Thorn Cycles Forum

Community => Muppets Threads! (And Anything Else) => Topic started by: Andre Jute on January 31, 2019, 02:35:50 pm

Title: Newton's Laws and perpetual motion engines
Post by: Andre Jute on January 31, 2019, 02:35:50 pm
(Reminds me of the person who asked me if the dynahub on the front wheel charged my e-bike battery ;)  )

You get used to it. Even before my bike was electrified, people would ask whether the Rohloff was an electric motor. When I had a waterbottle-shaped battery on the downtube to drive a front hub motor, they wanted to know if the front hub was a generator for my phone. And now that the battery is hidden in a rackpack and the hub dynamo is back on the bike because I have a centre motor, they wonder if the hub dynamo drives the motor.

I suppress the instinct to say something about Newton's Laws and perpetual motion engines.

Whole lotta folk aren't ready for the wonderful world of bicycling yet.
Title: Re: Newton's Laws and perpetual motion engines
Post by: Mike Ayling on February 03, 2019, 09:59:28 pm
We have been asked on several occasions if the Rohloff hub on our tandem was an electric motor.

Mike
Title: Re: Newton's Laws and perpetual motion engines
Post by: Andre Jute on February 04, 2019, 05:16:21 am
We have been asked on several occasions if the Rohloff hub on our tandem was an electric motor.

"Of course not. Nobody yet makes an electric motor that runs the other way round for application Down Under."
Title: Re: Newton's Laws and perpetual motion engines
Post by: mickeg on February 04, 2019, 06:17:33 pm
Bold text added for emphasis:

We have been asked on several occasions if the Rohloff hub on our tandem was an electric motor.

"Of course not. Nobody yet makes an electric motor that runs the other way round for application Down Under."

I fail to see the connection to Coriolis force in e-bikes or in internally geared hubs.
Title: Re: Newton's Laws and perpetual motion engines
Post by: Andre Jute on February 04, 2019, 06:51:20 pm
Bold text added for emphasis:
We have been asked on several occasions if the Rohloff hub on our tandem was an electric motor.

"Of course not. Nobody yet makes an electric motor that runs the other way round for application Down Under."

I fail to see the connection to Coriolis force in e-bikes or in internally geared hubs.

There isn't one. It's a hub-gearbox cyclist's version of the well-known (in Oz anyway) crack about bathtub water swirling anti-clockwise down the plughole in the Southern Hemisphere compared to clockwise in the Northern Hemisphere.
Title: Re: Newton's Laws and perpetual motion engines
Post by: jags on February 05, 2019, 11:41:34 am
 ??? huh  ::) ::)

why would a fella care what others think if it's a motor or not each to there own.
and you know that old saying when someone is being a nosy bugger if your going to tell a lie tell them a god one. ;) ;)
Title: Re: Newton's Laws and perpetual motion engines
Post by: mickeg on February 05, 2019, 04:56:57 pm
I took my truck to a shop to have it worked on.  Put my Nomad on the bike rack on back so I had it to ride home from teh shop.  The shop owner looked at my bike and asked where the battery was, then a long pause and he asked if the Rohloff was a motor or something else.  Since he is a mechanical engineer by training and worked as an engineer before taking over the family auto repair business, I assumed he would be interested so I explained how it had 14 gears, etc.  He was amazed.  He also was not familiar with dynohubs, so had to explain that too.  And the S&S couplings.  He got the full tour.

Title: Re: Newton's Laws and perpetual motion engines
Post by: Andre Jute on February 05, 2019, 10:25:52 pm
Since he is a mechanical engineer by training and worked as an engineer before taking over the family auto repair business, I assumed he would be interested so I explained how it had 14 gears, etc.  He was amazed.  He also was not familiar with dynohubs, so had to explain that too.  And the S&S couplings.  He got the full tour.

Buy a Rohloff, become an unpaid hub-gear educator and prosetylizer.
Title: Re: Newton's Laws and perpetual motion engines
Post by: John Saxby on February 05, 2019, 10:29:38 pm
Appearances can be deceiving...

On our annual spring charity run a couple of years ago, I passed a guy stopped at the roadside, who had a fatbike fitted with what looked to me like a Rohloff -- it was black enamel, and about the size of a Rohloff, with a single sprocket & chain ring, and no cassette at the rear.  So, I wheeled around to ask him if he'd fitted a Rohloff to his bike. "No," he said, "that's an electric motor."  He was moving on, so I didn't look  closely at the device, nor ask him any more questions.

There may well be more of these hubs around Eastern Ontario than Rohloffs, so perhaps it's not so unusual for people to think that our bikes are e-bikes.

(Anto, maybe you could get a used Rohloff, and lotsa people would think you had an e-bike   ;)  ;D  )

Title: Re: Newton's Laws and perpetual motion engines
Post by: mickeg on February 05, 2019, 10:55:12 pm
In USA, Rohloff hubs are quite rare.  I have seen one other on a new Tandem that a bike shop was setting up for the new owner.  I know some people that also have a couple other hubs, but have not seen the hubs.  And as of a few months ago according to CrazyGuyOnABike there are two new Thorn Ravens a few miles from my home but I have not seen them yet.

