Advertise on Bikeforums.net



User Tag List

Page 1 of 2 12 LastLast
Results 1 to 25 of 34
  1. #1
    ...poet... timo888's Avatar
    Join Date
    Jul 2008
    Location
    Mid-Atlantic USA
    My Bikes
    bikes
    Posts
    624
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Hub Gears: does near-perfect efficiency really matter?

    Do small gains or losses in efficiency really matter to commuters, multi-modal commuters, and leisure riders?
    "If racers, or even commuting or touring cyclists, could choose optimum gears
    they would be hundreds of meters ahead at the end of 60 km (37 mi)."
    -- The mechanical efficiency of bicycle derailleur and hub-gear transmissions
    Chester Kyle and Frank Berto, in HUMAN POWER: the technical journal of the International Human Powered Vehicle Association NUMBER 52 SUMMER 2001

    Regards
    T

  2. #2
    Senior Member
    Join Date
    May 2007
    Location
    London
    My Bikes
    2011 Jetstream P11 Alfine
    Posts
    858
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I think you have to decide if you are a leasure cyclist or a performance cyclist with sporting motivations or ambitions. If you are the latter, then it is going to matter to you, if you are the former, then as long as the gears are properly adjusted and maintained, I doubt you would know any difference. I'd include casual commuters as leasure cyclists, and also anyone who doesnt have a speedomter on their handlebars.

  3. #3
    Senior Member
    Join Date
    Dec 2005
    Posts
    217
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Don't notice any losses on my 3 speed Sturmey-Archer. Slightly noticeable on Nexus 8 speed, and horribly so on Rohloff 14 speed.

  4. #4
    The Legitimiser Sammyboy's Avatar
    Join Date
    Jul 2005
    Location
    Southampton, UK
    My Bikes
    Gazelle Trim Trophy, EG Bates Track Bike, HR Bates Cantiflex bike, Nigel Dean fixed gear conversion, Raleigh Royal, Falcon Westminster.
    Posts
    4,848
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Theoretically, however, the Rohloff is MORE efficient than the Nexus, isn't it?

  5. #5
    Senior Member
    Join Date
    Feb 2001
    Location
    England
    Posts
    12,419
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    The world record for cycling around the world was set using a Rohloff hub. It probably has more to do with ease of maintenance than simple mechanical efficiency.
    I like my new Alfine hub gears, they dont feel at all draggy.

  6. #6
    Bicycle Repair Man !!! Sixty Fiver's Avatar
    Join Date
    Sep 2007
    Location
    YEG
    My Bikes
    See my sig...
    Posts
    26,411
    Mentioned
    21 Post(s)
    Tagged
    2 Thread(s)
    Efficiency is important when the miles really start to pile up... there are a lot of commuters who log more miles than the most serious roadies.

    The reduced serive requirements of IGHs also cannot be overlooked.

  7. #7
    Senior Member Foldable Two's Avatar
    Join Date
    Aug 2005
    Location
    Vancouver, Washington and Ocean Shores, Washington, USA
    My Bikes
    2 - 2007 Custom Bike Fridays, 2 - 2009 Bike Friday Pocket 8's, Gravity 29'er SS, 2 - 8-spd Windsor City Bikes, 1973 Raleigh 20 & a 1964 Schwinn Tiger
    Posts
    1,312
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by timo888 View Post
    "If racers, or even commuting or touring cyclists, could choose optimum gears
    they would be hundreds of meters ahead at the end of 60 km (37 mi)."
    -- The mechanical efficiency of bicycle derailleur and hub-gear transmissions
    Chester Kyle and Frank Berto, in HUMAN POWER: the technical journal of the International Human Powered Vehicle Association NUMBER 52 SUMMER 2001
    How many casual/commuter type riders do 60 km (37 miles) per ride? Maybe 6 km (3.7 miles) is more like it, therefore the actual advantage would be in the TENS of meters. Not a really noticeable advantage.

    Disclaimer: I am a casual rider, but do stay in Direct Drive as much as possible on my Dual-Drive BF - I use the upper and lower ranges on more extreme terrain. Is there a big difference? I don't know, but will check it out on our next ride by staying HIGH range for the whole ride.

