Rear Cantilever Pushrod Suspension
With the rear pushrod suspension, initially the decision was made to use Sierra 4×4, for which I found that many websites claim the the rear track width to be 1468mm. I’m not sure where this comes from as it is actually 1550mm hub to hub.
Initially, I chose Cosworth 4×4, which meant selecting the right axle assembly. Each Sierra model has different drive shaft, hub, diff options etc. and some parts aren’t inter-changeable. However, the growing price and scarcity of Cosworth parts has led me to look for other options, especially considering I would take a hacksaw to whatever I bought. The rear suspension will probably end up a jumble of parts from the Audi A8, Granada 4×4, Cosworth Escort and Cosworth Sierra.
With custom made rear uprights, the suspension geometry would largely be down to preference.
As I will be using 19″ wheels the choice of brake discs and calipers is huge. I’m keen to fit 360mm discs with 6 pot Brembo Calipers.
The standard McSorley442 chassis has less triangulation than the Lotus. This is probably to make construction simpler, however a lot of triangulation has been added back into this version of the chassis.
This chassis version also employs a cantilever shock arrangement to give a rising spring rate in bounce and roll. The coil-over units will be from an off-road motorbike as will the cantilever bell cranks. Provision will be made for an anti-roll bar, but with rising spring rate in roll it will be road tested initially without.
As can be seen, all of the joint are standard urethane based. There will be a lot of adjust-ability via clevis joints. The drawing above shows standard 278mm Granada hub and caliper mounts. These will be replaced by custom ones that use ‘off the shelf’ bearings and will accommodate the huge discs I intend to fit.