First, a couple of component assembly shots. Note how delicate the radius rods and the Watt linkage rods look. This stemmed from a deliberate design strategy to avoid any component doing anything more than strictly necessary – so the rods operate primarily in tension and don’t need to be heavy. The car is pushed along/braked by the beefy torque tube and its cross member – the other bits just guide the axle gently!
Second, is a page from CAR magazine December 1976, from Leonard Setright’s four-page section ‘Any Other Business‘. Len had previously made some dismissive remark about the Rover SD1 live axle, and I had given him the full treatment, including sending him a copy of the patent document.
Bless him, he did take it on board, though he took the patent drawing a bit too literally – as usual with patent drawings, the artwork is rather schematic, and doesn’t represent the exact proportions and angles of the various parts – as you will see from looking at the photos of the actual suspension.
The patent was taken out by a Solihull Engineer, Dennis Warner, who I was sent to see by Spen King while gathering the technical story of SD1. When I later did the Design Award submission for SD1, I had further discussions with Dennis, an interesting guy to talk to. An important part of the design was the way it helped to package the fuel tank in a ‘safe’ location well forward of the rear wheel and thus clear of the rear crumple zone.
We didn’t win the Design Award for this one, largely because the Chair of the Awards Panel was Raymond Baxter to whom we had rather foolishly loaned a pre-production SD1 which had several glitches, such as the faulty oil pressure switch that shut the engine down because it thought wrongly that there wasn’t enough oil pressure – inconvenient at times to say the least!
Also on the panel was Marcus Jacobson, then Chief Engineer of the AA, who objected to things like the need to work inside the car to access the fuel pump in the tank. I pointed out that AA Engineers might be very pleased about this on a wet day!
A decent solution
Generally speaking, when properly set up, the rear suspension seemed to work quite well. There was one drawback that was discovered by John Bolster and Joe Lowry during the press launch.
They’d gone off our carefully chosen route (of course) and arrived at an unexpected downhill T-junction rather too fast, braking to a halt with the nose sticking well out into the busy main road, John Bolster had rammed it into reverse and given it maximum welly, whereupon the car did a bucking bronco impression – just like a torque-tube Austin Seven, he noted.
Back at the Chateau Impney, our launch base, Mike Brookes decided to try it for himself.Parked the car facing downhill on one of the Chateau roads and did an idiot start in reverse. It shook the car so much that it flung the bonnet open!
Why the P6 arrangement wasn’t used
But it was sad to lose the P6 de Dion rear end. It was partly for packaging reasons but probably more because of the on-cost, which was very substantial. A figure of £35 was quoted early on (over whatever was deemed ‘next best’ – an SD1-style live axle I’d guess). Spen King didn’t like random camber changes!
That was in the days when the P6 retailed at around £1300, so a lot in cost-control terms. It wasn’t very easy to assemble either – in fact, Rover turned the P6 shells upside down to insert all the suspension etc. Something many owners or service mechanics would have liked to do to change rear brake pads!
When we did the Press Launch, Spen King’s opening words referred to ‘schoolboy enthusiasms’ for exotic specifications such as de Dion suspension, as he justified the more rational design for low build and service costs etc.
A lack of drama?
It was ‘schoolboy enthusiasms’ that led Spen, Peter Wilks and George Mackie to concoct their own de Dion rear suspension on the P3-based Rover single-seater race car, and that led to de Dion on the T3 Turbine Coupe and the P6. The P8 was going to have a variation on the theme, too!
I ran several 2600 SD1s and never really found any issues, except one night going a wee bit too quickly in a dark country lane, suddenly seeing loads of weird green lights hovering around a few hundred yards ahead – not a UFO, but a flock of sheep who had got out of a field.
I then heard a large bang, followed by several other bangs as I stopped pdq. The first bang was my foot hitting the brake really hard before I’d actually decided to brake, the other bangs were the rear axle tramping! The sheep survived…
If you were at the coalface and have a tale to share, please do get in touch!
- I was there : Austin Maestro launch advert, January 1983 - 3 March 2023
- The cars : Rover Metro/100 suspension details - 4 September 2022
- I was there : Selling the Rover SD1’s rear suspension - 29 August 2022