Which Brakes? Avid Mechanical Disc? Magura Big or Marta HydraulicDisc?

roger merriman wrote:
On 29 Aug, 05:03, "Tom \"Johnny Sunset\" Sherman"
wrote:

I can lock up both from wheels on dry pavement with the Avid mechanical
disc brakes on my trike. The feel is mushy compared to a good hydraulic
system, however.

Thing is though that locking the wheels is one thing, stopping fast
and safely is another, my cheap hybrid can lock it's wheels, but i
would regard is brakes as poor, in that it wouldn't stop in hurry at
speed, while my moutain bikes will, which considering the rubber on
the road i'd probably struggle to lock wheels up.

like the other day had to do a emergency stop, squeeling of tires on
hot road but not locking.

Can you lock the front wheel on your hybrid? An upright bicycle will
"pitch over" before the front wheel will lock on dry pavement.
Conversely, due to weight transfer, the rear wheel can be locked with
quite weak brakes (or almost no brake at the point where the wheel is
about to be unloaded).

On a tadpole trike with a low seat, braking is limited by tire traction
only. The available braking force is generally about 40% more than could
be produced on an upright.

--
Tom Sherman - Holstein-Friesland Bovinia
A Real Cyclist [TM] keeps at least one bicycle in the bedroom.

--
Posted via a free Usenet account from http://www.teranews.com

Tom "Johnny Sunset" Sherman wrote:

roger merriman wrote:
On 29 Aug, 05:03, "Tom \"Johnny Sunset\" Sherman"
wrote:

I can lock up both from wheels on dry pavement with the Avid mechanical
disc brakes on my trike. The feel is mushy compared to a good hydraulic
system, however.

Thing is though that locking the wheels is one thing, stopping fast
and safely is another, my cheap hybrid can lock it's wheels, but i
would regard is brakes as poor, in that it wouldn't stop in hurry at
speed, while my moutain bikes will, which considering the rubber on
the road i'd probably struggle to lock wheels up.

like the other day had to do a emergency stop, squeeling of tires on
hot road but not locking.

Can you lock the front wheel on your hybrid? An upright bicycle will
"pitch over" before the front wheel will lock on dry pavement.
Conversely, due to weight transfer, the rear wheel can be locked with
quite weak brakes (or almost no brake at the point where the wheel is
about to be unloaded).

on the hybrid the the biggest danger in locking a wheel is looking
control than pitching over, it's weight means you'd really have to try,
possibly pitching your weight forward

but most uprights you really would have to try before pitching your self
over.

i'm used to mounatin bikes so i move my weight under braking so for
instance while it was close to i didn't lock the rear when i had to do a
emergency stop from about 20.

On a tadpole trike with a low seat, braking is limited by tire traction
only. The available braking force is generally about 40% more than could
be produced on an upright.

thats the same of any bike, certinaly if you move your weight around.

but again locking ones brakes while sounds impressive doesn't stop you
as fast or as incontrol as braking to just within the limits of the
tires.

roger
--
www.rogermerriman.com

On 30 Aug, 10:54, (Roger Merriman) wrote:
Tom "Johnny Sunset" Sherman wrote:

but again locking ones brakes while sounds impressive doesn't stop you
as fast or as incontrol as braking to just within the limits of the
tires.

roger
--www.rogermerriman.com

10% slippage is quoted as best accel and decel tyre slip rate
according to the motorsport boys - im not sure how or why they come to
that conclusion but IIRC its used in F1 so cant be far wrong?

Roger Merriman wrote:
Tom "Johnny Sunset" Sherman wrote:

roger merriman wrote:
On 29 Aug, 05:03, "Tom \"Johnny Sunset\" Sherman"
wrote:
I can lock up both from wheels on dry pavement with the Avid mechanical
disc brakes on my trike. The feel is mushy compared to a good hydraulic
system, however.

Thing is though that locking the wheels is one thing, stopping fast
and safely is another, my cheap hybrid can lock it's wheels, but i
would regard is brakes as poor, in that it wouldn't stop in hurry at
speed, while my moutain bikes will, which considering the rubber on
the road i'd probably struggle to lock wheels up.

like the other day had to do a emergency stop, squeeling of tires on
hot road but not locking.
Can you lock the front wheel on your hybrid? An upright bicycle will
"pitch over" before the front wheel will lock on dry pavement.
Conversely, due to weight transfer, the rear wheel can be locked with
quite weak brakes (or almost no brake at the point where the wheel is
about to be unloaded).

on the hybrid the the biggest danger in locking a wheel is looking
control than pitching over, it's weight means you'd really have to try,
possibly pitching your weight forward

but most uprights you really would have to try before pitching your self
over.

i'm used to mounatin bikes so i move my weight under braking so for
instance while it was close to i didn't lock the rear when i had to do a
emergency stop from about 20.

On my Trek 6000 (hard-tail) I can easily do a "stoppie", getting the
rear wheel a foot or so in the air as I come to a stop. Since I brace
myself properly, there is not real danger of going over the bars.
However, there is no front wheel skidding, even with the knobby off-road
tires.

