What is ASR?

Will ASR improve traction driving on dirt roads? Is it like positraction or having a limited slip differential? Exactly what is it?

Rick

lzcamper said:

Will ASR improve traction driving on dirt roads? Is it like positraction or having a limited slip differential? Exactly what is it?
Rick

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A typical muti-disc limited slip unit limits loss of traction, free spin of an axle shaft via plate friction on the inboard end of the axle shaft.

ASR limits free spin of an axle shaft via brake application friction on the outboard end of the axle.

The end result, drive restoration of the non spinning axle, is the same- but ASR does this without the typical disadvantages of a conventional mechanical limited slip. Those being- noise, expensive wear and tear of internal components, and adverse handling effects during hard cornering.

ASR can also assist when both rear wheels lose traction by inducing torque reduction and controlled frictional arrest of both axle shafts. Doktor A

Thanks, Doktor A for the explanation.

When do you turn the ASR switch "on"? The salesperson that delivered my Sprinter said to leave the ASR switch in the "off" position. One time, while driving on a short steep section of dirt road, the "exclamation mark" intermittently flashed when the van lost traction. That seems to indicate that the ASR activates when the switch is "off". Why have an "on/off" switch?

Rick

asr is always on, unless you push the asr button, once you exceed 40mph the asr turns back on. On icy/ slippery roads the asr keeps you from ditching your truck) among many other things), at low speeds in ice going up a slight grade from a stop causes the asr to initiate(this is only one of may examples) It causes the rear brakes to stop a wheel that is spinning, but it can make moving up this slippery incline very slow since the more you push the gas to go and the wheels spin, the more the rear brakes stop each rear wheel. This is a circumstrance where turning the asr off will get you moving again.

poiuytrewq said:

asr is always on, unless you push the asr button, once you exceed 40mph the asr turns back on. On icy/ slippery roads the asr keeps you from ditching your truck) among many other things), at low speeds in ice going up a slight grade from a stop causes the asr to initiate(this is only one of may examples) It causes the rear brakes to stop a wheel that is spinning, but it can make moving up this slippery incline very slow since the more you push the gas to go and the wheels spin, the more the rear brakes stop each rear wheel. This is a circumstrance where turning the asr off will get you moving again.

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Thanks. With your and Doktor A's explanation, I've gained some knowledge of how and when ASR works, but still don't understand the function of the switch and how it should be set for different driving conditions. My salesperson's instruction that I should always leave it "off" confuses my understanding of how and when to use it.

Under slippery conditions, does the ASR activate even though the switch is "off"? Is ASR always inactive unless the switch is "on"?

Should the ASR switch be "off" for normal driving conditions and "on" when road conditions offer limited traction?

Rick

your sales man is just that, not sure of what he is talking about. It is always on, if you hit the off button it turns back on when you exceed 40mph. It turns back on each time you start the van. I only turn it off if i am stuck and cannot get the truck to move- severe ice . The only time i turned it off was turning left at a icy intersection from a stop. The truck was trying to stop the wheel spin so well that i was barely moving.

Hereafter, I'll leave it "on" for most driving conditions, and only turn it "off" if it prevents the van from moving.

Thanks for the info!

Rick

My experience with the ASR is to ignore it, except when I have poor traction. Then it gets shut off. If it is on, I cannot drive up my gravel driveway. I don't know what the basic idea was or why they wasted the effort to build it. It never activates except on gravel roads, I mean NEVER. So, it's basically a waste of money and engineering. Probably the most useless system on the van, including the automatic door joke (which unlocks the doors whenever I start the van). A limited-slip differential is much more useful. My truck has no problem with the driveway.

It comes in handy if you pull to the side of the road. If the one wheel is on a slick surface (ice, mud) and you keep the other wheel on a solid surface it works good to get you going again. The other time I have found it useful is crossing a ditch at a angle and one of the rear wheels is in the air. I have used it a number of times. Yes, a electric locking diff. would be more to my liking and would have gotten me out of a few places instead of having to get the tractor out to get me out.


Doug
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