After 2 blowouts - what is the optimum tire pressure?

Wired2Cruze

Wired2Cruze

Member
Jun 11, 2010
122
Central OH
Boat Info
1996 Sundancer 250, Garmin 431S GPS, towed by 2006 Dodge durango
Engines
5.7L Merc w/BravoIII
Hey everyone,
Just got back from our inaugural Lake Erie trip over Memorial Day Weekend, and got to experience the 'wild' side of boating- blowing 2 trailer tires tires on the same trip!

I figure my total weight is somewhere around 8700 lbs (boat,trailer, gas, water, equipment & 2 of us), and I use a WD hitch on my Eagle tandem axle.
I was doing about 55-60 mph on a hot (90F) afternoon, when about 45 min into a 2.5 hour trip the first one blew.
Got it replaced w/the spare, which was about a 45-min exercise, then resumed, but at 45-50 mph. We stopped in Bucyrus (about the 1/2 way point) for dinner and a chance to let the tires cool.
About 10 miles from home we lost the 2nd one ( I could see the smoke as it blew!). Drove 1 mile at 3mph to a well-lighted parking lot, and dropped the boat & trailer.

Got a Goodyear Marathon this morning (ST225/75R15D), which was the same size/rating as the Carlisles I had on the trailer. I should add that the Carlisles were supposedly 3 years old w/500 miles on them, according to the former owner.
I put maybe another 500 on them last year.
I figured I may as well replace the remaining tires, so I got 3 more Goodyears.

The tire guy inflated the tires to 40 psi.
When I asked him what the optimal range was, he said anywhere 40-50, because the tires have a max psi rating of 60.
He said that given the conditions I experienced last nite (hot weather, tire age), tires can expand a max of 10 psi over their cold pressure, so he was cautious.
I should also note that the sticker on my trailer noting the optimal inflation pressure was too faded to read.

So now my question (sorry for the lengthy intro):

What is the optimal tire pressure for my rig, given the weight & tire ratings?

I feel 40 is a little low, but ok for just around here, we boat maybe 10 miles from our home. I'm leaning toward 45-50, thinking they would wear better.
Maybe I should keep them 50 for around home, then deflate to 45 for summer road trips?

What do you guys suggest?
Anybody have experience with under/over inflation?
 
I am generally 5 under on mine when cold. I check them after they heat up and adjust the pressure to the max psi. I blew two carlisles on the same trip one time, and have blown a goodyear on my 28 foot enclosed car trailer. I now carry two spares and have gone away from trailer tires. I am running E rated class truck tires and have not had a blowout since with Firestones.
 
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The max load for tires requires the max air pressure. So I always max out my tire pressure on all of my vehicles/ Trailers. I would have to check but I think I have the same Goodyear tires as you and I max them out at 60 PSI and never had a problem with blowing a tire yet. I put about 2000 miles on my tires each year.
 
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I agree...... max pressure for max load. I've never had a problem with a tire while fully inflated provided I don't do anything dumb like curb a tire, etc.

I've been told by racers who have been trailering much longer than I have and who are also tire experts that the correct approach is to fill to the max pressure rating when the tire is cold (has not been used for a while). Any heat will distort your readings and you won't reach optimal pressure. More pressure = less rolling resistance/flex = less heat. I still monitor temps to ensure I'm doing ok but generally I'm more concerned with brake temps, am I cooking hubs, etc.

Also, when I had my 230....... I killed a ton of Carlisles. Was not impressed by that tire. I'd steer clear of them if you can.

Good luck, at least you blew tires out and not mono-leaf leaf springs like I did one night (which also cooked a tire). Much easier to change a spare tire in a parking lot than swapping your whole trailer suspension ;-).
 
Low tire pressure creates heat and failures. Always run at max psi on trailer tires. I have only had one blowout and that was on a 15 year old trailer tire because of dry rotten sidewall. I use goodyear marathons from tirerack.com.....my Sea Ray trailer is running E load rating at 80psi, Mike.
 
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Wired, as others suggest, running the tires at max psi (50#) is where you need to be. The mechanic that told you he put tham at 40 to allow for the heat evidently doesn't understand that tire ratings are always in PSI cold. They are engineered to allow for the higher PSI that occurs when running. And yes underinflation will lead to overheating and blowouts when loaded up with the weight. From my own personall experience the Carlisle tires are junk. I've switched over to Goodyear Marathons without a single issue. I have over 60k miles now on my trailer in 4 seasons. You can read more about the long hauls and tire issues here http://clubsearay.com/showthread.php/29312-Another-eventfull-haul-from-MA-to-FL-done.
 
andy k said:
The max load for tires requires the max air pressure. So I always max out my tire pressure on all of my vehicles/ Trailers. I would have to check but I think I have the same Goodyear tires as you and I max them out at 60 PSI and never had a problem with blowing a tire yet. I put about 2000 miles on my tires each year.
Click to expand...

Just hauled my 350 Sundancer 1100 miles on Firestone E rated trailer tires rated for 60 PSI. Filled them to 60 cold and had no issues over the 2 days it took to complete the trip.
 
Sometimes crap happens and you can't always figure out a reason why, but...

Could anything else have caused them to blow? Nails, etc? Are the two axles aligned? Did you hit any potholes?

Yes, put them right to the max (cold) and be done with it. Every trailer that goes out of our shop has it's tires at max.
 
I work for a divison of Carlisle. I have been told by our tire and wheel company to always run max cold air pressure. As for tire manufactures all Goodyear, Firestone and Carlisle run pretty much the same rubber formulas.

