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KAIMIKAZEE
Joined: 18 Sep 2005
Posts: 129
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| Posted: Wed Apr 09, 2008 7:05 pm Post subject: on board air scale meters |
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anybody tried or have an "Air-Weigh" on board scale in their trucks...
just want to know how good and is it reliable???
also the price of the unit and installation... |
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countryhorseman
Joined: 04 Jan 2005
Posts: 696
Location: The Great State of Texas - Seguin
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| Posted: Wed Apr 09, 2008 7:22 pm Post subject: Re: on board air scale meters |
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KAIMIKAZEE wrote: anybody tried or have an "Air-Weigh" on board scale in their trucks...
just want to know how good and is it reliable???
also the price of the unit and installation...
They make for an excellent tool to save time and money! Although, when your weights are getting close to the legal limit, it is a good idea to occasionally have that certified scale ticket - too verify your air gauge is still in calibration!
As far as cost, shop around, there are big variance in the cost and quality of installs! |
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BigDiesel
Joined: 01 Apr 2007
Posts: 884
Location: Space... The Final Frontier
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| Posted: Wed Apr 09, 2008 7:49 pm Post subject: |
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I had this installed last summer with the trailer option, and it is neater than sliced bread. I have only used a Cat scale once since then, and not one overweight ticket either.
http://www.air-weighscales.com/download/pdf/AW5800_Bro_902-0035-002rev1.pdf |
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rank
Joined: 02 Oct 2006
Posts: 1252
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| Posted: Wed Apr 09, 2008 8:54 pm Post subject: |
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| I had plain old 100 psi air gauges installed on all of our trailers and the only truck that didn't have one. After a few scaled loads you get a pretty good idea. I can get within ~500 pounds on each axle. |
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RostyC
Joined: 21 Oct 2005
Posts: 1018
Location: Maryland
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| Posted: Thu Apr 10, 2008 2:21 am Post subject: |
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| Hey BigDiesel, what was the cost of that set up? Also, do you have to go to a specified shop to have it installed? or can you order it and have your own shop install. How long did it take to install. I like the fact that the gauge is in the cab. Any other details you can think of and share is good too. |
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NotSteve
Joined: 20 Mar 2007
Posts: 190
Location: Bar in Mexico
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| Posted: Thu Apr 10, 2008 2:48 am Post subject: |
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Keep in mind also that with plain old air pressure gauges you can be way off depending on barometric pressure, temperature and humidity. Also, if you calibrated the air gauge sitting on a level scale you could be way way off sitting on an incline of just a few degrees.
What someone needs to invent which would not be all that expensive is to design an inline device that is completley standalone and supports Blue Tooth which transmits results to the in dash gauge. This would eliminate all need for any wiring other than grabbing 12v from the ABS line or any other source.
Also keep in mind that these devices are not just simple read the pressure devices. There is a lot of math, normalization and inferencing that is taking place. Along with those equations are variables such as temp, air density and degree of incline. Not a simple task and usually requires the talent of a physicist. |
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Splitshifter
Joined: 19 Jun 2006
Posts: 638
Location: Right here
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| Posted: Thu Apr 10, 2008 4:26 am Post subject: |
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All you have to do is tap a generic air pressure gauge (0 to 150 psi capacity) into the line between the ride height valve and the air suspension bags.
This can be done on the tractor or trailer, or both.
Then put a legal load on, and scale the axles on a certified scale.
Be sure that the axles on the tractor & trailer are at legal weight.
Note the air pressure readings on the gauges and you have your benchmark. Any air pressure reading above that benchmark reading means you're overloaded on that set of axles. A reading less than the benchmark reading means that set of axles is loaded at less than the legal limit.
Pretty simple actually. |
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NotSteve
Joined: 20 Mar 2007
Posts: 190
Location: Bar in Mexico
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| Posted: Thu Apr 10, 2008 6:00 am Post subject: |
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Splitshifter wrote: Pretty simple actually.
