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, bo=
th 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 swi=
ng 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 o=
f these three cars, the Corvette and the 300 SL were front end heavy cars w=
hile the Porsche was rear end heavy. And, in the Porsche case the track wa=
s wider at the front, 1306mm to 1270mm at the rear and that car was loved b=
y professional drivers who wanted the rear end to come out to get through c=
orners 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 know=
n as plowing cars that you had to really crank over to get them around corn=
ers but were very stable at high speeds going straight. And, bias ply tire=
s on the motorhomes likely led to wanting the vehicle to under steer instea=
d of over steering which would argue for narrower front track. For t=
he 1966 Toronado, a car with 54%/46% front/rear weight distribution, Olds d=
esigned in 63.5 front and 63 rear track as a car with that weight distribut=
ion would not over steer to begin with. A 2010 Motor Trend article had=
an interesting observation about the 1966 Toronado that might shed some li=
ght on all this: quote - Olds designed it for 15-inch radial tires, bu=
t tests revealed unusually high wear, and 14-inch bias-plies were substitut=
ed at the last minute. Ultimately, the Toronado didn=E2=80=99t 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 bi=
as ply tires. I don=E2=80=99t know which is correct, but I think we can pu=
t 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 evidenc=
e suggests they did. Jerry Jerry Work The Dovetail Joint Fine fu=
rniture designed and hand crafted in the 1907 former Masonic Temple buildin=
g in historic Kerby, OR glwork
http://jerrywork.com =
Message: 1 Date: Mon, 11 Jun=
2018 12:08:49 -0600 From: Bill Bryant To: gm=
clist Subject: Re: [GMCnet] Another example of different =
wheel tracks front =09to rear Message-ID: Content-Type: text/plain; charset "utf-8" Rob, To d=
o what you suggest would have required new stampings for the L&R front fram=
e section which was already an existing Toronado part (as well as stabili=
zer bar, torsion bar cross member support & possibly other things I didn't =
think of). I suspect that "matching the front & rear treads" may be of=
importance to us at this point, but I doubt if it made the list in 1972. =
If we looked at the many makes and models of vehicles currently on the ma=
rket my bet is that a large number of them have a different front vs. rear =
track. I still believe the factors that determined the original design=
were: 1- use existing parts wherever possible. 2- costs, costs, costs=
That is pretty much what I heard from the original GMC MH Engineers I=
spoke with. PS. should be a good auction, no I won't be going. Have =
fun if you do. (looking for a mate for the T&C?) Bill -- Bill =
Bryant 1976~PB 1914 Ford 1965 Corvette GMC MH History CD & GMC Show=
room DVD Workprint DVD GMC development 11-70 to 3-71
http://bdub.net/b=
illbryant/