  8. #8
    rhm
    rhm is offline
    multimodal commuter rhm's Avatar
    Join Date
    Nov 2006
    Location
    NJ, NYC, LI
    My Bikes
    1940s Fothergill, 1948 Raleigh Record Ace, 1959 Allegro Special, 1963? Claud Butler Olympic Sprint, Lambert 'Clubman', 1972 Fuji Finest, 1983 Trek 720, 1984 Counterpoint Opus II, 1993 Basso Gap, 2010 Downtube 8h, and...
    Posts
    12,712
    Mentioned
    62 Post(s)
    Tagged
    1 Thread(s)
    Quote Originally Posted by timo888 View Post
    Do small gains or losses in efficiency really matter to commuters, multi-modal commuters, and leisure riders?
    No.
    Quote Originally Posted by timo888 View Post
    "If racers, or even commuting or touring cyclists, could choose optimum gears
    they would be hundreds of meters ahead at the end of 60 km (37 mi)."
    -- The mechanical efficiency of bicycle derailleur and hub-gear transmissions
    Chester Kyle and Frank Berto, in HUMAN POWER: the technical journal of the International Human Powered Vehicle Association NUMBER 52 SUMMER 2001
    I agree. An efficient pedaling style matched to a gear appropriate to the terrain makes a more of difference than is lost through the hub.

    For this reason I much prefer my Sturmey Archer 8-speed hub over my Sturmey Archer 3-speed hub; I believe the latter is a more efficient transmission, but the engine is more efficient with the 8-speed!

  9. #9
    ♋ ☮♂ ☭ ☯ -=(8)=-'s Avatar
    Join Date
    Feb 2005
    Location
    40205 'ViLLeBiLLie
    My Bikes
    Sngl Spd's, 70's- 80's vintage, D-tube Folder
    Posts
    7,906
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    My hub/shafty is a dream from a maintenance standpoint, but like a
    bad dream from an efficiency standpoint...one of those ones where you
    are running real hard but not going anywhere
    -ADVOCACY-☜ Radical VC = Car people on bikes. Just say "NO"

  10. #10
    Bicycling Gnome
    Join Date
    Apr 2006
    Location
    55.0N 1.59W
    Posts
    1,877
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by MichaelW View Post
    The world record for cycling around the world was set using a Rohloff hub. It probably has more to do with ease of maintenance than simple mechanical efficiency.
    I like my new Alfine hub gears, they dont feel at all draggy.
    That guy is on BBC1 tonight and for a few more nights in a series of programmes about his massive and triumphant ride. I think its 22.35. His name is Mark Beaumont and he did a hundred miles a day for about 195 days.


    By the way, I saw an engineering analysis that showed that an oil lubricated and run in sturmy archer three speed hub was more efficient than derailleur gears. Once the chain line starts to run out of true on a deraillieur the efficiency drops off quite sharply. The middle gear or direct drive on a srf3 is as efficient as single speed and the other two gears are only about 4% down on 100%. Plenty of the derailieur gears are that far down because of chainline issues as I understand it.
    Last edited by EvilV; 08-19-08 at 03:00 PM.

  11. #11
    New usename ThorUSA brakemeister's Avatar
    Join Date
    Nov 2004
    Location
    Southern Illinois USA
    Posts
    2,469
    Mentioned
    0 Post(s)
    Tagged
    1 Thread(s)
    it almost always depends on what you are trying to proove ......

    all kinds of statements can be twisted and turned just in the right direction that the findings seem to make sense .....

    just like the no service idea of all can hubs.... yes much less service, but than eventually they do need service and than what ? where to bring it?. do it yourself ? what if you need any spare part of any internal hub in the middle of Iowa ( or Illinois , Indiana .....) .... than all of the sudden a derrailleur doesnt seem to bad anymore.....

    so there is always a pro and con involved ..... I like cans as they just look cool in my opinion .... and they came a long way , indeed.... but like everything else they might have their limits as well...

    thor

  12. #12
    Senior Member
    Join Date
    Dec 2005
    Posts
    217
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by brakemeister View Post
    ...just like the no service idea of all can hubs.... yes much less service, but than eventually they do need service and than what ? where to bring it?. do it yourself ? what if you need any spare part of any internal hub in the middle of Iowa ( or Illinois , Indiana .....) .... than all of the sudden a derrailleur doesnt seem to bad anymore.....
    Yes but by that time you have worn out several derailleurs and cassettes.

