Steep Learning Curve in the Peak District.....

[JimB]

Nuvinci is a bad idea.
The new model has a freewheel, so the rear wheel spins like on a normal bike but the transmission loss is still around 18%. If you ride unpowered, it's hard work.

Thanks for your input Trex, in my ignorance of this technology I feared that might be the case but haven't been able to find any reports.

Having said that, if the bike really does manage 112 miles in ideal conditions, unpowered drag is a bit academic

 

[JimB]

Hi Jim,

Price for Nuvinci version is £2399. I have not ridden this type of system before but am aware of people noticing drag. Range depends very much on how you use the bike. I normally half the range quoted but it is largely dependant on assistance level used and terrain as well as rider weight and weather (longer range in warm, sunny weather). Happy for you to send me an email (dw@electrifyingcycles.co.uk) or private message for more information or give us a call. We have three KTM bikes in stock currently. Macina HS is also good which has hub gears and derailleur (SRAM Dual drive).

dw

Thanks again David

I'm going to give this thread, and everyone who has helped, a rest until I've done some more research.

I'll create a new thread in the proper place if I need any more info.

Thanks again.

JimB

 

[Electrifying Cycles]

Good idea and good luck. DW

 

[trex]

Thanks for your input Trex, in my ignorance of this technology I feared that might be the case but haven't been able to find any reports.

Having said that, if the bike really does manage 112 miles in ideal conditions, unpowered drag is a bit academic

Derailleurs don't lose much power through friction, hub gears and the Nuvinci do.
In the case of the Nuvinci, progress in reducing friction loss depends on oil chemistry.
At the contact point, you have two oil surfaces coming into near contact, one surface is the ball and the other the input (or output) disc. The two surfaces are still separated by a little oil. This oil gap is pulled apart by the two sides, cavitation forces line up oil molecules in the gap, thus the oil behaves like a solid rod connecting ball and disc (a solid is no more than molecules that got lined up and can't move out of position). This 'rod' changes immediately back into liquid form a millimeter or so away from the contact point. When a liquid solidifies, it releases heat, widh radiates into the surrounding. This heat loss explains why friction loss of CVT is higher than mechanical (eg Shimano) hub gears.
This loss is only incurred when you ride on the flat or going uphill. Going downhill uses the freewheel.

NuVinci Continuously Variable Transmission - Wikipedia, the free encyclopedia
http://www.fallbrooktech.com/sites/default/files/videos/N360_Datasheet_English_Web.pdf
[URL="http://forum.ctc.org.uk/viewtopic.php?f=5&t=38578&start=30"]http://forum.ctc.org.uk/viewtopic.php?f=5&t=38578&start=30

[/URL]

 

[103Alex1]

JimB, if you want a crank drive hub gear step-through, you could consider the Kalkhoff Agattus which have mechanical hub gears - either Alfine 8-sp or Alfine 11-sp. They're lovely bikes and they ride just like ordinary bikes unpowered or above assist limits.

Derailleurs don't lose much power through friction, hub gears and the Nuvinci do.
In the case of the Nuvinci, progress in reducing friction loss depends on oil chemistry.
At the contact point, you have two oil surfaces coming into near contact, one surface is the ball and the other the input (or output) disc. The two surfaces are still separated by a little oil. This oil gap is pulled apart by the two sides, cavitation forces line up oil molecules in the gap, thus the oil behaves like a solid rod connecting ball and disc (a solid is no more than molecules that got lined up and can't move out of position). This 'rod' changes immediately back into liquid form a millimeter or so away from the contact point. When a liquid solidifies, it releases heat, widh radiates into the surrounding. This heat loss explains why friction loss of CVT is higher than mechanical (eg Shimano) hub gears.
This loss is only incurred when you ride on the flat or going uphill. Going downhill uses the freewheel.

