wanted: Chev CMP chassis views

[Hanno Spoelstra]

Translating the above to identifying technical specs per vehicle type (limited to C30 and C60S as this the object of our discussion):

C30:

• Front axle with 5” steering ends
• Brakes, front drum: 14” diameter, 2” width lining
• Brakes, rear drum: 15” diameter, 3.5” width lining
• Wheel size: 16” rims
• Differential gear ratio: 7.16 to 1
• Rear spring leaves: 12

C60S:

• Front axle with 6” steering ends
• Brakes, front drum: 15” diameter, 3.5” width lining
• Brakes, rear drum: 15” diameter, 3.5” width lining
• Booster actuated brakes
• Wheel size: 20” rims
• Differential gear ratio: 7.16 to 1
• Number of rear spring leaves: 12 + 6 Aux.

So the Chevrolet I am trying to ID is a C60S, by virtue of having:

• 6” steering ends - see the picture with six cap screws
• 12 + 6 Aux. rear spring leaves - see the picture showing the auxiliary springs
• True, it is fitted with 16" rims, but it is possible to fit these on 15" diameter brake drums (C15, C30 have 16" rims on 15" diameter rear drum brakes)

Now, if I check if the subject vehicle has (had) a brake booster, I am sure this is a C60S rather than a C30.

Riddle solved!

[Tony Wheeler]

Originally Posted by Hanno Spoelstra

Translating the above to identifying technical specs per vehicle type

Excellent work Hanno. It occurs to me we've never seen the 15/30/60cwt differences specified like this before. They're always buried within tables containing other information. It's very useful to see them presented separately as you've done here.

It would appear the exact same differences apply to both Ford and Chev, although I wasn't aware of 14" & 15" brake drums. Evidently the Chev manual provides a lot more specs than the Ford manual.

All in all a very instructive discussion - I now have a much better understanding of the 30cwt CMP.