Getting technical with the Renault six-wheeler

Published by Mike on February 2, 2010

Renault six-wheeler

We encountered a little confusion last week when trying to determine the exact basis of the Renault-built six-wheeled Sahara-crossing rigs, and to our rescue comes John Robins, who discovered an entry on the cars in the book “Modern Motor Cars, Volume 3,” published by Caxton Publishing in London in about 1925.

According to the entry, the majority of the chassis comes from the 13.9hp Renault, including the 2.12-liter engine, but with significant modifications.

It follows normal car practice so far as the front portion is concerned, except for the twin wheels, but there is a propeller shaft drive to the front “rear” axle, and another cardan shaft drive to the rear “rear” axle from this. A three-speed gear box of the torque-tube assembly type, with sliding dog clutches, and central control lever is fitted. There is also another two-speed gear arrangement in the back axle, the two gear systems enabling the following six forward speeds to be obtained, with an engine speed of 2,000 r.p.m.: 1st, 4 m.p.h.; 2nd, 6 m.p.h.; 3rd, 6-1/2 m.p.h.; 4th, 11 m.p.h.; 5th, 13 m.p.h.; 6th, 21 m.p.h. The maximum road speed is 30 m.p.h.

These driving axles, separately, are of the usual 13.9 h.p. standard touring type. The final drive and the coupling are, however, of special design. The front end of the cardan shaft is fixed inside the gear box, while its rear end slides into a cardan joint situated just in front of the first driving axle. This cardan coupling, while allowing of ample movement of the driving axle, operates a shaft placed above the first pair of bevel pinions, behind which is a twin tapered pinion sliding dog. These tapered pinions mesh with one of the pinion wheels of the reduction gears fixed to the bevel pinion which drives the crown wheel of the first driving axle, as well as a double cardan coupling. The rear cardan coupling drives the bevel pinion of the second driving axle. To each of these cardan couplings is connected a horizontally-jointed end-piece which, by enclosing one in the other, forms a torque rod for the two driving axles and allows of independent movement of either.

Both helical bevel pinions mesh direct with their respective crown wheels (that of the first driving axle being on the left, and that of the second driving axle being on the right).

The two driving axles are connected by two stays running parallel to the springs, which in turn are parallel to the chassis side members.

The front springs of the six-wheeler are of the same type as those fitted on the standard 15-cwt. commercial chassis, type H.K. The straight rear springs pivot at the centre on spindles fixed to the chassis and form, as it were, compensators between the two driving axles.

The front ends of the rear springs are secured to the first driving axle, while their rear ends are connected by means of shackles to the second driving axle. The thrust of the first driving axle is taken by the springs, while that of the second driving axle is absorbed by the torque rods between the two axles.

The book goes on for another couple paragraphs just describing the brakes, which are mechanically operated, not hydraulically. Total shipping weight of the six-wheeler was 27 cwt (3,024 pounds), while curb weight was 30 cwt (3,360 pounds).

Thanks, John! Now, the question is: Where are these cars today?