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MARCHESINI TECHNICAL INFORMATION
For over 40 years Roberto Marchesini has been developing
advanced magnesium high performance products using sand cast magnesium
techniques. These products range from engine components for Formula
One, Fork Braces for motorcycles, mono arms for motorcycle applications,
and the leading line of high performance and racing magnesium
wheels that exist today.
Today additional manufacturing technology is available
which allows Roberto to expand his design concepts into wheels
that can give higher performance in specific applications. Marchesini's
objective is to give the performance and racing rider a specifically
designed product that will meet the highest standards of performance
and value.
The above objectives have been achieved by using
the latest manufacturing techniques in the areas of:
Sand Casting (discontinued):
Marchesini is the leader in developing sand casting techniques
that produce wheels with the highest mechanical properties for
excellent performance and value. This is proven by the fact that
virtually all of the leading Factory racing teams use Marchesini
wheels.Sand cast wheels are produced by a gravity casting process.
However, the gravity process does not normally provide pressure
to align the fibers of the magnesium for maximum strength. Marchesini
has greatly improved the gravity casting process by using 10 times
the volume of material in the mould so the weight of the additional
material helps create a stronger wheel. This is an expensive process
because 9 times the weight of the wheel is scrapped.. The wheels
are over designed using more material to gain the mechanical properties
needed. This overall design concept and process is excellent and
offers the highest value for many applications.
Forging: Another way
of forming aluminum and magnesium into a wheel is to use high
pressure forging techniques which aligns the fiber of the material
into the direction needed for maximum strength.. By compressing
the material in a 15,000 ton press a lighter and stronger product
can be produced because less material is needed to make the wheel.
Unique advantage of the Marchesini
Three Dimensional Forging Process: When you forge a piece
you normally come straight down and cut the part out like you
would make a cookie from a cookie mould.
This process is called "open die" forging
and is the simplest and lowest cost way of forging. You then have
to machine out the well and bead area which interferes with the
fiber structure of the material causing a loss of strength.
The forging process used to make the Marchesini wheels
uses a precision three piece mould, "closed" die process
which is "more expensive and complex," to not only form
both sides but also to form the well and bead seat of the wheel.
This process makes a superior wheel with higher mechanical properties.
However, you can understand the complexity of making
a three piece mould that must have side sliders operating under
15,000 ton pressures. The Marchesini forging three piece closed
dies are precision, complex, and very expensive. However, you
receive the benefit of this investment in technology.
The other advantage of the forged wheels is that
all surfaces are "machined" which creates a precision
wheel. The trueness of a forged wheel adds to the overall performance
of the wheel.
How do the different processes compare in the
areas of weight and mechanical properties (stiffness) under different
riding conditions?
| Type Wheel |
Weight |
Result* |
| Weight: |
|
|
| Cast |
6.00 lbs. |
0 |
| Forged Magnesium |
4.74 lbs. |
-20% |
| Carbon Fiber |
3.86 lbs. |
-35% |
| Radial Stiffnes: |
|
|
| Cast |
6.00 lbs. |
0 |
| Forged Magnesium |
4.74 lbs |
0 |
| Carbon Fiber |
3.86 lbs. |
-3% |
| Moment of Inertia: |
|
|
| Cast |
6.00 lbs. |
0 |
| Forged Magnesium |
4.74 lbs. |
+20% |
| Carbon Fiber |
3.86 lbs. |
+29% |
| Torisional Stiffness (bending): |
|
|
| Cast |
6.00 lbs. |
0 |
| Forged Magnesium |
4.74 lbs. |
+5% |
| Carbon Fiber |
3.86 lbs. |
0 |
| Moment of Inertia: |
|
|
| Cast |
6.00 lbs. |
0 |
| Forged Magnesium |
4.74 lbs. |
+3% |
| Carbon Fiber |
3.86 lbs. |
-7% |
*Stiffness means the amount of movement
of the material in the wheel under different riding conditions.
We are using the cast wheel as the "O" benchmark and
computing the amount of stiffness of the forged and carbon wheels.
A + means that the wheel type is better, a - means that it is
less stiff.
Cast: As you can see
the cast wheel offers a lot of performance and value in the areas
of weight and mechanical performance.
Forged: The forged magnesium
wheel is lighter and offers more stiffness. The rim is also a
little lighter which reduces dynamic weight and adds to the overall
performance. The forged wheel because it is completely machined
also runs very true which improves the performance of the wheel.
Carbon Fiber (unavailable):
The carbon fiber is the lightest of the three and is stiffer in
most areas. It is also the most expensive and can only be used
in certain race classes. It is also difficult to test carbon fiber
after an accident has been experienced to make sure the wheel
is safe to reuse. Carbon Fiber should be used in specific applications
by experienced riders who will take the extra care that is necessary.However,
carbon fiber offers high performance and will appeal to the rider
who wants the maximum performance in a wheel technology and is
not concerned about cost or extra maintenance.
TRACK RESULTS:
The Factory teams have been using and testing the Marchesini forged
magnesium and carbon fiber wheels since last August. The results
are as follows with each type of wheel. Again, the 5 spoke Marchesini
cast wheel is the benchmark.
Forged Magnesium: 1 Second less time. per lap.
Carbon Fiber: 2 Seconds less time per lap.
Type of Track: The more curves in the track the more
time will be reduced by the forged magnesium and carbon fiber
wheels.
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