On a tadpole trike with a low seat, braking is limited by tire traction
only. The available braking force is generally about 40% more than could
be produced on an upright.

thats the same of any bike, certinaly if you move your weight around.

I would be shocked if anyone on an upright could come close to matching
the braking of a tadpole with a low seat. Do the calculations, and you
will see that the upright pitches over between 0.6 and 0.7g, while the
tadpole is limited only by available friction.

but again locking ones brakes while sounds impressive doesn't stop you
as fast or as incontrol as braking to just within the limits of the
tires.

Agreed. However, my point is while proper hydraulic disc brakes can be
considered the best braking system for a tadpole, the Avid mechanical
discs are more than adequate.

--
Tom Sherman - Holstein-Friesland Bovinia
A Real Cyclist [TM] keeps at least one bicycle in the bedroom.

--
Posted via a free Usenet account from http://www.teranews.com

Tom "Johnny Sunset" Sherman wrote:

Agreed. However, my point is while proper hydraulic disc brakes can be
considered the best braking system for a tadpole, the Avid mechanical
discs are more than adequate.

But that reduces the argument to stopping power only. Hydraulics give
you more control over the power because your fingers don't need to do a
Big heave to get the power. That's why I prefer hydraulics, not
anything to do with absolute available power: they're just plain nicer
to use.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On 30 Aug, 13:02, Peter Clinch wrote:
Tom "Johnny Sunset" Sherman wrote:

Agreed. However, my point is while proper hydraulic disc brakes can be
considered the best braking system for a tadpole, the Avid mechanical
discs are more than adequate.

But that reduces the argument to stopping power only. Hydraulics give
you more control over the power because your fingers don't need to do a
Big heave to get the power. That's why I prefer hydraulics, not
anything to do with absolute available power: they're just plain nicer
to use.

Much like a comparison of a car with drum brakes and one with vented 4-
pot discs - the drums will (all too easily) lock up happily, but they
are a lot less pleasant to drive with.

CoyoteBoy wrote:

On 30 Aug, 13:02, Peter Clinch wrote:
Tom "Johnny Sunset" Sherman wrote:

Agreed. However, my point is while proper hydraulic disc brakes can be
considered the best braking system for a tadpole, the Avid mechanical
discs are more than adequate.

But that reduces the argument to stopping power only. Hydraulics give
you more control over the power because your fingers don't need to do a
Big heave to get the power. That's why I prefer hydraulics, not
anything to do with absolute available power: they're just plain nicer
to use.

Much like a comparison of a car with drum brakes and one with vented 4-
pot discs - the drums will (all too easily) lock up happily, but they
are a lot less pleasant to drive with.

quite the hills nr my folks place are steep, as in the 30% range, and
while i can hold safely the old mountain bike going down, even at some
speed i do need some effort, while the new one with disks requires a lot
less effort, back in south west london/surrey the hills have a flatter
profile so neither has a edge really.

roger
--
www.rogermerriman.com

Peter Clinch wrote:

roger merriman wrote:

Thing is though that locking the wheels is one thing, stopping fast
and safely is another, my cheap hybrid can lock it's wheels, but i
would regard is brakes as poor, in that it wouldn't stop in hurry at
speed, while my moutain bikes will, which considering the rubber on
the road i'd probably struggle to lock wheels up.

Indeed. And this is where hydraulics are better IMHO, as they let you
have high power combined with very sensitive fingertip control.

Pete.

the big thing for me is certinaly off road and back in wales is being
able to brake with out having to strain at the leavers so i can use a
softer more controlled brake thus keeping the braking smoother etc.

roger
--
www.rogermerriman.com

Paul Boyd usenet.is.worse@plusnet wrote:

Clive George said the following on 29/08/2007 15:16:

but the rim
brakes are fit-and-forget in the way the discs distinctly aren't :-(

Nothing against your opinion personally, but I've seen this sort of view
expressed before and I'm a bit puzzled by it. I fitted my hydraulic
disc brakes ages ago, and I've forgotten about them ever since. With
hydraulic disc brakes there's far less to go wrong than with any cable
brakes (can you even still get open systems?), and they just keep
working. They may need to be bled once every so often, but cables need
maintenance more than once every so often. All brakes need pads/blocks
replaced periodically, so I'm genuinely interested in why you think
discs aren't "fit and forget".

i love the disks on my new bike but reliable they have not been, jamed
on a few times, it's probably the use, or rather lack of, the bike has
seen the inside of 3 sheds but very little mud to play with.

(still probably wouldn't have cables though)

Agreed. I have had cables, then hydraulics, and the "feel" of the two
is worlds apart.

roger
--
www.rogermerriman.com

Quoting Peter Clinch :
But that reduces the argument to stopping power only. Hydraulics give
you more control over the power because your fingers don't need to do a
Big heave to get the power.

I never understood the "big heave" argument. At the end of a day on the
bike, it's not my fingers that are tired!
--
David Damerell Distortion Field!
Today is Second Monday, August.