With that being said you could have an alignment problem or a bad bearing. A good rule of thumb is when you stop to gas up etc. You should check wheel temp by feel. You may want to keep an eye on it.
 
Take this for what it's worth. Being in the RV biz, I see all these cheapo Chinese tires blowing out with just a couple hundred miles on them here in this heat. Carlisle went to crap and Marathons are right there with them. In the 15" range the best we have found are the Maxxis load range E, and the top of the line Hercules. I do not have experience with the Firestone. In the 16" size the Michelin LTX RIB is hands down the longest lasting tire on our 28' triple axle stacker toy hauler trailers that gross 20k lbs.

We have also found it best to run the max air pressure when fully loaded. CIP (cold inflation pressure) is set at 65 degrees F. General rule of thumb is for every 5 degrees rise add 1lb of air. But be cautious of the rim max pressure.
 
Ditto on the max cold air pressure, we also carry a hand held infrared thermometer and check the temp on the tires and hubs whenever we stop. It's a pretty inexpensive tool to carry, and it's quick and easy to see if you have any heat issues with the tires or wheel bearings
 
I was always told that low tire pressure can cause the tires to heat up and blow.

Is your trailer towing level? (didn't see this is your op) Not being level causes majority of blowouts.
 
I blow both of my carlisles out on the same return trip from Keowee last year. Blew right through the tread that still had 85% on them. No side wall damage at all.
Went to HD truck tires for this year.
 
Thanks everybody for your comments.
It looks like inflating them cold to the max pressure is the way to go. Makes sense to me about decreasing resistance, I'm thinking the tire store is more tuned to automotive applications and just doesn't have experience with trailering. I actually had to tell the guy to chock the opposite wheels on my trailer, since I had unhooked it from my truck!

As far as the trailer being level, I'm assuming that means as in the boat is centered on the trailer side-to-side?
I always spend a lot of time getting it right when pulling it out of the water, as placement has to be exact in order for it to ride level. I have a mark on the winch that lines up with the little metal 'scoops' near the boweye. Having this off by more than 1/4" means having to adjust it again, as it translates into the boat resting cock-eyed on the trailer. I measure the distance between boat bottom and fender top on each side to be sure.

If we're talking about under-inflated tires on one side, I don't think this was the case either, as I blew the right front and left rear, in that order!

As far as the axle alignment question, I'm not sure what that means. Does that mean they track one exactly behind the other, or does that mean one side is higher than the other?
I could sight by eye for tracking, and use a level on each fender, but I'm really not sure what I should be looking for here...

Lastly, Midtown, that 's an excellent idea about the infrared thermometer; I do have one. Do you know offhand what the acceptable temperature range is for tires, e.g., no more than 1.5 times the air temperature?
 
regarding level I mean that that the trailer should be nearly level when connected to the tow vehicle on flat ground. If trailer tongue is too low you get more weight on the front tires, if trailer tongue is too high you get more weight on the rear tires.
 
I like to keep my tires in the 110-120 degree temperature range. Here in Oklahoma the ambient air temperature fluctuates quite a bit. It can rise and fall 30 degrees or more in the summer. 70 to 80 degree mornings to 100 to 110 degree evenings. Its hard to get a true cold temp setting on the tires. My E rated tires have a max of 80 psi cold. I am not at the max of my tires so checking the temp and watching them for bounce around pot holes and speed bumps helps me get a good feel for the required pressure. I used to always have the tires on the recomended cold pressure but still kept blowing them. Once I moved to a different tire and watched the way they heated up and reacted with the road I stopped blowing them. And like Wish2fish mentioned, make sure your trailer is level from front to rear by having the correct tow bar if you have dual or triple axles. The pic below was towards the end of a 500 mile one way trip with the Formula, It was a white knuckle trip through a few good storms and hail...

DCP_2057.jpg
 
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Alignment: Making sure each axle is perpendicular to the centerline of the frame. A quick way is to measure from the rear of the frame to the center of each axle (near the shackles that hold the axle). The numbers should be the same from left side to right side. 1/4" or 1/2" off... I doubt that would matter.

This could just be a coincidence that it happened, too. Maybe the tires were actually older than you thought? Did you happen to check the date code?
 
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Thanks for the clarifications, Wish, Prater, & LazyDaze.
I will have to make those measurements for level & alignment this weekend.
I think it looks pretty level by sight, especially since I'm using a WD hitch, and my vehicle is rated for 9250 lbs (using the WD hitch).

Also, the roads are not too bad, I don't recall hitting any potholes or anything, and I was doing about 45-50 mph for the second 1/2 of the trip.

I did not check the date code on the tires, though I noticed they had decent amount of tread remaining.
This whole thing was a rush job, as I had to take time off work to go get one tire so I could move the boat & trailer out of a business' small lot where I was blocking customer parking.

I've heard some comments on this forum regarding Carlisle tires, apparently I'm not the first to have bad experience with them. The fact that 2 failed on the same 140-mile trip makes me think they were somewhat older than the 3 years I was told.

Anyhow, they're on their way to becoming rubber floor mats, and at least I have a limited warranty on my new tires.
I'm planning several more trips to Erie this summer, so I'm hoping this was an isolated incident, so I can get on to more important issues like which "North Coast" marinas the wife & I prefer for our stays up there.:smt001
 
Nice pooch, Randy!

Another thing that I forgot to mention... Did you happen to notice if there was any dry rot or cracking (sidewalls or between the tread)?

Have you looked into getting an extended swim platform? The 250 is a really nice boat, but navigating the platform (especially with the canvas up) can be a little sketchy since the seat back protrudes.
 
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