    Sturmey-Archer hubs are actually quite simple to fix if done by the book. Parts are readily available. Most of the problems they have are actually poor adjustment of the cables which can be quickly fixed.

    I would hope to get about 3-4,000 miles out of a derailleur and cassette. I would expect a hub gear to last the life of the bike.

    In cycling magazines I have covering several decades of the 20th century, there are many instances of people covering in excess of 50,000 miles on one hub, and this was not seen as remarkable. Hopefully improvements in technology means that modern versions should be capable of exceeding these mileages.

    As far as a round the world trip, I think I'd pick a 3 speed S-A. In direct drive (middle gear) it is as efficient as a single speed.

  13. #13
    ...poet... timo888's Avatar
    Join Date
    Jul 2008
    Location
    Mid-Atlantic USA
    My Bikes
    bikes
    Posts
    624
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by brakemeister View Post
    it almost always depends on what you are trying to proove ......

    all kinds of statements can be twisted and turned just in the right direction that the findings seem to make sense .....

    just like the no service idea of all can hubs.... yes much less service, but than eventually they do need service and than what ? where to bring it?. do it yourself ? what if you need any spare part of any internal hub in the middle of Iowa ( or Illinois , Indiana .....) .... than all of the sudden a derrailleur doesnt seem to bad anymore.....

    so there is always a pro and con involved ..... I like cans as they just look cool in my opinion .... and they came a long way , indeed.... but like everything else they might have their limits as well...

    thor
    Thor,
    I don't disagree with you -- service and parts availability are issues with any product that has limited market penetration ... or with proprietary parts in general, unless they happen to be de facto standards.

    But my question has less to do with internal hubs vs derailers than it has to do with the engineering focus of companies who make these hubs. If they're trying to find some "sweet spot" between Reliability and Efficiency, whose needs would be served by giving more emphasis to maximum efficiency over maximum reliability? Conversely, whose needs would be served by emphasizing reliability over efficiency ... assuming there's a tradeoff, i.e.that one comes at the expense of the other.

    What demographic(s) or sub-markets would you say are attracted to internal hubs?

    Regards
    T

  14. #14
    Drops small screws noteon's Avatar
    Join Date
    May 2008
    Location
    NYC
    My Bikes
    Heavily modified Xootr Swift, Trek 1000SL that's been turned into a brevet bike, two 20" Torker Interurbans
    Posts
    2,600
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by timo888 View Post
    Do small gains or losses in efficiency really matter to commuters, multi-modal commuters, and leisure riders?
    No. Even hundreds of meters over 60km don't matter much, since that's a difference of what, a minute at most? My commute varies more than that already, just as a function of my mood.

    But the words "less efficient" are scary to people who are new to it all.
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

  15. #15
    jur
    jur is offline
    Senior Member
    Join Date
    May 2005
    Posts
    6,289
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by timo888 View Post
    Do small gains or losses in efficiency really matter to commuters, multi-modal commuters, and leisure riders?
    No. I can readily see the difference between my various bikes, and commute on the bike for 70 minutes each way. I don't pick whatever bike I'm going to ride the day for efficiency; I pick it for applicability. Wet weather mostly sees the R20. Training days for long rides, I choose the Swift. Whimsically I take the Mini. Right now I'm multi-moding and am using the Yeah because of the easy folding. Efficiency never enters my mind.
    My folding bike photo essays www.dekter.net/

  16. #16
    Senior Member alhedges's Avatar
    Join Date
    Mar 2008
    Location
    Naptown
    My Bikes
    NWT 24sp DD; Brompton M6R
    Posts
    1,133
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    The small efficiency losses really don't matter - at least for my ride, any difference they might make is lost in the noise of more serious delays: red lights, me being tired, tires not optimally pumped, etc.

