolts were too long.