Why R Single speeds more efficient than multi-gear bikes?

In the last few days I've gone on a number of rides. I've used different bikes on different days. One thing I noticed is that my single speed seems to be a lot more efficient accelerating or climbing than what the multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All bikes have clean and unworn drivetrains.

So, what is it that make the single speed so much easier to accelerate and climb? Is it simply the absence of the extra moving parts such as derailleur pulleys?
Is a fixed gear with the same gear as a single speed even more efficient to pedal?

Cheers

On Mon, 19 May 2014 13:22:41 -0700, Sir Ridesalot couldnae haud thur
wheesht ony mair an' gied us this:

In the last few days I've gone on a number of rides. I've used different
bikes on different days. One thing I noticed is that my single speed
seems to be a lot more efficient accelerating or climbing than what the
multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All
bikes have clean and unworn drivetrains.

So, what is it that make the single speed so much easier to accelerate
and climb? Is it simply the absence of the extra moving parts such as
derailleur pulleys?
Is a fixed gear with the same gear as a single speed even more efficient
to pedal?

Cheers

I'm guessing it's mainly down to transmission losses, which would be
higher in multi-gear devices.

My fixed gear (44x16) feels a little bit quicker to accelerate and more
easily cruise at around 20-22mph, than my 27-speed bike.

Around 25mph and above, the multi-speed seems easier, whereas the fixed
is looking for a higher cadence which I can only sustain for a short
time. I suppose a higher ratio on the fixed would remedy this, but make
climbs a real chore around these hilly parts (west of Scotland).

On Monday, May 19, 2014 10:22:41 PM UTC+2, Sir Ridesalot wrote:
In the last few days I've gone on a number of rides. I've used different bikes on different days. One thing I noticed is that my single speed seems to be a lot more efficient accelerating or climbing than what the multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All bikes have clean and unworn drivetrains.



So, what is it that make the single speed so much easier to accelerate and climb? Is it simply the absence of the extra moving parts such as derailleur pulleys?

Is a fixed gear with the same gear as a single speed even more efficient to pedal?



Cheers

Compare the bikes with a fierce headwind or tailwind and come back to us. Sometimes it is better to accept the smal losses of two derailleur pulleys.

Lou

Per Sir Ridesalot:
So, what is it that make the single speed so much easier to accelerate and climb?

No clue here, but I also notice a diff.

Personally, I don't care for the single-speed experience but for me one
of it's redeeming features is the more responsive feel of the bike.

Weight has to be part of it, but I do not think it's the whole story.

OTOH, when my regular bike's Rohloff hub is in direct-drive mode (gear
11) I do not notice anything special.... so maybe it *is* the weight
diff.
--
Pete Cresswell

On 5/19/2014 4:22 PM, Sir Ridesalot wrote:
In the last few days I've gone on a number of rides. I've used different bikes on different days. One thing I noticed is that my single speed seems to be a lot more efficient accelerating or climbing than what the multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All bikes have clean and unworn drivetrains.

So, what is it that make the single speed so much easier to accelerate and climb? Is it simply the absence of the extra moving parts such as derailleur pulleys?
Is a fixed gear with the same gear as a single speed even more efficient to pedal?

Under what conditions do you feel it's "more efficient"? Surely, it has
to be under a very specific set of conditions - e.g. not a very steep
hill, not a very bad headwind.

Keep in mind, your perception could be due to the same mechanism that
makes red bikes faster.


--
- Frank Krygowski

On Monday, May 19, 2014 5:01:40 PM UTC-4, Lou Holtman wrote:
On Monday, May 19, 2014 10:22:41 PM UTC+2, Sir Ridesalot wrote:

In the last few days I've gone on a number of rides. I've used different bikes on different days. One thing I noticed is that my single speed seems to be a lot more efficient accelerating or climbing than what the multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All bikes have clean and unworn drivetrains.







So, what is it that make the single speed so much easier to accelerate and climb? Is it simply the absence of the extra moving parts such as derailleur pulleys?



Is a fixed gear with the same gear as a single speed even more efficient to pedal?







Cheers



Compare the bikes with a fierce headwind or tailwind and come back to us. Sometimes it is better to accept the smal losses of two derailleur pulleys..



Lou

Again we're talking a bout a single speed with a gear comparable to the same gear on a multi-gear bicycle. Headwinds and steep hills don't enter into it in this discussion.

Cheers

On Monday, May 19, 2014 5:50:22 PM UTC-4, Frank Krygowski wrote:
On 5/19/2014 4:22 PM, Sir Ridesalot wrote:

In the last few days I've gone on a number of rides. I've used different bikes on different days. One thing I noticed is that my single speed seems to be a lot more efficient accelerating or climbing than what the multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All bikes have clean and unworn drivetrains.



