Tires...Tires...Tires

[Bob Thompson]

You gotta' love this: Read post #22.....Maybe the wheel hasn't been invent yet! http://www.airforums.com/forum...on-2641-2.html

Then read post #133 in this thread. Why reinvent the wheel!

I've already drawn my conclusions!

[mmth11053]

I'm late to the discussion. But I also have a question....Any suggestion about tires for my 1960 28' Ambassador?

Paul

[ticki2]

Did some snooping at the local RV dealer . All the SOB'swere fitted wirh ST tires . Most were 2 ply sidewall with 6 or 8 ply rating . All had written on the sidewall the words " FOR TRAILER SERVICE ONLY ".

A few miles down the road was an equipment trailer dealer so I stopped to check their tires. All of of the trailers under 5000# GVWR had ST tires similar to the RV's. The trailers that had 6000# GVWR or more had 16" LT tires. I saw no wording of restriction on the LT tires . It would seem that LT tires can be used on a trailer or a passenger vehicle.

Since LT tires can be used on a vehicle with passengers and ST tires cannot , it would seem that LT tires are manufactured and tested to a higher standard . BTW , according to the federal DOT , the designation ST stands for Special Tire and not Special Trailer .

I don't think the number of actual plys in a tires sidewall has much bearing on sidewall stiffness since even 10 ply rated tires only actually have 2 plys. It doesn't seem that the plys of today hve much in common with the plys of yesteryear. I'm coming closer to the conclusion that LT tires are better and safer than ST tires for trailer use.

For those of you that feel that ST tires are better ,( and from the number of posts above there are many ), could you please post the resources that you used to come to that conclusion so we can all become better educated on this baffling subject. Thank you in advance

[Rog0525]

Originally Posted by Bob Thompson

You gotta' love this: Read post #22.....Maybe the wheel hasn't been invent yet! http://www.airforums.com/forum...on-2641-2.html
Then read post #133 in this thread. Why reinvent the wheel!
I've already drawn my conclusions!

I've read through both posts and the link and I really don't understand how any of this supports your position. I must be missing something.

Originally Posted by Beginner

Rog0525
Simply do as I did. Go into the shop manual and find out what size tire was originally installed on your unit. Email the manufacturer of that tire and find out what the outside diameter (OD) of that tire was and the width of that tire at its widest point on the same width rim that you now have on your unit.
Jim

Thank you for the advice but I've never had a problem in using the replacement tires recommended by Airstream customer support. I didn't ask them about horse trailers, U-Haul trailers or Bobcats. I only asked them about correct tire replacement on the particular travel trailer I owned at that time.

[Frank S]

Hi All--Had a few extra minutes in WalMart on Sat, and found they offer 5 tires that might apply to A/S, in their catalogs. Thought the info might be of general interest.

CARSISLE "USA Trail" ("comply with US DOT requirements")
ST225/75D15 C rated 2150#@50psi $60.97
ST225/75D15 D rated 2540#@65psi 67.22

GOODYEAR "Marathon Radial" ("Designed specifically for trailer use")
ST225/75R15 C rated 2150#@50psi 28.3"OD/8.7"wide $82.36
ST225/75R15 D rated 2540#@65psi 28.3"OD/8.7"wide 90.28

GOODYEAR 'Work Horse Rib" ("Bias Construction")
7.00-15LT D rated 2045#@65psi 29.8"OD/8.3"wide $107.20

WalMart also charges $9.76 which includes mounting, balancing, road hazard, & rotation with rebalancing. Said they would also do all tire work on the trailer if I brought it in.

I did not find any LT in the 225/75R15 size. Also the bias tire was not shown as available in C load range. My '73 Overlander has always run on 7.00-15 LT in C load range, which I believe was the originial size provided by A/S. If I change to radial, I will lose a 1/2" or more of ground clearance, and increase tire width slightly. Also will need a new spare due to change in OD (in the past used my best old tire as a spare). Haven't decided what to do for my next set of tires, but have sure read a lot of discussion in this thread.--Frank S

[markdoane]

Originally Posted by Frank S

. . . I did not find any LT in the 225/75R15 size.

I think you have discovered a funny thing about ST and LT tires sizes. If you look at them closely, the sizes alternate back and forth from LT and ST.

So you can find 205, 225 in ST, and 215, 235 in LT. Same is true in different diameters.

I have no idea why this is. It might be a conspiracy by the tire companies to keep me confused.

