Antilock braking for bicycles

Discussion in 'Cycling Equipment' started by Doug Goncz, Mar 15, 2004.

  1. Doug Goncz

    Doug Goncz Guest

    Wouldn't it be great if you could backpedal your multigear
    bike and get braking that would ease the front brake the
    instant the rear tire started to lift?

    I built such a bike in about 1992.

    It was a Shimano three speed coaster brake hub, on the
    cheapest frame I could get, salvaged from the cleanout of
    the Hollybrooke condominium bicycle storage room.

    The torque arm was supported by about a 10 x 25 mm cartridge
    bearing which in turn was spaced by a shim made from a
    polyethylene milk jug cap, the kind that you have to tear
    the tab off of to open. The rearranged axle lock nuts
    applied force from the outside through the now mobilized arm
    to the large (50mm) bearing of tiny (individual?) balls that
    was the left hub cup and cone. The cartridge bearing was
    therefore used at extrememly _low_ PV in its designed
    function, and at high P, zero V in its thrust ability. Such
    bearings do have thrust ability.

    The braking action was overly responsive in first, about
    right in second, and had a strange behavior in third. I'd
    say third on that bike was for no-traffic, no-hill
    conditions only, but I did ride it 14 miles from Greenwood
    Drive to Pickett Rd. to the bike shop and it did work, and I
    didn't have any accidents. You could instantly snap the
    shifter to any brake geometry you'd care so all in all it
    was fairly safe.

    Well, now I am building the wide range Thunderbolt and I
    would like to get rid of this one of about 120 boxes I have
    lying around. If you'd like to have a go, all the parts
    needed are in the box. Sorry, the frame is long gone. No
    spokes. No rims. Just the magic hub, fittings, cabling, and
    caliper brake, a good one if I remember correctly.

    I'd mount the shifter on the seat post and leave the
    handlebars gloriously bare, but your taste is not my taste.

    My physics project at NVCC: Google Groups, then
    "dgoncz" and some of: ultracapacitor bicycle
    fluorescent flywheel inverter

    4-1-9 Fraud
    http://www.secretservice.gov/electronic_evidence.shtml
     
    Tags:


  2. Jobst Brandt

    Jobst Brandt Guest

    Doug Goncz writes:

    > Wouldn't it be great if you could backpedal your multigear
    > bike and get braking that would ease the front brake the
    > instant the rear tire started to lift?

    Considering that few riders ever brake hard enough to raise
    the rear wheel, this is a solution looking for a problem.
    When people go over the bars, it is not from braking too
    hard, but rather from not bracing rider weight with the arms
    to keep from sliding off the saddle. The bicycle
    subsequently overturns when the rider's legs hit the
    handlebar, not from excess braking.

    http://draco.acs.uci.edu/rbfaq/FAQ/9.36.html

    Jobst Brandt jobs[email protected]
     
  3. meb

    meb New Member

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    Doug-

    Doesn’t quite fit the definition of antilock brakes.
    Locking occurs when the tires are not spinning, or a mild locking related phenomenon known as wheel slip occurs when the tire is moving at different speed than the ground beneath it (wheel is slower than ground in braking).

    Antilock brakes release brakes that are moving slower than the pavement beneath the tires. Automotive antilock brakes release and reapply brakes up to fifty times per second, at least that was typical in 1989-1991 time frame when I was writing antilock brake controller software as an engineer at General Motors- I haven’t really kept up with the ABS brake technology since I left General Motors in 1993 so it’s conceivable release cycles are faster nowdays.

    You can endo without locking the front, just decel fast enough to create a moment about the front contact patch caused by the decel of the rider-bike-position greater than the moment behind the patch caused by the gravity-position of the rider-bike.


    I think you’ve omitted details of your Anti-Flip Braking (AFB?) system.

    Was your 3 speed hub on the rear with movement of the arm operating a linkage to the front to release the brake?

