Tire Pressures and Temperatures

[Axion]

I am in the process of installing an active tire pressure and temperature monitor. It is made by Dakota Digital and is based on a SmarTire system.



It has user programmable alerts for both low pressure and high temperature. I was wondering what sort of a range I should use for both measurements. I run my truck tires and the trailer tires at 60 psi. I was thinking a low pressure alert between 55 and 57 would probably work. I have no idea about temperature. Since my trailer tires are 15" ST's I am limited to 65 mph and can only guess at what a normal temperature should be. And if the normal temp is say 115F would you set the temperature alert to be 5 or 10 degrees higher?



Any help would be greatly appreciated.

 

[EricBu12]

If you are able to program the low pressure and high temp, then go for 20% lower than your cold pressure. if I gets dow to there then the alarm goes off. the tire will go up about 5 psi when traveling. . don't know on temp. I have a system that screws on the stem and works good. my 70 psi cold tires go to 77 on my 3 axle trailer. get a infra red thermal gun to find out how hot they are when you stop. it don't hurt to overinflate 5 psi cold to help the temp and pressure.

 

[jelag]

I don't have the exact number, but I remember reading that you can have 10-15% of pressure increase during heat up from cold pressure... .

I'm not too sure that I'd be worried about the high end as much as I'd be worried about the low end... . I'd read the suggested pressure from the side wall of the tire and would set the low end for about 15% below max pressure... .

I have this system on my 05 Jeep, its factory installed and includes the spare... I'm surprised how good it works... .

 

[J.BURCHFIELD]

Tires for trailer only use are purposely engineered to fly apart after 5 years no matter how little they have been used. I learned this the hard way, from experience. The industry wants to sell tires. They make sure you buy more even when you do not use them by building them to disintegrate at aprox 5 years. The longest guarantee available is 4 years. Trailer tires as you might suspect are made in China. Some passenger car tires are too. Good Year is made in China. Tire shops will not instal a better tire on a trailer. They will sell them to you and you can put them on yourself. Sounds like a conspiracy to me.

 

[Axion]

I can indeed set my warning levels. Pressure is a low alarm that I can adjust in 1 psi increments. Temperature is a high alarm in 1 degree increments. I currently have the psi set at 3 psi lower than my cold inflation pressure. I guess I'll just have to play with the temperature.



I have had two blowouts on my trailer to date. Considering I've only had the rv for 6 months, I was somewhat concerned. I am hoping the monitor system will help. The first blowout may have been caused by road debris but none was found so I'll never know for sure. I'm told I would have seen the pressure drop before the temp went up and blew the tire, no damage to the trailer. The second was almost like the tire was a retread, about 30% of the tread just let go. The tire still had pressure, the tread ripped a bunch of stuff out of the bottom of the trailer. Again, I was told I would have probably seen a temperature increase before the tread let go.



The original tires were Greenball Tow Master V's, never again on a trailer I own. I replaced them with Goodyear Marathons. I hear the Goodyears are made in China as well but at least they have a better national warranty program. I wanted Michelin XPS Ribs but they are not made for 15" rims and I just could not afford to upgrade rims and all tires at once. If I continue to have problems with the Goodyears, I think it will be more than coincidence!



Thanks for all the input everyone. I'll update this thread once everything is installed and I get some numbers.

 

[rweis]

I run SmarTIre system on the truck and the RV.



I had a blowout with the SmarTire system and it gave no indication that the pressure was failing or the temps were excessive.



The OAT of the day was hot (105*) and I had slowed from 65 to 55 for about 30 minutes because the tire temps were starting to get into the 140*'s and they had cooled to about the high 120's (127*) and the tire blew.



The tire had almost 5 years on it, good tread, no obvious signs of weakness.



I replace all tires every 4 years now (see manufacturer comments by others above).



No road debris, smooth Interstate, pretty hot day, had just about finished up a 3000 mile trip. Very obvious what happened by the sound, SmarTire reported it immediately (it did not damage the SmarTire transmitter).



Simple change because I was ready and prepared.



Bob Weis

 

[SnoKing]

I can indeed set my warning levels. Pressure is a low alarm that I can adjust in 1 psi increments. Temperature is a high alarm in 1 degree increments. I currently have the psi set at 3 psi lower than my cold inflation pressure. I guess I'll just have to play with the temperature.



I have had two blowouts on my trailer to date. Considering I've only had the rv for 6 months, I was somewhat concerned. I am hoping the monitor system will help. The first blowout may have been caused by road debris but none was found so I'll never know for sure. I'm told I would have seen the pressure drop before the temp went up and blew the tire, no damage to the trailer. The second was almost like the tire was a retread, about 30% of the tread just let go. The tire still had pressure, the tread ripped a bunch of stuff out of the bottom of the trailer. Again, I was told I would have probably seen a temperature increase before the tread let go.



