Nexus 5 or 8

Nebulous

Veteran
Location
Aberdeen
Looking at a Kalkhoff for my wife. Two options, both around the same price. A nexus 8 with 50nm steps 6100, or a nexus 5 ebike hub with a 60 nm steps 6100.

We are struggling to see the difference. The higher torque is appealing and the 5 speed claims to be ebike specific.
Does the 5 have a more limited gear range? Would that matter on an ebike?
 

keithmac

Veteran
The 5 speed hub may be more stout to put up with the increased torque.

If you run out battery you may prefer the extra gears mind!.

Is it same battery on both?.
 
OP
N

Nebulous

Veteran
Location
Aberdeen
Just to say the two bikes are the kalkhoff agattu 1.S advance (8 speed nexus hub gears) and the kalkhoff agattu1.S season. (5 speed ebike nexus hub gears) The second one has the 60nm steps motor, which I think is a newer version.

Priorities are step thru, big battery (we currently carry a spare on an Ebco, using a 400 and a 320 watt) and walk assist.

We are struggling to separate them, and would probably do okay with either, but as usual we like to drill down into the detail.
 
Location
Kent Coast
Just an observation based on my cheap and cheerful Powacycle ebike:
It has 6 speed gears (derailleur) and I never seem to be stuck in an "inappropriate" gear. I would have thought that 5 speed ebike specific gears would be perfectly adequate, unless the rider is very fit and regularly exceeds the 15mph cutoff at which the motor stops. That is not a situation that ever happens to me!
 

Pale Rider

Legendary Member
Nexus hubs have been widely fitted to ebikes since crank drives became popular in the early 2000s.

Nothing to suggest they are anything other than reliable.

Range is not their strong point, so I would go for the one with the widest.

I rarely use top gear on my Rohloff equipped Bosch ebike, but I do use all the others.

The batteries on the Kalkhoffs are interesting for us ebike anoraks.

Routinely, Shimano Steps is offered with a choice of two smaller down tube batteries.

Kalkhoff is unusual in pairing the Steps motor with a chunky behind the seat tube battery, first seen in their early crank drive ebikes, which had a Panasonic motor.

Bosch motors will only work with Bosch batteries, which means a manufacturer has to spec a pairing of the two.

https://www.shimano-steps.com/e-bikes/europe/en/faq

https://www.edinburghbicycle.com/kalkhoff-agattu-1-s-advance-2021
 
OP
N

Nebulous

Veteran
Location
Aberdeen
Thanks - we're heading towards the 8 speed one. Despite the 5 speed nexus hub for e-bikes being released in 2018 its hard to find anyone with real life experience of it. It talks of having a 263% gear ratio, which seems impressive, but then I found a chart saying the nexus 8 has a 400% range.
 

Pale Rider

Legendary Member
Thanks - we're heading towards the 8 speed one. Despite the 5 speed nexus hub for e-bikes being released in 2018 its hard to find anyone with real life experience of it. It talks of having a 263% gear ratio, which seems impressive, but then I found a chart saying the nexus 8 has a 400% range.
The Rohloff has a range of 526% which is hardly excessive even on a crank drive ebike.

Half that would be too much of a compromise in mixed terrain.

The trusty old Nexus 8 is the one to go for.
 

CXRAndy

Guru
Location
Lincs
Are we talking HTC Google phones?
 
OP
N

Nebulous

Veteran
Location
Aberdeen
Just to update this. We bought it, and it has taken a bit of getting used to. It's big, longer wheelbase, 28" tyres compared to 26 and is quite a bit longer. My road bike seems like a toy alongside it.

My wife found it hard work, until I pointed out she is going faster. We rarely hit the 25km/hr limit before, but often seem to now. Average speed is up close to 2 km / hr.

She has also managed to fall off. The gears are an irritation, with a big gap between 5 and 6. In 5 she is spinning too much and then 6 is too high.

In spite of all of that, she is liking it. It has more toys - built in lights, walk assist, more information on speed / cadence etc. The use of battery seems much nuanced and the big battery has a much better range.
 

welsh dragon

Thanks but no thanks. I think I'll pass.
I have a nexus hub on my bike. 5 years old, never goes wrong, never misses a beat and has never needed to be serviced.

Whatever you choose, it will be very reliable. :okay:
 

Pale Rider

Legendary Member
Just to update this. We bought it, and it has taken a bit of getting used to. It's big, longer wheelbase, 28" tyres compared to 26 and is quite a bit longer. My road bike seems like a toy alongside it.

My wife found it hard work, until I pointed out she is going faster. We rarely hit the 25km/hr limit before, but often seem to now. Average speed is up close to 2 km / hr.

She has also managed to fall off. The gears are an irritation, with a big gap between 5 and 6. In 5 she is spinning too much and then 6 is too high.

In spite of all of that, she is liking it. It has more toys - built in lights, walk assist, more information on speed / cadence etc. The use of battery seems much nuanced and the big battery has a much better range.
All the Shimano hubs seem to have odd jumps between some ratios.

From memory, my Alfine 11 had a big jump which may have been between fifth and sixth.

If sixth is 'too high' you could lower the overall gearing by tinkering with the chainring or sprocket.

This would bring seventh and eighth into play, and might have the added benefit of putting the big jump somewhere less irritating in the speed range.
 

Stul

Über Member
My Raleigh has the 8 speed Nexus hub (and belt drive). It seems like a nice combination, but the trip computer has a "change down" (and up) indicator, and it always seems to be telling me to change down when I am in 8 unless I am on the flat/downhill, most of the time it seems to prefer being in 7, and occasionally 6...
 
Top Bottom