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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Scott & Heather on March 17, 2016, 08:19:40 AM

Title: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 17, 2016, 08:19:40 AM
Previous owner of my 102C3 moved and set up a regulator system for the tags that is in a much easier spot to reach just inside the curbside engine door. He had the tag pressure set to 35psi. Is that right or should it be more?
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Title: Re: What should tag bag air pressure be set to?
Post by: luvrbus on March 17, 2016, 08:30:29 AM
I wouldn't worry about it till you convert you bus then you will need to add more how much is going to depend on the final weight
Title: Re: What should tag bag air pressure be set to?
Post by: gumpy on March 17, 2016, 01:16:42 PM
Quote from: Scott Bennett on March 17, 2016, 08:19:40 AM
Previous owner of my 102C3 moved and set up a regulator system for the tags that is in a much easier spot to reach just inside the curbside engine door. He had the tag pressure set to 35psi. Is that right or should it be more?

Off the top of my head, I believe that's what the MC9 tag pressure is set at. Check your manual. Should tell you in there. I didn't check mine, but I seem to recall that's what it is.
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 17, 2016, 04:49:48 PM
Thanks! I'll leave it at 35 psi for now then and then after weighing the coach I'll come back to the table


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Title: Re: What should tag bag air pressure be set to?
Post by: luvrbus on March 17, 2016, 05:16:53 PM
Just remember the more air pressure in the tag the weight shifts to the front axle
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 17, 2016, 07:27:12 PM
Ok. I'll be weighing all my axles separately and adjust accordingly. Thanks again for pointing me in the right direction.


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Title: Re: What should tag bag air pressure be set to?
Post by: Jon on March 18, 2016, 04:27:40 AM
Why isn't the coach set up as it was built?

Messing with air bag pressures transfers weight among the axles. Maybe there is a benefit to doing that but the end result is now other systems are affected such as the brake chamber size, bearings and even structure which is all designed based on the weight distribution from the original design.
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 18, 2016, 06:08:06 AM
Thankfully we aren't messing with air bag pressures, the controls were moved to an easier access location by the previous owner and once I know my converted weights, I'm going to adjust them properly according to specs I find from MCI.


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Title: Re: What should tag bag air pressure be set to?
Post by: luvrbus on March 18, 2016, 06:19:16 AM
MCI has always had adjustable tags,1000's of time I wished Eagle had the adjustment the 1&7/16in wrench with a 4 ft bar and re indexing one used on a Eagle to adjust the weight on the front axle that sh!! get old in a hurry.FWIW the old dog drivers loved that feature to adjust to the driving conditions 
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 18, 2016, 02:45:15 PM
Cliff, I'll actually be putting gauges in up front so when I dump tag air I'll know it's actually working. I read somewhere that dumping tag air adds +or- 7,000lbs to drive axle. That's helpful when it's slick out and you know we drive in the snow more than we care to mention.


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Title: Re: What should tag bag air pressure be set to?
Post by: buswarrior on March 19, 2016, 07:56:13 AM
7k lbs may be a little high?

Go play on the scales. The MTO leave the scales turned on here in Ontario, when the coop is closed.

MCI doesn't lift like a Prevost, so the weight of the "Stuff" still rests on the ground. The Prevost is able to add the weight of the "stuff" as well, by putting it all in the air.

Best I saw on either of my MC8 was the tag carrying around 3k lbs aired up.

The switch on the side panel still leaves some air in the system (15 lbs vs 35 lbs) via a second regulator, vs the shut off valves down the back emptying them completely.

happy coaching!
buswarrior
Title: Re: What should tag bag air pressure be set to?
Post by: gumpy on March 19, 2016, 08:03:21 PM
Quote from: Scott Bennett on March 18, 2016, 02:45:15 PM
Cliff, I'll actually be putting gauges in up front so when I dump tag air I'll know it's actually working. I read somewhere that dumping tag air adds +or- 7,000lbs to drive axle. That's helpful when it's slick out and you know we drive in the snow more than we care to mention.



I think it's more like 5K.
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 19, 2016, 08:20:43 PM
Ok. Nice. I wasn't sure what the weight was. 7000 sounded high to me but I'm not an expert. I don't often need to dump my tag air. But I did once when I had my drive axle suspended in a small washout from a recent hurricane downpour. Dumped tag air and dropped the drive duals on the gravel and was able to get unstuck. Definitely useful when you need it.