[uwe]

It's a fact, though, that 15in tires are very hard to find, if at all, in a D or higher load rating...got to go to 16" rims and tires to get away from ST tires.
I look at my Marathons, and see a cheaply made product, with grooves and high ridges in the sidewalls, that are supposed to be "normal" for this kind of tire. This does raise questions in my mind about this entire ST tire debate.
Amazingly, I have not had any failures so far, running the Marathons on 2 different trailers.

[scottanlily]

Hello everyone,

The great tire debate rages on! I personally like the orignal look of the 700-15 bias ply tire. It has the heavy shoulder and good sidewall construction.The ones I have on my 60 trdwnd are hercules tires . They are LT tires. The sidewalls have 4 plies and the tread area is 5 plies .This information is on the sidewall and they are not rated plys as in 8 ply rated as many tires are. I am happy with them ,no problems. Always check them when we stop ,temperature check etc.good looking tire for a vintage airstream. They are load range D. The 700-15 was the standard size tire for what, 25 or 30 years .on airsteams .Radials will have less rolling resistance no doubt about it. They are smoother ,sidewall flexes alot more .So do the st tires .But flexing also generates some heat ,and if they cannot handle the load ,they come apart.They did not make this special trailer tire years ago so you went with the bias 700-15 for most older airstreams even in the 70s.trailers .I have read of the st tires on the single axle rigs feelingwishy washy not as stable. Adding more air pressure makes the sidewalls stiffer ,right? Run proper pressure for the load . airstream trailers want a smooth ride as inland andy says .

[SilverToy]

Hello all -

Reading this thread with interest. Got new tires about 1 year ago - replaced what was there with exact same tire - different manufacturor.

Wondering if I am running with incorrect pressures.

'92 34' Classic Lmtd - triple axle. ST225 75R15 on original 15x6 rims.
GVWR of 8900 (on tag).
GAWR of 2800 per axle. Is that per wheel, ie each side??? 2800 x 3 =8400 That is under GVWR!?

Same tag says to inflate to 50psi cold. Tire says cap. is 2450 at 65psi.

ARG@#(*%#(!!!!!!!!!!!!!!

Help!!

I think I confused myself into a panic here....

Thanks for all thoughts

Axel

[markdoane]

Originally Posted by SilverToy

. . . . .ARG@#(*%#(!!!!!!!!!!!!!!

Thanks for all thoughts

Axel

Axel,

You are in excellent shape. The axle rating is for two tires, so each tire needs to handle half the axle weight, or 1400 lbs.

That is only about 60% of the tire capacity, so 50 psi in the tire is a reasonable inflation pressure.

The axle rating plus the tongue weight is how the GVWR is calculated, so 8900# is a good number.

Now have a donut and pat yourself on the back!

[Action]

Originally Posted by SilverToy

'92 34' Classic Lmtd - triple axle. ST225 75R15 on original 15x6 rims.
GVWR of 8900 (on tag).
GAWR of 2800 per axle. Is that per wheel, ie each side??? 2800 x 3 =8400 That is under GVWR!?

Same tag says to inflate to 50psi cold. Tire says cap. is 2450 at 65psi.
Axel

Put another way.....

at 65PSI the tire cap is 2450 (I don't know what it is at 50 PSI) and you have 6 tires. So 6 X 2450 = 14,700 pounds of capacity for the tires. Take 90% (a 10% safety margin) and you really don't want to subject your tires to a total load of greater than 13,230.

Now your axles are rated for 2800 and you have 3. So 3 X 2800 = 8,400. Take 90% of that and you do not want to subject your axles to a total load of greater than 7560.

Do weigh your trailer in camping condition to find out if you are taxing your axles, since your total tire capacity far exceeds the axle ratings.

>>>>>>>>>>>>>>>>Action

[Porky Pig]

Originally Posted by Action

Put another way..... at 65PSI the tire cap is 2450 (I don't know what it is at 50 PSI) ...

2150 .

[Cracker]

This discussion finally came around to my question! During my factory vist, Airstream replaced my original Goodyear Marathon tires, load range "C," with new Goodyear Marathon, load range "D" tires. As Porky pointed out, the capacity of the "D" tires is 2,540 lbs at 65 psi, as opposed to 2,150 lbs at 50 psi for load range "C" or "D." Airstream originally recommended that the tires be inflated to 50 psi for my 2000 30' Excella. Accordingly, in order to achieve the softest ride, I would assume that the lower 50 psi pressure is still correct? I don't believe that Airstream is willing to arbitrarily increase my CCC by 1,560 lbs!

