Excessive weight on front axles

[wayne77590]

Five, rule of thumb for tire pressures and temperature is 2% change for every 10˚ change in temperature.  For car tires, 2% is approximately 1 PSI but for an RV tire  at 120 psi, 2% is about 3 psi.

Also for every 1,000 feet of altitude there will be a .48 psi change. As altitude increases. As altitude increase so will tire pressure. On the other hand, typically when going up in altitude it is colder so the 10˚ and 2% will offset it a little. Sort of a balance beam, just not quite a balance.

[jleamont]

2 hours ago, elkhartjim said:

I think that's a given, are you trying to make another point that I'm missing? BTW, it took me a minute to figure TP was tire pressure. That usually indicates something else on my shopping list. 

Me too !!

if the tires are over their weight capacity air pressure or how much air pressure is a moot point. Any overloaded equipment be it an axle, wheel, suspension, tire etc is a very dangerous situation. 

The tires being over loaded (which we do not know yet) if are in fact over loaded...personally I'd replace them. It wouldn't matter to me if they only had 100 miles on them. 

Everything else needs a proper inspection by a qualified person. Keep in mind even then something might not be detected today that can become a problem later. 

From my experience tag pressure is usually checked at the time of an alignment. This also brings up another good point, the coach was built an a finial assembly alignment wasn't performed. I'd have that checked and adjusted once the tag problem has been corrected. That's a thought one to swallow after a recent purchase. Between the selling dealer and the manufacturer someone else is footing that bill. 

[ctammyh@hotmail.com]

22 hours ago, elkhartjim said:

What about 9000# on the tag and drive 13,500#? 

Here again, I'm a novice but that seems way out of range. Like Joe said, I would be a little hesitant trusting Tiffin at this point. Newmar had a problem with front axle weights on the 2016 Dutch Star models and had a recall where they replaced the front axle and wheels. 

Please understand, I'm only wanting to gain more knowledge since I'm a first time tag owner with our Newmar. 

You mentioned mobile service being similar in cost to in house, I've never found that to be the case and most likely to find a qualified tech you're either going to a Freightliner shop or a major truck mechanic. I'll be interested in what you find in the Houston area.

Please keep us updated.

Update on leak:  Had a friend who was able to get up under the bus and found the power steering hose was leaking at the clamp.  He was able to get a 3/8 turn on the clamp and stop the leak so that issue is complete.

Bill

[ctammyh@hotmail.com]

22 hours ago, wayne77590 said:

I also am a 1st time tag axle owner and am interested in the topic.

 

Hi Wayne,

I copied this info and it shows what I am trying to do.  Hope it is helpful.

Bill

The problem of heavy steer axles on many 43' Tiffin coaches on the Powerglide chassis, they used a 60/40 proportioning valve to distribute the weight between the drive and tag axles. That ratio takes too much weight off of the drive and puts it on the tag and steer axles. I and others went through this several years ago. I had Tiffin replace the 60/40 valves with manual regulator valves. Then I did a lot of testing and weighing with the adjustments and arrived at 75/25 for the optimum proportion. My steer is rated at 15,640# and weighed 15,340 with full fuel with the 60/40 prop valves. After going to 75/25, The steer dropped to 14,700#. The drive went from under 14,000 up to over 19,000# and the tag went from 9200 down to 5500#. 

At that time, I sent my data to Gary Harris @Tiffin and they tried a 45' coach with a 75/25 prop valve. The result was a near perfect balance. They then tried one without a proportioning valve and ended up with a 70/30 ratio due to the difference in air bag sizes. To correct the 43' coaches on the Powerglide chassis, the only cure is to change the prop valves to a 75/25 ratio or go to a manual regulator valve and adjust it yourself. The earlier tag coaches on a Freightliner chassis, have an adjustable proportioning valve that can be adjusted to get the 75/25 needed to get the weights where they should be.

[manholt]

 Your not alone.  I get lost on some of the acronyms in here!  Hard enough to remember the ones from long ago (Army)! I saw the TP and got a vision of a Bear! LOL. 

[wayne77590]

Thanks Bill. Good information to know.

[wayne77590]

Regarding the TAG.  A few days ago I backed it out of the storage unit so the Sats-2-Go guy could change out the dish from Direct to DISH.  All finished and checked out I pulled it back into storage.

Getting ready for a trip and pulling it out of storage today I started it and when I put it in reverse the warning chime and the LCBU said !Tag Dump.  I shut it off and tried it again.  Told DW i was going to move it and when I stopped and put it in reverse again all was quiet. 

Anyone know what happened?

Don't want to Hi-jack this thread so if Brett wants to move it to another subject area - okay with me (has to be, right Brett?)

