FM Chassis Features

FM 4WD Chassis Features

(Please note that the FM 4WD chassis shown above does ship with dual rear wheels to satisfy Dana Corporation's engineering department. These photos were taken prior to mounting the inner tires on Accuride steel wheels. RUF, Inc does in NO WAY approve the installation of single rear wheels on chassis designed for dual rear wheels. Please see our explanation here.)

In the table below, you'll find images of some key chassis features, with technical descriptions of what you're viewing. All images in the left column are thumb-nailed for faster page loading, so you can click to enlarge.

	This photo give a good perspective of chassis size. It's 114" from the ground to the top of the cab, and 313" long prior to reducing the rear overhang by about 40".
	For any folks with Unimog experience, this shot gives you an idea how the FM chassis compares to a 404 Unimog (left) and U1300L Unimog (right).
	Here's the street side of the chassis. This example has a 182" wheelbase, and will lose 40" from the rear of the frame to allow the 204" AATREC (tm) cabin to be installed with an overall completed vehicle length under 25'. Customers requiring a longer chassis can order wheelbases up to 240". Please Contact Us with your requirements.
	While the FM chassis' leaf spring suspension design will never match Unimog's long-travel coil-sprung system, it is still capable of respectable articulation on uneven surfaces. It is important to note that this is a bare, un-laden Class VI cab and chassis in this photo. It has no trouble keeping all tires on the ground with almost 13.5 degrees of articulation. Available articulation will increase with payload on the chassis, while the AATREC (tm) steel/composite cabin on the rear is torsion-isolated with RUF's rubber-bushed Torsion-Free Subframe (TFS).
	Here's a close-up of the axles, articulated.
	For times when pressure on one rear tire decreases to the point of losing traction, RUF's custom-built Dana 22,000 lb. heavy-walled rear axle includes a Driver Controlled Differential Lock to put the power where it counts.
	Also on the rear axle, you'll find dual 73mm piston Bosch calipers squeezing 15" Gunite hub/rotor assemblies. Identical Bosch disc brakes are found at the front as well. The brakes are rated for 34,000 lbs per axle, or 68,000 lbs total, yielding capacity 3.5 times the weight of a completed motorhome. Factory ABS is maintained, of course.
	Up front, there's a 12,000 lb. driven steer axle. Note the heavy duty double-Cardan constant velocity joints in the photo, allowing bind-free turning on hard surfaces and greatly increased joint life. Maximum crimp angle is almost 40 degrees. This axle is also equipped with manually locking hubs to provide less wear and tear on the front drive system and increased fuel economy. The manual hub option may be deleted at the customer's request, for a small reduction in price. Inside the front Alcoa wheels, there's another set of Bosch 73mm dual piston calipers on steel discs.
	Sending power to the front axle is a heavy duty aluminum transfer case with constant mesh helical gears. It is a part-time air-shifted two-speed design, capable of 7,400 lb-ft of input torque. That rating is FOUR TIMES what the Fuso engine can produce when multiplied through the Allison in 1st gear. That's seriously overbuilt! As an option, this transfer case can carry a planetary proportioning differential offering full time all-wheel-drive with a torque-split of 30% front / 70% rear. Various PTO options are also available for the transfer case, as well as for the Allison LCT-2400.
	Wheel mount is a US-standard 285.75mm (11.25") bolt-circle ten-hole hub-piloted design, front and rear. Tires are Bridgestone M711 in 11R22.5 on 22.5 x 8.25" wheels. Note that optional Alcoa wheels are fitted to this chassis. (Standard wheels are Accuride steel discs, painted gray.)

Feel free to Contact Us with any questions or comments you may have.

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