Tag Axle Tires.

mpierce wrote:

bluwtr49 wrote:
Thanks again for the replies and they have been very helpful in clarifying my thoughts.

I really like the thoughts of moving my steer tires to the tag position but I'm not going to use the tag tire in the steer position....I feel the sidewalls are way to stiff. When I get to OR next month I will consult with the local Les Schwab dealer regarding what tires and pressures to run on the tag longer term.

As to why lower the tag axle loading: I do that to balance the fore and aft axle wts. By dropping the tag air pressure it transfers wt from the front axle back to the drive and tag axles. This has a lot of long term benefits especially if the front axle is close to or over the wt limits. This is the purpose for which tag axles are installed. In my case I'm currently running ~12,000 lbs on the front and would like to drop that to about 11,500 or so. Naturally one does not want to go overboard so there is some trial and error involved.

Partially correct. Dropping tag pressure will lower front wt. But, you say it adds wt. to the drive AND tag. Incorrect. Taking pressure out of the tag air bags will also LOWER the wt. the tag is carrying. ALL the added wt from the front and the tag goes on the drives.

Be aware too, that by lowering the wt the tag is carrying, you are much more likely to lock up just the tag tires in a quick stop, flat spotting them.

You are correct and I mis-spoke regarding transferring wt. to the tag. It is my intention to transfer wt from the steer axle which is loaded to ~ 85% to the drive axle which is loaded to ~70%. Plenty of capacity to play with. The adjustment is easy, just drop the tag air pressure using the regulator/pressure gage assy in the aft bay.

As for the tag potentially locking up in a hard stop....might or might not be an issue depending on how well the ABS works but I put that at a very minor potential problem and one that can be easily remedied if indeed a bit of flat spotting occurs.

Not familiar with your chassis, so no input on adjusting tag psi.

If you are only talking about running the steers on the tag for an additional year, as long as the dismount does not reveal any visual problems, I see not problems. Staggering the 8 tires into 6 and 2 at a time purchases over a two year period will allow spending the budget impact out too:)!

I'm in the school of 5-7 years, with 7 being the max, on aging out the tires. Sure, some tires manufactures say go to 10 with annual inspections. But seeing the damage of blowouts, and crashes as a result of blowouts - has always been my reasoning for the added safety edge of replacing tires within the 5-7 year cycle. (We just replaced 6 out of our 8 that were a little over 6 years of age. They are still in good shape, and the tire manger did a through inspection and felt I could have gone another season. I elected to replace them, as I had had problems finding young tires in my less popular size in the past, and he had a set that were under 3 months of age.)

Each has their own comfort level, and balance cost against risk.

Best to all, be safe, have fun,
Smitty

J&R wrote:
If you're steers are good, put them on your tag. If you put new steers on, say 5 years, and rotate back to tag. You will only ever have 6 tires to replace. We use our tractor steers, to trailers.

That is exactly what many bus companies do.

bluwtr49 wrote:
Thanks again for the replies and they have been very helpful in clarifying my thoughts.

I really like the thoughts of moving my steer tires to the tag position but I'm not going to use the tag tire in the steer position....I feel the sidewalls are way to stiff. When I get to OR next month I will consult with the local Les Schwab dealer regarding what tires and pressures to run on the tag longer term.

As to why lower the tag axle loading: I do that to balance the fore and aft axle wts. By dropping the tag air pressure it transfers wt from the front axle back to the drive and tag axles. This has a lot of long term benefits especially if the front axle is close to or over the wt limits. This is the purpose for which tag axles are installed. In my case I'm currently running ~12,000 lbs on the front and would like to drop that to about 11,500 or so. Naturally one does not want to go overboard so there is some trial and error involved.

Partially correct. Dropping tag pressure will lower front wt. But, you say it adds wt. to the drive AND tag. Incorrect. Taking pressure out of the tag air bags will also LOWER the wt. the tag is carrying. ALL the added wt from the front and the tag goes on the drives.

Be aware too, that by lowering the wt the tag is carrying, you are much more likely to lock up just the tag tires in a quick stop, flat spotting them.

I have ole good 1972 Prevost, where everything (almost) is mechanical.
I move the tag by manual valve under dashboard, I can change the main axle levels by moving the adjusting switches by hand and so on.
Sure human will forget something faster than computer, but also my stuff still works on original parts (beside air bags) for 44 years.
Found a buyer for old goode and will deliver it this weekend.
Only slight fear is about 10 years old tires.

Mr.Mark wrote:
Kayteg1, so, obviously your tag doesn't automatically lower. Do you get an alarm? I forgot what kind of coach that you have.

Our Dynasty automatically lowered, the new coach gives me an alarm.

MM.

Same here, I can force the tag to stay down but in the auto setting it raises in reverse and (I think) at speeds below 10-15 mph. The problem with keeping it in auto is that it uses a LOT of air and does allow the rear to settle a bit until the pressure builds back. That coupled with a lot of brake use will set off the LP alarm. I almost never raise mine.

Kayteg1, so, obviously your tag doesn't automatically lower. Do you get an alarm? I forgot what kind of coach that you have.

Our Dynasty automatically lowered, the new coach gives me an alarm.

MM.

To drop 500lb from front axle you need to lower tags load by about 3-4000lb.
You can as well drive with them lifted ;)
Sounds like you had your coach on scales, so you know what main axle load is.
My rear tires with tag lifted are not even at 90% of their max load and in fact, once I overlooked lowering the tag and drove almost 100 miles not noticing different driving characteristics.

Thanks again for the replies and they have been very helpful in clarifying my thoughts.

I really like the thoughts of moving my steer tires to the tag position but I'm not going to use the tag tire in the steer position....I feel the sidewalls are way to stiff. When I get to OR next month I will consult with the local Les Schwab dealer regarding what tires and pressures to run on the tag longer term.

As to why lower the tag axle loading: I do that to balance the fore and aft axle wts. By dropping the tag air pressure it transfers wt from the front axle back to the drive and tag axles. This has a lot of long term benefits especially if the front axle is close to or over the wt limits. This is the purpose for which tag axles are installed. In my case I'm currently running ~12,000 lbs on the front and would like to drop that to about 11,500 or so. Naturally one does not want to go overboard so there is some trial and error involved.

WHY are you going to lower the pressure to the tags, reducing the weight they are carrying? Let it carry the weight. Also, as stated, there is a lower limit to air pressure, because they do need a minimum pressure to prevent them from rolling off the bead in a tight turn.