I will chime back in here too. Bill is correct about many vehicles having differential track. Among them are the 1955 Corvette and the MB 300 SL, both front engine, rear wheel drive cars, one with a solid axle and one with swing axles, and the Porsche 356 rear engine, rear wheel drive car with swing axles. Most suspension publications I have read focus on reducing over steer by the front track being narrower than the rear track. In the case of these three cars, the Corvette and the 300 SL were front end heavy cars while the Porsche was rear end heavy. And, in the Porsche case the track was wider at the front, 1306mm to 1270mm at the rear and that car was loved by professional drivers who wanted the rear end to come out to get through corners faster, but it was disliked by amateurs for that same reason - they had a hard time controlling it. Both the Corvette and the 300 SL were known as plowing cars that you had to really crank over to get them around corners but were very stable at high speeds going straight. And, bias ply tires on the motorhomes likely led to wanting the vehicle to under steer instead of over steering which would argue for narrower front track.

For the 1966 Toronado, a car with 54%/46% front/rear weight distribution, Olds designed in 63.5 front and 63 rear track as a car with that weight distribution would not over steer to begin with.

A 2010 Motor Trend article had an interesting observation about the 1966 Toronado that might shed some light on all this:

quote - Olds designed it for 15-inch radial tires, but tests revealed unusually high wear, and 14-inch bias-plies were substituted at the last minute. Ultimately, the Toronado didn't get radials until most every American car did during the first gas crises in the 1970s. - end quote Another source says the production cars had 8.85 x 15 inch bias ply tires. I don't know which is correct, but I think we can put to bed any question about whether the designers knew what they were doing when they dialed in a narrower front track on our motorhomes. All evidence suggests they did.

Jerry

G'day,

Compare the Toronado frame drawing that BillW posted

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p64869-toronado-frame1.html

and the photo of the GMC front frame I posted:

http://www.gmcmhphotos.com/photos/aa-miscellaneous-photos/p64869-toronado-frame1.html

To me they sure don't look like the same stamping.

Regards,
Rob M.