Can I get taller trailer tires?

[Pacerized]

Andy if you or anyone with knowledge of trailer tires could advise me I would greatly appreciate it.

I took my 81 excella 25' down to our nearest airstream dealer today to have a window rock guard installed, and the axles, and tires checked. It turned out that I do need new tires as they are showing cracking between the tread due to age. The tires that the P.O. had installed were also just 4 ply passenger tires that I think are of a lower profile then the trailer tires should be. The tech said they use a local tire store that they have a contract with to take care of the tires, and that they would run about $100 each, which I found reasonable, and I told him to plan on changing them. He pointed out that the front of the trailer was riding a little high, and that I might want to have my hitch changed. I had just changed my tow vehicle tires a few weeks ago to a slightly larger tire that adds about an inch which I'm sure added to this problem. My hitch is welded with load equalizers, so I would have to replace it with an adjustable hitch to change the ball height. Since I'm getting new tires, and I believe the tires that are on it are too low I'd like to know what the tallest 15" trailer tires that I could go with are. If I can make up an inch in doing this, then I won't have to spend the $400 for a new adjustable hitch. I'm also wondering if I should go with load range C, or D. My trailer has a dry weight without hitch of 3600 lbs, and I think a loaded weight of about 4700 with tanks, and hitch added. Also would you recommend a specific brand tire?

Thanks: Charlie

[balrgn]

Originally Posted by Pacerized

Andy if you or anyone with knowledge of trailer tires could advise me I would greatly appreciate it.

I took my 81 excella 25' down to our nearest airstream dealer today to have a window rock guard installed, and the axles, and tires checked. It turned out that I do need new tires as they are showing cracking between the tread due to age. The tires that the P.O. had installed were also just 4 ply passenger tires that I think are of a lower profile then the trailer tires should be. The tech said they use a local tire store that they have a contract with to take care of the tires, and that they would run about $100 each, which I found reasonable, and I told him to plan on changing them. He pointed out that the front of the trailer was riding a little high, and that I might want to have my hitch changed. I had just changed my tow vehicle tires a few weeks ago to a slightly larger tire that adds about an inch which I'm sure added to this problem. My hitch is welded with load equalizers, so I would have to replace it with an adjustable hitch to change the ball height. Since I'm getting new tires, and I believe the tires that are on it are too low I'd like to know what the tallest 15" trailer tires that I could go with are. If I can make up an inch in doing this, then I won't have to spend the $400 for a new adjustable hitch. I'm also wondering if I should go with load range C, or D. My trailer has a dry weight without hitch of 3600 lbs, and I think a loaded weight of about 4700 with tanks, and hitch added. Also would you recommend a specific brand tire?

Thanks: Charlie

Thought I'd bump this one up, good luck in your quest.

[overlander63]

If you are going for height, 7.00x15 is about as tall as you can fit inside the wheelwells without damage. The 225 75 15 trailer tire is shorter and wider than the numerical tire.

[TomW]

From a safety standpoint, I think you would be better off with a lower profile tire. Higher profile tires, like what you are looking for, will raise the Airstream's center-of-gravity which will contribute negatively during sudden swerving manuevers.

Tom

[TomW]

Originally Posted by Pacerized

... Also would you recommend a specific brand tire?

Many people are now strongly considering Maxxis.

Tom

[Road Ruler]

We have been using 235x78's for the last 5 years. They work very well. My next set will be a lower profile. Like Tom says, tighter handling
during sudden swerving manuevers.

[overlander63]

Originally Posted by Road Ruler

We have been using 235x78's for the last 5 years. They work very well. My next set will be a lower profile. Like Tom says, tighter handling
during sudden swerving manuevers.

Is there room for 70 or 65 series tires in your wheelwells? Also, I like how your hubcaps match the color of your Pacer.

[Road Ruler]

The current tires are a bit of a struggle to get in and out of the wells. Would have to do some testing to see what options would work. I do know that the owner of Hensley had some high performance, low profile tires on his Airstream for a while.

The Pacer is painted Guards Red ( a real Porsche colour ) and the trim on our Airstream including the caps are a deeper red colour. It has been a while since I had that one mixed and can't recall what car colour it is. Would have to check the can.

[Inland RV Center, In]

Originally Posted by Pacerized

Andy if you or anyone with knowledge of trailer tires could advise me I would greatly appreciate it.

I took my 81 excella 25' down to our nearest airstream dealer today to have a window rock guard installed, and the axles, and tires checked. It turned out that I do need new tires as they are showing cracking between the tread due to age. The tires that the P.O. had installed were also just 4 ply passenger tires that I think are of a lower profile then the trailer tires should be. The tech said they use a local tire store that they have a contract with to take care of the tires, and that they would run about $100 each, which I found reasonable, and I told him to plan on changing them. He pointed out that the front of the trailer was riding a little high, and that I might want to have my hitch changed. I had just changed my tow vehicle tires a few weeks ago to a slightly larger tire that adds about an inch which I'm sure added to this problem. My hitch is welded with load equalizers, so I would have to replace it with an adjustable hitch to change the ball height. Since I'm getting new tires, and I believe the tires that are on it are too low I'd like to know what the tallest 15" trailer tires that I could go with are. If I can make up an inch in doing this, then I won't have to spend the $400 for a new adjustable hitch. I'm also wondering if I should go with load range C, or D. My trailer has a dry weight without hitch of 3600 lbs, and I think a loaded weight of about 4700 with tanks, and hitch added. Also would you recommend a specific brand tire?

Thanks: Charlie

The tire size must not be greater than 15 inch.

If your having height problems, you might check out your axles.

The following will teach you how.

