MDT-2003 FREIGHTLINER SPORTCHASSIS FL60

C Schomer wrote:
The big RV haulers that advertise 15mpg would HAVE to be geared more like a light P/U rather than something that was born to haul really heavy all it's life. The low gearing and top speed of ~80mph is the reason the empty and loaded mpg stay closer together.
Air brakes... you can have them, unless they are antilock and they might be these days. I walked away from trucking in 76. The old airbrake trucks had such huge brakes (16" x 7" shoes was the common size for class 8) they would lock up in an instant on a wet road (when unloaded or bobtail) and put the truck out of control until the slow releasing damn things unlocked. I did a bang-up brake job on my last semi and it had no problem locking all 16 duals on a dry hiway at 75 mph with 80k lbs. You also DON'T pump air brakes and that got a lot of drivers killed in the mtns.
If I ever used a truck with air brakes to do light work like RV hauling, I'd turn the compressor governor down to where there was enough psi to release the Maxis but not be able to lock up so quickly. Craig

This post is chock full of good 1976 air brake information.

Modern (last 15 or 20 years) air brakes are ABS. They are powerful, simple, durable, easy to maintain at a safe application level on downgrades to avoid fading, can overcome a minor system leak (the whole atmosphere is the "fluid"), operate at low pressure vs hydraulic brakes, let's see what else, use common components available just about everywhere, have self adjusting slack adjusters, (but are easy to check to make sure they are adjusted correctly)... oh ya available as air disc brakes for more ABS modulated braking power yet...

Current class 8 trucks braking standard is stop 5 axles & 80,000lbs from 60mph to 0 in 250 feet with no "lock up". That is around 3 vehicle lengths. Ol' FooFoo the swamper side pooch better be hanging on :)

ref:NHTSA brakes

So everyone be careful when you are tailgating heavy trucks these days...