Which Tire is best

[Go_Navy]

I recently bought a 2004 34' Classic which needs 6 new tires. The trailer still has the factory 15" wheels, which I want to keep. This is my first trailer and I am unsure which tires to get. Any advice/suggestions would be appreciated. Thanks.

[mojo]

Start here Tires - Airstream Forums

[Jammer]

Oh no, not again!

Go_Navy, tire questions are often asked and are debated endlessly.

I would suggest replacing them with Goodyear Marathons, which are probably what it has now.

[Globie64]

Thanks Jammer- I am here to post a thread titled tires- thoroughly confused. I've been reading all sorts of posts.... Isn't there some more or less simple answer?

[RLS]

There has been a lot posted about tires. You need to decide what you are comfortable and safe with. First, what type of tire - ST or LT ? Then what size - 15" or 16" ? Then what manufacture ? All has been talked about here, on this forum. Happy hunting

[Go_Navy]

Thanks. I will be keeping the 15" rims. So that part is an easy decision. I dont know which is better the LT or ST tires and frankly dont know anything about tires. I have read so many meandering posts about tires on this website..I was hoping for a pretty simple answer/recomendation on which brand and which type (LT or ST).

[polarlyse]

I had Maxxis tires on our '85 Excella and was pleased with the service from them
over 4 yrs. and probably 25-30k miles. Our current trailer has GYM's and also with no issues. So despite what I read about them the GYM's have also given good service. That's 2 years and maybe 20k miles. When I need new tires I'm still not sure which direction I'll go. I will consider LT but need to carefully look at the max. weights.

[Phoenix]

See short summary of tire posts on this forum, below. Other forum members, please feel free to correct or amend, as necessary.

ST = Special Trailer
LT = Light Truck
XL = Extra Load


Options for original 15-inch wheels

* OEM Goodyear Marathon (GYM), ST tires, load range D (65 psi max). This is probably what came as standard equipment on your Airstream.

* Other brands of ST tires, load range D (65 psi max).

* GYM or other brands of ST tires, load range E (80 psi max), which have slightly higher load carrying capacity. A few common brand names include Maxxis, Carlisle and Tow-Master.

* Bias ply tires with specifications similar to ST tires. (These tires appear to be used mostly on much older Airstreams, which may have come with bias ply tires; and this substitution is not common on newer models.)

* Slightly oversized XL tires, with specs similar to old load range C (50 psi max). Typical size is 235/75x15. This substitution is relatively new; and there is very little history on their use. Also, the load carrying capacity of XL tires may be insufficient for some Airstream models.

Note: There are no LT tires made in size 225/75x15; so for 15-inch wheels, selection is limited to ST, XL and other tires listed above.


Options for 16-inch wheels

Some owners have switched to 16-inch wheels and LT tires, because they are very close in physical size and rating to the OEM 15-inch wheels and ST tires; and 225/75x16 is a common LT tire size that is widely available from many manufacturers.

Note: While it appears from anecdotal evidence that LT tires may be more reliable than similarly spec'd ST tires (especially for those who exceed the ST's 65 mph maximum speed rating), many AirForum members seem to be satisfied with GYMs and other ST tire brands (in 15-inch sizes).

The most common LT tire used is the 225/75x16, Michelin LTX M/S (or M/S2), load range E (80 psi max), which comes standard on Eddie Bauer models and is optional on several other Airstreams.

It appears that numerous AirForum members have switched to 16-inch wheels and tires, and there have been no reported failures that I can recall in the past year or two. However, there is no detailed data available to support this best-guess estimate.

A few AirForum members have switched to commercial-grade LT tires with steel sidewall plies (e.g., BF Goodrich Commercial T/A's and Michelin XPS Ribs). While these Airstream owners generally feel that commercial tires provide an additional margin of protection against tread separation and blowouts; these tires are significantly more expensive, and there is currently no supporting data to justify their use. However, it appears that owners using commercial tires feel that the additional confidence and peace of mind justifies the extra expense.

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Additional reading:

http://www.airforums.com/forums/f438...res-16506.html

http://www.airforums.com/forums/f465...res-69297.html

http://www.airforums.com/forums/f438...oll-76867.html

[HiHoAgRV]

I believe those of us that have 6 tires on the ground have an advantage...the weight per tire is low considering the mass of a 34' trailer. That make life for tires easier than, say, a 30' Slideout with 4 tires and about the same weight.

Knock wood, I've been happy with my Marathons.

