Automatic Traction Control & Tire Chains

[BlitzfireSolo]

My department is ordering new apparatus with automatic traction control (ATC), and we are considering removing the On-Spot chains from the spec. The unit will be a tandem axle pumper-tanker, and will be heavily utilized during lousy winter road conditions (heavy snow, ice, slush, etc).

For those with experience using ATC and/or automatic tire chains on large pumper-tankers and rescue-pumpers during slippery winter road conditions, what are your thoughts? Would ATC preclude the need for On-Spot chains, or are we best off keeping both?


(Also: Does anybody use automatic tire chains on BOTH tandem rear axles? Some manufacturers say it can't be done, and others say it is possible, depending on the type of suspension and the make of automatic chains)

[Rescue101]

Our experience with the On spot chains is they are very effective when used with ATC.But they are only really good in Ice,light to moderate snow,and some slush.Real heavy snow or slush reduces their effectiveness.I'd be careful about doing both axles.The results would be similar to "chaining up"both sets on a tandem.All that energy has to go somewhere and if the differential can't shed some of it in "slip"somethings gonna give.And it's probably expensive. T.C.

[BirkenVogt]

There is nothing wrong with chaining both tandems, all the big trucks do it all winter over Donner Pass here. The power divider still functions exactly like always. If you were chained AND had the power divider locked then you might have the same sort of problems as locking it on the dry pavement, but even that is not that bad, just causes cumulative wear.

ATC is great but it is primarily a slow speed thing where on-spots are more medium speed, they need the speed to keep them flung out and operating. So I think one might complement the other nicely. Whatever you do make sure you get the ABS/ATC with 6 sensors/6 modulators, otherwise the computer will not be able to independently control each slipping wheel.

The main reason for the Onspots not being on all axles is probably just clearance. If you can only get two then I would make sure it has a manual power divider lock that you use when on snow so the axle without traction will not be taking away from the axle with traction, and relying on the ATC all the time. That will be herky-jerky to drive, and wear out brake shoes in a hurry. Better to engage the lock beforehand and prevent a spin rather than deal with a spin after it happens.

Birken

[chaunz15]

They are great. We have used them and work great. You can slow down lower the chain and keep going. I think it beats the old chains BIG time.

[BVFD1983]

If you are not skilled enough to drive on snow/ice then do not drive. Simple as that.

If you cannot keep your foot out of it enough to limit wheel spin, then you should not be driving.

Call me old fashion but I do not want some computer deciding how much power I get to apply and to brake a certain wheel, etc.

Just spec chains and a limited slip or a locker and be done.

[BirkenVogt]

Limited slip and/or lockers on big trucks are trouble. They cause broken axles, drive shafts, etc. And during the course of normal driving they are still always there, changing driving characteristics of the vehicle and wearing themselves out. ATC is my first choice because it is much more gentle and is inactive when not needed. I cannot think why having it that part of it on any truck would be a bad thing. On Meritor systems at least, the wheel slip throttle control feature can be defeated by a switch installed in the cab, and then you can spin the tires all you want. The question is why would you want to? To ensure that you have buried yourself really deep so you guarantee work for the tow truck or Cat operator?

Second choice is the manual locker. Like the ATC it only operates when needed but if engaged when a wheel is spinning it can grenade and when engaged the truck wants only to go in a straight line. Getting them to disengage usually involves going around a corner in the opposite direction or backing up. It is OK if the drivers understand it.

Birken

[BVFD1983]

IF the drivers understand it? Why would someone be driving who does not understand how to operate it?

[BirkenVogt]

You tell me, that is a commonly cited reason not to use something readily available on a fire apparatus though...the operators won't understand it

I am a fire mechanic and I see lots of examples of people who didn't understand things though. It should not be normal but it almost is. Part of the problem is ignorance is fashionable and if a person knows too much about a subject he is looked at as a bookworm or nerd.

Birken

[Rescue101]

Birken,Come on.Driver error? Nah, couldn't be.We ran limited slip for a good number of years with no problems.But you need to change the lube once in awhile and add the "banana oil".Most of our stuff now has air lockers on it. I like the full lockup on the tandems(user controlled)but I agree it can get you in deep trouble rapidly.Particularly in black ice or mud.ATC? I've got one in my second dept and I like it very much.I get to tow the stuff to the shop so I know as well as you what a "experienced"driver can do to a rig.Spin 'em in,flip the switch,spin 'em in,then break both "pigs".Gonna be another one of those days,Hehe T.C.