Silent Drive

In the early ’50s tag axles were gaining in popularity, but it soon became apparent that they lacked in traction. In an effort to address this problem, a company was started in 1953 in Sioux City, Iowa, producing large pulleys to be installed between the dual tires of the drive axle and tag axle. By connecting these pulleys with a large V-belt, the drive axle powered the tag axle.Since the tag axle was powered by silent V-belts instead of noisy gears, the company was called Silent Drive. 

 

 
 

Just a bit before my time, but i believe a local carrier here had them on a Mercedes in the 1970's.  Apparently they worked, but rocks/stones were troublesome.

Brett.

Remember a subbie for Pioneer running bogie arse Commers with that set up and Permatrak suspensions, around the Liverpool NSW area, think it was Len Madden, but LONG time ago!
Dave_64

Up here in the States they we nick named "Rubber Band Drive" Wrangler Blue Jeans had some on their 1959 "China Closet" Diamond T's...
Tony Champion of Rockhampton NSW has an H model Mack in his gallery with that set up on Page and Page suspension.

Back in the '60s a bloke up the north coast had a 4x4 Bedford fitted with a tag axle with a similar system, but it was just a huge v belt in the gap between the tyres, From memory it was a drilling rig.

A logging company in the Otways was using these in the late 70's still
Didn't know they were called silent drive

Paul

Luya Julius fitted out one of Broadbents TK Bedfords with a lazy & a belt between the axles in the early 70's. The truck was used for carrying Rocla pipes & had to operate on muddy worksites. Not sure who made it but apparently the system worked ok.

Many many years ago I was contemplating buying a truck with work carting Besser blocks. The truck was a Commer Knocker repowered with a V6 GM and a lazy axle, but it had the belt drive system. Thankfully I never went ahead with the deal. Seemed like hard work to me. Can’t beat loading under a hopper and tipping it out at the other end.

Would the rear suspension have to be walking beam to keep a constant distance between the wheels?

I would have thought springs would allow the drive to either tighten or loosen over bumps?

While I have no experience with these units seem to remember the photos having a loose belt with dependence of pulling from the top gripping in to the rear groove.
The variable speed threshing drum on our headers use adjustable width vee pulleys the driven being spring loaded and driver hydraulically adjusted, in addition the outer driven sheave can move independently and drive against ramps to compress spring and increase grip if load goes up, all of this for correct tension.
It does not take much side wear for a vee belt to become loose, in short the Silent Drive could be a bit of help.
David.