Gerard, we might get into a more technical discussion that we could adequately cover here (or that anyone would want to read)./w3tcompact/icons/laugh.gif You're right in that weight shifts forward during deceleration. And I also agree that you <font color=blue>physically can TOW a lot more than you can safely stop</font color=blue> (the key word being "safely"). You're also right that you don't want to lock up the brakes and slide, although the reason is more for directional control than for any reduction in braking drag. And you're right that most of your braking is done with the front wheels when you are not pulling a trailer. When you are pulling a trailer, then a number of other factors come into play. What's the weight of the trailer, number of tires, size of tires, etc. as compared to the towing vehicle? What's the tongue (or pin, in the case of 5th wheel or gooseneck trailers) weight? Are you using a load distributing hitch? If so, how is it adjusted; i.e., how much of the tongue weight was distributed to the front wheels of the towing vehicle? And <font color=blue>if you had a choice of losing your trailer brakes OR your vehicle brakes which do you think would be more effective in stopping your vehicle?</font color=blue> Well, it just depends . . ../w3tcompact/icons/wink.gif What's the relationship of my towing vehicle (size, weight, tires, etc.) to the trailer and what are all the answers to the questions above? In this hypothetical case, there are too many unknowns. However, I'll agree with you that, in most cases, I would rather lose the trailer brakes.
I was amazed several years ago when we put a questionnaire to some officers asking if they lost the brakes on one end of their car, which end would they prefer losing, and many of them thought it would be preferable to have brakes on the rear and lose the front ones. It's actually the opposite as I think you know. If the front ones lock up, you will tend to slide in a straight line (more or less), but if the rear ones lock up, you'll probably get sideways. And of course, as you know, the front ones are more effective in braking. That explains why a lot of vehicles have anti-lock brakes on the rear, but not the front.
Now that explains also why you normally wear out the front brake linings (or disk brake pads) much quicker than you wear out the rear ones. However, when you put a trailer into the equation, things start to change. Example: I pulled a 5th wheel trailer a lot of miles behind a one ton dual wheeled Chevrolet pickup. The trailer usually had about 7,300 pounds on the axles and about 2,500 pounds on the pin. And I actually wore the rear brake linings just a little faster than the front brake pads on the truck. I guess you know that the porportioning valve, and anti-lock system, are affected by the rear end of the vehicle rising a bit during rapid deceleration, something that does not necessarily happen with a heavy load on the rear of a towing vehicle.
I guess the bottom line is that I think you're right in most repects and your point's well taken, but I also still have to stand by my earlier responses. But I'll 'fess up to not being an engineer./w3tcompact/icons/wink.gif