    As for antilock bicycle brakes- here’s an all mechanical ABS brake system:
    http://www.blackbirdsf.org/brake_obscura/images/brovedani.jpg
    http://www.blackbirdsf.org/brake_obscura/brovedani_man.pdf
    www.blackbirdsf.org/brake_obscura/



    -works by using a roller cam on the rim to lift the pads periodically.
    Since this manufacturer is a supplier of automotive brake components, I’m not sure if this was produced for the bike market or was merely a concept demonstration by someone in the ABS field.

    Unfortunately, modulation is only wheelspeed dependent.
     
  4. meb

    meb New Member

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    Endo’s and rear tire lifts are a result of having a moment about the front contact patch caused by the bike-rider mass times the decel rate times the center or gravity (cg) height over the ground exceeding the competing moment caused by the mass times the distance the cg trails the front contact patch. Bracing harder on the handlebars transfers the force of the decelling rider to the handlebars, but does not change the location of the rider-bike combination’s cg nor remove it from the system. Somewhere between a .5 and .65G decell, road bikes endo.

    I’ve endoed many times on my road bikes never having left my seat.

    Short wheelbase recumbents flip under braking with the rider not even leaving the seat, bracing with the handlebars has little to do with whether the rider would leave the seat on a swb bent during braking.

    Another way of looking at it is when you brace with the arms on the handlebars, you are forcing the handlebars forward about the contact patch. The same rider mass that forces the rear down under gravity is inertia resisting velocity change under braking and forcing the handlebars forward of the front contact patch.
     
  5. Peter

    Peter Guest

    meb wrote:

    > Doesn’t quite fit the definition of antilock brakes.
    > Locking occurs when the tires are not spinning, or a mild
    > locking related phenomenon known as wheel slip occurs when
    > the tire is moving at different speed than the ground
    > beneath it (wheel is slower than ground in braking).
    >
    > Antilock brakes release brakes that are moving slower than
    > the pavement beneath the tires. Automotive antilock brakes
    > release and reapply brakes up to fifty times per second,
    > at least that was typical in 1989-1991 time frame when I
    > was writing antilock brake controller software as an
    > engineer at General Motors- I haven’t really kept up with
    > the ABS brake technology since I left General Motors in
    > 1993 so it’s conceivable release cycles are faster
    > nowdays.
    >
    > You can endo without locking the front, just decel fast
    > enough to create a moment about the front contact patch
    > caused by the decel of the rider-bike- position greater
    > than the moment behind the patch caused by the gravity-
    > position of the rider-bike.
    >
    >
    > I think you’ve omitted details of your Anti-Flip Braking
    > (AFB?) system.
    >
    > Was your 3 speed hub on the rear with movement of the arm
    > operating a linkage to the front to release the brake?
    >
    > As for antilock bicycle brakes- here’s an all mechanical
    > ABS brake system: http://www.blackbirdsf.org/brake_obscur-
    > a/images/brovedani.jpg http://www.blackbirdsf.org/brake_o-
    > bscura/brovedani_man.pdf
    > www.blackbirdsf.org/brake_obscura/
    >
    >
    >
    > -works by using a roller cam on the rim to lift the pads
    > periodically. Since this manufacturer is a supplier of
    > automotive brake components, I’m not sure if this was
    > produced for the bike market or was merely a concept
    > demonstration by someone in the ABS field.
    >
    > Unfortunately, modulation is only wheelspeed dependent.

    A very simple mechanical Anti-Flip braking system was
    illustrated in the Bicycling Science book by Wilson and
    Whitt. That system works by having the rider only have
    direct control over the rear brake which operates in the
    usual fashion on the rim but is mounted on a spring-loaded
    sliding mount so that it moves forward as a result of
    engaging the rear rim. There is a cable attached to the
    moving rear brake mechanism that then pulls on the front
    brake which provides the bulk of the stopping power.