No, it's not. Like I said above, temp, barametric pressure, humidity and incline can throw you WAY over the legal limit. Just sitting on an incline without compensation can make you believe your 10,000 under on your drives. |
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BigDiesel
Joined: 01 Apr 2007
Posts: 884
Location: Space... The Final Frontier
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| Posted: Thu Apr 10, 2008 11:38 am Post subject: |
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RostyC wrote: Hey BigDiesel, what was the cost of that set up? Also, do you have to go to a specified shop to have it installed? or can you order it and have your own shop install. How long did it take to install. I like the fact that the gauge is in the cab. Any other details you can think of and share is good too.
I know that I paid retail plus for the units and installation.... about $1400.
The install for the tractor portion was done at my Pete dealer and the trailer at the Utility dealer. You could do it yourself, but I am not mechanically inclined and impatient. |
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Splitshifter
Joined: 19 Jun 2006
Posts: 638
Location: Right here
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| Posted: Thu Apr 10, 2008 4:49 pm Post subject: |
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NotSteve wrote: Splitshifter wrote: Pretty simple actually.
No, it's not. Like I said above, temp, barametric pressure, humidity and incline can throw you WAY over the legal limit.
The only one of those factors that is valid is incline, but since I said initially the truck should be weighed on a certified scale (which will be level), all you have to do is make sure the tractor & trailer are always level whenever checking the suspension air gauges.
Quote: Just sitting on an incline without compensation can make you believe your 10,000 under on your drives.
See above.
BTW, temp, barometric pressure and humidity are irrelevant here, it will take the same PSI to support a given amount of weight no matter how cold or hot or dry or humid, or whether the barometric pressure is 29.50 and rising or 30.50 and falling. |
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RostyC
Joined: 21 Oct 2005
Posts: 1018
Location: Maryland
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| Posted: Thu Apr 10, 2008 5:22 pm Post subject: |
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| thank you BD |
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rank
Joined: 02 Oct 2006
Posts: 1252
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| Posted: Wed Apr 16, 2008 8:42 pm Post subject: |
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| I agree that the truck + trailer need to be level to get an accurate reading.....but as for the other stuff.....well I've charted ~100 readings on CAT scales in winter and summer and I've noticed no inaccuracies. |
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Malaki86
Joined: 28 Aug 2004
Posts: 1976
Location: West Virginia
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| Posted: Thu Apr 17, 2008 7:31 am Post subject: |
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rank wrote: I agree that the truck + trailer need to be level to get an accurate reading.....but as for the other stuff.....well I've charted ~100 readings on CAT scales in winter and summer and I've noticed no inaccuracies.
Cat scales don't use air pressure to measure the weight. They use load sensors which are basically a piece of metal that gets "squashed" when you drive on them. The computer reads the "amount of squashing" to give the weight. |
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Doghouse
Joined: 21 Mar 2007
Posts: 827
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| Posted: Thu Apr 17, 2008 7:33 pm Post subject: |
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I use 2 right weigh gauges mounted in the dash. They are within 500lbs. Also it's a good idea to get the truck/trailer level after they load you, because the scales will show 2,000lbs off depending on which is on the down side.
All in all my investment has almost paid for itself,...$200 for the scales and I've only scaled 3 times out of 30. |
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rank
Joined: 02 Oct 2006
Posts: 1252
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| Posted: Mon Apr 21, 2008 9:24 pm Post subject: |
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Malaki86 wrote: rank wrote: I agree that the truck + trailer need to be level to get an accurate reading.....but as for the other stuff.....well I've charted ~100 readings on CAT scales in winter and summer and I've noticed no inaccuracies.
Cat scales don't use air pressure to measure the weight. They use load sensors which are basically a piece of metal that gets "squashed" when you drive on them. The computer reads the "amount of squashing" to give the weight.
Um, yeah. :)
What I meant was, I've scaled a bunch of loads and also taken the pressure gauge readings on each axle for those same 100 loads. i.e 80 psi on the rear axle of trailer = 40,000 lbs. Then I made a chart using all these loads so whatever the psi is, we can get a pretty good idea what the axle weights are. If it's sitting level. |
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