Dura Torque Axle

Andy

[Road Ruler]

Originally Posted by Inland RV Center, In

The tire size must not be greater than 15 inch.

Andy

Andy. is there a reason for this other than a problem with too much diameter?

[Pacerized]

I'm not saying that the trailer has a height problem, or that the axles are an issue although I am having the axles inspected while at the airstream dealer. Perhaps I didn't word the post as well as I thought.

I bought the trailer last year, and it appears that the previous owner had installed the wrong tires, a lower profile passenger tire. I may be fine with the profile if I simply put the correct tires on the airstream. Could anyone tell me what the tallest 15" tire a 25' airstream could use within airstream specs???? I found a p235 15" trailer tire that I think would solve my problem if this size tire is within airstream specs.

Thanks: Charlie

[Pacerized]

Sorry, I'm also wondering if I should buy class C, or D rated tires for a 25' duel axle trailer that weights 4700 loaded, and 3600 dry.

Thanks: Charlie

[overlander63]

Airstream spec would be an ST225 75R15 tire.

[Pacerized]

Originally Posted by overlander63

Airstream spec would be an ST225 75R15 tire.

Thanks that's what I was wondering. Beginner sent me a message on this as well. I think what I have on it are p205 passenger tires, and I hope that just going back to this will solve my problem. I think I only need about an inch, maybe 1 1/2 inchs for my hitch to fit perfectly level. I think I'll ask about the 235 75 15's as well. This is the only trailer I plan to haul for a long time, so I hate to have to change the hitch if changing the tires will do it, especially since I have to buy new tires anyway.

Thanks: Charlie

[bhayden]

In '81 weren't they still specifying 7.00x15 tires? I didn't think they switched to the 225/75R15 metric sizing until later. The old 7.00x15 tire size was a hair over 30" in diameter. Virtually impossible to find now days (in a radial anyway). It's the reason some of us are looking at the switch to 16" rims; so we can get back to the tire diameter and ride height the trailer was designed for.

-Bernie

[JimGolden]

You can figure out the theoretical height using the tire's description:

The new tires are metric rated, such as 225/70-15

What this means is that the tire's section width is 225mm, the tire's wall height is 70% of the section width (which would be 70% of 225mm), and the rim diameter is 15"

So if you do the math, the overall height of the tire (neglecting "squish") would be:

Height = { (225mm/25.4)*(0.7)*(2) } + 15

Height = 27.4"


You divide the mm by 25.4 to get it in inches. You have twice the wall height because you have rubber both above and below the wheel.

So, you can use this formula to calculate the height of any tire.

A 235/75-15 would thus be 235/25.4*.75*2 + 15 = 28.9"

Conversely, the other format commonly used for truck tires would be like a 31x10.50, where the height is 31" and the section width is 10.50".

I'm afraid I don't know the older rating system. A 7.00x15 I'm assuming the section width was 7" and the rim 15", but I don't know what the wall height is.

Best of luck,

[47WeeWind]

Originally Posted by Pacerized

Sorry, I'm also wondering if I should buy class C, or D rated tires for a 25' duel axle trailer that weights 4700 loaded, and 3600 dry. Thanks: Charlie

Hi Charlie:

I don't have a copy of the 1981 Airstream travel trailer catalog, but I do have the 1980 Airstream travel trailer catalog which includes a 25' Excella II, so I'll give you the tire data for it, which might (or might not) apply to your 1981 version of that trailer.

All 1980 Excella II trailers (25', 28' and 31' lengths) had as the standard base model four bias belted black wall tires in load range C tires on automotive style steel wheels with wheel covers as standard (no tire or wheel size is listed).

Optional tires for the 1980 Excella II and International trailers were either:

four 700-15 LT (Light Truck) load range C bias belted white wall tires, or
four 700-15 [Michelin model] XCA load range C steel radial black wall tires.

on optional forged aluminum wheels (no wheel width listed, but it would have a 15" diameter). Hope this data helps.

[Pacerized]

Thanks for looking that up Weewind:

It surprises me that LT tires were optional since I've read on here to stay away from anything other then trailer tires ST. I guess the LT tires come in a 6 ply to be load range C. I do have the optional aluminum rims, but I wouldn't think that would matter so much. I guess I should stick to the C's since that's what came on it. I don't want more vibration in the trailer then I should have. The 4 ply passenger tires I have on it now actually ride very well. I never get any sway while I'm driving. Being lower in profile might make up for the softer side walls.


Charlie

[Action]

Just moving out of a pass. tire may give you some height. Not sure what size pass tire you have on it now - you didn't say.

And your hitch set up, .... not sure because you are not specific, is the ball on a removeable square tube? If so you could buy a drop down ball assy and adjust for a small amount.

Any tires you buy for your trailer will have to be twice as tall as the amount needed. IE if the amount you need is 1" than the replacement tire would have to be 2" taller in diameter than the existing tires. The amount of tire above the center of the wheel does not lift the trailer any.

And because the trailer is 26 years old the axles may have settled as mentioned above. Having the axles inspected as you state above is a wise move.

So several factor are at play. The pass tires. Possible axle settleing or lowering of the trailer. And a drop down ball assy may all be factor.

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

[Beginner]

Pacerized
Go to the web site of the company that manufactured the tires on your trailer now.
There you will find a "Specifications" Page that will give you the Maximum sidewall width and the Outside Diameter of your tires.
With that information you can determine what different tire you want to go to by looking up the tire you are interested in.
If you need help with this tell me what you want to know and I'll try and find it for you.
You said that the tires on the trailer are P205. What are the other numbers (P205/70R15 or P205/75R15?)
It can be confusing.
Beginner.