Advice needed

[rsyme]

Any advice for a person about to buy a first pedelec on Kalkhoff Agattu i8 v's KTM Macini with the Nuvinci gears? How good are the Nuvinci gears? Are they reliable?

Cheers!
Robbie

 

[Jonah]

You can get a Kalkhoff with the Nuvinci gears (Sahel i360 Harmony) or a KTM Macini with Nexus 8 (or Alfine 11) so really it comes down to a choice between the Impulse and Bosch motor / battery combination. In my opinion, both motors are great, smooth and powerful. Bosch slightly noisier but not significantly. Battery range is significantly greater on the Kalkhoff so if you want greater range this would be the obvious choice.

With respect to the Nuvinci gears, I haven't heard a bad word against them. Smooth and effective and well suited to an electric bike where the marginal increased inefficiency is of less consequence.

Try them both if you can - you're unlikely to be disappointed by either bike.

 

[flecc]

The NuVinci has proved to be very reliable and has the highest torque loading ability of any bicycle hub gear. Have no fears on that account. It's not quite as efficient as other types of bike gears, but on an e-bike that's not important, given the added motor power.

 

[Electrifying Cycles]

Also a larger number of Bosch powered bikes with NuVinci including Harmony e.g. Blue Label, KTM, AVE etc. So plenty of choice

 

[Croxden]

Zeb has a problem with derailleur gears, ah the joy, the fun, the expense. That is why I went for the NuVinci, no regrets at all.

 

[greyhound_dog_1]

After several winters of freezing cables, adjusting derailleurs and occasionally emergency stopping in traffic and ending up in the wrong gear, I have been trying bikes with different hub gears debating if my next bike should go this way.

From trying bikes and reading around, I came to the conclusion that: since mid-motor drive through pedals or chain, it takes a fraction of a second to come 'off load' when you stop pedalling. As such, basic nexus has issues with rapid shifting under load (it won't), alfine is better shifting under load but I've read thiese hubs are not particularly reliable long term, due to complexity. Nuvinci N360 shifts under load, has reasonable gear range, by design is very reliable. Every post I read on the N360 has people praising how bullet-proof it is...also seems these are the preferred weapon of choice for people doing trans-america cycling. Thanks Flecc for the confirmation.

I am looking forward to trying an electrically operated/autoshift Nuvinci Harmony, which would seem to be the ideal solution to winter freezing cables too.

 

[Deleted member 4366]

I've bought one for my GNG mid-drive that I run at 1200w from the battery, so we'll soon know how robust they are. I'm just waiting for the rim and spokes to arrive. They should come early next week.

 

[rsyme]

Decided to go with a Kalkhoff Impulse Ergo. Seems to be the best of both worlds with decent range and NuVinci gears.

 

[103Alex1]

^^ Good choice. Hope you enjoy .

The only reservation I have with Nuvinci is the gearing range. It's about 350% vs the Alfine 11's 409%. If you use highest / lowest gears a lot (and I personally use the highest gears on my Alfine 11 a great deal as well as the 1st / 2nd on very steep hills) then my thoughts are the Nuvinci just won't be enough. But for less performance expectations I think it would suit moderate cycling fine, a bit like an automatic car vs a manual sports car. Alfine 11 has given me no problems with loading - but the chain needs to be kept tight. It's not particularly complex !

I've only had a test ride on Nuvinci on a pretty tame slope and also not taken it on a long steep downhill where I'd want to use a very high gear and so can't compare from personal experience unfortunately.

 

[Deleted member 4366]

I can just make the Nuvinci slip if I use too high a gear up hills, but that's with about 25 amps showing, so it would be fine with a Bosch or Pansonic motor. Apart from the extra weight, there doesn't seem to be any loss of efficiency.

 

[trex]

Is it possible to build a NuVinci system into a crank motor?

 

[Deleted member 4366]

Is it possible to build a NuVinci system into a crank motor?

You could build it into any motor, but it wouldn't make sense to do it with a crank motor. The reason for crank motors is to be able to use the gears. If the gears are already in the motor, you could drive the wheel directly.

