single speed efficiency,why?
#1
Junior Member
Thread Starter
Join Date: Feb 2008
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
single speed efficiency,why?
Single speed drive trains are said to be more efficient than derailluer systems. I think it's true, but I'd like to know exactly why. Commonly listed reasons include: fewer moving parts = less friction, shorter chains = less chain mass and less friction, straight chainline = less friction(?), less angular momentum change since they don't have to zigzag through the derailleur (?), ,,, Must be lots of opinions about this. List the reasons in rank order.
Last edited by dwarner1; 02-26-08 at 03:34 PM. Reason: misspell
#2
Sir Fallalot
Join Date: Jul 2006
Posts: 5,286
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 13 Times
in
11 Posts
Please read the article from page 3 to page 12.
The mechanical efficiency of bicycle derailleur and hub-gear transmissions
When you have read that, do you have any more questions?
I warmly recommend to anyone posting in this thread to read that article.
The mechanical efficiency of bicycle derailleur and hub-gear transmissions
When you have read that, do you have any more questions?
I warmly recommend to anyone posting in this thread to read that article.
#5
Instigator at best
Join Date: Jan 2007
Location: Columbia, Missouri
Posts: 1,086
Bikes: Motobecane Jury
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Single speed drive trains are said to be more efficient than derailluer systems. I think it's true, but I'd like to know exactly why. Commonly listed reasons include: fewer moving parts = less friction, shorter chains = less chain mass and less friction, straight chainline = less friction(?), less angular momentum change since they don't have to zigzag through the derailleur (?), ,,, Must be lots of opinions about this. List the reasons in rank order.
One extra thing that's true for fixed is that the momentum of a fixed drivetrain pushes your feet through the dead spots. But that's not applicable to ss.
#6
Senior Member
Join Date: Oct 2004
Location: Melbourne in Australia
Posts: 568
Bikes: Old 12-speed commuter, When I earn enough I'll get a fixed KHS flite 100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Unfortunately there is nothing mentioned on the efficiency of a fixed gear drivetrain. Most of the drivetrains measured an efficiency of around 92 to 94 on average in the article, which is lower than I expected. I had the assumption that all drivetrains were nearly 100 percent transfer of energy, and that all the differences were miniscule. Plus when you add in dirt and old chain and everything else that modern bikes develop, I'm guessing these numbers would be even lower.
#7
Uber Goober
I have been assured that it is Zen Effect and Perpetual Motion, and who am I to doubt it?
__________________
"be careful this rando stuff is addictive and dan's the 'pusher'."
"be careful this rando stuff is addictive and dan's the 'pusher'."
#8
Junior Member
Thread Starter
Join Date: Feb 2008
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Fascinating reference. Thanks for the heads-up.
But it doesn't address the question at all, except for a short textual note about smallest derailleur sprockets being the least efficient.
I guess am most curious about which features of a singlespeed (or derailleur for that matter) drivetrain are most or least likely to be detrimental to efficiency, and to what comparative degree---especially as to what 'mistakes' in setups may be most damaging to performance.
But it doesn't address the question at all, except for a short textual note about smallest derailleur sprockets being the least efficient.
I guess am most curious about which features of a singlespeed (or derailleur for that matter) drivetrain are most or least likely to be detrimental to efficiency, and to what comparative degree---especially as to what 'mistakes' in setups may be most damaging to performance.
#9
Dances With Cars
Join Date: Jan 2006
Location: Toronto, Canada
Posts: 10,527
Bikes: TBL Onyx Pro(ss converted), Pake SS (starting to look kinda pimped)
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
No such thing as a 100 percent transfer of energy in a mechanical system.
An off kilter chainline can affect efficiency with more friction compared to a straight chainline. With constant rubbing the parts wear faster... and the noise will make you nuts. In a single speed context, the chain being too tight can affect performance as well.
An off kilter chainline can affect efficiency with more friction compared to a straight chainline. With constant rubbing the parts wear faster... and the noise will make you nuts. In a single speed context, the chain being too tight can affect performance as well.
#10
Senior Member
This has nothing to do with mechanical efficiency and everything to do with halfassed lazy pedaling technique. A fixed gear drive train does not have a magical extra energy source that ss drive trains lack.
#11
Instigator at best
Join Date: Jan 2007
Location: Columbia, Missouri
Posts: 1,086
Bikes: Motobecane Jury
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
That's what I said: It makes my lazy-ass technique more efficient.
#12
Senior Member
Join Date: Nov 2004
Location: Davis CA
Posts: 3,959
Bikes: Surly Cross-Check, '85 Giant road bike (unrecogizable fixed-gear conversion
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 6 Post(s)
Likes: 0
Liked 4 Times
in
3 Posts
But it's true! It is about perpetual motion. I just know it!
