Country Coach Owners Forum Country Coach Motorcoach Forum

adjusting pressure on Tag

March 28, 2013, 05:20:00 pm

Yahoo Message Number: 86740

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I was wondering the feasibility of increasing the pressure on Tag Tires to get a better hug on the road with my road wandering front end issue. Being a newbie to the tremendous amount of information that one is subjected to with a new coach (06) i appreciate any advice.
If I am correct the front axle is 18k (40' 06 Affinity 25000 miles) and the 315 XZA2 are good for 9090 apiece at 130#.
My certified weight is as follows.
STEER AXLE 15540#- DRIVE 30040# - GROSS 45580#.
I have testimony form one owner (brother in law) that a increase load on Tag cured his wandering problem. Is this possible and how is it done?

OJinOK

06 Affinity #6614

PS. Tammy how is our sister Affinity working out for you guys? Great I hope.

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Re: adjusting pressure on Tag

Reply #1 – March 28, 2013, 06:18:23 pm

Yahoo Message Number: 86742

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I have no Affinity experience, so will not be able to help on the Tag. Though my instincts are you should run the tag per the actual weight carried, per my comments below.
I wanted to be sure you knew how important it was to get one side of the coach axle weight, to then subtract from the full axle weight. For example your steer of 15540#, could be 8000 Right, and 7540 Left. So for looking up PSI levels on the tire manufacturers charts, you would want to use the highest of 8000#, and alway make the tires paired the same (Both the Front Left/Right, would be set to the PSI of the 8000#'s, in this example.)

Two other things that I do, which may be overkill:

1) If say the 8000# level is towards the top range of a PSI setting. Perhaps 7250-8250# = 100PSI. I 'bump' up the PSI setting to the next level. (I kind of eyeball it, and if within 25% of the top of the range, that is when I make the jump)
2) I then also add an additional +5 PSI to the tire charts PSI. So if it was 105PSI (for the next level above 7250-8250#) + 5 PSI = 110 PSI tire setting.

I have no doubt that the tire manufactures PSI settings have safety margins already rolled in. But I bump up to the next level when close, in case I have more cargo weight then normal. I also then do the + 5 PSI, to cover weight transfers while on the road. (I recall one run in Montana, where I had a sustained cross wind of over 30 knots, for about 45 minutes. The tires away from the wind, were 'loaded' with the wind push to that side.)
Public scales, CAT scales, or better yet individual wheel scales (Escapees has these at different locations and events.). On a large scale, besides getting the Steer/Drive/Tag weight, then run down one side or the other and only get one axle of the same Steer/Dive/Tag. As well as the full weight of the coach.
Hope others have input to you on the tag PSI question, and I apoligize if you have already got the side axle weights, and done this caclulation. Tire safety is so important, I did not think it would hurt to be sure. (And if I worded this poorly enough to mess you up, send me a PM and I'll try again:)!)

Be good, have fun, be safe,
Smitty

04 Allure 31017

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Re: adjusting pressure on Tag

Reply #2 – March 28, 2013, 07:20:06 pm

Yahoo Message Number: 86745

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Smitty,

I have the feeling that you misread the post either that or I did. I think that he wants to increase the downward pressure applied by the tag axle not the pressure in the tag axle tires. I could be wrong.
The amount of downward pressure that the tag applies to the road surface will change the load that the tag axle shares with the rest of the suspension. It is certainly possible that having the tag pick up more of the weight is going to change the dynamics of things but I am not qualified to say in what way. Heavy trucks with floating tag axles have control over how much pressure is going to the air bags and through experience they know what they are doing. The CC tags can be adjusted but CC certainly didn't advertise it much. Personally I don't think it is a thing to consider unless you know exactly what you are doing.

Don Seager

Former CC owner

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Re: adjusting pressure on Tag

Reply #3 – March 28, 2013, 08:00:31 pm

Yahoo Message Number: 86749

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Thanks for the input guys. At this time I do not have side to side front weights. I am trying to understand why LakeLand (Butch Williams) would recommend to prior owner, to run 130# air in the new 315 XZA2. My current Steer weight of 15540# (knowing it could be off several hundred pounds per side) tells me I could easily drop PSI in steer tires to 120# and still be safe on the ratings (120# rated 8530# single.
YOUR THOUGHTS?
OJinOK

06 Affinity.

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Re: adjusting pressure on Tag

Reply #4 – March 29, 2013, 12:30:10 am

Yahoo Message Number: 86753

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Hi Don - Nope, reading the bottom part of his post again - I too now read this as tag downforce(? For lack of knowing the proper term.). The part about axle weights made me jump to tag tire PSI.
I'll follow the post, as one of my tag's has quite a bit more weight on it then the other. But the drive axle does not match this large variation. I assumed I had a flaky reading when trying to get one sides tag weight on such a large scale. Figured I would know for sure after I get each wheel weight at an Esapees scales session in the future.
If the weight reading is correct, I could have a tag downforce pressure problem with one of my tags. Though my coach seems to ride well.

Thanks for your catch, and best of luck to the OP.
Smitty

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