NuVinci Continuously Variable Transmission - Wikipedia, the free encyclopedia
http://www.fallbrooktech.com/sites/default/files/videos/N360_Datasheet_English_Web.pdf
[URL="http://forum.ctc.org.uk/viewtopic.php?f=5&t=38578&start=30"]http://forum.ctc.org.uk/viewtopic.php?f=5&t=38578&start=30

[/URL]

That's interesting - so there is a downside to Nuvinci CVT relative to mechanical hub gears after all !

 

[JimB]

JimB, if you want a crank drive hub gear step-through, you could consider the Kalkhoff Agattus which have mechanical hub gears - either Alfine 8-sp or Alfine 11-sp. They're lovely bikes and they ride just like ordinary bikes unpowered or above assist limits.



That's interesting - so there is a downside to Nuvinci CVT relative to mechanical hub gears after all !

Very interesting info from trex....thanks again!

The info dribbling through to my little grey cells has pretty much put me off the Nuvinci system.

The Kalkhoff Agattu is on my (now very short) list along with the KTM Macina HS 400 which seems to have a very similar spec but with Bosch drive.

JimB

 

[wissy]

Hi and welcome.

Your short list seemed to match my final (and ever changing 'final') shortlist.. I decided on the KTM Macina HS dual 400 from electrifying cycles in the end due to the reach position and varying customer service issues. Another one I almost bought from electrifying cycles was the AVE ones.. Quite a few choices but again the reach was the main issue I recall. I did not want a walkthrough one so that limited choice of frame a bit. Got the sloping frame one as a nice compromise.

The bike is a gem and can now keep up with my partner. The bike is heavy compared to my Boardman hybrid but was really surprised how fast it went unassisted. More difficult to keep higher speed than 15 mph on it and get overtaken. In the wind also brilliant. Gear changes easy and smooth. I now love steep hills...!

 

[JimB]

...........Your short list seemed to match my final (and ever changing 'final') shortlist.. I decided on the KTM Macina HS dual 400 from electrifying cycles in the end due to the reach position and varying customer service issues. .................QUOTE]

Yes Wissy, very nice bike!

I've just spent some considerable time trying to plough through the KTM catalogue (link via Electrifying Cycles site). I wonder if maybe they have too many options. I have been confused over the spec of the bike due to one dealer (not EC above) having a very good picture of the wrong bike and hadn't realised that the one I'd identified (the HS 400) had Sram Dual Drive 8F when I thought it was Nexus 8 hub.

So it seems my final choice pair are not quite as similar as I had thought.

However, having started the other thread about the NuVinci auto drive I've learned a bit more about things and I'm now coming around to thinking that if I don't go NuVinci I will go derailleur so that's now giving the KTMs the edge.

I'm beginning to lose the will to live and apart from anything else it appears that none of my choices are even available in the UK yet. Maybe a car trip to the Netherlands or the like will shortly be on the cards.

I should say that apart from the obvious help and advise I've had here, Dave from KUDOS BIKES has spent a lot of time on me behind the scenes PMing useful information. Thanks Dave!

JimB

 

[Electrifying Cycles]

Always happy to help if you have any questions. I agree KTM range is proabably a bit too larger but there are some great bikes within the range. Welcome to give me a call or send me a pm. I am sure you will be happy with your final choice, whichever bike you choose

 

[JimB]

I should have said I much prefer the battery location on the semi frame (not sure what it's actually called) to the rack position on the stepthru.

Apart from the aesthetics the CG will be a trifle lower ( not make a lot of difference with 15 stone planted up on the seat!) and the frame looks stronger although that could be an illusion.

Thanks again DW, once I've decided I'll be in touch. Just wish I'd started thinking about this a few weeks ago when we did a short freezing tour of Norfolk and must have passed close to your door. But not in the 'Allo, Allo' way.

Close shave for you there!



JimB

 

[Electrifying Cycles]

No worries, you are always welcome to visit perhaps when it is a bit warmer . I prefer battery position on frame as well rather than on rack.