Tire pressure

Topic: Tire pressure (Read 2611 times) previous topic - next topic

Re: Tire pressure

Reply #25 – September 08, 2015, 09:16:48 pm

"How's the wear pattern? Straight across? What pressure versus weight?"

There's no wear pattern, it's evenly worn straight across on all six tires. When I checked my tires during preflight inspection when I last drove it two days ago the front tires were 106 psi and the rears were 102 psi. It's a 36' U300 lightly loaded and the tires are rated for 110 psi. I haven't weighed my coach. I'm sure it's nowhere near the 30,000 lbs stated on the data plate. I haven't experienced any tire problems except a leaking schrader valve which was replaced immediately when I noticed it during preflight inspection over two years ago. I always always always check my tires along with several other important items before I even start the engine.

I saw the exact same tires as mine, same size and everything, on the front of a tow truck in Santa Fe. It's the tow truck with Mighty Mouse on the side of it. Maybe someone on this forum has noticed it? The tires are badly weather cracked but have about the same tread depth as mine. All the mechanics at Hal Burns were standing there so I asked them if those tires were safe with that amount of weather cracking. Their response was unanimous, every single one of them said the same thing... Anyone care to guess what their response was? ...I should have taken a photo of the tires with my cell phone! haha

Re: Tire pressure

Reply #26 – September 08, 2015, 09:23:22 pm

tow truck company probably bought them at the tire store second hand...off the fancy motorhome just ahead of him.

Re: Tire pressure

Reply #27 – September 08, 2015, 09:37:27 pm

Quote from: Doug Weil – September 08, 2015, 09:23:22 pm

tow truck company probably bought them at the tire store second hand...off the fancy motorhome just ahead of him.

Had a Canadian couple staying with us in Yuma a couple of winters ago with a Newmar wanted to buy new tires in the U.S. to save a few bucks. The tire store did not want to give him anything in exchange for his old tires plus wanted to chg. for disposal. I advertise on Craigslist, trucker meet us at the store...win win for both parties!!

Re: Tire pressure

Reply #28 – September 08, 2015, 09:44:28 pm

But that tiny surface crack that goes 1/100th of the way into the sidewall is bad news.

Re: Tire pressure

Reply #29 – September 08, 2015, 09:46:57 pm

Thanks Scott for the factual info.

I hope others will report on their actual wear, weight and pressure and what exact tires they are using.

Would seem to be a useful thing for the forum to have a pinned or some other way to have a easily accessible file for the info. Being as it is one of the most expensive things for our coaches.

My tires varied from each other on the rear by up to 6/32nd's

And we're up to 6-7 32nd's off across the tread.

Zxa–1's

Obviously not carefully cared for as far as alignment by a previous owner before the barks.

Re: Tire pressure

Reply #30 – September 08, 2015, 10:36:29 pm

Quote from: krush – September 08, 2015, 09:44:28 pm

But that tiny surface crack that goes 1/100th of the way into the sidewall is bad news.

On my five year old dated tires the steel belts were exposed. The tire guy was surprised.

Desert home in the past I understand. At least for the first year on the 2010 tires on the rear.

Fronts were ten years old with similar depth cracks? Who knows? Bad chemicals on the sidewalls?

Gingerly drive the coach to get new shoes.

What is the consensus for storage. Tire guy mentioned about no concrete. Others say asphalt?

Re: Tire pressure

Reply #31 – September 09, 2015, 03:02:18 pm

Get a moisture barrier between whatever you park on long term and the tires. Remnant sheet vinyl flooring works good. I got mine free. Home Depot usually has them at low cost and you can get matching pieces.

Folks who store their Corvettes over the winter get curved plastic ramp like things that are the same radius as the tire. Tires sit in them supported in the curve rather than the flat. No thumping tires. I thought about this idea, it would be easy to make from some left over LVL. You still want to isolate the tire from a wooden ramp.

Re: Tire pressure

Reply #32 – September 09, 2015, 05:42:33 pm

Many of you have seen it in another Forum thread probably — or you already know from having been at past GrandVentions — but there will be the opportunity to have coaches weighed in Columbus, IN, on October 17. Made our appointment today.

Since we are newbies, we want all the info we can get. Grateful for everyone's perspective in this thread.

