Saddleless bikes and the law

En message <[email hidden]>, Mike Sales
<[email hidden]> ecrit

Quoted message said:

Does the law require a saddle on a bike? A neighbour has asked me this, and
whilst my guess is that it never occurred to the law makers that anyone
would
be daft enough to make a bike like that, I have no idea really.
Mike Sales.

The only reference to saddles in the Pedal Cycles Construction and Use
Regulations 1983 is in Reg 7 where the size of bicycles, measured by the
height of the saddle above the ground, determines how many braking
systems must be fitted.

--
Soloriens

In news:[email hidden],

Mike Sales said:

Does the law require a saddle on a bike? A neighbour has asked me
this, and whilst my guess is that it never occurred to the law makers
that anyone would
be daft enough to make a bike like that, I have no idea really.
Mike Sales.

I've seen bikes without a hole for a seat post, so no possibility of a
saddle. These are some kind of trick bike? I don't know, youth is not on my
side. How could you have a law requiring a saddle?
--

Martin Bulmer

On Wed, 12 Jan 2005 22:49:22 +0000, soloriens <[email hidden]>

Quoted message said:

The only reference to saddles in the Pedal Cycles Construction and Use
Regulations 1983 is in Reg 7 where the size of bicycles, measured by the
height of the saddle above the ground, determines how many braking
systems must be fitted.

Could the absence of a saddle (which therefore makes the above law
unworkable) be a loophole for fixies who prefer not to have a front
brake?
--
Amazon: "If you are interested in 'Asimov's I-Robot',
you may also be interested in 'Garfield - The Movie'.
... erm, how do they figure that one out?

"Mike Sales" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Does the law require a saddle on a bike? A neighbour has asked me this,
and
whilst my guess is that it never occurred to the law makers that anyone
would
be daft enough to make a bike like that, I have no idea really.
Mike Sales.

There is a "don't sit down" unwritten law.

Richard Bates said:

Could the absence of a saddle (which therefore makes the above law
unworkable) be a loophole for fixies who prefer not to have a front
brake?

I don't think fixies need a front brake to be road legal. Isn't the
requirement that the bike shall have two independent braking
mechanisms, which the rear brake and fixed drive train provide.

--

Call me "Bob"

"More oneness, less categories,
Open hearts, no strategies"

Email address is spam trapped, to reply directly remove the beverage.

En message <[email hidden]>, Call me Bob
<[email hidden]> ecrit

Quoted message said:

Richard Bates said:

Could the absence of a saddle (which therefore makes the above law
unworkable) be a loophole for fixies who prefer not to have a front
brake?

I don't think fixies need a front brake to be road legal. Isn't the
requirement that the bike shall have two independent braking
mechanisms, which the rear brake and fixed drive train provide.

No. Fixies must have a front brake. A cycle [of a defined size] cannot
be used on the road unless

"... if the cycle is so constructed that one or more of the
wheels is incapable of rotating independently of the pedals, it is
equipped with a braking system operating on the front wheel"

for bikes made since 1984 the saddle height is the definition of size.
Before that it was the wheel size (Mr Moulton spoiled that rule).
--
Soloriens

On Thu, 13 Jan 2005 07:32:30 +0000 someone who may be soloriens
<[email hidden]> wrote this:-

Quoted message said:

No. Fixies must have a front brake.

Why would the rider of one not want a front brake?

--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.

David Hansen said:

Why would the rider of one not want a front brake?

"It's all about the purity, man! It's like. Thing. Zen. Y'know?"

Jon

soloriens said:

No. Fixies must have a front brake. A cycle [of a defined size]
cannot be used on the road unless

"... if the cycle is so constructed that one or more of the
wheels is incapable of rotating independently of the pedals, it is
equipped with a braking system operating on the front wheel"

for bikes made since 1984 the saddle height is the definition of
size. Before that it was the wheel size (Mr Moulton spoiled that
rule).

What is the specified saddle height, and how would that relate to, say,
a Trice Micro?

--
Dave...

David Hansen said:

On Thu, 13 Jan 2005 07:32:30 +0000 someone who may be soloriens
<[email hidden]> wrote this:-

Quoted message said:

No. Fixies must have a front brake.

Why would the rider of one not want a front brake?