[manholt]

Wayne.  When you started your engine, where you at proper ride height when you put it in gear?  Other is, you either accidentally dumped the air in your tag, or you manually did (my toggle is on left side, near air horn on, switch.  The dump tag has come on in mine, but only when I put it in gear, before I was at 127 pounds.

[wayne77590]

It had been high idling for several minutes will I disconnected the 110.  I checked the switch and it was in "auto" mode. My switch is off/auto/dump tag.  I leave it in auto except when backing in to drive way. I put it in off before it gets to 8 mph which will raise the tag.

 

[manholt]

When you, "shut it off", was that the engine or you put it in N, then R?

[elkhartjim]

If your switch is the same as mine, it's a goofy switch. If I understood correctly and that's a big if, it's only a two way switch. It is either on/auto or off.  The auto tag dump nomenclature is the name of the switch according to the help desk. I was getting the same message whenever I applied the brakes at low speed. I have the passive steer also if that makes any difference. I cannot raise my tag, only relieve the downward force (pressure).

[five]

On 2/24/2018 at 4:41 PM, wayne77590 said:

...rule of thumb for tire pressures and temperature is 2% change for every 10˚ change in temperature.  For car tires, 2% is approximately 1 PSI but for an RV tire  at 120 psi, 2% is about 3 psi...

Yes, the 2% figure works better on the bigger tires.  Also, I mistyped in my earlier post, I typed "your TP goes down one degree" should have been "TP goes down one PSI"

[manholt]

Wayne.  Mine is pre set, so it's on all the time, then I can dump the air and it makes cornering easier, not much but easier on the scuffing.  Yours is a combination because it's also a steering tag (I think on Freightliner it's +/- 11 degrees) .

 

[ctammyh@hotmail.com]

On 2/25/2018 at 5:23 PM, wayne77590 said:

Regarding the TAG.  A few days ago I backed it out of the storage unit so the Sats-2-Go guy could change out the dish from Direct to DISH.  All finished and checked out I pulled it back into storage.

Getting ready for a trip and pulling it out of storage today I started it and when I put it in reverse the warning chime and the LCBU said !Tag Dump.  I shut it off and tried it again.  Told DW i was going to move it and when I stopped and put it in reverse again all was quiet. 

Anyone know what happened?

Don't want to Hi-jack this thread so if Brett wants to move it to another subject area - okay with me (has to be, right Brett?)

On my Tiffin the tag always dumps when placed in Reverse.  I was told to be sure I didn't use Reverse before entering or while on the scales as I would get a bad reading.

[wayne77590]

I shut the engine off and then back on.

My switch is three position, Off - Auto - tag dump and it is a rocker switch.

I'm not really sure how it all works but I haven't scraped the driveway backing in - yet. As I'm coming up the road to the house and over 8 mph I turn the tag off.

Mine also dumps when transmission is placed in reverse and it also dumps below 8 mph.

[hermanmullins]

The tag on our Monaco had an up/down switch. When in the up position the tag will rise about two inches off the ground and will beep an alarm when up until I believe about  5 to 8 mph. When in the down position the tag will return to the down and support position. 

One problem is that when I forget to lower it the DW will ask, "Is the tag UP?" With my hearing I can't hear the alarm, just in the wrong pitch.

Herman

[jleamont]

1 hour ago, hermanmullins said:

our Monaco had an up/down switch

What happened to the switch?

I can see from the comments our 1st tag axle coach will be altered by me to make some sense. 1st it will be adjustable 2nd have adequate controls at the drivers seat position to control when its up and when its down, ill make that call not some computer that thinks this situation should be x. Most modern day electronics in motor vehicles are programmed by people that have no clue. Ill take that back to the driver to manage.

[ctammyh@hotmail.com]

Update:  We had the 2 proportional valves replaced along with 2 manual air valves at Lakeshore Custom RV in Iuka, MS.  The valves were set by Tiffin and the tech that installed the had worked at Tiffin and knew what to do.  He said he had installed many and the 2 proportional would not work without the 2 manually adjustable valves. Total work time was 2 hours and their rate was $75.00 hour.

 Lakeshore completed 28 items over the 2 days we were there and we were excited that they could do everything from replacing the slide toppers to programing the electronic door locks or replacing the electric window shade panel.  It didn't matter what we asked them to do they knew the system it it was fixed before we could turn around unless the had to get the parts.  We were so happy we didn't have to bounce around from place to place, they even serviced and replaced the fluid in the Hydro Hot.  They can also work on other brands of RV's.  If you are considering going to Red Bay you may want to consider them.  Their office number is 662-273-1002, Nathan's Cell is 256-668-2195.  Nathan was one of the few who was an inspector in every stage of production at Tiffin for 14 years.

Bill