Rohloff SPEEDHUB 500/14 (for mid drive)

[kriskros]

i run a nuvinci 360 with a cyclone 1650w motor...44 1/2v,20amp lipo... 48v,40 anmp controller... often peakinf well over 40amps on hills...no problems at all...put the nuyvinci in mid rage high and run up a longhill[5to6 degrees] and hold 20mphwith no pedaling...max speed high gear 17.8mph... max speed low gear 30mph

 

[MitchJi]

Hi,

Yes todays x rate, that is $1326 US dollars. LBS Was quoting around $1400 last I checked. Will keep looking.

Try google:
http://www.google.com/search?q=rohl...a=X&ei=51H7UaTCN4fpigLjvIDYCA&ved=0CAoQ_AUoBA

 

[Secret1511]

i run a nuvinci 360 with a cyclone 1650w motor...44 1/2v,20amp lipo... 48v,40 anmp controller... often peakinf well over 40amps on hills...no problems at all...put the nuyvinci in mid rage high and run up a longhill[5to6 degrees] and hold 20mphwith no pedaling...max speed high gear 17.8mph... max speed low gear 30mph

Can the nuvinci hold 5kw?

 

[Chalo]

Can the nuvinci hold 5kw?

The old model N171 can. The N360 is not rated for that much power.

 

[speedmd]

The old model N171 can.

I see them listed at 4100 grams? Possible? 9 pounds, wow.

 

[Chalo]

The old model N171 can.

I see them listed at 4100 grams? Possible? 9 pounds, wow.

You read that right. They are heavy.

They also take lots of power, are always in gear, and are just about the smoothest transmission you can imagine. So at least you get something worthwhile along with the weight.

 

[speedmd]

Wonder if it can take the colossus 12KW.

 

[Miles]

I'm curious as to how the efficiency of the Nu-Vinci varies against torque/power throughput... Maybe efficiency starts to drop off beyond a certain level, as it's a non-positive drive?

 

[Chalo]

I'm curious as to how the efficiency of the Nu-Vinci varies against torque/power throughput... Maybe efficiency starts to drop off beyond a certain level, as it's a non-positive drive?

Within human power levels, it's like other gearhubs, with efficiency improving as load increases. That regime probably breaks down at some power level, but I wouldn't know where. I've been told that the N171 carries 30hp on the test stand and I've seen it used as a jackshaft transmission in a motor buggy with probably 20hp. How reliable it is in such circumstances is an open question.

It's not a toothed drive, but it doesn't normally exhibit slippage like a belt CVT.

 

[bobc]

Miles - I think the nuvinci is just plain draggy, there is (allegedly) no slip, so no losses due to slippage. I also believe they "run in" to much lower levels of loss than straight out of the box. Let me repeat my experience in the greenpower races in UK (this is effectively an efficiency contest...) no nuvinci equipped cars have ever done well. Most illuminating was a car called "iwhoosh" which ditched its nuvinci in favour of plain chain reduction last year - whereupon it was transformed into the leading car in its class (won the f24+ championship last year). We put up to 1kW through a nexus 8 (effectively in a 16" wheel) for about 5000 miles in competition & probably as much again in practise & testing with no issues at all in one car, somewhat less in another. We had killed 2 nexus 7's in short order under the same conditions (also the 7 loses 6th & 7th gear when you spin it over ~700rpm).
Quite a few of the richer teams (you know, private schools...) have used rohloffs - I've heard of a few failures but rohloff have always fixed 'em FOC & fast. The issue with the rohloff seems to be that it is extremely positive in its action, the gears change with a bang; the shimanos are somehow smoother. The rohloff IS efficient compared to nexus/alfine, but I don't think by as much as they claim - from what I remember they claim 97% but independent tests reckon it's more like 93%. The nexus in the same test was around 85% & I suspect the nuvinci would be nearer 70%, but I can only go by race performance of other teams for that.

 

[boostjuice]

Taken from: http://www.ihpva.org/HParchive/PDF/hp52-2001.pdf

Keep in mind these data points are taken at wheel rotation speeds, so results will be a bit different at higher RPM's exhibited in a jackshaft arrangement (I suspect slightly less efficient as bearing friction and/or oil-bath lubrication turbulance becomes a more significant source of loss than gear tooth friction).