Beat me - my main-means-of-transport fixed has cantilevers
front and back (it was built in the 80's before discs were common)

BugBear

"Martin Bulmer" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

In news:[email hidden],

Mike Sales said:

Does the law require a saddle on a bike? A neighbour has asked me
this, and whilst my guess is that it never occurred to the law makers
that anyone would
be daft enough to make a bike like that, I have no idea really.
Mike Sales.

I've seen bikes without a hole for a seat post, so no possibility of a
saddle. These are some kind of trick bike? I don't know, youth is not on

my

Quoted message said:

side.

Probably a 'Trials' bike used exclusively as you say for trick type riding.

Steve.

"Martin Bulmer" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

In news:[email hidden],

Mike Sales said:

Does the law require a saddle on a bike? A neighbour has asked me
this, and whilst my guess is that it never occurred to the law makers
that anyone would
be daft enough to make a bike like that, I have no idea really.
Mike Sales.

I've seen bikes without a hole for a seat post, so no possibility of a
saddle. These are some kind of trick bike? I don't know, youth is not on

my

Quoted message said:

side.

Probably a 'Trials' bike used exclusively as you say for trick type riding.

Steve.

On Thu, 13 Jan 2005 07:32:30 +0000, soloriens <[email hidden]>

Quoted message said:

No. Fixies must have a front brake. A cycle [of a defined size] cannot
be used on the road unless

"... if the cycle is so constructed that one or more of the
wheels is incapable of rotating independently of the pedals, it is
equipped with a braking system operating on the front wheel"

I don't know for certain, since I just heard this from a tricyclist,
but it is apparently legal for both brakes to work on the same wheel
so long as those two brakes operate independently.

In the case of a trike, however, having the brakes on the front wheel
gives a more powerful brake than two brakes on the rear wheel (of a
bicycle).

I was just curious for the purpose of being curious. I too think it
would be daft not to have a front brake.
--
Amazon: "If you are interested in 'Asimov's I-Robot',
you may also be interested in 'Garfield - The Movie'.
... erm, how do they figure that one out?

As some bicyclists are sufficienty skilled to pronounce the rear brake
pretty useless, would there be any benefit gained by having two brakes
on the front wheel. With modern equipment, the two brakes could be,
say, a cantilever and a disc?

Just curious ...

--
Amazon: "If you are interested in 'Asimov's I-Robot',
you may also be interested in 'Garfield - The Movie'.
... erm, how do they figure that one out?

Quoted message said:

As some bicyclists are sufficienty skilled to pronounce the rear brake
pretty useless

Hey, he thinks I'm a skilled cyclist! Pity it was sarcasm. For the record
there's no skill involved. Get a decent brake, slam it on. All the weight
shifting to the front and the back wheel having no weight on top of it
takes care of the rest.

Quoted message said:

would there be any benefit gained by having two brakes
on the front wheel. With modern equipment, the two brakes could be,
say, a cantilever and a disc?

Yeah, but only if the stongest brake couldn't lock the front wheel/send you
over the bars on its own. I'm guessing that with two good front brakes
you'd be able to stop incedibly quickly (if you don't count the
cartwheeling through the air bit).

Mark Thompson said:

Quoted message said:

As some bicyclists are sufficienty skilled to pronounce the rear brake
pretty useless

Hey, he thinks I'm a skilled cyclist! Pity it was sarcasm. For the record
there's no skill involved. Get a decent brake, slam it on. All the weight
shifting to the front and the back wheel having no weight on top of it
takes care of the rest.

No sarcasm involved. It was a genuine comment: Some cyclists claim
that with a good braking technique, the rear brake does no work, and
there is no risk of cartwheeling. I assume they shift their weight
backwards (front brake only probably doesn't work when not sitting on
the saddle.

Quoted message said:

Quoted message said:

would there be any benefit gained by having two brakes
on the front wheel. With modern equipment, the two brakes could be,
say, a cantilever and a disc?

Yeah, but only if the stongest brake couldn't lock the front wheel/send you
over the bars on its own. I'm guessing that with two good front brakes
you'd be able to stop incedibly quickly (if you don't count the
cartwheeling through the air bit).

I'm guessing that having two brakes on the front wheel may allow
better control. The point between a brake providing maximum
deceleration and locking the wheel is quite fine. Let's call this the
"critical brake point". Sharing the force between two brakes, both
more distance from the CBP could perhaps give better deceleration with
less risk of wheel-locking?

