Constantly blowing tires

[BuickTurbo]

We have a 52' race trailer with 2 sw tandems. It was designed for a single dragster and all of the nice features like a bathroom, toolchests and such.

We gutted it and now haul two 2700 lb cars.
The tires are 12R 22.5 - as I understand are usually used on busses and firetrucks. The trailer weighs about 25k dry, so about 36k loaded.
Pressures are set at 120 psi every morning at pre-trip and I see an average of 140-150 psi hot.

This company has had issues with this trailer blowing rubber way before I signed on. I thought it was wierd and due to lack of maintenance....until I took over. Had a blowout in Atlanta a couple of days ago, and now I see another tire starting to split.

The trailer is rated at 40K , the tires I believe to be rated at around 7390 lbs each.

So the tires allow about 30k total, my guess is it's overweight. Is 6K lbs enough to constantly blow rubber?

[Double L]

Are they recaps or virgins? If they are recaps then the heat is their worst enemy cause them to blow if too hot. Especially in the summer in extreme hot weather such as Texas or the southwest. With recaps if they get too hot they expand and the tread starts to peel and will eventually blow. That is why with recaps you should stop and let them cool but also with recaps they don't like to go any faster than 65 I think. Feel free to correct me if I'm wrong, it's been awhile since I talked about a mississippi tennis shoe (recap).

[Bobby]

That's a long trailer for only two axels IMO.
If your overloading those tire by that much that's the problem. Pull into the truck scales and they won't let you leave.

You have a liability to think about too, if their is a wreck because of a blow out and they find the trailer to be overloaded, They will throw the book at you.

[Bobby]

That's a long trailer for only two axels IMO.
If your overloading those tire by that much that's the problem. Pull into the truck scales and they won't let you leave.

You have a liability to think about too, if their is a wreck because of a blow out and they find the trailer to be overloaded, They will throw the book at you.

Edit: Is this a fifth wheel trailer ?

[Bobby]

Check the tire ratings and weigh it loaded to see what you have on them, then stay within their limits.
You can go to a heavier tire and rim if a bit wider tire isn't an issue.

If the tires are within their limits, check to see how old they are by the DOT code on the sidewall.

The last two digits will be the year of Mfg. and the two digits before that the week of that year.

It seems to me a 1200 22.5 rates higher than 7,320. ??

[BuickTurbo]

each tire's load rating is 7390.
Here's a newb question.
Is it best practice to bleed the tires back down to cold pressure after a couple of hours driving?

I have been through the scales in several states without issue. I guess for now I will back down to 65 for safety's sake. Believe me I don't mind being the slower truck.

I have been told that the tires on the trailer were bought new, but I dissagree. I will have virgin rubber before the next trip (Sunday).

I also have been informed that new tires had been put on before and she still lost one.

I sincerely appreciate the replies guys. My concern is the driving public as I am not hauling commodity.

yes, this is a fith wheel pulled by a Pete 387

[Bobby]

If the tires are running single @ 7,390 ratings and your hauling heavier by quite abit then that would be the problem IMO.

And no don't drop the pressure. You shoudn't have to worry about these tires failing.

My guess is they are old rubber, older than five years. Or you are overloading them. Even when you buy them new if they have been sitting along time in the tire shop, they still age.

Go to a private scale and see just what's on them. If your say 36000 lbs alot of that weight should be on the truck. But maybe the way the trailer is loaded there is too much weight on the trailer axels.

Edit: when you go to a private scale, weight the whole truck, pull forward then weigh the back axels on the trailer pull forward again and see what's on the farthest back axel only on the trailer.
And, or ? just weight the front axel on the truck if your curious.

[BuickTurbo]

Again, thanks for the help, advice, and comments.

One of the cars is directly on top of the drive axles of the tractor.
The other sits on top of the rear axles, but the weight of the car is in the rear.

This orientation was changed by me as the cars were then before placed on top of the rear trailer axles - one on top of the other. At one time both cars were on the upper rear deck......unacceptable to me as the trailer is fairly narrow and tall. So I changed it to over the tractor and over axles to spread it out.
We don't have all that much gear on board. A couple of tool boxes, pit stand (1000lbs), golf cart, and 5 small motorscooters.