On a fixed gear bike, your legs turn the pedals. But as anyone who has ever tried to stop pedaling a fixed gear bike knows, the bike makes the pedals go around.
So the faster you pedal the bike, the faster it moves the pedals around for you. So the faster you go, the more the bike starts pedaling itself. If you go fast enough, it just takes off like a rocket.
The oil companies and the Big Three auto makers do not want you to know about this unique feature of fixed gear bicycles, and that's why a brown GMC Suburban with Texas plates now follows me everywhere I go on my bike.
On a fixed gear bike, your legs turn the pedals. But as anyone who has ever tried to stop pedaling a fixed gear bike knows, the bike makes the pedals go around.
So the faster you pedal the bike, the faster it moves the pedals around for you. So the faster you go, the more the bike starts pedaling itself. If you go fast enough, it just takes off like a rocket.
The oil companies and the Big Three auto makers do not want you to know about this unique feature of fixed gear bicycles, and that's why a brown GMC Suburban with Texas plates now follows me everywhere I go on my bike.
#13
gridlock junky
Join Date: Dec 2006
Location: Los Angeles
Posts: 201
Bikes: 1944 JC Higgens Cruiser, 1988 Univega Aero Speed, 1993 GT Ricochet, 2005 Electra Cruiser, 2006 Cervelo Dual, 2007 IRO Mark V
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
(custom cadence x best power) (centrifical force + perpetual force - friction) = [fixed gear]
(varied cadence x varied power) (intermittent force + friction) = [geared]
thats why some time trialists use one gear
(varied cadence x varied power) (intermittent force + friction) = [geared]
thats why some time trialists use one gear
#14
*****es love tarck
Join Date: Apr 2006
Location: Sandy, UT
Posts: 3,301
Bikes: so many
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#15
Senior Member
#17
ThumperChump.
Join Date: Nov 2007
Posts: 701
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
dude, its just like you're one with the bike, and like you're connected with god in a way, like he's pushing you along with his magical powers. it's very spiritual. especially when you're baked.
#19
馬鹿野郎!
Join Date: Nov 2007
Location: HELLsinki, Finland
Posts: 545
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#20
Grad Student for Hire
Join Date: May 2005
Location: Toronto
Posts: 361
Bikes: 2006 Lemond Tourmalet; 198(?) Gardin mid-fixie conversion
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
#21
Spelling Snob
Join Date: Dec 2005
Location: Plano, Texas
Posts: 2,862
Bikes: Panasonic DX4000, Bianchi Pista
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Likes: 0
Liked 2 Times
in
1 Post
My Ultegra rd pulleys use 24 teeth in total that do not transmit any chain force into forward movement of the bike. Thats exactly where the friction is.
__________________
The first rule of flats is You don't talk about flats!
The first rule of flats is You don't talk about flats!
#22
Spawn of Satan
Great article! I have not read it all but I will.
I have been looking for an article/study on the difference in efficiency between fixed and geared drive trains. We have talked about his several times on this forum. I have never found information/study directly relating to this question.
What comes to mind for me is the Sturmey-Archer three speed fixed gear hub. The major downfall of these are the efficiency of the gears. There are many positives to them but the efficiency is lacking in all internally geared hubs.
I have been looking for an article/study on the difference in efficiency between fixed and geared drive trains. We have talked about his several times on this forum. I have never found information/study directly relating to this question.
What comes to mind for me is the Sturmey-Archer three speed fixed gear hub. The major downfall of these are the efficiency of the gears. There are many positives to them but the efficiency is lacking in all internally geared hubs.
#23
Sir Fallalot
Join Date: Jul 2006
Posts: 5,286
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 13 Times
in
11 Posts
Great article! I have not read it all but I will.
I have been looking for an article/study on the difference in efficiency between fixed and geared drive trains. We have talked about his several times on this forum. I have never found information/study directly relating to this question.
What comes to mind for me is the Sturmey-Archer three speed fixed gear hub. The major downfall of these are the efficiency of the gears. There are many positives to them but the efficiency is lacking in all internally geared hubs.
I have been looking for an article/study on the difference in efficiency between fixed and geared drive trains. We have talked about his several times on this forum. I have never found information/study directly relating to this question.
What comes to mind for me is the Sturmey-Archer three speed fixed gear hub. The major downfall of these are the efficiency of the gears. There are many positives to them but the efficiency is lacking in all internally geared hubs.
#24
Elemental Child
Join Date: Feb 2008
Location: Minnesoter
Posts: 232
Bikes: 1989 Schwinn World workhorse, 1979 Trek Summer Bike, 1995 Schwinn Moab that never gets ridden
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Now I'm back to a straight chainline and the (near) silence is golden.