 

[speedmd]

Thanks for the post and link.

Confirms what I and many long time cyclists have felt. Hard to give up my 17,18,19 tooth hub combo. The 18 is critical in a range filler for me at least.

cheers

 

[bobc]

That ihpva article is the only credible independent source I've seen for efficiency data & the info I was trying to remember above. Just to summarize the figures...
what's not given is efficiency of a fixie - I'd guess at 97 to 98%
Next best is 3 speed hub gears with sachs at nearly 95% and sturmey archer (incredibly) at over 93%
Then comes a deraillieur at about 93%
Then the rohloff at less than 90.5%
Then we get into the cheaper multi gear hubs in the 90% zone (much closer to rohloff than I remember!!!) (my memory stinks....)
To put the nuvinci performance into perspective I'd have to look at the greenpower race team performance from 2011: "iwhoosh's" best performance with the nuvinci was 40.6miles at the southern heat in F24+; in the final after ditching it they went 55miles (at the same track this info available on http://www.bbk-online.net/gpt/). That's an average speed increase of 35%. If this were the only change and the drag were all aerodynamic this would suggest that a power increase of 1.35^3 was available, i.e. x2.5!!! This suggests an efficiency of just 40% for the transmission, which, frankly, I don't believe for an instant, I'm sure it's nowhere near as poor as that.

 

[speedmd]

Hi Bobc

Great article in the ihpv. I am looking for a sachs 3spd in good shape at the moment to play with. The 44/20 was showing 95%, and the 44/16 some 94.5% in a triple setup. The 44/16 max's out at better than 97% when corrected for 300+ watts. Would love to see some of the higher end road doubles with some of the more moderrn cogs and chains tested. Chain lines are better also. Bad comparison to take average efficency of the 27speed when it averages some gears that should never be used.

 

[bobc]

Another point to note from that article was the alarming drop in efficiency of any "cog combo" involving a tooth count of 12 and under.... probably the most important note for chain users. (BTW the small cogs wear out incredibly quickly as well).

 

[Miles]

There was a follow-up to the article in HP52. I've attached HP55 which contains it (it isn't on the HP site for legal reasons....).

 

[bobc]

yeah - not really a follow-up Miles, it's written by Mr Rohloff himself, presumably to justify the difference between their advertising claims and the independent measurements, which he tries to do by questioning the accuracy of their tests, producing his own numbers & questioning the usefullness/validity of their methods.
I think he should have kept his mouth shut. It's a "disappointing" reaction. Those same independent tests fully demonstrate what a superb piece of kit the speedhub is. Absolute efficiency is not the "end of the world" as far as most cyclists are concerned (reliability & ergonomics are more important) - but it was the primary concern for our greenpower racecars. And the speedhub IS more efficient than other mullti geared IGHs. Similarly nuvinci make an incredible piece of kit - but you will not get a straight answer out of them regarding efficiency.

 

[speedmd]

the alarming drop in efficiency of any "cog combo" involving a tooth count of 12 and under

I gave up the 12 tooth cog the past few seasons on my pedal bike. Was running the standard 12-24, 10 speed and never felt good in the 12. Always felt too tall and seemed to want to stall unless I was trying to catch a group while going down hill or had a decent tail wind. Not enough of that on any of my rides to matter much. I traded it for a 13-26, and find myself faster in most every situation with much better climbing speed and got my 18 back which is super efficient and a blessing when trying to hold speed on gradual climbs or in head winds. I give up being able to pedal down hills at 40 + MPH with the 13 topping out in the high 30's but I rarely get dropped going down hill, so it is no real loss.

 

[Chalo]

And the speedhub IS more efficient than other mullti geared IGHs. Similarly nuvinci make an incredible piece of kit - but you will not get a straight answer out of them regarding efficiency.