    But - tying in with Thor's point - I think it is also a mistake to assume that modern IGHs (especially those with multiple gears) will last forever just because the old-school SA 3-speeds did. A friend of mine had two Nexus IGH malfunction (a 7 speed and an 8 speed); each lasted around a year and was basically irreparable. The hubs were on Trek Navigators, which, interestingly, seems to no longer sell models with IGHs.

  17. #17
    Bicycling Gnome
    Join Date
    Apr 2006
    Location
    55.0N 1.59W
    Posts
    1,877
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by timo888 View Post
    Thor,
    But my question has less to do with internal hubs vs derailers than it has to do with the engineering focus of companies who make these hubs. If they're trying to find some "sweet spot" between Reliability and Efficiency, whose needs would be served by giving more emphasis to maximum efficiency over maximum reliability? Conversely, whose needs would be served by emphasizing reliability over efficiency ... assuming there's a tradeoff, i.e.that one comes at the expense of the other.

    What demographic(s) or sub-markets would you say are attracted to internal hubs?

    Regards
    T
    But is that the trade off that is made. I don't see there really being a continuum with efficiency at one end and reliability at the other. I don't think these variables are even remotely related. In fact although I am far from being an engineer and am only a bodging dabbler, I feel sure that there are two quite different variables here and that the continuums (plural?) range from reliability -> unreliability and a quite separate one of efficiency -> inefficiency. I'm pretty tired just now so maybe I missed something here.

  18. #18
    Drops small screws noteon's Avatar
    Join Date
    May 2008
    Location
    NYC
    My Bikes
    Heavily modified Xootr Swift, Trek 1000SL that's been turned into a brevet bike, two 20" Torker Interurbans
    Posts
    2,600
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    This reminds me of a related question that I never remember once I'm off the bike.

    Is there anything on an IGH that's analogous to cross-chaining? One of the most useful ratios on my Xootr Swift (SRAM Dual Drive + 11/32) is the highest DD gear and lowest cassette gear. It slots right in between two of my basic cruising speeds. I can't think of why it would cause any problems, but better to ask than assume.

    (And if the answer is "No, you moron, that's the whole point of an IGH," then that gives us another advantage to add to the list: Access to all ratios without fear of cross-chaining.)
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

  19. #19
    Bicycle Repair Man !!! Sixty Fiver's Avatar
    Join Date
    Sep 2007
    Location
    YEG
    My Bikes
    See my sig...
    Posts
    26,411
    Mentioned
    21 Post(s)
    Tagged
    2 Thread(s)
    You will get some chaion deflection on the SRAm dual drive but that won;t be any m,ore severe than what you get on a derailer equipped bike when you are running off the middle chain ring.

    I am not sure what gear on the SRam hub is direct drive... on an SA 3 speed hub it is it's 2nd which is about as efficient as a drive gear gets and older SA hubs tend to be far better made than later production models.

  20. #20
    Drops small screws noteon's Avatar
    Join Date
    May 2008
    Location
    NYC
    My Bikes
    Heavily modified Xootr Swift, Trek 1000SL that's been turned into a brevet bike, two 20" Torker Interurbans
    Posts
    2,600
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If I understand that answer (which I'm not sure I do), you're talking about chain deflection between the chainwheel and the cassette, yes?

    My curiosity--and please bear with me if I'm not stating it clearly--is about the relation between the IGH and the cassette. Do the kinds of combinations that cause cross-chaining concerns between a cassette and triple chainwheel pose any problems with an IGH and cassette?

    And if not, are there any concerns? Or can I just use whatever combination results in a ratio that feels good at the moment--e.g., highest IGH gear with lowest cassette gear?
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

  21. #21
    Senior Member
    Join Date
    Aug 2005
    Location
    San Rafael, California
    Posts
    1,554
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by noteon View Post
    If I understand that answer (which I'm not sure I do), you're talking about chain deflection between the chainwheel and the cassette, yes?

    My curiosity--and please bear with me if I'm not stating it clearly--is about the relation between the IGH and the cassette. Do the kinds of combinations that cause cross-chaining concerns between a cassette and triple chainwheel pose any problems with an IGH and cassette?

