I think the S type's rear brake bias was inherited from the Mk2. It's hidden or ameliorated in the Mk2 by the strong understeer. I've even heard front brake upgrades criticised for eliminating what would usually be regarded as a negative quality. Personally, I think there must be safer ways of 'bringing the tail around.'

 

Exactly Peter. The S Type is known for marginal over-steer on the limit which is easily corrected/handled by the Driver with the IRS. Numerous road tests have proven this. I have them all. Frankly speaking a very neutral steering car.

 

Have just been through my book of all S Type Road Tests and a few not in the book.

Only 1 US Magazine detected very slight under-steer but that was on cross-ply, whitewall tyres. On radial-ply tyres all detected slight over-steer at the limit. Jaguar was between a rock and a hard place at the time. Radials were not available yet with white walls. So if a customer insisted on white wall tyres they got cross-ply tyres. The US was slow to adopt radials. Their over compliant (soft bushings etc), soft springing & lack of stiff bodies made them dangerous vehicles in anything but a straight line. Why they were happy with cross ply tyres & white walls.

The IRS gave of it's best with Radial Ply tyres. In fact Lyons was reluctant to let out any S Type to the media without Radial Ply tyres fitted. Why the US press was invited to come over to the UK and test drive RHD cars shod with radials.

In fact Dudley Gershon's (Engineering Director '63 to '72) Book on Aston Martin makes interesting reading. They bought a new example of the American's favourite glass fibre body "sports car" ~ cart springs & all, to take a close look at, and let customers drive vs an Aston until they got tired of pulling it out of a ditch somewhere such was the difference in handling. They learned nothing from the over compliant vehicle other than, he admits, something about air conditioning.