Thats all the Rohloffs that I know of in a community of about a third of a million people.  And to reiterate, other than mine I have only seen one other with my eyes.  A neighbor is a bike mechanic and mine is the only one he has seen.

Based on that, I am surprised that more people do not ask me where the battery is.
Title: Re: Newton's Laws and perpetual motion engines
Post by: jags on February 05, 2019, 10:55:46 pm
wishful thinking john  ;D
Title: Re: Newton's Laws and perpetual motion engines
Post by: Danneaux on February 05, 2019, 11:08:30 pm
I live in a town with two bicycle factories. One fits Rohloff and Pinion gearboxes to a large number of its offerings, the others just a few. Even so, I rarely see another Rohloff locally, as these companies sell most of their stock outside the area.

More often, the birds (Rohloff's mascot is the raven) fly away rather than nest close to home.

Best,

Dan.
Title: Re: Newton's Laws and perpetual motion engines
Post by: energyman on February 06, 2019, 03:07:50 pm
Talking of Pinions, anybody got one and what are they like to ride ?
Title: Re: Newton's Laws and perpetual motion engines
Post by: onmybike on February 06, 2019, 11:13:05 pm
Talking of Pinions, anybody got one and what are they like to ride ?

I recently hosted a German tourist riding a new Pinion bike. He'd previously toured on a Rohloff bike. I asked him how he found the Pinion and his initial response was the correct one; "ask me in three years". He then elaborated based on the few months he'd been using the Pinion with comment that he liked the extra gear range (he had the 18 speed version) and preferred the feel of the bike when it was unladen as the lighter back wheel didn't feel as 'thumpy' on rough tracks. Apart from that he thought he probably should have stuck to chain drive rather than belt, if only to keep spares commonality with his wife's Rohloff bike and save himself from having to carry a spare belt because of the obvious scarcity of replacements in rural Australian bike shops.

I can understand his 'ask me in three years' comment. As much as I appreciated my Rohloff from the get-go, its best qualities (reliability and low maintenance) get further emphasized with each passing year. Hell, after 10 years and 55,000km+ mine is about to receive its first ever cable change and even then only because I have to replace the twist grip rubber as it's been worn down to a sticky rounded nub, and figured I may as well do the cables at the same time.
Title: Re: Newton's Laws and perpetual motion engines
Post by: Andre Jute on February 07, 2019, 12:38:30 am
I live in a town with two bicycle factories. One fits Rohloff and Pinion gearboxes to a large number of its offerings, the others just a few.

Dan, do you know the price difference between a Rohloff and a Pinion gearbox on roughly the same frame by function from either maker?

Do you know which gearbox do they sell more of?
Title: Re: Newton's Laws and perpetual motion engines
Post by: mickeg on February 07, 2019, 01:17:02 am
I have never seen a Pinion, but have seen photos and youtube videos with them. 

It is my understanding that the 18 speed Pinion has a range of about 636 percent to the Rohloff 526 percent. 

I have commented before that for around home use on my Nomad (Rohloff) bike I use a 44T chainring, but for touring I use a 36 to get lower gears.  I find it intersting that if I had a double set of chainrings and a front derailleur with those two chainrings on my Nomad, I would have a total range of 643 percent, or almost the same as the Pinion.  With my Rohloff narrower range I find that when I am using the 36 on a tour that there are times when I spin out on a shallow down hill, which I probably would not do if I had the Pinion 18 speed.  In that regard I see a clear advantage to the Pinion.

I used to have a range on my Sherpa of 630 percent, but I cut out some of the highest gears, now have a range of 558 percent.  I would like lower gearing than I have, but that would require a different crank which I am not going to bother with.

If I did have a Pinion with that greater range, I would not need to use two sets of gearing like I do with my Nomad where I swap between the two chainrings for different types of riding.

I think that if you wanted one or the other on a mountain bike with full suspension, the Pinion would provide lower unsprung weight.  I am not a mountain biker so I can't say anything about that, but I know that unsprung weight is something that motorcycle enthusiasts get excited about.

A Pinion bike is Pinon only no matter how you look at it.  You can't fit a regular bottom bracket.  I thought for a long time on whether or not I should get the Nomad.  I was nervous about getting a bike that is setup for a Rohloff and excluded a derailleur hanger.  A lot of the other bikes that are set up with Rohloffs have a derailleur hanger option in case you decide that the Rohloff is not for you.  So in that regard if you chose a bike that can use either a Rohloff or derailleur, you have more flexibility than any of the pinion bikes.

I am sure there are lots of other differences, but since i have not seen a Pinion and know nobody that has one, I am quite ignorant of the Pinion bikes.