    So the front brake cable is pulled by the reaction force on
    the rear brake and the moment the rear wheel starts to leave
    the ground this reaction force is reduced and that partially
    releases the front brake to prevent a flip.

    The rider can therefore pull as hard as he wants on the
    brake lever and the bicycle will automatically stop with a
    deceleration that is just on the verge of lifting the rear
    wheel off the ground. Of course he better have a firm grasp
    on the handlebars so he doesn't fly off the bike anyway. The
    leverage of the cable pull on the front brake can be
    adjusted depending on how much of a 'power brakes' effect is
    desired by the rider.
     
  6. meb

    meb New Member

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    Peter-Impressive approach.

    I assume you're referring to the Calderazzo brake system shown on pp210-212 or the the 1982 edition of Bicycle Science.

    Was this system ever manufactured?

    I think this might work also work well when trying to control 4 brakes with 2 hands on my quadribent.

    Thanks
     
  7. On the few occasions that I had to brake that hard, I throw
    my butt as far back behind the saddle as is reasonably
    possible and still remain in control. This helps hold the
    rear wheel on the ground.

    Not perfect, of course. Nothing is. But my cycling brain
    knows enough that the rear tire starting to skid is a sure
    sign that there is no longer enough weight to safely hold
    the rear wheel on the ground. At which point I let up
    slightly on the front brake.

    So far <me, rapping on my bed frame>, I have not experienced
    the event lovingly known as a "face plant".

    "May you have the wind at your back. And a really low gear
    for the hills!"

    Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

    Chris'Z Corner http://www.geocities.com/czcorner
     
  8. Peter

    Peter Guest

    meb wrote:

    > Peter wrote:
    > > meb wrote:
    > > > As for antilock bicycle brakes- here’s an all
    > > > mechanical ABS brake system: http://www.blackbirdsf.org/brake_obscur-
    > > > http://www.blackbirdsf.org/brake_obscur-
    > > > a/images/brovedani.jpg http://www.blackbirdsf.org/brake_o-
    > > > http://www.blackbirdsf.org/brake_o-
    > > > bscura/brovedani_man.pdf
    > > > www.blackbirdsf.org/brake_obscura/
    > > >
    > > >
    > > >
    > > > -works by using a roller cam on the rim to lift the
    > > > pads periodically. Since this manufacturer is a
    > > > supplier of automotive brake components, I’m not
    > > > sure if this was produced for the bike market or was
    > > > merely a concept demonstration by someone in the ABS
    > > > field.
    > > >
    > > > Unfortunately, modulation is only wheelspeed
    > > > dependent.
    > > A very simple mechanical Anti-Flip braking system was
    > > illustrated in the Bicycling Science book by Wilson
    > > and Whitt. That system works by having the rider only
    > > have direct control over the rear brake which operates
    > > in the usual fashion on the rim but is mounted on a
    > > spring-loaded sliding mount so that it moves forward
    > > as a result of engaging the rear rim. There is a cable
    > > attached to the moving rear brake mechanism that then
    > > pulls on the front brake which provides the bulk of
    > > the stopping power. So the front brake cable is pulled
    > > by the reaction force on the rear brake and the moment
    > > the rear wheel starts to leave the ground this
    > > reaction force is reduced and that partially releases
    > > the front brake to prevent a flip. The rider can
    > > therefore pull as hard as he wants on the brake lever
    > > and the bicycle will automatically stop with a
    > > deceleration that is just on the verge of lifting the
    > > rear wheel off the ground. Of course he better have a
    > > firm grasp on the handlebars so he doesn't fly off the
    > > bike anyway.
    >
    > Peter-Impressive approach.
    >
    > I assume you're referring to the Calderazzo brake system
    > shown on pp210- 212 or the the 1982 edition of Bicycle
    > Science.

    That's the one.
    >
    > Was this system ever manufactured?

