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There's a load of info about it somewhere online with Rohloff.
Found this on their website. http://www.rohloff.de/en/technology/efficiency/ I need to look over it when I'm a bit more sober though. Their conclusion seems to be that more research is needed but there's definitely some interesting stuff in there.
Another question, any tests been done into how long hub gears last compared to derailleurs?
Another question, any tests been done into how long hub gears last compared to derailleurs?
Wasn't one of the round the world cyclists a year or so back using a Rohloff? I don't doubt that a well designed hub gear will last a while, but then again a derailleur will last a while as well.
I do wonder what the average mileage of mtbers is though, it is all well and good saying a hub or mech will last, for arguments sake, 20,000 miles, but if the average rider is doing 2000 per year will they really keep the bike for 10 years so that the part has worn out?
The weight and weight distribution issue may be partially solvable by relocating the hub gear to the bottom bracket, quite how i am not sure and I don't know how much this would help with drag, but it would take a major collaboration between Shimano/Sram and Trek/Specialized/etc to get it into the marketplace. I don't think it can be done cost effectively by any niche player. Your going to need a lot of redesigning of frames to accomodate such a move.
There was a link on the [url= http://www.thorncycles.co.uk/forums/index.php?board=25.0 ]Thorn forum[/url] to an article on the [url= http://www.bhpc.org.uk/ ]British Human Power Club website[/url] with some very good research on the drag of hub and derailleur gears.
The link's dead now and nothing comes up with a search for Rohloff on BHPC.
From what I remember, there wasn't a great deal of difference, although I think it depended partly on which gear the Rohloff was in. 11th is direct drive and has the least drag.
With regards to hub gears etc, I refer to a learned fellow on this very forum:
[url= http://www.singletrackworld.com/forum/topic/stu-mcgroos-lets-put-this-alfine-weight-issue-to-bed-once-and-for-all-thread ]Stu McGroos lets put this alfine weight issue to bed once and for all thread[/url]
Seemed to make things pretty clear...
ex-pat, and if i also refer you to that thread, a bit further down the page, it states the hub weighs more. What you also need to consider is what was being upgraded from and to in the original post. It was not like for like.
As i said earlier, you should compare price and weight wise, i am sure that a hub gear could be lighter than some derailleur combos, but wuld comparing £500 of hub with £50 or derailleurs be fair? I think not.
It's not quite that simple though, is it ?
My Rohloff uses one chainring and one sprocket and has very little in the way of external vulnerable components.
Add up the extra cost of replacing three chainrings and a cassette, plus the occasional bent hanger or broken rear derailleur and, over the life of a bike, the price gap narrows.
bluetooth would seem the be the way forward especially now they are working on transmitting power through it too....would mean no wires/cables, infinitely tuneable by pc and easy swapping of bits through pairing
i was thinking earlier how little we as a species have advanced in the last 20 years.....in the 60s we we went from being earth dwellers to landing on the moon....now all anyone cares about is stopping a bit of ice melting! same seems to apply for the bike industry....but thats mostly down to the uci who still think it is the 60's
I read ages ago an article about derailleur efficiency. It reckoned a chain was 98% efficient with a straight chain line but that dropped to 85% or something at acute chain lines, even the ones that you might actually ride.
It'd probably be worse still when your lube wears off and gets replaced by grit and mud.
i was thinking earlier how little we as a species have advanced in the last 20 years
Lol. As you sit here debating an inconsequential subject with hundreds of people all over the country, probably whilst doing something else like working, on a machine that surpasses any 60s engineer's wildest fantasties by a factor of a million on a network that links almost the whole world together..
Irony?
He said "as a species" not our technology
Yes, he said species then went on to talk about technology.
I don't think a species can be expected to advance much in less than a generation.
I would take it to mean human technology rather than humans themselves.
On efficiency if you read the rohloff article it mentions that the efficiency drops depending on ratio.
I can't see a Rohloff being less efficient than a derailleur caked in the Peak District's finest clay?
11th is direct drive and has the least drag.
ie zero as it's direct 1:1 drive 🙂 My simplistic efficiency check was to ride up the steepest hill I could only to find the gearbox casing still at ambient temperature. Any significant friction would have warmed it up at least a little. However, as copiously documented by me previously, the Rohloff cannot tolerate even minor immersion which makes it a non starter for our typical trail conditions 🙁
There will always be some drag, it may be least, but that doesn't mean no drag.ie zero as it's direct 1:1 drive
On the Rohloff, noted the other thread about dodgy bearings, doesn't sound to good on something costing that much. Particularly if they have to go back to Germany for service.
There will always be some drag
OK, yes in the main bearings, same as any other hub, but if there's no relative movement between the internal gears they cannot cause friction.
The Acros A-Gear setup is fully rebuildable. There is 248 individual parts inc 29 bearings that make up the entire set. Because each and every part is made in house, in Germany, a rear mech or shifter etc can be rebuilt from the ground up and you will never need to replace and entire mech.
Provisional pricing is $2300USD or around 1500Euro's/1400GBP.
The 2 small hoses will be combined into one housing per shifter for the production model. Depending on the frames cable routing, its also possible that all 4 hoses can be combined from the headtube back to neaten everything up.
A-Gear was a concept by Christian Muthers that has been realised and bought to life by Acros. Acros had the tooling, finances and power to bring the project to the market and Christian now works for Acros in a development role.
J