One post in this thread was interesting, re: there being a market for tires removed. We took off two perfect-looking Michelin XZA3 steer tires last month, because they hit 8 years. I'd heard from a guy in the park where we're staying that he sold his to a local tire dealer for $100 each because farmers, who remain local and drive slowly, put them on trailers. No luck. Called 4 dealers. Best I was offered was $50 for the two tires. Three other dealers didn't want them. Since the tires were taking up all the space in the largest bay of our coach, it was worth more to Susan & me to get the bay back to its normal contents, than to rent a small trailer and drag the tires down to the dealer. Maybe we missed a better deal?

Re: Tire pressure

Reply #33 – September 09, 2015, 07:44:55 pm

I got $75 each for the 6 Michelin take offs, they were about 5.5 yr old. The Michelin dealer was delighted to get them, very little wear at 50,000 miles. Good tires are good insurance to me.

Re: Tire pressure

Reply #34 – September 09, 2015, 08:16:44 pm

Michelin and bandag have age limits on tires that can be recapped. I think it is 7 years.

Re: Tire pressure

Reply #35 – September 09, 2015, 09:20:13 pm

Quote from: Tim Fiedler – September 09, 2015, 08:16:44 pm

Michelin and bandag have age limits on tires that can be recapped. I think it is 7 years.

Might be the case with Michelin casings

How Long Do Truck Tires Last? - Tire Review Magazine

Re: Tire pressure

Reply #36 – September 10, 2015, 10:38:26 am

Thanks, all. Dave M — I'm with you. Good tires are good insurance.

For what it's worth, a friend who is an exec with a tire company, and has run some of their truck tire plants, says 7 years. He even replaces the spare in his car at 7 years. Granted, if I were a skeptic, a tire company exec would have reason to recommend replacement (sells more tires). But he's a friend, too. If I understood (no guarantee that's so), his reasoning seemed to be that after 7 years — no matter how good they look from outside (sidewall condition, tread depth, etc.), they begin to deteriorate from the inside.

Inherent moisture trapped during the manufacturing process affecting the steel belts? I dunno! Never made a tire. Just know I've seen too many blowout films. http://www.youtube.com/watch?v=9LkLeljt4t0

Re: Tire pressure

Reply #37 – September 10, 2015, 11:02:22 am

I'd like to point out that there are upper limits to aie pressure also. I blew the sidewall out of a 2 yr old xza3 lrh using a combination of clip on chuck, the 120 lb governed air supply of coach, and head firmly up aah...not paying attention.

Re: Tire pressure

Reply #38 – September 10, 2015, 02:23:48 pm

Quote from: Chuck Pearson – September 10, 2015, 11:02:22 am

I'd like to point out that there are upper limits to aie pressure also. I blew the sidewall out of a 2 yr old xza3 lrh using a combination of clip on chuck, the 120 lb governed air supply of coach, and head firmly up aah...not paying attention.

Chuck,

The upper limits where a tire will explode according to the Bridgestone Truck Tire site are more than twice the maximum pressure listed on the side of the tire. Here is Bridgestone's quote: In actual tests, modern truck tires can often be inflated to over twice their maximum rated pressure before failing.Plus, most wheels break down before the tire does.

Your tire had some kind of previous damage for it to explode.

Pierce

Re: Tire pressure

Reply #39 – September 10, 2015, 04:12:49 pm

Chuck, I'll agree with Pierce on this. you're "not paying attention" skirted you from having a expensive and dangerous blow out on the road.
Here's an example of a rim giving out under pressure.
http://www.youtube.com/watch?v=Q-3U-TRkJx8&feature=youtube_gdata_player

Re: Tire pressure

Reply #40 – September 10, 2015, 08:17:59 pm

I used the original 50 year old bias ply spare tire in my 1965 Impala a couple of years ago on the freeway in Dallas... no really!

...it's still in like new condition and I'm still alive

Re: Tire pressure

Reply #41 – September 10, 2015, 09:41:55 pm

We just put six new Michelins on our coach last month, the steers were '02 XZE's and the drives were '04 & 05 XZA1's. We bought it that way and they were way over due. All had cracking.
Replaced with 275/80R/22.5 XZE's

One tire dealer told us that max life on car and light truck tires should be 5 or 6 years and heavy truck tires 7 to 10 years max. Depending on how the tires were used and cared for, driven a lot or stored and sheltered or exposed to the elements. Not all tires age the same. Another tire dealer insisted that 5 years should be the max on all tires. Two different dealers can't agree, only thing in common other than both were Michelin dealers was they both make a living off of selling new tires.