[SteveSueMac]

Phoenix - if you go to a 15" ST E rated tire, how do you confirm whether the existing wheel can handle the higher pressure? My trailer's placard says the wheel is a 15x7jj but a google search on that doesn't produce info on tire pressure. Thx!

[Phoenix]

Previous response to the same question in another thread:

The maximum pressure is molded into the aluminum on the inside of the wheel (visible when the tire is removed. I think the OEM 15-inch wheels say 110 psi, but not absolutely sure. In any case, 80 psi is OK. Also, for trailer applications, most tire stores, including Costco and Discount Tire, recommend inflating to maximum pressure that appears on sidewalls of tires, which is 65 psi for load range D and 80 psi for E's.

[SteveSueMac]

Thanks - not sure how I missed that... :-/

[CapriRacer]

Originally Posted by Globie64

.......Isn't there some more or less simple answer?

Yes, but there isn't agreement on what that answer is.

[Lance M]

Originally Posted by Go_Navy

I recently bought a 2004 34' Classic which needs 6 new tires. The trailer still has the factory 15" wheels, which I want to keep. This is my first trailer and I am unsure which tires to get. Any advice/suggestions would be appreciated. Thanks.

Since you are asking for opinions, I'll give you mine.
In my opinion, the best 15" tire that would handle the weight of your trailer is the Michelin LTX M/S2 P 235/75/15XL. It is a "P" tire, so the weight rating on the sidewall must be derated when used on a trailer.

Have fun reading!

[Globie64]

Originally Posted by Top

Since you are asking for opinions, I'll give you mine.
In my opinion, the best 15" tire that would handle the weight of your trailer is the Michelin LTX M/S2 P 235/75/15XL. It is a "P" tire, so the weight rating on the sidewall must be derated when used on a trailer.

Have fun reading!

Derated by how much?

[toastie]

Maxxis M8008 ST Radial 225/75R15 10 ply.

M8008 ST Radial

toastie

[CapriRacer]

Originally Posted by Globie64

Derated by how much?

By a factor of 1.1

[Lance M]

Originally Posted by Globie64

Derated by how much?

The factor is 1.1 Thanks Capri Racer.

So for this Michelin P tire it is 2183/1.1=1984.5
The same load rating (adjusted) as a load range C LT 235/75/15 tire at 50 PSI.
Michelin used to make this tire as an LT load range C when it was the LTX M/S, but it was made a P tire when the LTX M/S2 replaced it. Not sure why exactly.

[ZoominC6]

A number of years ago we ditched the Good Years for Carlisle ten plys on our 2004 30' S/O and just replaced them again. They've provided us with good service; however, I was a bit shocked at how much the cost of new tires has increased during the past four years! Good luck.

[switz]

The tire derating regulation is:

49 CFR 571.110
Tire selection and rims and motor home/recreation vehicle trailer load carrying capacity information for motor vehicles with a GVWR of 4,536 kilograms (10,000 pounds) or less.

S4.2.2.1
Except as provided in S4.2.2.2, the sum of the maximum load ratings of the tires fitted to an axle shall not be less than the GAWR of the axle system as specified on the vehicle's certification label required by 49 CFR part 567. If the certification label shows more than one GAWR for the axle system, the sum shall be not less than the GAWR corresponding to the size designation of the tires fitted to the axle.

S4.2.2.2
When passenger car tires are installed on an MPV, truck, bus, or trailer, each tire's load rating is reduced by dividing it by 1.10 before determining, under S4.2.2.1, the sum of the maximum load ratings of the tires fitted to an axle.

S4.2.2.3
(a) For vehicles, except trailers with no designated seating positions, equipped with passenger car tires, the vehicle normal load on the tire shall be no greater than 94 percent of the derated load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.
(b) For vehicles, except trailers with no designated seating positions, equipped with LT tires, the vehicle normal load on the tire shall be no greater than 94 percent of the load rating at the vehicle manufacturer's recommended cold inflation pressure for that tire.

One could put six Michelin LTX (P) 235/75R15 XL tires on your existing 15" rims at 50psi and have a derated load capacity of 11,898 pounds versus 13,098 pounds for six per the tire sidewall rating. That would be a 15% safety factor at the derated capacity for a trailer with a 10,000 pound GVW. And the 50psi is lower than the 65 psi of ST tires, so the wheels would have less internal stress.

I installed five (including the spare) of these Michelin tires on my 25FB that has a GVW of 7,300 pounds and I purchased them at Costco. I carried the wheels in two at a time for the installation so the trailer was not in the Costco parking lot.