Author Topic: Whither the future: Thorn's derailleur vs Rohloff bikes  (Read 64148 times)

energyman

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #90 on: December 07, 2015, 09:43:15 PM »
Then of course we could progress onto Pinion gears ?

Bill C

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #91 on: December 07, 2015, 10:01:21 PM »

David Simpson

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #92 on: December 07, 2015, 10:26:25 PM »
I hope I'm not taking this thread off topic...

This is the first I've heard of shaft drives for bikes. Does anyone here have experience with them? What are their pros and cons?

- Dave

Bill C

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #93 on: December 07, 2015, 10:40:51 PM »
i best not have an opinion, but if they make it in carbon Jags will buy one  ;)

David Simpson

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #94 on: December 07, 2015, 10:44:15 PM »
i best not have an opinion, but if they make it in carbon Jags will buy one  ;)

Don't say things like that while I'm drinking. I laughed and the Coke almost came out of my nose. :)

- Dave

Bill C

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #95 on: December 07, 2015, 10:59:59 PM »
i best not have an opinion, but if they make it in carbon Jags will buy one  ;)

Don't say things like that while I'm drinking. I laughed and the Coke almost came out of my nose. :)

- Dave
good i hope it burns, not enough laughter if you ask me
« Last Edit: December 07, 2015, 11:02:23 PM by Bill C »

John Saxby

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #96 on: December 07, 2015, 11:13:07 PM »
Quote
Does anyone here have experience with them? What are their pros and cons?

No hands-on experience with pedal-bike shafties, Dave, but I first saw them on a visit to Québec City in 2008.  The rear half of the bike looked a bit undernourished or denuded, but the combination of bevel drives fore and aft looked elegant, if nothing else. The ones I saw had an IGH, but I don't know what it was. I sorta liked the idea of twin shaftie two-wheelers in yard, Hans the airhead and a pedal-bike cousin, but it never happened, 'cos --

I asked my then-LBS about them, and they said they'd carried the for a season or two, but had encountered reliability problems, and not enough people bought them. I didn't pursue the specifics (IGH?) (novelty only?)

Andre Jute

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #97 on: December 08, 2015, 12:05:52 AM »
I looked into shaft driven bikes about 12-15 years ago but they were too plasticky for me. Even plastic bevel gears. Yech! Biomega dropped them back about then and I took the hint....

Bill C

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #98 on: December 08, 2015, 12:48:41 AM »
the ones i linked to aren't 10/15years old the spec isn't that bad

Tempo Street 8

Specification
Frame 6061 Aluminium with custom hydroformed tubing
Front Fork Chromoly custom
Gearing Shimano Alfine 8 speed premium internal hub
Shifter Shimano Alfine 8 speed rapidfire shifter
Transmission Dynamic Shaft Drive System Crankset
Dynamic forged alloy crank arms 170mm
Brakes Avid BB7 disc brakes with 160mm stainless steel rotors
Brake Levers Tektro alloy 2 finger
Rims Alex double wall alloy with 32x14G stainless steel spokes
Tyres Schwalbe Durano 28mm Folding
Handlebar ZOOM Alloy anodised black flat
Stem FSA 110mm 6 degree stem
Seatpost ZOOM Alloy 400mm
Grips Lock on Red Anodised round grips
Saddle Selle Italia X1 Flow
Weight 11.9kg
Frame Colour Chrome

no idea about how the shaft drive is but they have made an effort at making a reasonable spec bike,
they have spent enough to make me think it might not be that bad, mind you it could just be a polished turd
certainly isn't going to be a thorn, but if shaft drive ever comes of age i'd be try curious, maybe even buy curious

il padrone

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #99 on: December 08, 2015, 07:22:29 AM »
I hope I'm not taking this thread off topic...

This is the first I've heard of shaft drives for bikes. Does anyone here have experience with them? What are their pros and cons?


