Cyclecraft Query

[asqui]

"Cyclecraft" by John Franklin (1997 edition),
Chapter 7, "Non-traffic hazards",
Page 121, "Slippery surfaces"
Paragraph 2:
"Whenever slippery surfaces are likely, reduce speed and take extra care
turning or braking. Keep your weight low and both hands on the handlebars.
If you see a definite hazard, cross it keeping straight and upright, with
the brakes off. Changing to a lower gear can help. Going downhill, you will
be more stable if you pedal against the brakes."

Changing to a lower gear can help what? Help you to cross a hazard whilst
keeping straight and upright? I don't follow.

Pedalling against the brakes? I would have thought you'd be more stable
while freewheeling because there's no shifting of your weight, no movement,
etc. Again, I don't follow.

Any insight?

Dani

[Jim Price]

asqui wrote:

> "Cyclecraft" by John Franklin (1997 edition),
> Chapter 7, "Non-traffic hazards",
> Page 121, "Slippery surfaces"
> Paragraph 2:
> "Whenever slippery surfaces are likely, reduce speed and take extra care
> turning or braking. Keep your weight low and both hands on the handlebars.
> If you see a definite hazard, cross it keeping straight and upright, with
> the brakes off. Changing to a lower gear can help. Going downhill, you will
> be more stable if you pedal against the brakes."
>
> Changing to a lower gear can help what? Help you to cross a hazard whilst
> keeping straight and upright? I don't follow.

Changing to a gear with bigger cogs might help stop the chain from
jumping off, perhaps? I'd have to say that with front and rear
derailleurs, this is rather unlikely to happen.

> Pedalling against the brakes? I would have thought you'd be more stable
> while freewheeling because there's no shifting of your weight, no movement,
> etc. Again, I don't follow.

If you were not wearing toeclips, it might help to keep your feet on the
pedals, I suppose, but more stable?. I do think he means crossing a
hazard while going downhill on a slippery surface. Pedalling might help
to stop the rear from locking, but I would doubt the usefulness of this,
as you might get worse results if any bumps in the hazard cause any
brake modulation. Perhaps he's offering this as an alternative to the
idea of taking your brakes off while crossing the hazard, which is what
I would probably do. I'm not convinced, though.

--
Jim Price

http://www.jimprice.dsl.pipex.com

Conscientious objection is hard work in an economic war.

[Rick Onanian]

On Fri, 8 Aug 2003 13:11:34 +0000 (UTC), asqui >
wrote:

> Changing to a lower gear can help what? Help you to cross a hazard whilst
> keeping straight and upright? I don't follow.

Maybe if the hazard slows you down, you'll be able to pedal
directly after going over it.

> Pedalling against the brakes? I would have thought you'd be more stable
> while freewheeling because there's no shifting of your weight, no
> movement, etc. Again, I don't follow.

Possibly to avoid skidding the rear tire for people who are
unable to modulate their rear brake?

> Any insight?

Sounds like the author had a crack-cocaine abuse problem.

> Dani
--
Rick Onanian

[asqui]

David Kerber wrote:
> In article >,
> says...
>> "Cyclecraft" by John Franklin (1997 edition),
>> Chapter 7, "Non-traffic hazards",
>> Page 121, "Slippery surfaces"
>> Paragraph 2:
>> "Whenever slippery surfaces are likely, reduce speed and take extra
>> care turning or braking. Keep your weight low and both hands on the
>> handlebars. If you see a definite hazard, cross it keeping straight
>> and upright, with the brakes off. Changing to a lower gear can help.
>> Going downhill, you will be more stable if you pedal against the
>> brakes."
>>
>> Changing to a lower gear can help what? Help you to cross a hazard
>> whilst keeping straight and upright? I don't follow.
>>
>> Pedalling against the brakes? I would have thought you'd be more
>> stable while freewheeling because there's no shifting of your
>> weight, no movement, etc. Again, I don't follow.
>
> I think it would be similar to using engine braking in a car: you can
> slow down by forcing the wheels to turn slower than the car's speed by
> allowing them to slide a bit, but you don't lock them up completely,

Engine braking afaik entails reducing the throttle to the point at which the
engine is being forced to higher revs by the momentum of the car,
transmitted through the wheels and gearbox. It is not necessarily corellated
with making the wheels "turn slower than the car's speed by allowing them to
slide".

I can't see that anything like engine braking could take place on a bike
equipped with a freewheel. If you coast you are not putting any power out,
but you are not actively inhibiting your progress either. If you pedal you
are putting out some quantity of power. At no point are you putting out
"negative" power -- on a fixed gear I assume this would entail trying to go
through the motions of pedalling backwards, while the cranks are still
rotating "forwards".

> making it easier to keep control. I've never tried this on a bike,
> but
> it certainly works in a car with a manual transmission.

