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uprated discs |
pads | large
diameter discs | brake anatomy |
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cosworth discs & calipers
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pots | the ultimate? |
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rear disc conversion | braided
hoses | links |
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Uprating your brakes is an essential
modification to make when increasing the power of your car. Brake upgrades
are available in many stages, from aftermarket disc and pads, to full
blown 4 pot caliper and large diameter disc conversions. It is also
possible to convert the rear drums on a Fiesta to discs. |
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Uprated discs |
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The standard setup on all the Fiestas consists of 240mm vented discs and single
pot (piston) calipers. This combination is just about enough to stop the
standard car, but totally hopeless for anything quicker. The main problem faced
with the standard system is brake fade. This happens when braking hard,
the discs and pads heat up quickly and loose there effectiveness. The harder you
brake, the hotter they get, and the less effective they become. Plenty of
companies, such as Black Diamond and Tar-Ox, produce aftermarket replacement
discs for the Fiesta. These discs are a standard sized direct replacement, so
they can be fitted to cars with the original size wheels. They use different
methods of reducing fade. Which one is best depends on your driving style. All
of them will perform the same as standard discs when driving normally, only
under hard braking will the difference become apparent. Grooved discs tend to
perform better than drilled, but transmit more vibration though the steering
wheel and are noisier.
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Black Diamond discs
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Cross drilled discs are so called because of the holes drilled into them (!). These
holes help disperse heat, reducing brake fade.
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Grooved discs help to de-glaze the pads. This ensures greater friction
between the pad and the disc. They will wear them out faster though. |
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Drilled and grooved discs combine both technologies. These discs are therefore
more expensive than x-drilled or grooved. |
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Uprated pads
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These pads are available in a variety of compounds, depending on their intended
use. The names vary, depending on manufacturers. EBC's range are named as
follows. Fast road pads are designed for tuned road cars and perform
well at low to medium temperatures. This is the type recommended for road
going modified cars. Rally formula pads have a slightly higher
operating temperature range, and are designed for rally and light track use.
Race formula pads have the highest operating range and are only
suitable for hard track use. The compound of these pads is most effective at
the extreme temperatures generated by track use and would perform very
poorly on a road car until the pads heated up considerably. Fast road pads
have a much lower optimum range, so they are effective when cold as well as
under hard use. The temperature is never going to reach that of race cars,
so the level of brake fade at that heat is not a consideration.
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Mintex, Ferrodo, Tar-Ox and Pagid all produce
pads for the Fiesta. EBC's Greenstuff pads came out top in recent
magazine test and are formulated to produce 80% less brake dust than
similar pads. Ideal for show cars with expensive or difficult to clean
alloys. |
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Large diameter discs |
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As explained above, simply swapping the discs
will help under hard braking, but make little noticeable difference to the
overall feel and effectiveness of the brakes. In order to increase the
car's stopping power, other methods have to be employed. The first method,
explained here is increasing the leverage on the disc. |
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If you imagine your cars wheel, with the car
jacked up so the wheel car turn freely. If you put your hand on on of the
spokes, near the centre of the wheel and try and turn the wheel,
considerable effort is required to make the wheel turn. now if you place
your hand on the edge of the rim and do the same, a great deal less effort
is needed. This is the same principle with large diameter discs. The
larger size gives the caliper more leverage to stop the disc rotating,
slowing the car down quicker. |
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There are two factors that limit the maximum size of disc that can be used:
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The size and type of wheel. If the car still has 14" rims, huge discs physically
won't fit behind the wheels. The other point to take into consideration is
the spoke design of the wheel. "Deep Dish" wheels such as the TSW
Big Deep, have spokes that curve inwards, towards the centre of the wheel.
The design of the wheel may mean that with big discs fitted, the caliper
comes into contact with the spokes. On the opposite end of the spectrum,
wheels like the Evo R have spokes that extend beyond the tyre mounting edge
of the rim, giving more clearance behind the spokes.
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2. |
How far the caliper can be spaced out. All large
disc conversion kits come with a mounting bracket to move the caliper
father out towards the edge of the disc. The largest disc kit that works
with standard calipers at the time of writing is 305mm. Larger discs can
be used with replacement calipers. |
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The table below shows the size of wheel in
relation to the maximum disc size that will fit. They will be differences
depending on rim design, offset and wheel width. |
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Size of wheel |
Maximum disc size |
13" |
240mm |
14" |
260mm |
15" |
285mm |
16" |
305mm |
17" |
315mm |
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Although the size of the disc is increased, when
using standard calipers, the area that comes into contact with the pads
remains the same. This leads to rust towards the centre of the disc, that
will not be removed by the pad when braking. Another consideration is the
size of the disc leads to a gain in the car's rotating weight, which can
affect handling. As a result of these problems, the larger discs (300mm
+), come with as bells and rotors, rather than a solid disc. The bell is
the alloy centre of the disc, that mounts onto the wheel hubs, and the
rotor is the part the calipers will grip. Having the bells made from alloy
saves weight, and as all the surface area on the rotors will come into
contact with the pads, there is no area that will be left rusty. The photo
below shows the grooved rotors and yellow bells. |
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Brembo
brake kit with separate bells and rotors.