One of the Five Horsemen of the Cycling Apocalypse  ::) :P :(


Along with:

Oval/ellyptical chainrings
Automatic gears
No-nose saddles
Airless tyres


All first developed for bikes in the 1890s bike boom. All periodically re-invented (about every 5-10 years). None ever truly commercially successful, to the point of mass-market adoption. Much less successful and accepted than the Rohloff  ;D


Quote from: Sheldon Brown
Shaft drive

 An alternative drive system, replacing the chain and sprockets with right-angle bevel gears and a shaft running inside the right hand "chainstay."
Shaft drive was briefly popular around 1900, and occasional attempts are made to revive the design. Unfortunately, shaft drive turns out to have more problems than advantages.

A shaft drive requires heavier frame construction around the bevel gears to maintain their precise alignment under load. The drive system is heavier and less efficient than a good chain drive.

For reasons of clearance, the bevel gears of a shaft drive bicycle must be considerably smaller than the typical sprockets used with a chain drive. The smaller size of the gears causes an increase in the stresses on the whole support system for the shaft. This problem is exacerbated because the stresses from the shaft drive are not perpendicular the triangulated structure of a bicycle frame, and so are not well-resisted. .

Most of the advantages touted by proponents of shaft drive are only advantages compared with open-chain, derailer gear systems. Many proponents of shaft drive use specious (if not dishonest) arguments "comparing" shaft drive systems with derailer gear systems. Any such comparisons are meaningless, it's like comparing apples and locomotives.

A valid comparison of shaft vs. chain drives can only be made if both bikes use the same type of gearing, whether single-speed or with an internal gear system.

These same advantages can be obtained with chain drive using a fully-enclosing chain case, as with old English roadsters and many current Dutch bikes.

Shaft drive proponents also often compare sealed, enclosed shaft drive systems with open, exposed chain drive systems. This is also a misleading comparison. All of the advantages claimed for shaft drive can be realized by the use of a chain case.

Once the shaft-drive's bevel gears wear a bit their efficiency plummets. Whereas a conventional chain drive maintains close to 97% efficiency and loses really very little even when worn.

Devil begone !!
« Last Edit: December 08, 2015, 07:34:35 AM by il padrone »

jags

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #100 on: December 08, 2015, 09:57:25 AM »
i best not have an opinion, but if they make it in carbon Jags will buy one  ;)

Don't say things like that while I'm drinking. I laughed and the Coke almost came out of my nose. :)

- Dave
i seen a fellas nose explode doing that trick not nice.

Bill C

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #101 on: December 08, 2015, 02:02:09 PM »

 Much less successful and accepted than the Rohloff  ;D

shaft drive = Much less successful and accepted than the Rohloff 

so follow that reasoning and ?
rear mech and chain?  Much more successful and accepted than the Rohloff  8)

why fight it derailleurs are still very much better than hubs for a lot of us, and most of the arguments against hub gears are in sheldons description of shaft drive

chain and mechs =
not as complex
not as heavy
not as expensive,
more effcient
greater gear range
easier to remove rear wheel

before you say i'm starting to slag the hoff again remember i didn't know what a hoff was till i signed up here 6 years ago everything i have read about them has been on here,
you lot do Rohloff no favours with all the constant moaning and angst you write on here about them,
to us mech uses it just seems like it really aint worth it after reading all your posts
sorry but i'm impressionable and the impression set here is a lot of expense and constant faffing, not of an ultra reliable worry free bit of kit

ps i hope this post isn't going to provoke more arguments







jags

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #102 on: December 08, 2015, 03:38:38 PM »
but look mechs work to perfection and they don't cost the earth unlike rohloff.
so why build a bike around a rohloff hub.
my buddy  toured around the world few years back on a  thorn nomad  shimano front and rear mechs he didn't have any problems  at least i dont think he had .

David Simpson

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #103 on: December 08, 2015, 05:39:19 PM »
These are valid points, and here are my thoughts.