It doesn't necessarily make it easier to keep control, it just saves using
your brakes by cleverly using gearing and throttle to control speed.

[Chris Neary]

>on a fixed gear I assume this would entail trying to go
>through the motions of pedalling backwards, while the cranks are still
>rotating "forwards".

Bingo.

Using the legs to resist the momentum of the cranks is a skill just about
all fixed gear riders learn, even those running brakes.


Chris Neary


"Science, freedom, beauty, adventure: what more could
you ask of life? Bicycling combined all the elements I
loved" - Adapted from a quotation by Charles Lindbergh

[Dave Pushee]

asqui wrote:

> "Cyclecraft" by John Franklin (1997 edition),
> Chapter 7, "Non-traffic hazards",
> Page 121, "Slippery surfaces"
> Paragraph 2:
> "Whenever slippery surfaces are likely, reduce speed and take extra care
> turning or braking. Keep your weight low and both hands on the handlebars.
> If you see a definite hazard, cross it keeping straight and upright, with
> the brakes off. Changing to a lower gear can help. Going downhill, you will
> be more stable if you pedal against the brakes."
>
> Changing to a lower gear can help what? Help you to cross a hazard whilst
> keeping straight and upright? I don't follow.
>
> Pedalling against the brakes? I would have thought you'd be more stable
> while freewheeling because there's no shifting of your weight, no movement,
> etc. Again, I don't follow.


A section of my commute includes a downhill (not too steep) section of
what passes for beach sand. I find that keeping a little power to the
wheels while also braking slightly helps.

These conditions require a slow and cautious approach with weight
shifted well back to avoid trigging the front wheel. At the same time,
you want to avoid stalling out. The resistance from the sand tends to
vary, and sometimes you need to add power. I think I can react quicker
to the subtle changes when I am already applying power to the wheel.

- Dave

>
> Any insight?
>
> Dani
>
>
>

[Chris Neary]

>> Using the legs to resist the momentum of the cranks is a skill just about
>> all fixed gear riders learn, even those running brakes.
>
>Do many ride without brakes? Wow. Don't fix me up!

The messenger crowd in particular appears to favor going brakeless.
Ref: http://www.oldskooltrack.com/

My friends and I, as well the majority of fixed gear riders, run front
brakes.



Chris Neary


"Science, freedom, beauty, adventure: what more could
you ask of life? Bicycling combined all the elements I
loved" - Adapted from a quotation by Charles Lindbergh

[David Kerber]

In article >,
says...

.....

> >> Pedalling against the brakes? I would have thought you'd be more
> >> stable while freewheeling because there's no shifting of your
> >> weight, no movement, etc. Again, I don't follow.
> >
> > I think it would be similar to using engine braking in a car: you can
> > slow down by forcing the wheels to turn slower than the car's speed by
> > allowing them to slide a bit, but you don't lock them up completely,
>
> Engine braking afaik entails reducing the throttle to the point at which the
> engine is being forced to higher revs by the momentum of the car,
> transmitted through the wheels and gearbox. It is not necessarily corellated
> with making the wheels "turn slower than the car's speed by allowing them to
> slide".

In slick conditions (with which I became well-acquainted while learning
to drive in the midwest), you can often see on the speedometer that the
wheel speed drops dramatically when you downshift, but the car doesn't
slow significantly. In good conditions, of course, you are correct.


> I can't see that anything like engine braking could take place on a bike
> equipped with a freewheel. If you coast you are not putting any power out,
> but you are not actively inhibiting your progress either. If you pedal you
> are putting out some quantity of power. At no point are you putting out
> "negative" power -- on a fixed gear I assume this would entail trying to go
> through the motions of pedalling backwards, while the cranks are still
> rotating "forwards".

I'm guessing (and it's just a guess, since I haven't tried it that I can
recall), you might be able to get a little better control while braking
in very slippery conditions if you keep pedaling against the brake
pressure. That would allow the rear wheel to keep turning, perhaps
giving you a little more control while still getting some stopping
power.

When I was growing up (7th through 10th grade), I rode my bike to school
every single day, year 'round, even in several inches of snow. If it
was slick, I normally stopped by using the brake lightly and dragging my
feet. Of course, the seat had to be lower than normal to allow this.


> > making it easier to keep control. I've never tried this on a bike,
> > but
> > it certainly works in a car with a manual transmission.
>
> It doesn't necessarily make it easier to keep control, it just saves using
> your brakes by cleverly using gearing and throttle to control speed.

No, keeping the wheels turning makes the car much easier to control in
very slippery conditions. I know this from first-hand experience. It's
stupid to use the clutch to slow down when brakes are designed for this,
and are much easier and cheaper to replace.

--
Dave Kerber
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