I'm with TC on this one.
There are four pistons (two sets of opossed pistons) on our original
calipers,
just the same as the R 1 ones and are
working on a fixed housing. The rotor or disc is also fixed. As you pump
fluid into the four pistons, the first one to move will be the one with the
least
resistance then one after the other they will search for the rotor surface
and
then the braking will take place ( that is only during the first pumping
while
you are bleeding the circuit). This means that the pistons as long as the
rotor
is not totally out of center, which is not the case for the standard or the
R1
calipers on our Max, the pistons will center themselfs out against the rotor
(self centering device). If the disc or rotor is slightly off centered the
pistons
will make up for that and even if the left set of pistons are out more than
the
right, this makes no difference on the braking performance.
A different thing would be if for some reason the alignment between the
piston
travel and the discs were not at 90� or square. Once the are in contact with
the disc they will stay there, but exerting no force whatsoever till you use
the
brake.
When you don't have equal oposing pistons then you need the housing
(caliper) to float and find its proper position related to the disc or
rotor.
Regards,
Charles ( [EMAIL PROTECTED] )
----- Original Message -----
From: Eric Harnish <[EMAIL PROTECTED]>
To: V-MAX TECH LIST <[EMAIL PROTECTED]>
Sent: Tuesday, October 24, 2000 4:08 PM
Subject: Re: Brakes
> TC
> No war here . The pistons on a caliper will retract at the same amount
> if all is well . If the caliper is not centered on the rotor it will
> cause the master cyl piston to travel further
> to obtain braking force . This is something I learned over 20 yrs ago in
> a situation on a formula car that I had fitted a new brake system to .
> I have also seen this problem in the shops with techs turning rotors on
> European autos with ridged mounted calipers . They were use to floating
> US systems & did not pay attention to what they were doing when turning
> the rotors . They would get good brakes but with a low pedal . A
> floating system does not care .
> A ridgid mount system can not adjust for off set .
> This is not something that I just thought up. It is my personal
> experience & one of the few things that I've learned in the past 30 yrs
> of turning a wrench for a living :)
> Your Friend
> Eric H
> ----- Original Message -----
> From: "TC" <[EMAIL PROTECTED]>
> To: "V-MAX TECH LIST" <[EMAIL PROTECTED]>
> Sent: Tuesday, October 24, 2000 9:40 AM
> Subject: Re: Brakes
>
>
> > Eric,
> > I don't want to contribute to a "brake" war but I have to agree with
> > Sat Tara on this one. IMHO, (and we all know what opinions are worth),
> > consider the following:
> >
> > Floating calipers are required for self alignment only when the
> > piston/pistons are mounted on one side of the caliper. Our calipers
> > have pistons on both sides and will auto align, (assuming that in a
> > fully retracted position there is some clearance between the brake
> > shoes and the surfaces of the rotor). When you only have
> > piston/pistons on one side of the caliper then the caliper must be
> > able to move in order to apply pressure equally to both sides of the
> > rotor.
> >
> > Also IMHO ... Thomas has stated that his pistons relax an excessive
> > amount when the lever is released. This is because the "check-valve"
> > operation has been compromised. A master cylinder without a check
> > valve, (on one in the line), can only be used on drum brakes. All disc
> > systems must have some type of check valve mechanism to eliminate
> > excessive clearance between the rotor and the pads, (usually about 3
> > lbs in an automobile and 1 lb in a bike). Releasing the handle and
> > gaining this much relaxation of the pads indicates that Thomas's check
> > valve is not doing crap and as a result it will take excessive fluid
> > movement to take up the slack and get any braking action when the
> > brakes are re-applied.
> >
> > During normal operation the only thing that will push the pads away
> > from the rotor is rotor run-out .. and when it is excessive you will
> > gain lever travel to close things up before you begin to get any
> > braking action.
> >
> > I have not had one of these master cylinders apart and I can not tell
> > if the check valve is in there or built into the distribution tee that
> > splits the line to each side of the front wheel ....... I am sure
> > there must be a brake expert on the list that has had this experience
> > before ... I suspect however that the little "flap" in the bottom of
> > the master cylinder has something to do with this.
> >
> > Anyhow ... just my opinion ........
> > campbell
> >
> > ----- Original Message -----
> > From: "Eric Harnish" <[EMAIL PROTECTED]>
> > Subject: Re: Brakes
> >
> >
> > > Sat,
> > > Ridgid mounted calipers will not compensate for a caliper
> > > that is mounted off set to the rotor . Only floating calipers will
> > > compensate for this condition . On a car with ridged mounted
> > calipers if
> > > you turn the rotors you must remove exactly the same amount from
> > each
> > > side or will give you a low pedal . The guys both changed their
> > calipers
> > > to non stock . Even a few thousands will effect braking performance
> > &
> > > master cyl. action . My stock brakes were
> > > off on the right side by .005 . and the rear was .006 . People who
> > ride
> > > my bike always comment on the brakes .
> > > My brakes are bone stock . I just detailed the system .
> > > Now don't get me wrong the coefficient of friction is not increased
> > just
> > > the feel and I have immediate brakes at my disposal which instills
> > > confidence in the rider .
> > > Eric H.
> > >
> >
> > > > Eric,
> > > >
> > > > These clearances should be self-adjusting.
> > > > The only way there should be appreciable
> > > > difference is if a piston seal is binding, holding
> > > > the piston away from the pad.
> > > > best,
> > > > Sat Tara
> >
> >
> > .............................................
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> > .............................................
>
>
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