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Title: Re: What should tag bag air pressure be set to?
Post by: mikelutestanski on March 20, 2016, 10:46:53 AM
Hello     My  72 mci 7 weighs in at 6K on the axles  as a conversion.
   The 30 or 35 pound set point is right on.  WHat you dont want is to have the reguator go to full pressure . YOu can pull the bus frame apart with full pressure.  I saw one in NY where the regulator was broken and the operator just hooked up full air to one side. the framework above the bellows was crushed and the bag destroyed.   
    I had to turn down the welding repair because the operator was not reliable about paying his bills.. and he was a chronic complainer.
    regards   mike
Title: Re: What should tag bag air pressure be set to?
Post by: luvrbus on March 20, 2016, 11:34:35 AM
He is dealing with a C3 aren't they different ? my D has 14,000 lbs tags the air pressure is a lot more than 35 lbs
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 20, 2016, 02:55:56 PM
And the plot thickens


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Title: Re: What should tag bag air pressure be set to?
Post by: buswarrior on March 20, 2016, 05:51:21 PM
A "C" is same tag design style as MC 7-8-9-102 etc... rated for gross of 6000lbs.

bunch of metal grafted onto side of beam, bags on an angle down towards the back.

design changed to vertical bags and a straight style axle with the "D"

And load carrying went up with it.

Generally speaking, the tag is rated about the same as the steer in the 45 footers.

happy coaching!
buswarrior
Title: Re: What should tag bag air pressure be set to?
Post by: Scott & Heather on March 20, 2016, 06:13:11 PM
Thanks BW. Just what I needed. Btw, I read on the Canadian charter forums that a few of the MCI D drivers said those coaches road a little too firm in their opinion suspension-wise. I know they have much less lean and side to side rocking with the newer outboard bellow suspension design but is the ride really that firm?


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Title: Re: What should tag bag air pressure be set to?
Post by: lostagain on March 20, 2016, 06:34:56 PM
I drove a 1995 D3 with S60 12.7 and 7 speed EatonFuller for several years for the Junior hockey team. The ride is not too firm by any means. You could say that it is nice and solid on the road. Feels very secure. Albeit that is the latest model bus I have driven, so I am comparing to older buses. I suppose a fancy late model Prevost or MCI would feel even better, but I don't know. The only complaint I have about the Ds, is that it is not very well designed for driver comfort. An after market seat would improve that over the stock seat. The dimmer switch on that shelf off the floor to the left gets tiring if you have to drive at night lots, which I did. I would replace it with a stalk off the steering column. A really good bus nevertheless.

JC
Title: Re: What should tag bag air pressure be set to?
Post by: luvrbus on March 20, 2016, 07:09:50 PM
I am putting my dimmer and turn signals on the column,I thought I may like the turn signals on the floor but I don't care for it to many switches for 1 foot 
Title: Re: What should tag bag air pressure be set to?
Post by: buswarrior on March 20, 2016, 07:23:33 PM
I drive new J and H345 regularly.

The independent front suspensions in new stuff might be "softer"?

But...

you can't go hot into a highway ramp with near the confidence, they lean over... which disturbs the customers...

And I wonder if it makes a difference in a cross wind?

If the D is "harder riding" then I'll take it. I liked the D models just fine myself.

happy coaching!
buswarrior
Title: Re: What should tag bag air pressure be set to?
Post by: Emcemv on March 20, 2016, 07:24:40 PM
I'm going to thicken the plot a little more, we have a MC-7 combo, it has a 8V92T out back and 100 gallons of water just above it under the bed.  I have individual control over the air bags, it appears that I have been running the tag pressure too high at 60lbs, anyone know what pressure should be on a combo setup? The bags are setup just like the drive, vertical and same size. The combo has full duals on the tag and was used for carrying freight.  
Title: Re: What should tag bag air pressure be set to?
Post by: luvrbus on March 20, 2016, 08:35:44 PM
I have a friend in Oregon that had a 7 combo he ran 55 to 60 in his tag
Title: Re: What should tag bag air pressure be set to?
Post by: harpold700 3 on March 21, 2016, 07:58:52 AM
start putting too much air in that tag and you start taking weight off your drivers, read spin out.