    I don't believe so, but the prototype was reported to work
    well until the fork failed from the stress of too many
    demonstrations of high- speed stops.
    >
    > I think this might work also work well when trying to
    > control 4 brakes with 2 hands on my quadribent.
    >

    There was an article in Bicycling a couple decades or so ago
    with a similar arrangement on a tandem that was used to
    increase braking power rather than anti-flip. It used a rear
    hub brake as the actuating mechanism and attached a cable
    from the reaction arm of the hub brake to a rim brake. In
    that particular case the rim brake was also on the rear
    wheel and the purpose was to control both brakes with a
    single pull and to substantially multiply the force applied
    to the rim brake. The design looked easier to construct than
    the Calderazzo one since the hub brake already has the
    reaction arm.
     
  9. Tom Sherman

    Tom Sherman Guest

    meb wrote:

    > ... Short wheelbase recumbents flip under braking with the
    > rider not even leaving the seat, bracing with the
    > handlebars has little to do with whether the rider would
    > leave the seat on a swb bent during braking....

    If the seat (and therefore combined rider/bicycle center
    of mass) is low enough, the SWB recumbent will not have
    enough front wheel traction to overturn. I can easily lock
    both front wheels on my trike [1] without the chainring
    hitting the ground. The same is true for my lowracer [2],
    but in this case locking the front wheel leads to a loss
    of balance.

    [1] http://www.ihpva.org/incoming/2002/df1a.jpg
    [2] http://www.ihpva.org/incoming/2002/sunset/Sunset001.jpg

    Tom Sherman - Quad Cities (Illinois Side)
     
  10. Dvt

    Dvt Guest

    Doug Goncz wrote:
    > Wouldn't it be great if you could backpedal your multigear
    > bike and get braking that would ease the front brake the
    > instant the rear tire started to lift?

    [snip description]

    This thread about anti-flip brakes has me wondering... What
    do you do in the rain/snow/ice/gravel/whatever? I tend use
    my rear brakes more in inclement weather, since a front-
    wheel slide is quite possible and hazardous.

    Side note: that's probably why I go through more rear
    brake pads than front. I use the front brakes more often,
    but the rear brakes are used in the conditions that
    accelerate pad wear.

    --
    Dave dvt at psu dot edu
     
  11. meb

    meb New Member

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    I was deeming lowracer to be distinct from swb bents rather than a subset. The very low CG of the lowracer keeps them from having all their weight transfered off the rear under braking, even at faster .7 G decels.

    Many persons's classify lowracers as a subset of swb recumbents, so to the extent one deems lowracers as a subset of SWb rather than distince, then there is a significant minority of swb immune to braking endos. However, most SWB bents, have sufficiently high seats relative their rearward placement that they endo under heavy braking.

    BTW Tom, I recently saw a Sunset advertised with a caption that it was one of only 18 built. Would he have been referring to that particular model of Sunset or was that all Sunsets total?

    As for the tadpole trike, that doesn't surprise me since tadpoles have low a low cg, have the rider positioned so that there is typically a static 60% rear bias before braking. What I wonder, is just how much faster a tadpole can decel-any figures?
     
  12. meb

    meb New Member

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    On low coefficient of friction surfaces, anti-lock brakes would give you more steering control since the wheels continue to spin so you can steer and balance with effect rather than an ineffective slide. Anti-lock brakes stop faster on most surfaces since the coefficient of sliding friction is lower than the coefficient of static friction, and anti lock brakes continuously and more rapidly than humanly possible make corrections to keep the wheel spinning. On a handful of surfaces such as sand, gravel, or snow, a car actually stops slower with ABS because the locked tire pack the loose surface forward of the tire helping to stop quicker. With the thinner round surface contour bike tires, I’m not sure if you’d get enough packing effect or if the loose surface would pass by on either side of the tire.

    Under these low coefficient of friction surfaces, braking endo risks are substantially eliminated.

    The weight penalties of a microprocessor controlled or analog motor controlled antilock brake system would be excessive in most bicycle applications.

