Aspire Tire Pressure After Individual Weighing

[96 Wideglide]

I'm gona guess his tow car !

[Curtisgeiger]

I put the other four on my trailer.

[brobox]

Originally Posted by Whatnobeer

Hi Curt...I know the coach has 8 tires so where do you strategically put the other four? I know there would be a purpose for this. Sorry to hi-jack but I was just curious.

On his trailer or towed vehicle. They need to be monitored as well.

[ShadowBolt]

Originally Posted by brobox

On his trailer or towed vehicle. They need to be monitored as well.

I'm sorry for the hijack but I use four sensors on the race car trailer then move them to the jeep Commander when we pull it as a toad. I can tell you this company (Truck System Technologies) is as good at customer service as Entegra. GREAT service.


JJ

[Marcosdad]

Originally Posted by Whatnobeer

Hi Curt...I know the coach has 8 tires so where do you strategically put the other four? I know there would be a purpose for this. Sorry to hi-jack but I was just curious.

I'm jumping in here, but the additional sensors go on the towed.

[Whatnobeer]

I feel foolish.

[Saltydog44]

X2 on TST customer service

[Kuppajoe]

Originally Posted by DSL417

Big Mike at Spartan said if the weight difference is less than 1000# on each axle, you're good to go, and 1500# wasn't that bad (although 1500, JMHO, that seems high and you might be able to adjust your loading). Mike then offered, choose the higher tire pressure associated with the weight.

You underscore the point that axle weight is not giving you enough information. You could mistakenly set tire pressures five or ten psi too low on one side--particularly if the weight difference is 1500 lbs side to side on a particular axle.

[jadatis]

Originally Posted by Kuppajoe

This thread has drifted a bit from my original post so I am requoting the point. I did get individual weights of each wheel at Josam's Alignment in Orlando. Based on those weights and the posted on-line pressures shown for Goodyear G670 RV tires, I came up with 110 psi for the front tires and 90 psi for all six back tires. My point is that the on-line chart shows the minimum inflation for the 275/80/22.5 to be 90 psi--no less--regardless of weight. For anyone interested, the heaviest side of the front axle was 7100 lbs, the heaviest drive axle side weight was 9000 lbs. and the heaviest tag axle side weight was 4200 lbs. The heaviest front side was on the driver corner and the back two axle sides on the passenger side were the heaviest. The side to side difference on any axle did not exceed 650 lbs. which is acceptable (I am told). Since the kitchen and washer/dryer are on the back passenger side, the weight difference makes sense and since the propane tank is just behind the driver front tire, the weight difference there seems logical.

If you can give the other weights and the loadkind of tire ( G load is 110 psi for instance) I can put it in my pressure calculator and it also gives information about loadifference.

The crossed weight differences is a thing you often see for motorhomes.
Can also be courced by heavy things behind the rear axles out of the middle.
But the weightdifference must be seen as a percentage of the total axle load, so for high loads the weighdiffences are allowed higher.

The 90 minimum is because the calculation of the tire-makers gets to much off from the to natural laws right calculation. If you use the right formula you can even go as low as 20 % of the pressure belonging to the tire, thoug thats never needed.
I made extra save pressure/loadcapacity-lists with to my opinion the formula that comes closest to the ever to be constructed ideal formula, mayby a bit pessimistic even. Can be found in this map on my public map of skydrive.
https://skydrive.live.com/?cid=a526e...E092E6DC%21904
Open the USA map and search for the maxloadpressure belonging to your tire, wich is not the maximum pressure.
Then you can use per tire/per axle single or dual so you dont have to do the division yourselfes.
Open that PDF and search for the maximum load in first row and then the load you want to know it for and read the needed pressure above or below that .
Best is to add 10% to the weighed loads first .

But you can also use my calculator in next map on that same drive.
https://skydrive.live.com/?cid=a526e0eee092e6dc#cid=A526E0EEE092E6DC&id=A526 E0EEE092E6DC%21793
First download the newest version by Rightclicking and then choose download. After download open in Excell or Open office CALC on your computer.