So, what is it that make the single speed so much easier to accelerate and climb? Is it simply the absence of the extra moving parts such as derailleur pulleys?

Is a fixed gear with the same gear as a single speed even more efficient to pedal?



Under what conditions do you feel it's "more efficient"? Surely, it has

to be under a very specific set of conditions - e.g. not a very steep

hill, not a very bad headwind.



Keep in mind, your perception could be due to the same mechanism that

makes red bikes faster.





--

- Frank Krygowski

One man's steep hill can be another man's gentle hill.

Cheers

On 19/05/2014 23:13, Sir Ridesalot wrote:

Again we're talking a bout a single speed with a gear comparable to the same gear on a multi-gear bicycle. Headwinds and steep hills don't enter into it in this discussion.

There are the obvious answers :

Lower weight
Lower resistance from the chain (vs derailleur bikes) not having to go
round loops
No extra gear wheels to turn (internal or external)

These are real advantages, and will be measurable, albeit small if
you're comparing clean drivetrains.

However it's more complicated than that - a bike isn't the sole part of
the system, the rider is very important too.

There is a mental difference, which is what Frank touched on with his
mention of red bikes. For many people (including me), if your bike feels
faster, you'll put more effort in. So it's not that it's physically that
much easier to accelerate and climb, it's that the small gains mentioned
above are encouraging you to put extra power in.

You also don't have the choice of gearing down, so just have to go for
it in whatever gear you're using - again encouraging you to pedal harder.

You'll need a power meter to see if this is a factor.

Fixed will probably be slightly more so - the lower weight probably
won't make a measurable difference, but the feel of the bike pushing
your pedals for you if you slack off makes a difference.

(All of this is the same reason why I don't believe people who justify
riding a great heavy clunker by saying it's better exercise are right.
When I got my shiny bike, I was measurably faster - and more knackered
at the end :-) )

The final part is the body. If you've got any real climbs, descents or
winds in your ride, it's pretty indisputable that the bike with gears +
rider is more efficient than the single speed bike + rider. The losses
in the geared drive train are more than made up for by the lower losses
in the body arising from being able to put in a consistent effort.

(it would be interesting to see how a pro with eg a 53/12 singlespeed
would do on a flat race - I suspect they'd actually do pretty well,
possibly till the end where those with an 11t cog would be able to push
the speed a bit too high)

The important bit however is how it feels for you. It sounds like it
feels like a great bike to ride. I suspect it is encouraging you to
pedal harder, and isn't actually very much more efficient at all, but
that's a good thing, because that means more fun :-)

On 5/19/2014 6:13 PM, Sir Ridesalot wrote:
On Monday, May 19, 2014 5:01:40 PM UTC-4, Lou Holtman wrote:
On Monday, May 19, 2014 10:22:41 PM UTC+2, Sir Ridesalot wrote:

In the last few days I've gone on a number of rides. I've used different bikes on different days. One thing I noticed is that my single speed seems to be a lot more efficient accelerating or climbing than what the multi-gear 27 speed, 18 speed (2 x 9) or the 14 speed bikes are. All bikes have clean and unworn drivetrains.







So, what is it that make the single speed so much easier to accelerate and climb? Is it simply the absence of the extra moving parts such as derailleur pulleys?



Is a fixed gear with the same gear as a single speed even more efficient to pedal?







Cheers



Compare the bikes with a fierce headwind or tailwind and come back to us. Sometimes it is better to accept the smal losses of two derailleur pulleys.



Lou

Again we're talking a bout a single speed with a gear comparable to the same gear on a multi-gear bicycle. Headwinds and steep hills don't enter into it in this discussion.

Ah. That wasn't clear from your original post.

The very slight weigh difference is easy to quantify. I doubt that
makes a perceptible difference.

The double 180 degree bend through the jockey pulleys won't impart much
friction, since it's on the low-tension side of the chain. You can get
a handle on that small friction loss by draping a loose chain over one
jockey pulley, and seeing how much longer one hanging side of the chain
must be to allow the chain to allow the chain to roll off. It's not
much, assuming your pulleys are well lubricated.

I'm guessing the biggest friction loss may come from chain misalignment
on a derailleur bike. That probably causes some friction between the
chain's side plates. But that's a factor only if you're in a gear that
doesn't perfectly aligns the chainwheel with the cog, so at least a
couple derailleur gears should have negligible losses.

I'm still thinking it's mostly the red bike effect.

--
- Frank Krygowski

- Sir Ridesalot / Mon, 19 May 2014 22:22:41 +0200

So, what is it that make the single speed so much easier
to accelerate and climb?

I suppose, it is for the fact that the chain runs
in a straight line.



jk



--
no sig