What I take from this is "change you tires between 5 and 10 years". $:-\$
New tires can blow out at any time, but the older they are the greater the chance that they might.

Re: Tire pressure

Reply #42 – September 11, 2015, 01:11:07 am

Quote from: Pierce & Gaylie Stewart – September 10, 2015, 02:23:48 pm

Chuck,

The upper limits where a tire will explode according to the Bridgestone Truck Tire site are more than twice the maximum pressure listed on the side of the tire. Here is Bridgestone's quote: In actual tests, modern truck tires can often be inflated to over twice their maximum rated pressure before failing.Plus, most wheels break down before the tire does.

Your tire had some kind of previous damage for it to explode.

Pierce

Actually, I'm kind of glad to hear this, I'd been kicking myself for ruining a good tire. Though they drive well my Michelin experience has not been good.

Re: Tire pressure

Reply #43 – September 11, 2015, 10:31:18 am

A few tidbits for tire age, retreads, etc:

Bridgestone-Firestone has a lot of tire info online. They have about the best reputation for the quality of casing construction of the major manufactures in reading quite a few tire forums. I was surprised to find out that well over 50% of replacement tires are retreads. Bridgestone in the PDF also states that the tires in the survey are between 10 and 15 years old. Also, the cracks we see in the sidewall are from ozone and unless badly cracked as seen in some of the photo examples, are not a reason to reject a tire.

http://www.ncleg.net/documentsites/committees/JLTOC/2011-12_Biennium/Archive/2008-04-23/Presentations/Tire%20Retread%20Study/How%20Long%20Do%20Commercial%20Truck%20Tires%20Last.pdf

This is an excellent article with good insight into tire lifespan and the amount of retreads on the road. A good read for an RV owner.

In reading between the lines, Bridgestone has a much different take on tire lifespan compared to local dealers. Wonder why dealers recommend replacing sooner?

Pierce

Re: Tire pressure

Reply #44 – September 11, 2015, 12:56:13 pm

Mine blew out at 8 years. Steel braids inside rubber were rusted, and I expect that caused failure

Re: Tire pressure

Reply #45 – September 11, 2015, 01:29:51 pm

Quote from: Tim Fiedler – September 11, 2015, 12:56:13 pm

Mine blew out at 8 years. Steel braids inside rubber were rusted, and I expect that caused failure

That's one reason why nitrogen inflation is supposed to be better, since most air that's used for inflation is actually rather wet.

Re: Tire pressure

Reply #46 – September 11, 2015, 01:55:56 pm

Quote from: D.J. Osborn – September 11, 2015, 01:29:51 pm

That's one reason why nitrogen inflation is supposed to be better, since most air that's used for inflation is actually rather wet.

The Michelin shop that replaced my 6 only does the nitrogen, interesting that after a year they have not lost any psi even with the Pressure Pro screwed on em.

Re: Tire pressure

Reply #47 – September 11, 2015, 02:08:17 pm

Aircraft propeller unfeathering accumulator tanks get only nitrogen. With coach air, a dryer in the hose to the air chuck will keep the moisture to a minimum. A lot of gas stations never drain the water from their compressor tanks. Either way, dry is good.

Our fire trucks never had dryers and always spit out quite a bit of water when drained during each morning's warmup.

Pierce

Re: Tire pressure

Reply #48 – September 11, 2015, 09:39:14 pm

Is not the air line output in our coaches from a source after the air dryer?

Re: Tire pressure

Reply #49 – September 12, 2015, 12:45:03 am

Bob,

I keep an extra dryer in the line as can be seen in the attached photo below (gold at the top of the photo). Since I keep all the tires at 110 psi, I don't want to wait for the engine compressor to cycle so keep a contractor's compressor ready to go for tires or the coach air system if the engine failed and it had to be towed. It goes much higher and will run the big impact if needed. I also keep a large diameter air supply hose and a tank with a short hose to the 1" impact. Photo #2 shows the stainless accumulator tank with the large quick connect I use for the larger air hose. The industrial strength 1" impact is just visible behind and to the right of the air jack.

Yes, the air at that location from the engine compressor is dry or at least, should be.

Bob, you're still pretty sharp. Was wondering how long it would take someone. ;-)

Pierce

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