I have seen photos of a Pinion bike bike with S&S couplers, but I do not know if that bike in my size (I have a 590M Nomad) could be packed in a S&S case due to the change in frame shape.
Title: Re: Newton's Laws and perpetual motion engines
Post by: Danneaux on February 07, 2019, 01:44:29 am
Quote
Dan, do you know the price difference between a Rohloff and a Pinion gearbox on roughly the same frame by function from either maker?
Yes, this is easy to answer because the higher volume maker offers some frames with a choice of gearboxes (keeping in mind they differ at the mounting points and how the drivetrain is tensioned).

One of their popular models is priced this way and the difference between gearbox prices is typical across their line whether production or custom frames (prices in USD$):
• Frame Only ($1995)
• SRAM 2x10 Mountain Kit ($1500)
• Rohloff 14-spd Internal Hub ($3565)
• Pinion 12-spd Gearbox ($3855)
• Pinion 18-spd Gearbox ($4720)

The derailleur option uses a chain, of course, but the sealed gearboxes all use Gates CenterTrack drive belt & rings. Generally, OEM offerings with belt drives seem to be a bit more expensive than chain drive, so keep that in mind when looking at the listed prices.

Quote
Do you know which gearbox do they sell more of?
I believe they have sold more Rohloffs to date because they have been on the market longest, so have the largest sales history. I am not sure how sales break down currently, but I think Rohloffs likely still lead , as they are the cheapest sealed gearboxes offered. Though more than twice as expensive as the 2x10 derailleur drivetrain, the Rohloff looks a bargain compared to either of the two Pinions, but the drivetrains differ in overall gear range, steps between gears, how they fit into the frame, shifting options, and how the driveline is tensioned.

The other factory specializes in folding bicycles and Rohloff drivetrains make up a miniscule number of their overall sales. Their current offering mates the Rohloff Speedhub with a belt drive at a starting price of USD$4295.00. They don't do a Pinion drive bike.

Best,

Dan.
Title: Re: Newton's Laws and perpetual motion engines
Post by: mickeg on February 07, 2019, 01:55:13 am
I was curious on price, so I checked, but Dan was checking at the same time.  So, I deleted the redundant information here. 

The way to read Dan's prices is to add the frame cost to the drive train cost, in other words the 2X10 bike is not $495 USD less than a frame only version.  Add $995 for S&S couplers.  I had heard that about half of their bikes are fitted with a Rohloff. 

I commented recently that I have only seen one other Rohloff in my community other than mine.  It was on a tandem that was made by the same company that Dan provided the pricing for.

Keep in mind that in USA we do not have a VAT tax, so do not try to compare that price to the price of a British bike that is bought in the UK or EU. 

I usually use Reuters for my currency conversion.
https://www.reuters.com/finance/currencies/quote?srcAmt=1.00&srcCurr=USD&destAmt=&destCurr=GBP&historicalDate=
Title: Re: Newton's Laws and perpetual motion engines
Post by: onmybike on February 07, 2019, 02:31:47 am
I live in a town with two bicycle factories. One fits Rohloff and Pinion gearboxes to a large number of its offerings, the others just a few.

Dan, do you know the price difference between a Rohloff and a Pinion gearbox on roughly the same frame by function from either maker?

Do you know which gearbox do they sell more of?

Andre - I've just been on the Tout-Terrain configurator (Dan remove the brand name if I'm crossing any boundaries here) on their website and compared their Tanami models with Rohloff and Pinion options. A Tanami with the 12 speed Pinion (600% range, 17.7% jumps between gears) is a couple of hundred Euro cheaper that the Rohloff equivalent. With the 18 speed Pinion (636%, 11.5% jumps) you're looking at 840 Euros more than the Rohloff but being the top-of-the-range model there may have been other components that added to that difference.

My recent Pinion riding guest said the shop in Germany where he bought his bike told him they sold far more Pinions than Rohloffs... but as fewer shops sell Pinions than Rohloffs you'd have to assume that people who want a Pinion are going to search out the dealers who stock them, so that may not be too surprising.

Nice article here on the weight differences between drivetrains: https://www.cyclingabout.com/weight-difference-between-derailleur-pinion-rohloff-bikes/
Title: Re: Newton's Laws and perpetual motion engines
Post by: John Saxby on February 07, 2019, 02:59:39 am
Thanks for that reference, Syd.  Cyclingabout is usually good value.

Cheers,  John
Title: Re: Newton's Laws and perpetual motion engines
Post by: Andre Jute on February 07, 2019, 06:12:44 am
Thanks Dan, George, Syd. Those Pinion gearboxes, if they will prove as long-lived as the Rohloff, seem pretty well-priced, particularly in Germany, considering their pedigree.

I suppose a Pinion would concentrate the bike's centre of gravity closer to the ground, and to the centre of the bike. But my bike has such a long wheelbase, and is naturally set up for comfortable understeer as a safety measure, that I appreciate the barbell effect of heavy hubs near the extremities for when I want to provoke it. That's one thing I find a disadvantage about the Bafang BB motors, though others may find it an advantage: whether it is a feature or a bug, depends on where you start from.