I am curious about the NuVinci in that regard. Because it's so smooth and has no perceptible drag when freewheeling, and because it has no reference gear ratios to compare under controlled conditions, it's tough to figure out how much loss there is under power. To me, it feels draggier in its lowest ratio range than in the more usual gear range. But in most of its range it feels no less efficient than the couple of Nexus 7 hubs I have-- which is to say, not excellent but not a deal breaker either.

 

[bobc]

Yeah I did a look of searching back in the day because a CVT with automatic control SHOULD have been the perfect A* solution for greenpower....
When the CVT first became available (5 or 6 years ago now) they did make (fairly ambitious) efficiency claims, then quite suddenly all such claims disappeared. This was in a 2 week period after I became aware of them - I'm guessing their engineering dept was saying things to the marketing dept along the lines of "you can't say that in the ads, it's plain wrong....."

 

[speedmd]

I don't believe the Rohloff or any other hub tyranny can be made closer than a few percent poorer than a chain and sprocket the same ratio when it comes to efficiency. Went back through the initial report and it is a bit more clear to me, they are taking what some would consider the worst case in chain drives for the comparison. Using a run of the mill triple and then using 22/12 and a 32/12 is crazy. Who would do that and average it in unless you trying to make it worst case. Even a 44 is small by most crank standards and forces much too small (and inefficient) a rear sprocket to get usable ratios. The expensive hubs seem just a bit too Guchi for my tastes.

 

[Chalo]

Went back through the initial report and it is a bit more clear to me, they are taking what some would consider the worst case in chain drives for the comparison. Using a run of the mill triple and then using 22/12 and a 32/12 is crazy. Who would do that [...]

I speak frankly to you as a longtime cycle mechanic when I say this: Almost everyone who has such gearing cross-chains it between small sprockets. It's not just that those are the first to wear out, which they are-- it's the telltale polished marks on the chainrings and sprockets, and most of all the chances that those are the gears they are in when they've turned their bikes over to me for flat tire repair or whatever. Small/small is one of the most popular gears for most bike riders. I don't know why; it just is. I think that's what a lot of bicycle manufacturers have in mind when they use a bottom bracket spindle 15mm too long for correct chainline.

People cross-chain. Rampantly. That's one of the reasons that gearhubs are a better choice for many people. Most of the folks who are better candidates for derailleurs are not more conscious about how they use their gears, either. They should use derailleurs because they are the kind of folks who say to themselves, "my gears are popping and making noises; I should take my bike into the shop for service when I go on vacation month after next." It's cheaper and easier to repair and replace destroyed derailleur drivetrains than knackered gearhubs, is all.

Anyway, I know working messengers who cross-chain, pedicabbers who cross-chain, and racers who cross-chain. Those ratios are definitely to be considered when deciding what the real efficiency of derailleur drivetrains is, especially in this epoch of short chainstays and 9 or 10-speed clusters. Poor chainline is simply a fact of life anymore, unless you use a gearhub or single-speed with proper initial setup.

 

[speedmd]

Good point Chalo

Lots of dodos out there and no way to edumacate them. You give the best example where electric shifting may have a big advantage so these poor gear choices can be programed out.

 

[Bike_on]

These are standard on optibikes, fyi.

I wouldn't say "standard". The base model still comes with a SRAM 9 speed derailleur. Some kind of internally geared hub should be standard though. Even at a kW I wouldn't subject a customer to a derailleur.

Hm, i thought they eliminated anything like a standard model. When i visited them, i just saw the 850s and 1100's, both with rohloff hubs on 'em. I remember it distinctly since some kind of clutch/gear would slam every time you applied the power hard, due to their shitty controller spitting out large torque spikes every time you even moderately twisted the throttle from 0..

You' all like to Optibash on this forum. How many DIY designers have 1100W mid drive, integrated cables, full suspension, hydraulic brakes and a 19ahr battery? Lots of nit picking and boastful quotes, "My bike has more power. It has poor performance compared to me, etc"

If the Optibashers built a bike that, "every time you applied the power hard, .... controller spitting out large torque spikes every time you even moderately twisted the throttle from 0.." they would be claiming how responsive their controller is and that they have the torquiest bike out there.

Just sayin.

 

[Chalo]

Did someone gore your rat? Just asking.