[Bobby]

Maybe your close to solving the problem with the weight re-arranged.

I'll bet the tires were old even thought they had lot's of tread.

What kind of racing are you doing ?

[BuickTurbo]

http://www.ferrarichallenge.com/

We have 3 F430's in our camp. The field is about 40 cars. I haul 2 and the other driver had his own custom truck and trailer built. I will link you to some picks of the trucks side by side.

I hope we are figuring it out. I have two brand new tires coming tomorrow. This will make a complete set of new rubber.

Another thing we figured out is that the wheel wells on this particular trailer act like ovens - not a whole lotta flow through there being a single wheel. So I am going to make some intake ducts over the top of the wells to force air over the wheel assembly. I'm going to use our tire pyrometer and measure temps along the drive to Sonoma. I will close the vent and drive for an hour or so, record temps, open them up and do it again. This finally may be the culprit.

[Double L]

I wish you the best of luck!

[Bobby]

Yes, an enclosed tire with the lack of air flow isn't good. You might be able to do some research on acceptable tire temps for this type tire and load.

Isn't your Buick a V6 ?

[BuickTurbo]

http://www.texasstreetcars.com/viewtopic.php?t=953

Here's the link.

I have been trying to rebuild and refurbish that trailer since I hired on. We have a tight budget if you can fathom that. I can only do so much as the season is busy for me. Once in the off-season, she will be done right.

The red trailer is completely decked out in stainless inside. Satellite tv, internet, and streaming race data from the car. It also has an office inside.

It's pretty, but it only holds 2 cars.....mine holds 4 and we're there to race.


Yep....just a little V6.

[solo379]

Is it best practice to bleed the tires back down to cold pressure after a couple of hours driving?

Yes,..... if you want it to keep blowing. :wink:
Rated pressure, is the cold pressure only! You might need some readjustment tho, when seasonal temperature is changing (winter- summer).

[BuickTurbo]

Yeah...about the bleeding.

I contacted my old shop foreman and he read me the riot act about not touching a hot tire, unless it needed air after a cool down.

I was just curious as we do hot tire bleeding on our racecars. I KNOW...two completely different animals.

[special k]

I run 12/80R22.5's on my trailer singled out like yours. Our axle weight is around 13000 lbs. I run 16 ply Bridgestone R250's and don't have any issues. You could go to a 315/80R22.5 on a 9" wide rim or there is a actual coach wheel and rim that a lot of guys are running on their front axles. The tire is a Michelin XZE 365/70R22.5 and the rim is around 10" wide. Those last two sizes are good for about 16,000 to 18,000 lbs per axle.

[BuickTurbo]

Thanks for the info.

I cut the fender bolsters off the trailer today to open up the wheel wells. Hopefully this will let the area breathe a little more.

[roadranger]

The tire manufacturer should have a chart of proper air pressure for the actual load you have (once you get her scaled). For general use we usually run a fixed (high) pressure since it is too much trouble to set the pressure differently with different loads but in your case you should be able to set them for your actual weight and get better ride and wear from them. Also check to see if you can use 11R22.5's instead as I think the 12's generally have a lower speed rating and run hotter? Plus the 11's are the most common size. Four 11's are only good for about 24k total though - but it sounds like you are under that? For sure go through a truckstop scale and see where you are at on axle weights!

[roadranger]

...about 36k loaded. [...] So the tires allow about 30k total, my guess is it's overweight. Is 6K lbs enough to constantly blow rubber?

Almost half your weight should be on the hitch and not on the trailer axles if you are using a fifth wheel hitch and a single axle dually tractor with at least a 20k rear - so you should only have about 20k on the trailer tandems!

[DaveFromColorado]

I knew someone that had this issue with an old 50' race trailer - he got tired of spending tons of money on tires and had a "friend of a friend" with an alignment shop check the alignment of the two axles to one another and found they were a couple degrees off, this caused some scrubbing of the tires which increased the heat a LOT ...

may not be the actual issue, but something to look into ... I don't know if the tires were ever "cupped" or not.

--Dave.