The original tires were Greenball Tow Master V's, never again on a trailer I own. I replaced them with Goodyear Marathons. I hear the Goodyears are made in China as well but at least they have a better national warranty program. I wanted Michelin XPS Ribs but they are not made for 15" rims and I just could not afford to upgrade rims and all tires at once. If I continue to have problems with the Goodyears, I think it will be more than coincidence!



Thanks for all the input everyone. I'll update this thread once everything is installed and I get some numbers.

Sorry to be the one to tell you this, but if you read the RV.net info the new GY Marathons from China are like chinese fireworks. You should have just spent the money that you put into the monitoring system on the wheels and the Michelin RIBs.



I do not believe that a monitoring system is going to tell you anything ahead of time when a tire has a sudden catastrophic failure.



Junk tires are just that, junk tires. And ST tires are junk, that do not have to meet any government standards.



SNOKING

 

[Matt42]

I can indeed set my warning levels. Pressure is a low alarm that I can adjust in 1 psi increments. Temperature is a high alarm in 1 degree increments. I currently have the psi set at 3 psi lower than my cold inflation pressure. I guess I'll just have to play with the temperature.



I have had two blowouts on my trailer to date. Considering I've only had the rv for 6 months, I was somewhat concerned. I am hoping the monitor system will help. The first blowout may have been caused by road debris but none was found so I'll never know for sure. I'm told I would have seen the pressure drop before the temp went up and blew the tire, no damage to the trailer. The second was almost like the tire was a retread, about 30% of the tread just let go. The tire still had pressure, the tread ripped a bunch of stuff out of the bottom of the trailer. Again, I was told I would have probably seen a temperature increase before the tread let go.



The original tires were Greenball Tow Master V's, never again on a trailer I own. I replaced them with Goodyear Marathons. I hear the Goodyears are made in China as well but at least they have a better national warranty program. I wanted Michelin XPS Ribs but they are not made for 15" rims and I just could not afford to upgrade rims and all tires at once. If I continue to have problems with the Goodyears, I think it will be more than coincidence!



Thanks for all the input everyone. I'll update this thread once everything is installed and I get some numbers.

Tire pressure and temperature are an issue where I live and tow. The ambient air temperature is very frequently higher than 115F, so a 115F temperature warning threshold here isn't useful. I've towed in temperatures as high as 130F, indicated by the truck's thermometer, and the one on the outside of our TT. That was the outside upper-end extreme, but it's common for us to tow at temperatures in excess of 118F. Road surface temperatures are higher still, and tire heat buildup can be scary.



That said, we replaced the ST205/75R15 load range C trailer tires with Michelin LTX LT215/75R15 load range C truck tires. The difference was difficult to describe, but utterly amazing. Much less heat buildup (based on the palm-of-hand method), less sensitivity to crosswinds and 18 wheeler bow waves. We may have picked up some fuel economy, but I can't say for sure. The Michelin tires are slightly wider and about 1/2 inch larger in diameter. Space will be an issue in a tight wheel well. The tire dealer had no qualms about installing them on my TT. They do a lot of that kind of swap here, due to the heat.



The LTX tires aren't as heavy-duty as the XPS Rib tires. They are quite satisfactory, though. (I use XPS Rib tires on an equipment trailer. )

 

[klenger]

I did some research on this a while back, and determined that a good rule of thumb was 1 lb increase in tire pressure for every 10° F temperature rise. Don't ask me where I found this as I have CRS.

 

[Matt42]

I did some research on this a while back, and determined that a good rule of thumb was 1 lb increase in tire pressure for every 10° F temperature rise. Don't ask me where I found this as I have CRS.

That comes pretty close to matching my observed experience.

 

[Axion]

Bob;



Thanks for the temps. Now I have somewhere to start.



Snoking;



I had already ordered the monitoring system before I blew the second tire and ended up replacing all four tires. With hind sight being 20/20 I guess you're right I should have just upgraded at the time. Timing was also an issue, I blew the second tire right at the beginning of my trek to SW Colorado for work. I did not have the luxury of waiting for tires and rims to be ordered in. Everyday I sat was costing me work. I think its kind of like voting for a politician; you just have to pick the best of a bad lot! I have heard some people recommend replacing trailer tires every 2 years regardless of condition. When the time for replacement comes, I will have all new 16" XPS Ribs waiting.

 

[Matt42]

Bob;



-snip- When the time for replacement comes, I will have all new 16" XPS Ribs waiting.

That will probably be the end of your problems. Well, trailer tire problems. :-laf