Update Nexus 8 into a Alfine 11 HUB

[Dizer]

I'm planning to buy an ebike with the following setup:

- Bosch Active Line Plus
- Nexus 8
- 125T Gates CDX Belt
- 50T sprocket front
- 24T sprocket rear

I'm not quite happy with the gearing setup, i want to decrease the required cadance to go beyond 25km/h

2 options: replace the sprockets or replace the hub.

Replacing the sprockets is questionable, i'm not sure yet which sprockets will fit, i have to respect the required center distance. I don't know the minimum and maximum available center distance of the ebike.

Hence, replacing the Nexus 8 Hub with an Alfine 11 hub will always do the trick.

Question, is this doable? Is it a lot of work? Are there any points that require extra attention? I've never done this, so it will be a mini project.

Bike: https://www.winora.com/en/GB/ebikes/900/2019-sinus-i-r-8-f/?colorId=231&frame=3
Gear calculator: http://ritzelrechner.de/?GR=SNI8&KB=39&RZ=19&UF=2150&TF=90&SL=2.6&UN=KMH&DV=speed&GR2=SA11&KB2=39&RZ2=19&UF2=2150

 

[pn_day]

I've never owned a Bosch system, but believe that they are pretty good at stopping you from bypassing the required speed limit, so would be surprised if your proposal actually worked.

In addition, in the early days of the Alfine there were lots of reports of the 11 being less durable - I read a couple of people who had gone back to the 8 for improved durability.

So in summary, I don't think that this is a good idea. Keep the bike as it is and enjoy it, or get something else would be my advice.

Good luck,
Phil

 

[Dizer]

I've never owned a Bosch system, but believe that they are pretty good at stopping you from bypassing the required speed limit, so would be surprised if your proposal actually worked.

In addition, in the early days of the Alfine there were lots of reports of the 11 being less durable - I read a couple of people who had gone back to the 8 for improved durability.

So in summary, I don't think that this is a good idea. Keep the bike as it is and enjoy it, or get something else would be my advice.

Good luck,
Phil

To be clear, this topic is not meant for tuning, the Bosch ALP engine is a low resistance engine, hence if you cycle over it's support, it will feel as a normal (heavy) bike. Only for that reason i want to adjust the gearing setup.

I'm planning to buy the SG-S7001-11 hub, it should have an improved performance for both E-BIKE and non-E-BIKE usage.

SHIMANO ALFINE Internal Geared Hub Disc Brake 11-speed | SHIMANO BIKE-EU

The SHIMANO ALFINE S7001-11 hub offers a wide 409% gear range and an improved internal structure for better gear engagement. It is approved for E-BIKE and non E-BIKE use and is available in black and silver.

bike.shimano.com

 

[Artstu]

To be clear, this topic is not meant for tuning, the Bosch ALP engine is a low resistance engine, hence if you cycle over it's support, it will feel as a normal (heavy) bike. Only for that reason i want to adjust the gearing setup.

I'm planning to buy the SG-S7001-11 hub, it should have an improved performance for both E-BIKE and non-E-BIKE usage.

SHIMANO ALFINE Internal Geared Hub Disc Brake 11-speed | SHIMANO BIKE-EU

The SHIMANO ALFINE S7001-11 hub offers a wide 409% gear range and an improved internal structure for better gear engagement. It is approved for E-BIKE and non E-BIKE use and is available in black and silver.

bike.shimano.com

Surely it will be better to buy a more suitable bike? what's the cost of converting to 11-speed? £500+ ?

 

[Dizer]

Surely it will be better to buy a more suitable bike? what's the cost of converting to 11-speed? £500+ ?

There are barely any Shimano Alfine 11 ebikes and they are very expensive.

Basically all the belt ebikes have the same setup, except if they have a Rohloff hub or a Shimano Nuvi 360 hub.

The plan was to avoid a derailleur setup, because of the maintenance in the winter.

 

[peter.c]

I have converted a gates belt drive from alfine 8 to 11, I would not recommend it the overall gearing will bog the motor down and the top gears will become useless think super overdrive

 

[Dizer]

I have converted a gates belt drive from alfine 8 to 11, I would not recommend it the overall gearing will bog the motor down and the top gears will become useless think super overdrive

Why did you converted the Alfine 8 hub to an Alfine 11 hub, and what exactly do you mean with: will bog the motor down?

 

[peter.c]

The gates drive gearing was out top gear run out at 20mph legs turning like a mad hamster
the 11 is over geared in top gears the motor will bog down [ risk of burn out ] trying to turn the ratio .
After market rear sprocket is about £90..00 if you can find one with various teeth it will require a different belt to
From personal experience not worth the spend for the gates set up stick with a chain

 

[Nealh]

Stick with the Nexus 8 it is reliable if cared for.
If changing gearing you need ideally to keep 2:1 gear ratio or more for warranty work. Your chain ring needs to be double that of the rear sprocket.
Going under 2:1 = higher torque and possible failure
The internal ratios give the following approx. low and high gear options.
24T sprocket is comparable to 15/46 cassette.
so equivalent to 15,17,20,24,28,32,37,46.
23 = 14/44 14,16,19,23,27,31,36,44.
22 = 14/42 14,16,18,22,26,29,34,42.
21 = 13/40 13,15,17,21,25,28,33,40.
20 = 12/38 12,14,16,20,24,27,31,38.
19 = 12/36 12,13,16,19,22,25,30,36.
18 = 11/34 11,13,15,18,20,24,28,34.
16 = 10/30 10,11,13,16,19,21,25,30

 

[Artstu]

Was about to say pulleys and belts aren't so cheap but you edited before I could quote you Nealh

 

[Nealh]

Yes quite right, Gates drive components aren't cheap if OP is going to be messing. He needs either shop to spec the gearing better or go with chain set up where sprockets are a lot cheaper.

 

[anotherkiwi]

There are barely any Shimano Alfine 11 ebikes and they are very expensive.

There is a reason for that, the motors are specially de-tuned so that the gearbox doesn't break.