What about on a recument *bi*cycle
--
Amazon: "If you are interested in 'Asimov's I-Robot',
you may also be interested in 'Garfield - The Movie'.
... erm, how do they figure that one out?

Richard Bates said:

I'm guessing that having two brakes on the front wheel may allow
better control. The point between a brake providing maximum
deceleration and locking the wheel is quite fine. Let's call this the
"critical brake point". Sharing the force between two brakes, both
more distance from the CBP could perhaps give better deceleration with
less risk of wheel-locking?

An interesting point. And I think the answer is no.

If the two brakes are totally independent of each other and (for the
sake of argument) approximately identical, and the rider is experienced
enough to reach critical point on both more or less simultaneously, you
will have twice the braking force (and hence twice the deceleration).
However, you'll also have *twice* the probability of locking up the
wheel, since now a small increase on *either* brake will lock up the wheel.

(If the two brakes are no longer independent but operate from one
control, that's almost the same as simply doubling the length of the
brake pads. Almost but not quite, since heat dissipation on the
double set will be slightly better (more surface area per unit volume).
That probably doesn't make a significant difference in normal
conditions, however.)

R.

Richard Bates said:

No sarcasm involved. It was a genuine comment: Some cyclists claim
that with a good braking technique, the rear brake does no work, and
there is no risk of cartwheeling. I assume they shift their weight
backwards (front brake only probably doesn't work when not sitting on
the saddle.

It depends on the circumstances. Maximum breaking on level solid ground
will be achieved when the front wheel is almost but not quite locked (at
your "critical point"😉 and the back wheel is unweighted. If you go
further and lock the front wheel, one of two things will happen:

a) if the coefficient of friction between the front tyre and the ground
is sufficiently high, the back wheel will start to lift. A reasonably
skilled rider will let off the front brake at this point to avoid going
over the bars. Going over the bars is not inevitable in any case; the
energy contained in the system has to be sufficient to lift the mass of
you + bike over the apex of the inverted pendulem. BOTE calculation: a
70 kg rider on a 10 kg bike with a 0.5m top tube has a centre of mass
normally about 1m above the ground. To go over the handlebars with a
locked front wheel requires 80 kg to be raised 0.5m, ie 400 Joules of
energy. This can come from a velocity of just over 3 m/s or ~7 mph.
Less than that, and you'll simply lift off the ground at the back, but
then be deposited back again as it fails to get "over" the hump. A
significant weight shift backwards is hard - you'd probably only get a
few cm change in position of your CoM. On the other hand, it'd be easy
to weight-shift forwards and reduce the speed required to go over the top.

b) if the coeff. of friction between the front tyre and the ground isn't
high enough for (a), the front wheel will skid. Again, best practise
is to release it pronto before you fall off.

If the ground isn't solid (and is, say, loose gravel) you can sometimes
stop faster by locking everything up. The wheels act as ploughs and the
energy is dissipated in shifting gravel into a heap in front of the
tire. But, again, with both wheels locked you lose most of your ability
to balance and all of your ability to (effectually) steer.

R.

Quoted message said:

No sarcasm involved. It was a genuine comment: Some cyclists claim
that with a good braking technique, the rear brake does no work, and
there is no risk of cartwheeling. I assume they shift their weight
backwards (front brake only probably doesn't work when not sitting on
the saddle.

There's no technique to it (on drops at least). Just slam the brakes on
hard and it happens automatically. I do brace when I do this, but mostly
through fear of being splatted by whatever I'm trying to avoid. Moving to
a dual pivot on the front was what enabled me to do it.

<snippity>

Quoted message said:

I'm guessing that having two brakes on the front wheel may allow
better control. The point between a brake providing maximum
deceleration and locking the wheel is quite fine. Let's call this the
"critical brake point". Sharing the force between two brakes, both
more distance from the CBP could perhaps give better deceleration with
less risk of wheel-locking?

Of course! <slaps hand to forehead> Half the pressure on the levers needed
for the same braking power, so twice the margin for error.

Quoted message said:

What about on a recument *bi*cycle

Yeah, it would be almost impossible to go over the bars, whilst those with
under seat steering are used to being over the bars anyway. Reason #34 for
buying a recumbent: So I can investigate the limits of front wheel dual
braking in perfect safety.