[Alan JS]

[QUOTE="azbuzzard;1707597"]After weighing we run. Front 110 PSI Drive 90 PSI Tag 90 PSI[/QUOTE





The last trip to Spartan authorized dealer showed me how little perspective they have on MH. They merely looked at the tire sidewall and determined I needed 120 psi all around. No axle weights, nothing. Kind of surprised me that a diesel shop had no scales. Well I drove the Aspire back to storage down the turnpike and nearly rattled my fillings out. Felt like driving cement truck on cement. Bounced terribly and made no sense to me. I would love to get some actual weights but that may have to await trip back to Orlando Prior to leaving on our trip to Okeechobee based on consensus of posts I dropped front end with Goodyear 295's to 110 psi, drive axle with 275 s to 95 psi and tag to 90 psi. I think it feels close and handles nicely. Perhaps I might bump front end up to 115 if it feels like it wanders at all. Having 120 all around just seemed like too much stress on wheels and tires at highway speeds and extremely uncomfortable. It is moderate temp here in Florida now around 70 so doubt it will heat up much. Does anyone know why tag is higher or lower than drive axle?

[Sky_Boss]

Originally Posted by Alan JS

The last trip to Spartan authorized dealer showed me how little perspective they have on MH. They merely looked at the tire sidewall and determined I needed 120 psi all around. ...

I had a similar thing happen when I bought my DSDP in January and got 8 new tires. I wasn't smart enough to think ahead and check tire pressures. DUMB ME! I ASSUMED they would use the recommended tire pressures in the tire sticker by the driver's seat. Talk about ballooning down the road! (OH...I guess it wasn't that bad compared to the 39' gasser I just traded in. )

If you don't have corner weights then using the tire sticker next to the driver's seat is the best place to start. Generally your steer tires will be have the most PSI because of being single and carry a lot of weight. The drive wheels will be next because they carry the most actual weight but because of being duals will use less pressure. Tag wheels always carry the least weight and thus less pressure. In fact, often the tag wheel (and sometimes the drive wheels when a tag is present) will require use of the minimum tire pressure for the tire because the actual weight they carry is below the loading charts.

Remember that tire pressure is set COLD! If they sit in the sun or are driven more than a mile, they are NOT cold. I always try to do mine in the evening before a trip if I expect sunny skies.

[Alan JS]

Originally Posted by Sky_Boss

I had a similar thing happen when I bought my DSDP in January and got 8 new tires. I wasn't smart enough to think ahead and check tire pressures. DUMB ME! I ASSUMED they would use the recommended tire pressures in the tire sticker by the driver's seat. Talk about ballooning down the road! (OH...I guess it wasn't that bad compared to the 39' gasser I just traded in. ) If you don't have corner weights then using the tire sticker next to the driver's seat is the best place to start. Generally your steer tires will be have the most PSI because of being single and carry a lot of weight. The drive wheels will be next because they carry the most actual weight but because of being duals will use less pressure. Tag wheels always carry the least weight and thus less pressure. In fact, often the tag wheel (and sometimes the drive wheels when a tag is present) will require use of the minimum tire pressure for the tire because the actual weight they carry is below the loading charts. Remember that tire pressure is set COLD! If they sit in the sun or are driven more than a mile, they are NOT cold. I always try to do mine in the evening before a trip if I expect sunny skies.

As an update, we have taken numerous semi cold weather trips since last November. Trying to keep weight centered at each trip but not perfect.
On our Aspire we have placed 115 psi on steer tires, 95 in each of the four drive tires and 90 in the two tags.
It drives like a dream. Smooth as silk without any special or fancy suspension add on.
We experimented with changes of 5 psi here or there but always the ride suffered.

[Sky_Boss]

Originally Posted by Alan JS

As an update, we have taken numerous semi cold weather trips since last November. Trying to keep weight centered at each trip but not perfect.
On our Aspire we have placed 115 psi on steer tires, 95 in each of the four drive tires and 90 in the two tags.
It drives like a dream. Smooth as silk without any special or fancy suspension add on.
We experimented with changes of 5 psi here or there but always the ride suffered.

Those number are pretty close to what I use. Per tire inflation charts I should use 112 front, 78 driver & 75 tag. At the minimum, the tag is "over inflated" per the weight it holds but the minimum is 75. With those numbers I actually use 115/85/75. I add extra PSI to the drive to make them carry a bit more to help them stay rounder. The idea is to use the drive wheels like fulcrum and let the rear of the coach unload a bit of weight on the front.

Glad you got it all sorted out.