wanted: Chev CMP chassis views

[Hanno Spoelstra]

Originally Posted by Tony Wheeler

As far as I can make out, the only SPECIFIED difference between C60S/F60S and C30/F30 is wheel size. This gets back to our earlier discussion concerning CMP load class rating, which appears to based solely on wheelbase and wheel size.

Tony,

Agree on the misnomer to describe CMP axles in terms of load rating, that is why I also use the "heavy" and "light" designations, by which I mean the same as your "large" and "small" designations. When I write "3-ton axle" I mean to say "the type of axle fitted to a truck with a 3-ton load rating".

Indeed the factory specifications do not specify a load rating for the axles themselves. But, next to wheel size they also list the differential ratio and number of spring leaves. It is this combination which was required to match the specified load rating for a certain type of truck. The C60S and C60L are thus fitted with 20" wheels, 7.16:1 differential ratio and 18 (12+6 aux.) spring leaves on the rear axle, which enables them to carry a 3-ton load.

So in the case of the subject vehicle, does the fact that it has "heavy"/"large" steering ends (the type with six bolts on top) means nothing to identify it? Or is it the case that an axle with "heavy"/"large" steering ends always has the 7.16:1 differential ratio?

One fact which helps to ID this truck is that it is fitted with 18 (12+6 aux.) spring leaves on the rear axle, which was fitted to the C60S and not the C30 which had only 12 spring leaves on the rear axle. As per factory spec it should thus be fitted with 20" wheels and not the 16" wheels it currently has.

H.