Disclaimer: I have a Thorn Nomad with a Rohloff, and I think the Rohloff is great (for my purposes).

why fight it derailleurs are still very much better than hubs for a lot of us
That is the key point: "for a lot of us". Derailleurs will be around for a long time, since they work great and have been refined for decades. Those of us who love Rohloffs are not saying that Rohloffs are the best for everyone and every situation. But for certain situation, Rohloffs are superior to derailleurs.

not as complex
True, but complexity must be weighed against the benefits that a more complex device provides. If simplicity was the overall goal of a bike, and we removed any component that contained any hint of complexity, we would end up with walking stick.

not as heavy
True. However, the weight gain of the Rohloff is not as much as some people think, since you need to subtract the weight of the additional chainrings, the front and rear derailleurs, and the sprockets. Also, the weight is concentrated at the center of the wheel, so it has less effect on rotational momentum (acceleration). But yes, the Rohloff does add weight.

not as expensive,
Your honour, my client pleads no contest, except perhaps insanity. Guilty as charged.
[Edit: While the up-front cost is much higher, I believe that in the long run, the Rohloff will actually be cheaper than a derailleur because of its extremely long service life.]

more effcient
Yes, but only slightly. I don't think you would notice the difference. The Rohloff website has a good article about efficiency:
http://www.rohloff.de/en/technology/efficiency/index.html
Ironically, the Rohloff is a German design, and I have never heard of the Germans been accused of inefficiency. :)

greater gear range
Yes, this is true. When I switched from my 27-speed mountain bike to my Nomad, I gave up the top gear. My bottom gears are almost identical, and the top Rohloff gear is almost the same as the second-top gear on my derailluer. Since I ride a lot of hills, I gave up the top gear rather than the bottom gear. I would argue that while you do give up a bit of gear range, a 526% range is still sufficient for most cases.

easier to remove rear wheel
I don't understand this point. In both cases, you undo the axle nut or quick-release and drop the wheel out. Are you referring to needing to reduce the chain tension before removing the wheel on a Rohloff? I've never needed to remove my wheel (so far -- it's only been 2-1/2 years), so I can't remember any additional steps.


sorry but i'm impressionable and the impression set here is a lot of expense and constant faffing, not of an ultra reliable worry free bit of kit
Yes, a lot of expense, but I haven't heard of "constant faffing". (What does "faffing" mean, anyway? Tinkering and adjusting?) Maybe you are referring to different ways of tensioning the chain. I love the Rohloff for the precise reason that I don't need to do adjust, clean, or fix it. I do a lot of riding in the rain, and my derailluer didn't last long with all the road grit in the gears. Also, I ride in city traffic, and have a Rohloff is almost like have a (semi-)automatic transmission. I'm always in the right gear, and changing gears is effortless and always precise.

ps i hope this post isn't going to provoke more arguments
Me too. Debates about the technical merits of a design are good and helpful, but name-calling and personal insults have no place here.

I love my Rohloff, but I realize that it is not for everyone. In the same way, I love my Nomad, but I realize that many people would call me an idiot for commuting up my hills with a heavy bike. I don't care. It works great for me.

- Dave
« Last Edit: December 08, 2015, 06:09:37 PM by davidjsimpson »

Andre Jute

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Re: Whither the future: Thorn's derailleur vs Rohloff bikes
« Reply #104 on: December 08, 2015, 05:56:02 PM »
Are you guys -- Bill and Anto -- for real? You don't compare a Rohloff to an Alivio and then say one is expensive and the other is cheap. The sort of fellow who splashed out on a Rohloff has at least considered a Dura-Ace transmission, or probably had one on his bike, and compared to the number of Dura-Ace transmissions a high mileage cyclist will wear out before a Rohloff breaks down irretrievably (hasn't happened in about twenty years and over 200,000 units, I remind you), a Rohloff is the cheap option.

Not that it matters that the Rohloff is the cheap option, because that's about number 99 on the graded list of considerations; I just mention it because you did. A Rohloff has much more important advantages than that in the long term it will be cheaper than derailleurs. Here's a deceptively simple but very important triplet:

With a Rohloff you have the opportunity to fit a Chainglider and so you don't have the cost of chewed-up trousers bottoms and drycleaning and mending, and you're not getting your hands filthy all the time cleaning the wretched derailleur, and instead of cleaning the transmission daily, you're out there riding.
« Last Edit: December 08, 2015, 06:28:50 PM by Andre Jute »