 

[Kudoscycles]

When I first rode the Nuvinci system I didn't like it but the latest Nuvinci is so much better,now smooth change,lighter weight,lower drag.
I spoke to the Nuvinci people at Eurobike,they were amazingly helpful and know their product,in contrast to the Shimano tech guys who were very unhelpful.
One big advantage of the Nuvinci is if you get a puncture...its a simple clip to disconnect the gear cable and then the wheel drops out as simple as any bike,reattach and the system needs no readjustment.
I didn't get an opportunity to try the full auto change Harmony system but it looked well engineered,maybe wait awhile for production and r&d to settle down.
Crank drive needs the Nuvinci to overcome the high loading problems of derailleur gears and chain....Shimano tech guys had no gear solution when combined with crank drive they just advised using the Bosch low start software solution but in my opinion this makes the uphill progress so dull,to be honest unless you wanted to spend £1k plus on some Shimano Ultegra electric change fitted to your £10k Specialized or Bianchi they weren't interested,the ultimate bike snobs!!!!
They are the losers,I have a higher budget bike at the spec stage and am at the point of deciding brakes,the Shimano XT levers have no power cutoff so can't be used on a pedelec but even if they could I would use Tektro-Auriga or Magura (lovely but very expensive)just because of the arrogant attitude of Shimano,ok only 120 sets of brakes,peanuts I suppose to Shimano.
Whilst I am having a rant I liked the look of the Cube Step Thru bike but the Dutch guys on the Cube stand basically said that the low volumes of the UK were just not worth bothering with,anyway they would want a minimum order quantity of 50 units.
KudosDave

 

[103Alex1]

Crank drive needs the Nuvinci to overcome the high loading problems of derailleur gears and chain....

Not necessarily - the Shimano Alfine 11 has worked great for me and has a large gear range. Nuvinci is just another hub gear solution. I personally like having manual control of gear shifting and don't think automatic or electric gear shifting is something we all need to be talked into believing is the "right" way forward. After trying the Harmony with auto change I came back and realized I preferred what I had already.

 

[trex]

let's be honest, if you know how to look after your derailleur, how often you bang your chain while changing gears?
NuVincis are heavy and expensive, bought by people with more money than sense.

 

[Deleted member 4366]

They're relatively expensive compared to cheap derailleur gears, so I guess that you're right about people with more money buying them,, but i'd say that they're bought by sensible people because they're the perfect system for a crank-drive bike, especially one with a speed-control controller. You should try one on your bike before passing comments like that. I'd be surprised if you didn't change your opinion.

 

[trex]

Sense: the probability that you break the derailleur is very likely to be lower than that of running out of battery going up a hill, then you'll have to lug the extra 2kgs and pedal 12% harder.
Puncture repairs: more time consuming.
Replacing rim: more time consuming.
The NuVinci has also its points of failure like all other mechanical systems except there is little if no information about them.

 

[Deleted member 4366]

Sense: the probability that you break the derailleur is very likely to be lower than that of running out of battery going up a hill, then you'll have to lug the extra 2kgs and pedal 12% harder. The NuVinci has also its points of failure like all other mechanical systems except there is little if no information about them.

As I said, you should try one before passing judgement.

 

[trex]

well, the popular opinion is that they are rock solid and can't fail.
I just googled NuVinci fauilure, see this:
NuVinci N360 Failed Broken Freehub Body Mechanism - YouTube

and this:
NuVinci N360 breaks during ride - YouTube

Their stories are similar. Conclusion: the technology is still being developed, early adopters beware.
I can see the advantage of having CVT built into the crank motor, if it fails, does not matter, you just carry extra weight but don't have to pedal harder.
The NuVinci pushes the torque limit up a bit - to 130NM - it's good but on hills, human effort and strong crank motors can overwhelm this limit. Even no name derailleur can do better than that.

 

[Deleted member 4366]

I guess anything can break. youtube is also full of videos of broken Bafang motors, Bosch motors and rear derailleurs, so would you advise people not to use them?
broken rear derailleur - YouTube