Text 27251, 61 rader
Skriven 2009-02-05 12:57:51 av Roy Witt (1:397/22)
  Kommentar till text 27226 av Bob Ackley (1:300/3)
Ärende: Trailer brakes
======================
03 Feb 09 05:46, Bob Ackley wrote to Roy Witt:

 RW>> Wrong. Both vehicles' brakes are engaged. The trailer brakes a
 RW>> synchronized to the vehicle brakes, thus there is more braking power
 RW>> for both vehicles and less effort required.

 BA> You're talking about electric brakes, which are indeed synchronized
 BA> with the tow vehicle's brakes through a brake controller in the tow
 BA> vehicle.

Yes, that's how those work. They're not necessarily synchronized.

 BA> Surge brakes have no connection with the tow vehicle other than the
 BA> ball hitch, they are hydraulic and the master cylinder for them is in
 BA> an assembly on the trailer tongue.  The big trailers and car trailers
 BA> (not tow dollies) at your local U-Haul outlet probably have surge
 BA> brakes on them, the ones around here do.

With a 1 axle trailer, you then have 3 axles doing the braking. The third
(trailer) axle brakes are in tune with the other two, aka synchronized.

 BA>>> I pulled a 36' travel trailer (GVW ove 10,000 pounds, 8800 on the
 BA>>> axles and 1800 on the trailer tongue, with electric brakes) from CA
 BA>>> to NE and was able to use engine braking only on most of the
 BA>>> downgrades I encountered on I-80.

 RW>> Towing with your old 5.5mpg Dodge?

 BA> Yep.  I also moved the rig from Nebraska to Wichita Falls and back.
 BA> That's why I know it only gets 5.5 mpg loaded.  And at the time the
 BA> truck was brand spanking new, pulled that trailer up the west side of
 BA> the Sierras on seven cylinders (one wire was routed too close to the
 BA> exhaust manifold at the factory and the insulation on it melted,
 BA> shorting that plug).

I went deer hunting with a buddy of mine in the SW corner of Colorado,
c1976. He provided the 1974 Chevy pickup, which also got 5mpg carrying a
fully self contained camper (bath with a shower, drinking water, heater,
etc.) plus towing my AMC Miti-mite off-road vehicle. He figured (against
my advice) that if he changed the rear-end gear ratio to a numerically
lower ratio (from 3.42 to 4.10), he'd get better fuel mileage and have
more power to make the long grades from San Diego to Colorado thru four
corners at Arizona and Utah. Instead of better mileage, we got 4mpg and
the engine had no more pulling power than before, since it ran out of rpm
to do so. The power to weight ratio was too much for the emmission devices
load on the engines capability to breath. Had it been two years older,
like mine, it wouldn't have had that problem. My 72 Chevy pickup had an
Alaskan (telescoping top) camper on it and not only did it get better
mileage, it was able to go up and down the California mountain passes
while the Santa Ana winds blew other campers off the road. The California
highway patrol waved me and most cars thru, while everyone else got waved
into the holding area, which contained campers and trailers, but also
semi-trailers as well. Nancy and I were hunting in the valley, while
everyone else waited for the winds to die down.

                R\%/itt



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