TrailManor Owner's Forum - View Single Post

**Denny_A** · 07-30-2004, 10:00 PM

[quote author=SeeKae link=board=20;threadid=1379;start=msg15171#msg1517 1 date=1091233383]
Well, I have one answer regarding this question. A WDH is not recommended. It fools the antilock This could cause an acdcident or worse, failure of the braking system on a grade. I know I have that quiestion ansered.
[/quote]

My thoughts (based on a previous vehicle) ragarding fooling the antilock brakes.

Chances are(?) that as the 4Runner is loaded and the rear end settles, a mechanical device is used to increase proportional braking to the rear wheels. So if one were to load 500 lbs over the rear wheels, a panic stop would result in a bunch more braking being applied to the rear wheels. Regardless, the antilock *must* function based on time-rate-of-change of the angular velocity of the wheel. Normally the slip ratio (when antilock kicks in) will be such that the wheels turn at 90% of vehicle speed. If a wheel suddenly decelarates too quickly it's released until vehicle speed is regained, then reapplied.

If a WDH is used, the vehicle stays level. The proportional braking feature is defeated. However, it seems that a brake lockup would still be prevented by the antilock sysyem. Braking, from the rear brakes, would be less. Still, with the trailer brakes assisting, that shouldn't result in an unsafe condition. The only other problem I can see might occur if the weight in the rear of the 4Runner were several hundred pounds. If the WDH were cinched to the point that the additional braking needed to account for the heavy trunk load weren't available, and a heavy trailer is also attached, and the trailer brakes were not working well - the trailer could tend to destabilize the rear of the tv. The extra cargo weight, along with low braking could cause the rear of the tv break loose laterally. Antilock is not designed to deal consistently with both straight ahead AND cornering loads simultaneously.

Since I don't overload cargo in the 4Runner, and do adjust/test my trailer brakes, I plan to keep on "living dangerously"! 8)

Denny_A

07-30-2004, 10:00 PM	#17
Denny_A Former TM Owner Join Date: Jul 2002 Location: Greenville, WI Posts: 517	Re:Toyota 4Runner replaces Honda ODY [quote author=SeeKae link=board=20;threadid=1379;start=msg15171#msg1517 1 date=1091233383] Well, I have one answer regarding this question. A WDH is not recommended. It fools the antilock This could cause an acdcident or worse, failure of the braking system on a grade. I know I have that quiestion ansered. [/quote] My thoughts (based on a previous vehicle) ragarding fooling the antilock brakes. Chances are(?) that as the 4Runner is loaded and the rear end settles, a mechanical device is used to increase proportional braking to the rear wheels. So if one were to load 500 lbs over the rear wheels, a panic stop would result in a bunch more braking being applied to the rear wheels. Regardless, the antilock must function based on time-rate-of-change of the angular velocity of the wheel. Normally the slip ratio (when antilock kicks in) will be such that the wheels turn at 90% of vehicle speed. If a wheel suddenly decelarates too quickly it's released until vehicle speed is regained, then reapplied. If a WDH is used, the vehicle stays level. The proportional braking feature is defeated. However, it seems that a brake lockup would still be prevented by the antilock sysyem. Braking, from the rear brakes, would be less. Still, with the trailer brakes assisting, that shouldn't result in an unsafe condition. The only other problem I can see might occur if the weight in the rear of the 4Runner were several hundred pounds. If the WDH were cinched to the point that the additional braking needed to account for the heavy trunk load weren't available, and a heavy trailer is also attached, and the trailer brakes were not working well - the trailer could tend to destabilize the rear of the tv. The extra cargo weight, along with low braking could cause the rear of the tv break loose laterally. Antilock is not designed to deal consistently with both straight ahead AND cornering loads simultaneously. Since I don't overload cargo in the 4Runner, and do adjust/test my trailer brakes, I plan to keep on "living dangerously"! 8) Denny_A