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



C

Clive George

Guest
"Artemisia" <[email protected]> wrote in message
news:[email protected]
> Thanks for all the answers, but I'm a bit out of my depth in all this
> technical talk.


Oops, sorry, most of it wasn't at all relevant to your original request.

> Might someone explain:
>
> What is brake "bleeding" and why is it necessary (or not)?


Hydraulic systems work using fluids which are pretty much incompressible.
Air is the opposite - if you increase the pressure, a given lump of air gets
smaller - which you can see with a bike pump. If you get air in the brake
system, it won't work nearly as well. Bleeding is the process of getting rid
of air, which basically involves pushing fluid through until there are no
more bubbles.

And if you've got it set up right for you, you won't ever need to do it.

> What are maggies? HS33s? What kind is Magura Big?


"maggie" is I believe short for Magura, HS33 are their rim brakes, so
irrelevant to your application.

> What does "open" and "closed" mean?


A closed system has a piston at each end of a pipe. Move the piston at one
end, it will move at the other - conventional hydraulics there. However if
you warm the fluid up, it will expand, and the two pistons will move apart -
which may not be a good thing.
An open system is more like what a car has. There's a small reservoir at the
top, and when the brakes are off, the pipe is connected to that, allowing
expansion and contraction of fluid (and automatic adjustment of pads).

> What is a rim brake? I don't think any are on offer for my
> Scorpion...?


A rim brake is like what you have on normal bikes - the pads are applied to
the rim.

> I hope I can delegate any eventual problems and adjustments to my bike
> mechanic? Ditto for eventual maintenance? If I buy the brakes as part
> of my initial setup, do I still have to do all sorts of adjustments
> and setups on my own? See, I don't feel confident to tackle all this
> new science and don't have time to take a qualifying degree in bike
> maintenance (that my have to wait till I retire!).


Yes, you should be able to.

cheers,
clive
 
C

Clive George

Guest
"Peter Clinch" <[email protected]> wrote in message
news:[email protected]

>> On another tack: does a recumbent trike actually have _3_ brakes,
>> including the one aft? I think the system I'm going for (I mean the
>> Magura Big) includes an Avid v-brake on the back which also acts as a
>> parking brake with a velcro strap. Wouldn't that on its own
>> significantly increase stopping power in relation to 2-wheelers?

>
> The back brake is really just there as a parking brake. It won't have
> too much effect on your real stopping power which will be taken up
> front, because as soon as you slam on the anchors all the weight will be
> on the front wheels and all you'll get by braking at the back is locking
> the wheel and skidding.
> I think you'll be happily surprised about how much stopping power you
> get on a low recumbent trike with properly specified brakes.


I suppose I could mention here that I never missed having a back brake on
the greenspeed tandem we had for a while. The two front disks gave plenty of
stopping power.

cheers,
clive
 
C

CoyoteBoy

Guest
On 30 Aug, 11:42, "Clive George" <[email protected]> wrote:
>
> cheers,
> clive


Clive - well summarised! We did rather go off on a tangent didnt we!

In essence, buy the best brake you can afford and make sure its set up
correctly (a decent shop should sort it for you) and you will have few
problems, be they cable or hydro. Any half decent shop should be able
to repair / maintain them for you but they are generally simple enough
to "tweak" on your own - if you have any problems pop back on here and
someone will answer you in 30 seconds - then no doubt we'll go off at
a tangent and argue about the shape of the moon :)
 
T

Tom \Johnny Sunset\ Sherman

Guest
Roger Merriman wrote:
> Tom "Johnny Sunset" Sherman <[email protected]> wrote:
>
>> roger merriman wrote:
>>> On 29 Aug, 05:03, "Tom \"Johnny Sunset\" Sherman"
>>> <[email protected]> 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
 
P

Peter Clinch

Guest
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 [email protected] http://www.dundee.ac.uk/~pjclinch/
 
C

CoyoteBoy

Guest
On 30 Aug, 13:02, Peter Clinch <[email protected]> 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.
 