    The anti-flip brakes would not be a great choice for low coefficient of friction surfaces.
    These anti-flip brakes are using rear wheel torque on the brake not rear wheel lock to release the front. A locked rear wheel would still be applying force to the front brake linkage. It would exhibit a mild anti lock element since the force on the brake would be reduces when the locked rear wheel is sliding since the lower friction sliding coefficient of friction would transfer less force to the front brake.

    With the anti-flip brakes you are modulating front wheel control with feedback from the opposite wheel, no antilock component controlling the rear wheel, and no significant wheelspeed feedback. Also, differing coefficient of frictions would have differing preferred front/rear-brake bias and optimal front–rear weight transfers. Without some significant wheelspeed feedback, you’d not be calibrated for differing coefficient of friction surfaces.

    Perhaps the Brovendani anti-lock calipers or something building upon that concept would be a good choice if you had those surfaces on your ride regularly since they are lightweight and provide some benefit albeit they are much more primitive than a microprocessor controlled abs.
     
  13. Tom Sherman

    Tom Sherman Guest

    meb wrote:

    > ... BTW Tom, I recently saw a Sunset advertised with a
    > caption that it was one of only 18 built. Would he have
    > been referring to that particular model of Sunset or was
    > that all Sunsets total?...

    There is some controversy on this subject. 18 is the
    generally accepted total production number, but a couple of
    people claim 19 Sunsets were built.

    Earth Cycles had orders for more Sunsets (and Dragonflyers),
    but was unable to pay its vendors for the parts and
    subcontracted labor on the ones already built. :(

    Tom Sherman - Sunset 3 of 18 (or 19)
     
  14. Ted Bennett

    Ted Bennett Guest

    meb <[email protected]> wrote:

    > As for the tadpole trike, that doesn't surprise me since
    > tadpoles have
    low a low cg,
    > have the rider positioned so that there is typically a
    static 60% rear bias
    > before braking. What I wonder, is just how much
    faster a tadpole can
    > decel-any figures?

    That 60% rear bias is way off for any modern trike. It's
    more like 30 % rear, which much improves high speed
    cornering.

    Although I don't have any figures concering tadpole
    decelerations, I can offer this anecdotal info: While riding
    with ordinary bicycles, a tadpole rider quickly learns not
    to brake too hard when being followed. I have been rear-
    ended more than a few times. Which suggests that a decent
    tadpole can fairly easily exceed the 0.6g maximum of a
    typical bike.

    --
    Ted Bennett Portland OR
     
  15. Ted Bennett

    Ted Bennett Guest

    > So far <me, rapping on my bed frame>, I have not
    > experienced the event lovingly known as a "face plant".
    >
    > Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

    Never ridden a penny farthing, then?

    --
    Ted Bennett Portland OR
     
  16. Ted Bennett <[email protected]> wrote:
    >> So far <me, rapping on my bed frame>, I have not
    >> experienced the event lovingly known as a "face plant".
    >>
    >> Chris Zacho ~ "Your Friendly Neighborhood Wheelman"
    >
    >
    > Never ridden a penny farthing, then?

    that is a pretty reasonable assumption.
    --
    david reuteler [email protected]
     
  17. meb

    meb New Member

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    Or at least one minus anti flip brakes :D
     
  18. I'm sure a lot of people are going to say the same thing,
    but it seems pretty redundant to me. I mean, I'm already the
    "anti lock brake" system on my bike.

    It's not like some old lady in a minivan with the stereo
    going, that only has to brake completely unexpectedly and in
    a panic. When I brake hard on my bike (on and off road) I'm
    fully concentrating, and I know what I'm doing.
    Furthermore.. I can feel the tires, I can hear the tires..
    and I can see the front wheel and I know exactly what kind
    of surface I'm on.

    Unlike mindlessly stamping on a brake pedal in a car, I have
    very precise controls for each individual wheel that I'm
    actuating with my hand. I've never wished that I had
    computer control intervention...

