role of shocks in heavy on-highway trucks
role of shocks in heavy on-highway trucks
(OP)
Greetings!
there is an interesting disagreement between "mechanics" and a driving team of a major trucking company here in the Western US.
The "mechanics" are claiming that airbag suspension systems don't really need shocks, that the shocks are just there to keep the suspension from over-extending!
The driving team is complaining of ride and handling problems, and of physical ailments due to the ride problems.
The last set of tire lasted well enough, but were showing odd wear. They looked like they were hopping or something...
I would think truck suspension would need damping every bit as much as auto suspension- and that air bags would not have the inherent frictional damping that leaf springs do.
feedback or suggestions?
thanks
Jay
there is an interesting disagreement between "mechanics" and a driving team of a major trucking company here in the Western US.
The "mechanics" are claiming that airbag suspension systems don't really need shocks, that the shocks are just there to keep the suspension from over-extending!
The driving team is complaining of ride and handling problems, and of physical ailments due to the ride problems.
The last set of tire lasted well enough, but were showing odd wear. They looked like they were hopping or something...
I would think truck suspension would need damping every bit as much as auto suspension- and that air bags would not have the inherent frictional damping that leaf springs do.
feedback or suggestions?
thanks
Jay
Jay Maechtlen
RE: role of shocks in heavy on-highway trucks
Not an expert as such, but I have had experience desigining air susps for heavy duty tractors, and they will bounce around like hell with little or no load on and no shockers.
RE: role of shocks in heavy on-highway trucks
Jay Maechtlen
RE: role of shocks in heavy on-highway trucks
I don't know what it's like over there in the US, but here in old blighty the authorities take a dim view on bad maintenance. Consider the possibility that one of the vehicles is involved in a serious accident, an engineer's report will undoubtably show that your truck is in an un-roadworthy condition. Best case scenario, you can kiss your insurance cover goodbye, worst case, negligence and even manslaughter. Regardless of where the blame of the accident lies, you are still in the sh*t. If one of a fleet of vehicles is found to be faulty, especially if it's deemed to be through lack of maintenance, the whole fleet is checked out as procedure.
Also, if the drivers claimed for rsi, or other work related injury, you wouldn't have a leg to stand on.
For a set of shocks at 20quid a pop, it really isn't worth the risk, and if that's the attitude of your 'mechanics'...
RE: role of shocks in heavy on-highway trucks
Jay Maechtlen
RE: role of shocks in heavy on-highway trucks
Norm
RE: role of shocks in heavy on-highway trucks
Randy
RE: role of shocks in heavy on-highway trucks
Shabba doubted that shocks limit travel, well at least in Europe they certainly do. The dampers we use (Koni) even have a rebound system that gives extra resistance in the last 20 mm of outward travel, I expect that the competitors have something like that too.
It could be that american suspension designs have steel cables to catch the axle on outward travel though.
RE: role of shocks in heavy on-highway trucks
I just had a nice visit with my Sister and her husband- the driving team originally mentioned.
The trucking company is so boneheaded, they conducted the following test:
They test-drove an in-service truck around some course (I think it was on local streets), then removed all shocks from the rear axles, and repeated the same course. They couldn't tell the difference.
Only one minor catch: The truck in test had about 300,000 miles on it. Since the company doesn't ever change shocks, these were the originals...
So, imagine that! They showed that old shocks don't work...
Of course, they didn't have enough sense to install NEW shocks and repeat the test.
The team spent some $500+ of their own money and had new shocks installed on their rig. At least THEY can ride in a reasonable vehicle. Funny- when the shocks were installed, a mechanic took the rig around the yard, and absolutely raved about how great it rode! But, management: I don't think they want to know. Boneheads- it has to reduce life of cab and related equipment, it has to reduce driver safety...
regards
Jay
Jay Maechtlen