First
of all, it's important to know how the MOMO Racing works when you
press down the pedals. The built-in electronics constantly monitors
and stores all minimum and maximum values on all axis (brake, accelerator
and steering). Using these margin values it automatically recalibrates
itself, to allow precise control. This auto calibration starts when
wheel is plugged into USB port and operating system has booted up.
To erase stored values one of the following needed: OS reboot, disconnect
from USB or unplug pedal connector from wheel. As you will see this
method has both advantages and disadvantages.
The problem is, that under extensive and/or long usage, the gap
between pedal shaft and bracket increases and allows a bit of sideways
movement for the pedal. This means, when the pedal is fully pressed
down, you can move it left and right without lifting off. When this
happens the potentiometers in pedal set can turn a bit more than
normally and report back increased values to electronics. After
that the electronics re-adjusts usuable pedal range based on new
marginal values, but those maximum values could not be reached reliably
again.
So games and even DirectX thinks you did not press pedal completely
down, as the maximum value was recorded by false reading. This phenomenon
is called "spiking" and could decrease pedal range by
5-20%.
To make sure your pedals suffer from this effect, check proper connection
between pedal set and wheel, then press down pedals completely and
try to move them sideways, while checking raw axis values in DXTweak2
(link at the end). If the raw values bounce up and down, then it's
clear. Usually brake pedal is not affected as it has two separate
springs on each side, which decreases or completely removes the
possibility of sideways movement.
There are four possibilities to cure the pedals:
 unplug wheel from
USB
disconnect pedal
connector
restart OS
reduce slack on
pedal shaft
I will talk about the fourth solution which seems
to be a reliable and permanent one. First you have to clear all
calibration data using a program created by Logitech (link at the
end) and remove-reconnect USB plug. After this take pedal set apart,
but be cautious and observe the original place of parts as it's
a little tricky. You have to remove twelve screws, four of them
are under the rubber pads. Watch out for position of carpet grip
system parts!
Now you can see that the pedals (1)
rotate in a plastic bracket (2),
and there are two potentiometers (3)
attached to them sitting in small retainers (4).
Only one spring (5) is attached to
accelerator, but two (6) to brake
pedal to increase stiffness.
According to my observation, the spiking effect
is caused by one or more of following reasons:
loose pedal shaft
loose connection
between pedal and potmeter
 (very small possibility)
loose potmeter in
retainer
dirty / faulty potmeter
In my case it was enough to fix the first one
to cure the problem, but for others the third one had to be done
too. Some of them had to use a little super glue to fix it to the
retainer (7). However I didn't do
that as I don't want to place too big strain on the potmeters.
First I've taken out the pedals and removed springs. Cleaned them
from grease and applied one layer of non-conductive tape to the
end of the shafts (8) to reduce slack.
Don't place there too much tape as the springs won't be strong enough
to push back the pedals.
After this I've checked the pots too see if there is any grease
in them or not. If you find grease on pots, clear them and use some
electrical contact cleaner spray too. Next step is to make sure
pots have smooth range, so checked values in DXTweak2 while turning
them manually with my hand.
When everything was back in place I've checked values again, while
holding pedal in bracket firmly with my hand. During re-assembly
the only problem was with the carpet grip system, it's a bit tricky...
VERY IMPORTANT! Make sure that you use grease
which won't harm the plastic! Don't tighten all screws completely,
otherwise you may experience difficulties.
Step by step guide:
clear calibration
data
remove-reconnect
USB plug
take pedal set apart
watch out for carpet
grip system
take pedals out,
remove springs
remove grease from
shafts
apply one layer
of tape strip to shafts
put springs back
apply grease to
shafts, use proper grease,
not to harm plastic
check if pots are
free from grease
clean them if needed
check if pots have
smooth range, by turning it
manually with
hand, while checking DXTweak2
connect pot to pedal
put pots back to
retainers and pedals to brackets
fix
pots to retainers if needed (optional)
check again pots
have full range when moving
pedals (hold
pedals in place firmly with hand)
put back screws,
assemble everything together
clear calibration
data
remove-reconnect
USB plug
make sure pedal
set is properly connected
check DXTweak2 again
for original problem
Click on pictures for more detail
DXTweak2, clear calibration
utility:
Wingmanteam
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