    Sorry if I come off cocky, I do appreciate your technical
    work though.. experimenting is fun.

    Mike http://mikebeauchamp.com

    " Doug Goncz " <[email protected]> wrote in message news:[email protected]
    m29.aol.com...
    > Wouldn't it be great if you could backpedal your multigear
    > bike and get
    braking
    > that would ease the front brake the instant the rear tire
    > started to lift?
    >
    > I built such a bike in about 1992.
    >
    > It was a Shimano three speed coaster brake hub, on the
    > cheapest frame I
    could
    > get, salvaged from the cleanout of the Hollybrooke
    > condominium bicycle
    storage
    > room.
    >
    > The torque arm was supported by about a 10 x 25 mm
    > cartridge bearing which
    in
    > turn was spaced by a shim made from a polyethylene milk
    > jug cap, the kind
    that
    > you have to tear the tab off of to open. The rearranged
    > axle lock nuts
    applied
    > force from the outside through the now mobilized arm to
    > the large (50mm) bearing of tiny (individual?) balls that
    > was the left hub cup and cone.
    The
    > cartridge bearing was therefore used at extrememly _low_
    > PV in its
    designed
    > function, and at high P, zero V in its thrust ability.
    > Such bearings do
    have
    > thrust ability.
    >
    > The braking action was overly responsive in first, about
    > right in second,
    and
    > had a strange behavior in third. I'd say third on that
    > bike was for
    no-traffic,
    > no-hill conditions only, but I did ride it 14 miles from
    > Greenwood Drive
    to
    > Pickett Rd. to the bike shop and it did work, and I didn't
    > have any
    accidents.
    > You could instantly snap the shifter to any brake geometry
    > you'd care so
    all in
    > all it was fairly safe.
    >
    > Well, now I am building the wide range Thunderbolt and I
    > would like to get
    rid
    > of this one of about 120 boxes I have lying around. If
    > you'd like to have
    a go,
    > all the parts needed are in the box. Sorry, the frame is
    > long gone. No
    spokes.
    > No rims. Just the magic hub, fittings, cabling, and
    > caliper brake, a good
    one
    > if I remember correctly.
    >
    > I'd mount the shifter on the seat post and leave the
    > handlebars gloriously bare, but your taste is not my
    > taste.
    >
    >
    >
    > My physics project at NVCC: Google Groups, then "dgoncz"
    > and some of: ultracapacitor bicycle fluorescent flywheel
    > inverter
    >
    > 4-1-9 Fraud
    > http://www.secretservice.gov/electronic_evidence.shtml
     
  19. Tom Sherman

    Tom Sherman Guest

    Ted Bennett wrote:

    >>So far <me, rapping on my bed frame>, I have not
    >>experienced the event lovingly known as a "face plant".
    >>
    >>Chris Zacho ~ "Your Friendly Neighborhood Wheelman"
    >
    >
    >
    > Never ridden a penny farthing, then?

    He parachutes to the ground after going over the bars while
    braking. ;)

    --
    Tom Sherman - Quad Cities (Illinois Side)
     
  20. Doug Goncz

    Doug Goncz Guest

    >From: "Mike Beauchamp" [email protected]

    >I'm sure a lot of people are going to say the same thing,
    >but it seems pretty redundant to me. I mean, I'm already
    >the "anti lock brake" system on my bike.

    Hell, yes! I ony suggest this as another _way_ to rock and
    roll, not a better system for any class of rider. It is
    just a topology, a geometry, a configuration. It was loads
    of fun to ride.

    I mean, the main advantage is no levers on the bars. So
    what? Stylish? Doesn't matter.

    Still, if one of you would like to try the parts kit, I've
    still got it.

    My physics project at NVCC: Google Groups, then
    "dgoncz" and some of: ultracapacitor bicycle
    fluorescent flywheel inverter

    4-1-9 Fraud
    http://www.secretservice.gov/electronic_evidence.shtml
     
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