    And if not, are there any concerns? Or can I just use whatever combination results in a ratio that feels good at the moment--e.g., highest IGH gear with lowest cassette gear?
    That's the beauty of Dual Drive.. big gear range, no cross chain issues... use whatever feels good...

  22. #22
    Banned
    Join Date
    Oct 2006
    Posts
    2,296
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by noteon View Post
    If I understand that answer (which I'm not sure I do), you're talking about chain deflection between the chainwheel and the cassette, yes?

    My curiosity--and please bear with me if I'm not stating it clearly--is about the relation between the IGH and the cassette. Do the kinds of combinations that cause cross-chaining concerns between a cassette and triple chainwheel pose any problems with an IGH and cassette?

    And if not, are there any concerns? Or can I just use whatever combination results in a ratio that feels good at the moment--e.g., highest IGH gear with lowest cassette gear?
    I don't know anything about it, but from what I understand the cross chaining problem is that, as the various cogs and rings of a derailleur system are located in different positions, when the chain is in the leftmost position in the rear and the rightmost position in the front (or vice versa) it gets pulled sideways, thus, causing the chain to rub against the ring and cog.

    Since there's no chain or any other movable part connecting the cassette to the internal gears on a DD setup there can't be anything that gets pulled into a rubbing position as with cross chaining. So whatever problems the setup may or may not have I find it hard to imagine how they could possibly be described as "analogous" to cross chaining.

  23. #23
    Drops small screws noteon's Avatar
    Join Date
    May 2008
    Location
    NYC
    My Bikes
    Heavily modified Xootr Swift, Trek 1000SL that's been turned into a brevet bike, two 20" Torker Interurbans
    Posts
    2,600
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That's what I was hoping to hear. Being able to shift into that gear without worrying about the chain coming off is lovely.
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

  24. #24
    Drops small screws noteon's Avatar
    Join Date
    May 2008
    Location
    NYC
    My Bikes
    Heavily modified Xootr Swift, Trek 1000SL that's been turned into a brevet bike, two 20" Torker Interurbans
    Posts
    2,600
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by makeinu View Post
    Since there's no chain or any other movable part connecting the cassette to the internal gears on a DD setup there can't be anything that gets pulled into a rubbing position as with cross chaining. So whatever problems the setup may or may not have I find it hard to imagine how they could possibly be described as "analogous" to cross chaining.
    The concept of pairing extremely opposed gears and having mechanical problems as a result would be the crux of the analogue.

    (I can probably also find a way to use the word "synecdoche" in there if pressed...)
    RIDE: Short fiction about bicycles • RUSA #5538
    Learning to wrench better this year—current project: Fixie from build kit

  25. #25
    Banned
    Join Date
    Oct 2006
    Posts
    2,296
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Foldable Two View Post
    How many casual/commuter type riders do 60 km (37 miles) per ride? Maybe 6 km (3.7 miles) is more like it, therefore the actual advantage would be in the TENS of meters. Not a really noticeable advantage.
    Yup, and taking your full attention away from effective pedaling in order to shift a few times over those 3.7 miles probably loses you tens of meters anyway. Sometimes less is more (as I'm sure the members of the SS FG subforum would attest if they ever took a break from trying to be cool).

    Quote Originally Posted by noteon View Post
    The concept of pairing extremely opposed gears and having mechanical problems as a result would be the crux of the analogue.

    (I can probably also find a way to use the word "synecdoche" in there if pressed...)
    I believe the late Sheldon Brown may have destroyed a Nexus 8 speed by pairing it with a wide cluster and a triple and using the lowest possible gear.

    The moral of the story being that some gears of an IGH perform better than others and if you use an inefficient combination of external gears to drive an inefficient gear on the IGH the two choices will compound to a doubly inefficient overall drive (perhaps even out of spec). Though I think you'd be hard pressed to create such an issue with a 3 speed IGH like a DD (just like I doubt you'd be able to create an issue of cross chaining with a 3 cog cluster).

    Does that fit the bill?

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •