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.

 

[Chris Neary]

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

In a larger gear the power delivery is apt to be more "choppy" with big torque alternating with
dead spots in the cadence. Such uneven power delivery is more likely to break a tire loose on
slippery pavement.

In a lower gear you are more apt to "spin", with more even power delivery around the stroke.

Chris Neary [email protected]

"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 <[email protected]>, [email protected] 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, 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.

--
Dave Kerber Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

 

[Rick Onanian]

On Fri, 8 Aug 2003 13:11:34 +0000 (UTC), asqui <[email protected]> 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 <[email protected]>, [email protected] 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 [email protected]

"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

 

[Rick Onanian]

On Fri, 8 Aug 2003 21:23:49 +0000 (UTC), asqui <[email protected]> wrote:
> Engine braking afaik entails reducing the throttle to the point at which engine is being forced to
> higher revs by the momentum of the car, transmitted through the wheels and gearbox. It is not
> necessarily with making the wheels "turn slower than the car's speed by allowing them to slide".

Well, engine braking is usually done for the purpose of avoiding using your brakes while still
slowing your vehicle.

However, the end result can be, in fact, that your wheels spin significantly slower than your
vehicle, resulting in some sliding, but some lateral traction maintained.

In practice, at that speed, you would most likely damage something in your vehicle, like your
transmission, or head gasket, or maybe bend a valve.

> 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 but you are not actively inhibiting your
> progress either. If you pedal 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

The slow, sliding, but still spinning wheel would result from braking a lot and pedalling a little.

>> 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.

I agree there.

It's not necessary to have a manual transmission to do this, but you may not want to do it on an
automatic that is feeble, or one that is new and you really don't want to damage. That said, I did
it regularly on two cars whose transmissions lasted much longer than the rest of the car.

--
Rick Onanian

 

[Rick Onanian]

On Fri, 08 Aug 2003 21:59:12 GMT, Chris Neary <[email protected]> wrote:
> 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!

> Chris Neary [email protected]
--
Rick Onanian

 

[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 [email protected]

"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 <[email protected]>, [email protected] 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 Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.