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Large disc kits are available from Rally
Design, Hi-Spec, Godspeed and The Braking Point. |
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Brake
Anatomy |
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Cosworth discs and calipers |
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The second method of increasing braking power is to change the calipers for
units that can grip the disc harder. This is fairly self explanatory, the
harder the caliper can squeeze, the quicker the car will stop.The most common brake upgrade on tuned Fiestas is the set up from a
Cosworth. This consists of the single pot calipers and 285mm discs. The
Sapphire 4x4 and Escort systems will fit straight on, and the 4 pot calipers
from the 2wd cars fits with a spacer bracket. Both discs and calipers are
readily available, with many Cosworth owners having upgraded to AP or other
high-spec set ups.
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The Cosworth calipers can be used with the
larger discs as mentioned above. |
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Fiesta Frenzy
Ian Howell's 430bhp Type R, with Escort Cosworth
calipers and 315mm cross drilled Fiesta Frenzy discs.
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Many tuning companies offer this conversion, as well as brake specialists
like Godspeed. The cost varies depending on condition of the units and where
they are purchased from, but expect to pay around £400 fitted. In theory it
should be possible to fit an aftermarket kit designed for an Escort
Cosworth, as logic suggests that if Escort brakes fit, any brakes
constructed to fit an Escort will also fit. Tar-Ox and AP Racing both
produce kits for the Escort, though due to the light weight of the Fiesta,
even 400bhp plus examples do not require this level of braking power.
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4 pots
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The calipers Ford fitted to the Fiesta are single
pot. This means there is one piston inside the caliper that pushes the
pad on to the disc. Many high spec aftermarket calipers use four or more
pistons. This is for two reasons. The additional pistons provide more
force to squeeze the disc with, and with more than one piston, the force
is more spread out over the pad area. |
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2wd Sierra Cosworth's have 4 pot calipers, and a
pair of these can be picked up for around £150. As they are likely to be
at least 10 years old, it is advisable to have them reconditioned if they
have not already been. Any brake specialist should be able to carry this
out. |
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Wilwood produce one of the largest ranges of 4 pot calipers. Most of their
units are designed for racing, and therefore lack the dust seals necessary
for road use. The Dynalite and Superlite calipers are dust sealed and are
suitable for road cars.
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Wilwood
Dynalite billet caliper
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Wilwood
Superlite II billet caliper |
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The
ultimate? |
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Bremsport produce a kit for the Fiesta RS Turbo,
based on 304mm rotors with anodised aluminium bells, 4 pot billet calipers
and carbon metallic pads. The kit also contains high tensile mounting brackets
and performance brake fluid. you will need to have 16" wheels to fit
the kit, probably not a problem if you can afford the £900 (plus fitting)
asking price... |
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Bremsport Fiesta RS Turbo kit
304mm rotors
aluminium bells
4 pot billet calipers
carbon metallic pads
£900... |
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Rear
disc conversions |
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It is possible to fit rear discs to the Fiesta, but it's really only for
looks rather than function. Something like 80% of the braking on the car is done by the front brakes. The rears don't really do much at all, hence Ford's decision to fit drums, even to the high performance models. This also saves money of course. Discs are obviously going to work better than drums, so if you have discs on the rear the rear brakes
will be more effective. This will upset the brake balance and if you drive around with it set like that, you can imagine what happens the first time you brake while cornering. The back end will step out and the whole car will spin out. Not good. |
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You can't have the discs set to work better that the original drums, so their only function now is to look good. They do look better than drums, but the cost of fitting discs is fairly
expensive. |
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If you do want to fit them the parts required
are as follows: |
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the discs - Escort RS2000 MK5/MK6 or Sierra 2wd rears
are usually used |
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calipers - Escort RS2000 MK5/MK6 or Sierra 2wd rears |
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a brake bias valve - to adjust the balance between front and rear.
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a handbrake cable - from an Escort RS2000 MK5/MK6 |
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flexible brake hoses |
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brackets to mount the calipers |
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You will also need to modify your drums to use as hubs, the bell needs to be removed then machined down so the disc will fit over it. The total cost of the parts is around £400 plus fitting costs. Companies like Hi-Spec, Godspeed and Braking Point can supply kits for around £400-£500. |
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It's a little expensive just to look good, and
it's better to spend it on the front brakes. It's possible to get 4x4 Cosworth
calipers and 285-315mm discs for that sort of money. |
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Braided
hoses. |
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A worthwhile upgrade that eliminates that
"spongy" pedal feel, caused by the brake lines flexing. The
braided hoses are a lot less flexible, resulting in a firmer pedal action
and instant response. Black Diamond and Goodridge both produce kits for
the Fiesta, at round £40. |
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Links |
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www.wilwood.com
www.raldes.co.uk
www.brembo.com
www.apracing.com
www.tarox.com
www.ebc-brakes.com
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Wilwood, USA
Rally Design, Wilwood's UK importers
Brembo
AP Racing
Tar-Ox
EBC, Greenstuff pads
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