R

Roger Merriman

Guest
CoyoteBoy <[email protected]> wrote:

> On 30 Aug, 13:02, Peter Clinch <[email protected]> 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
 
R

Roger Merriman

Guest
Peter Clinch <[email protected]> wrote:

> Paul Boyd wrote:
> > Peter Clinch said the following on 29/08/2007 18:21:
> >> The feel and control is just /sooooooooo/ much better.

> >
> > That's really the crux of the matter. Any brake should be able to lock
> > up your wheels, therefore provide more than enough raw stopping power,
> > but it's how you can control that power that makes the difference.

>
> Agreed, and IME there was a very big difference between reading about it
> in theory and actually experiencing it.
>
> I went from sceptic feeling there wasn't really anything wrong with my
> brakes as they were to "Oh! *Now* I see what the point is, I think I'll
> be getting some of these!" over the course of a day's riding on an
> otherwise rather unimpressive demo bike.
>
> Pete.


hills do it as well, taking the new bike down some of the hills that
where real forearm pumpers before, now i could just glide down.

roger
--
www.rogermerriman.com
 
R

Roger Merriman

Guest
Peter Clinch <[email protected]> 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
 
R

Roger Merriman

Guest
Paul Boyd <[email protected]> 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
 
D

David Damerell

Guest
Quoting Peter Clinch <[email protected]>:
>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 <[email protected]> Distortion Field!
Today is Second Monday, August.
 
R

Roger Merriman

Guest
David Damerell <[email protected]> wrote:

> Quoting Peter Clinch <[email protected]>:
> >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!


need to ride down a proper hill then! ;-) my old mountain bike, used off
or on road as i used to nr my folks place has terrible brakes, back to
around london/surrey it's fine if not quite good.

it's only down long steep hills or other extremes that you'll see the
differnace. on older weeker calipers (1) your forearms will acke by the
time you reach the bottem, with super wizz bang disk brakes you don't
have to hang on to the brakes, but just squeeze them as and when needed.

on road it makes less differnace so the reason to have them is less.

(1) yes i know calipers differ greatly in power.

roger
--
www.rogermerriman.com
 
D

David Damerell

Guest
Quoting Roger Merriman <[email protected]>:
>David Damerell <[email protected]> wrote:
>>Quoting Peter Clinch <[email protected]>:
>>>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!

>need to ride down a proper hill then!


I've ridden down every hill in the country [1] with two people's lard to
brake and only one person's air resistance. It still wasn't my fingers
that were tired at the end of each day.

[1] on a long line between LE and JOG.
--
David Damerell <[email protected]> flcl?
Today is Second Tuesday, August.
 
R

Roger Merriman

Guest
David Damerell <[email protected]> wrote:

> Quoting Roger Merriman <[email protected]>:
> >David Damerell <[email protected]> wrote:
> >>Quoting Peter Clinch <[email protected]>:
> >>>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!

> >need to ride down a proper hill then!

>
> I've ridden down every hill in the country [1] with two people's lard to
> brake and only one person's air resistance. It still wasn't my fingers
> that were tired at the end of each day.
>

on the road brakes really are less of a issue, even travelling fast,
you'd have to be going very fast before it did.

the road that drops from the havard down to though to crickhowel is
fairly steep one and long and yet even that you only get slight i'm
useing the brakes a bit feel not a attaully twinge. unlike off road
where decending with old bikes and old brakes by the time you'd reached
the bottom you can feel it in your forearms, if you mostly ride on road
then you not need to brake for as long nor as hard.

> [1] on a long line between LE and JOG.


not a acronym i know sorry.

roger
--
www.rogermerriman.com
 
C

Clive George

Guest
"Roger Merriman" <[email protected]> wrote in message
news:1i3ood8.1350ga83fid1oN%[email protected]

> the road that drops from the havard down to though to crickhowel is
> fairly steep one and long and yet even that you only get slight i'm
> useing the brakes a bit feel not a attaully twinge. unlike off road
> where decending with old bikes and old brakes by the time you'd reached
> the bottom you can feel it in your forearms, if you mostly ride on road
> then you not need to brake for as long nor as hard


I find it's the bumpiness which gives the grief, not the hanging on to the
brakes per se. Hanging onto both the bars and the brakes gives my arms a
harder time than just the bars on their own.

