Whatever the rims, five main points
a) Which insert will be fitted (to choose between single part rim or two parts bolted rims) ? Inserts for heavy conditions need a two parts bolted rim
b) How the air flow of the CTIS system will cross from the
compressor to the tire valve ? Only aluminium rim can be crossed by the air flow. In case of steel rim,
it will be necessary to use an external air pipe, fragile point in case of shoot
C) By the way, single or two parts ?
> In case of single part rim, stamped steel is the right solution because single part alu rim are molded (die casting) and have not shock resistance. > In case of two parts bolted rims, obviously best solution is hot forged aluminium rim. Material and process offer the best performances.
D) About the cost: Aluminium is more expansive than steel, especially for small series. Nevertheless experience says that sometimes looking systematically for the low cost solution is more expansive than the “right” solution.
E-About design, important point is the “offset”. Not about performances but about the possibilities to use the same forging tools for different wheels in case of aluminium rims
Our alu rims join two bolted parts made in hot forged
aluminium 6061. Hot forging technology
changes the molecular composition. It is similar to the forging of swords and
sabres. Forged blocks are pre-machined and machined. The gap is small (0,1mm)
and the quality is constant.
Special technical paints and surface treatment are available.
Cost is sometimes expansive for
prototypes or small series because it is necessary to create the forging tools
(around 100 000€ by rim design) or to machine aluminium full blocks.
Nevertheless, considering forging tools can be used for manufacturing around 50 000
rims or more, cost can be very interesting at long time.
In comparison with steel rims, aluminium two parts rim offers:
- Light weight (40 Kg lighter than steel), authorising more payload
- Best mobility (reduction of G Force) facilitating heavy off-road
- Excellent rigidity, facilitating beadlock function
- Integrated air circuit for CTIS flows through the face of the rim, more secure than external air pipe. Our rim-integrated air flow system is patented in all countries. We are only two manufacturers in the world with this asset...
Nota about the ratio weight/cost: Taking in consideration a 15 tons military armoured 4x4, difference
between aluminium and steel rim is around 200kg, increasing the payload.
This difference correspond for example in 200 litres fuel, meaning maybe
800km of range increasing... The difference of cost is around 6% of the
cost of the vehicle, decreasing at 2,8% for a heavy 8x8...
Process of manufacturing is deep drawing, stamping and welding of steel sheets. Cost of manufacturing is low: Specific stamping tools are not expensive, life duration of the machine tool is around 60 years. It is efficient for prototypes, small and large series.
Steel rims are an alternative to hot forged aluminium rims in
- Very large diameter and no fast off-road using (Trailers for tanks or missiles carriers, for example).
- Light vehicles in normal conditions or soft off-road
- Low cost systematic concept of the vehicle
A steel wheel is designed to withstand the increased weight and
forces of modified vehicles, for applications such as light armoured vehicles
or cash in transit applications.
RFI steel rims offer high load wheels for some of the most popular armoured light vehicles including Toyota Landcruiser (up to 2200kg load rating), Toyota Hilux, Nissan Patrol, Mercedes G Wagon, Mercedes S Class, Audi A8, Ford F550…
In comparison with hot forged aluminium wheels (and not with die
casting alloy), characteristics of steel rims are: