Author Topic: Newton's Laws and perpetual motion engines  (Read 951 times)

mickeg

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Re: Newton's Laws and perpetual motion engines
« Reply #15 on: February 07, 2019, 02:17:02 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.

Danneaux

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Re: Newton's Laws and perpetual motion engines
« Reply #16 on: February 07, 2019, 02:44:29 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.

mickeg

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Re: Newton's Laws and perpetual motion engines
« Reply #17 on: February 07, 2019, 02:55:13 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=

onmybike

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Re: Newton's Laws and perpetual motion engines
« Reply #18 on: February 07, 2019, 03:31:47 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/

John Saxby

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Re: Newton's Laws and perpetual motion engines
« Reply #19 on: February 07, 2019, 03:59:39 AM »
Thanks for that reference, Syd.  Cyclingabout is usually good value.

Cheers,  John

Andre Jute

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Re: Newton's Laws and perpetual motion engines
« Reply #20 on: February 07, 2019, 07:12:44 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.