>> [1] on a long line between LE and JOG.

>
> not a acronym i know sorry.


Blimey, you've been around here long enough. Traditional ends of this island
of ours.

cheers,
clive
 
A

Artemisia

Guest
On 30 août, 17:51, David Damerell <[email protected]>
wrote:

> I never understood the "big heave" argument. At the end of a day on the
> bike, it's not my fingers that are tired!


Aren't they now? I consider carpal tunnel problems one of the biggest
limiting factors to my cycling day. My hands hurt the blazes when I'm
on tour, and yes, I wear cycling gloves of course.

EFR
Ile de France
 
P

Peter Clinch

Guest
David Damerell wrote:

> I never understood the "big heave" argument. At the end of a day on the
> bike, it's not my fingers that are tired!


Nor are mine, but during use hydraulics are more pleasant because you
don't need to heave right there and then, whether or not fingers are
tired later on.

I never understood the arguments for hydraulics before I used them.
Having used them somewhat by accident (a demo 'bent had some HS11s on),
I bought some, and have never regretted it. They are simply much better
in use than cable brakes IME.

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 [email protected] http://www.dundee.ac.uk/~pjclinch/
 
P

Peter Clinch

Guest
Artemisia wrote:

> Aren't they now? I consider carpal tunnel problems one of the biggest
> limiting factors to my cycling day. My hands hurt the blazes when I'm
> on tour, and yes, I wear cycling gloves of course.


Something you can happily leave off on a hot day on the Scorpion! :)

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 [email protected] http://www.dundee.ac.uk/~pjclinch/
 
R

Roger Merriman

Guest
Clive George <[email protected]> wrote:

> "Roger Merriman" <[email protected]> wrote in message
> news:1i3ood8.1350ga83fid1oN%[email protected]
>
> > the road that drops from the havard down to though to crickhowel is
> > fairly steep one and long and yet even that you only get slight i'm
> > useing the brakes a bit feel not a attaully twinge. unlike off road
> > where decending with old bikes and old brakes by the time you'd reached
> > the bottom you can feel it in your forearms, if you mostly ride on road
> > then you not need to brake for as long nor as hard

>
> I find it's the bumpiness which gives the grief, not the hanging on to the
> brakes per se. Hanging onto both the bars and the brakes gives my arms a
> harder time than just the bars on their own.


yes off road that is the issue, and why good brakes make all the
differnance but there are some roads that are steep enought that you
have to pull the leavers hard enought that you can feel it in your
forearms the old tram road out of brynmawr which follows along along the
clydach gorge, at it's end essently plumits down to crickhowel.

<http://www.bikely.com/maps/bike-path/clydach-gorge> check out the
elvation profile, you really can't miss the hill!

but essently i agree with you for most rides you feel it in your legs
not your arms. very few hills are steep enought.
>
> >> [1] on a long line between LE and JOG.

> >
> > not a acronym i know sorry.

>
> Blimey, you've been around here long enough. Traditional ends of this island
> of ours.
>

acronym's are something of blind spot here.

> cheers,
> clive


roger
--
www.rogermerriman.com
 
A

Artemisia

Guest
On 31 août, 09:41, Peter Clinch <[email protected]> wrote:

> Something you can happily leave off on a hot day on the Scorpion! :)


Actually I wear the gloves always, even when not cycling. My balance
is so bad that I have to be constantly grabbing at things - stair
bannisters, bollards, traffic signs - to stay upright when walking in
the street, and I'd rather have the filth accumulate on the gloves
than on my hands. Fortunately they're very washable and fast-drying.

OTOH, what about the head lid on the Scorpion? Carol Hague told me she
never wears a helmet on her Greenspeeds as the kind of head injury one
would get from tipping off an upright just isn't going to happen. But
all the darth websites show the people on the trikes in head-lids, and
there is always my superstitious fear of riding unlidded. I must say I
do find my helmet very sweaty and headache-inducing and as it is now
coming up to three years old, probably needs to be changed anyway. It
would be lovely to dispense with that.

So Dark Siders, do you ride with lids? I'm not trolling and I don't
need justifications or attacks or tables of statistics, I'm just
curious.