Tire Pressure

[KathyandDave]

This turned out to be lengthy, so grab a coffee...
I'm trying to figure out the optimal inflation pressures for the TV and the trailer. We know that we are not at the maximum rating for the duallies. It's a challenge! So, after much searching...Eureka, I've got it!

For the TV, we have General Ameritrac tires LT215/85R16E. The General website gives no info, except maximums. The plaque on the TV door says that, for the rear axle, the maximum cold pressure is 65lbs., the rated maximum load is 3720kg (8200lbs). Our weighed rear axle with trailer = 3300kg (weighed on an Ontario MTO scale when the officers were not present) = 7273lbs, so each of four tires of duallies = 1818lbs. In the Goodyear http://www.goodyear.com/truck/pdf/pr...Brochure_P.pdf, we find the line for the Goodyear equivalent of our tires and we see that the recommended inflation pressure is between 50 and 55 lbs. A similar exercise for the trailer tires and the TV front tires.

To inflate to the maximum would mean that we are over-inflated, resulting in many deficiencies, including poor traction.

Can I safely transfer Goodyear data to General tires? I think my next tires will be Goodyear or other manufacturer who offers good engineering info!

Places to look at tire info: Tirerack.com (many clear articles), Wikipedia (shows entire load index table and lots more), carbibles.com/tyre_bible.html

One thing that the tyre bible guy emphasizes and other material (including MOC tire guide) hints at is that you MUST replace your tires every five or six years, no matter what, because the rubber compound deteriorates with time, not with usage. When buying a tire, look at its DOT manufacture date number. Some tire shops keep stock on the shelf until it sells, so you may be buying a tire that is already past its stale date!

Cold pressure is measured at 65 degrees F. Offset +1 PSI per 10 degrees colder. There's a rule of thumb for temperate climates to offset -2 PSI for reading in the afternoon, -4 for recent driving, -6 for recent long-haul driving. Do this agree with what the Pressure Pro and other units show?

[Delaine and Lindy]

I suggest you get a Pressure Pro system, it will save you money. As for tire pressure I always run my Truck tires for what the sticker says on the door jam. The 5th wheel calls for 110 lbs and thats what I run. And with the Pressure Pro system your tire pressure is at you finger tips. Keep in mind our 5th wheel (SOB) is heavy. Good Luck... GBY....

www.PressureProSystem.com

Talk to Mike or Pat they are very Professional and full timing.

[richfaa]

We had a very good seminar at the Fall rally by Goodyear Tire.These guys build tires so should know a bit more about them than the average person. My tires on my 08 Ford are OEM BF Goodrich, Rugged Trial T/A LT 245-75R/R17/121/118B-M&S. The sticker on the door says
Front GAWR 6K 75psi cold Rear GAWR 9K 60 PSI cold dual.

Those tires can be on different brand trucks of multiple configurations. Goodyear tire said to pressure your tires as recommended by the manufacturer..I figure the folks who build tires and the folks who build trucks understand what pressure should be in the tires on my truck..so that is where I pressure them...We also have the pressure pro system.

[PatMcFall]

Thanks Jack & Terry and Delaine & Lindy for your support and kind words. As we've said many times, we are available 7 days a week for questions or assistance. We may not be the cheapest TPMS on the market, but the PressurePro System has a proven record and will stand behind their product.

If we can answer any questions or be of assistance, please give us a call.

Pat and Mike
850-294-0281

[garyka]

How difficult is it to add or remove air on the tv dually's with the pressure-pro caps on?I'm getting the pressure-pro system before heading south in a couple of months.

[richfaa]

The pressure pro system that we have(purchased over two years ago) does not measure tire temp.I think that would be a handy feature. The pressure pro does monitor pressure and the increase in pressure is caused by heat so a increase in pressure means a increase in tire temp.On the tires we run I know that if I would see a pressure of much over 90 I would be pulling over and checking.

[KathyandDave]

I AM looking for the manufacturer's recommendations. My previous post was a brain dump. Here's the short form...
The pressure given on the truck door or on the trailer is the maximum, corresponding to the GAWR and GVWR. Goodyear publishes a chart of recommended tire pressures for various lesser loads for the truck tires and the trailer tires (see http://www.goodyear.com/rv/pdf/rvbrochure.pdf , also shown on the splash page of this forum). If we had Goodyear tires, then I would just follow the chart - which ARE the manufacturer's recommendations. However, we have General Tires. General does not publish a chart of recommendations, just a bunch of warnings not to over-inflate for the load. I have sent their customer service department a request for recommendations. I'll post their response.

[ols1932]

There are some who swear by the systems that measure temperature. My question is, "So if the temperature is high (or seemingly high to me) what do I do? Do I stop traveling until they cool down? There is a natural heating of the tire even in cold weather, just not as high as traveling in 100° temps. I firmly believe that if the manufacturers place a "full load" pressure indication on the tire when cold, they have taken into consideration the pressure and heat buildup during travel. I also believe that having a system that gives a pressure readout is very handy in letting you know when the pressure is dropping. Isn't that what we're primarily interested in?

Orv

[PatMcFall]

quote:Originally posted by garyka

How difficult is it to add or remove air on the tv dually's with the pressure-pro caps on?I'm getting the pressure-pro system before heading south in a couple of months.

Hi Gary,

It is no more difficult to add or remove air with the PressurePro Sensor on than it is with a regular valve cap on. You just unscrew the Sensor, add or remove air, and screw the Sensor back on. You need to leave the Sensor off for at least a minute before screwing it back on (it can be off 10 minutes, an hour or several days) but no less than a minute. When you screw it back on, that will reset the base pressure.

FYI(and others on the forum), the updated version of PressurePro does not monitor temperature but it does monitor "High Pressure". It alerts at a determined percentage (24% set by the factory) over the initial "base pressure" at installation but can be set at different percentages by the customer. A tire location with a high pressure alert will flash it's pressure and position while the alert sounds. This could be a good indication of a brake dragging or bearings overheating.

I hope this answers your question. If we can be of further assistance, please give us a call.

Safe Travels,

Pat and Mike

PS: We are at the HDT Rally in Hutchinson, KS. One of your fellow Montana Owners is here at the Rally....Robb & Carole Isaacs. They also bought one of our PressurePro Systems way back in 2005.

[av2pilot]

Picked up the Pressure Pro from Pat while I was in Colorado (after blowing 1 mission tire with the other VERY close!). On our way back to Florida now and I feel ALOT better KNOWING the tires are still good! I also bought the repeater since I have a swivel wheel trailer and monitor it too. I HIGHLY recommend it!