[Beginner]

Here is something I read recently about adjusting tire pressure to load. Just wanted to get some feed back on this concept. This is easier with two people.
Take a piece of chalk and draw a line across the tread from sidewall to sidewall.
Move the unit forward enough for the tire to make two or three revolutions and stop with the remnants of the line so you can see it.
Check the line on the tire. If the line is gone in the center of the tire and fresh at the sholders then you have too much air in the tire. Conversely if the line is gone at the sholders and remains in the center, the tire is underinflated. The idea is to have the line disappear evenly across the tire from sholder to sholder.
I tried this with my tv. I still have the portable scales. I weighed each wheel and wrote the weight down. then did the chalk thing. When the chalk wore off evenly, I rechecked the tires and sure enough the tire with the least weight on it had the least pressure in it and the least amount of pressure seemed reasonable to me.
Any one ever heard of this. Any reason why not to use this method? Sure seems simple.
Again...Beginner, but learning

[GoldFever]

Should tires be replaced periodically even if not used much and showing little wear? I had two blowouts on my 25 foot Excella trailer roughly 4 years ago to tires that were on the trailer when I bought it. I believe they were about 3 to 4 years old when they blew. A friend (also with a 25 foot trailer) swears by replacing tires every 4 years no matter what condition. Safety and peace of mind on trips makes for a happy traveler.
PS - I am approaching the 4 year "anniversary" of new tires.

[Inland RV Center, In]

Tires are replaced because of mileage, and because of time, no matter how few miles they may have traveled.

Replacing tires because of wear, is not a question.

Replacing tires, that have aged, but that have but a few miles on them, seems to be an uncertainty.

Rubber, has a memory, and must be flexed frequently, or the memory simply dies.

Flexing the tire itself, leads to a greater useful life, because of that flexing.

All of us have rubber bands at home, that are years old, because we use them often.

Most of use have also seem rubber bands, that were seldom used, that just simply turned gummy or brittle, and yet were from the same package as those that are still good.

Tires, basically react to use or non use as the case may be, in approximately the same way.

The Airstream trailer is some what the same way.

Historically, those owners that use their trailer very often, will typically pay "less" for routine repairs, than those owners who use the trailer just a few days a years.

Our repair records, more than prove that point, over and over again, year after year.

And besides that, Grandma, who is always right, still contends that, " if you don't use it, you will lose it".

I know she is talking about the Airstream trailers, because Grandpa, is still around.

Andt

[dwightdi]

The tire companies know their products better than anybody else. Their rubber engineers/chemists have spent years developing the very complex rubber compounds which go into making tires. There may be up to 30 compounds in a single tire. Some of these compounds contain special additives which leach to the surface to protect the rubber from Ozone and UV attack. Flexing them causes the additives to come to the surface faster, so there is some truth in tire may age more just sitting around. The bigger variable however is the environment they are in. Tires in CA,AZ,NM,TX, FL, and the rest of the south are exposed to more sun and Ozone than those parked in a barn in Wisconsin. You really can not apply the same aging rules to all enviroments. The Trailer rated tire have more anti-aging additive because the companies know they will not get as much wear per year as a car or truck. We should get someone out of the tire industry to make a contribution to this thread. What a dealer learns from his experience in California does not necessarily apply to possible tire usage in New England.

[scottanlily]

i would say the tire rule is a good one,My 60 tradewind I purchased in nebraska had tires in excellent shape ,at least visualy,no cracks ,as new tread .YES a blow out on I 70 .The trailer was not loaded with anything heavy ,no water or cargo ,no sheets on the bed even. I checked inflation before traveling.The tires were not new however,just looked fine.They were some years old,still looked great.They failed .I go with the 4 year rule.I agree about harsher sun environments ,they are harder on an exposed tire.Sitting in a barn unused ,the tires still deteriorate ,cannot stop that from happening .
sitting unused they too deteriorate. dwightdi posted very good and informative information.I agree with most of it except the last sentence
which I dont get .If gnorgan is from hemet then he needs to change those tires,hemet is hot !! in the summer easily 100 degrees.

Scott

[acrane]

My husband and I have a 31", 7100 lb Excella. Have been recommended to purchase a ST225/75R15 E Carlisle.

I have heard the Carlisle are not good.

Any recommendations?

Alice Crane

[Inland RV Center, In]

Originally Posted by acrane

My husband and I have a 31", 7100 lb Excella. Have been recommended to purchase a ST225/75R15 E Carlisle.

I have heard the Carlisle are not good.

Any recommendations?

Alice Crane

Since you own an Airstream, you must have some faith in the company.

That being the case, would it not be a wise idea, to also trust them with their choice of tires for the past many many years?

They use Goodyear Marathons, for a number of good reasons.

If you chose to use another brand, then you are doing the testing.

Andy