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SnoSheriff · 05-25-2009, 08:32 PM

I need to replace all 4 tires on my camper. I read various threads here for the comparable sizes. What's tire size is recommended for 1979 31' Sovereign?

225/75 R15 or 235/75 R15

What brand would you recommend and what online website would recommend for tires?

overlander63 · 05-25-2009, 08:42 PM

ST225/75R15 is closest radial to 7.00x15 tires. You would want load range D. We have had Marathons on the last 3 Airstreams we've had, with good luck on all of them.

SnoSheriff · 05-25-2009, 08:45 PM

I also read that the 225's are a bit smaller in diameter that the 7.00x15. Is that true and other than sitting lower what impact does that have on the trailer?

overlander64 · 05-25-2009, 08:49 PM

Greetings SnoSheriff!

I just had new tires installed on my '64 Overlander. Since my GoodYear dealer couldn't obtain a set of ST 225/75 R 15 Marathons for my coach, I went on a scavenger hunt for an ST tire with a recognizable name. Finally located a Carlisle tire dealer who carried the Carlisle Radial Trail ST tires. I stayed with my usual ST 225/75 R 15 Load Range D tire and it worked well for my Overlander. The Carlisle tires ran just enough bigger than my usual Marathons (same size and rating) that it required that the tires be deflated so that they could be worked into the wheel well.

Good luck with your research!

Kevin

overlander63 · 05-25-2009, 08:53 PM

Quote:

Originally Posted by SnoSheriff

I also read that the 225's are a bit smaller in diameter that the 7.00x15. Is that true and other than sitting lower what impact does that have on the trailer?

They are slightly smaller diameter, and slightly wider.

SteveH · 05-26-2009, 05:37 AM

Actually, Yokahama makes a radial direct replacement for the 700x15, and they call it a 7R15. It is a light truck tire, and D load range rated, but they won't tell you the speed rating. See data here: http://www.tirerack.com/tires/Spec.j...ma&model=Y742S

overlander63 · 05-26-2009, 07:23 AM

Quote:

Originally Posted by SteveH

they won't tell you the speed rating. See data here: Tire Specs for Yokohama Y742S

That's because it's an off-road tire.

hampstead38 · 05-26-2009, 07:23 AM

For our '67 Overlander, I went with Maxxis ST225/75/R15. It was a little "snug" getting them into the wheel well (inflated). I used a little dish soap rather than deflate the tires.

SteveH · 05-26-2009, 07:36 AM

Quote:

Originally Posted by overlander63

That's because it's an off-road tire.

That was the first hit that came up on Google, and they at least used to make it in highway tread.

I considered buying them for my trailer because they were LT tires.

Aage · 05-26-2009, 09:11 AM

Goodyear appear to be in some "churn" over the Marathon. I asked two different Goodyear dealers, and was told by both (who called Goodyear) that their Canadian and US warehouses had no inventory, and the the earliest date they would give was four weeks. One said that means "at least" four weeks.

Another tire that was suggested to me was the Michelin LTX MS 235/75 15 Load Range "C". I also came across a Carlisle ST225/75R15 LR "D" that has the right specs, too.

I would be interested in hearing comments from anyone that has actually used either of these tires on their AS. big difference on the prices. I know the Michelin is a light truck tire, but as was pinted out to me in a previous thread, that's what trailers used before there were ST tires.

I sure wish that there was better information from independant sources on trailer tires. Each dealer I talk to has a different opinion, mostly conflicting.

overlander64 · 05-26-2009, 09:57 AM

Greetings Aage!

I recently switched to the Carlisle Radial Trail ST 225/75 R 15 on my Overlander. Thus far, with about 200 miles on the tires they are at least equal to my previous Marathons (used since 1980). They are a bit larger than the comparable Marathon so had to be deflated to fit into my wheel wells -- clearance is adequate, but just barely. The tread design is so close to that of the Marathons that other than branding and the slight size difference it would be hard to tell the tires apart.

It is good to be aware that Carlisle produces five different lines of ST tires. When purchasing mine, I went through their descriptions on the Carlisle website and selected the model that I wanted. My local dealer only had that tire in stock in the load range E model, but ordered a set for my in Load Range D and they arrived in only three days.

SteveH · 05-26-2009, 10:03 AM

Quote:

Another tire that was suggested to me was the Michelin LTX MS 235/75 15 Load Range "C". I also came across a Carlisle ST225/75R15 LR "D" that has the right specs, too.

If a 225 has to be deflated to get clearance to be installed on the older trailers, a 235 would be even worse.

Ahzmyrah · 05-26-2009, 10:18 AM

I have not used the Michelin LT but have used the Carlisle ST in 225/75R15 Load range D on my '79 31' Excella. Put them on in Sept. '07 replacing 750-15 bias ply tires. No problem with clearances and we have towed this unit from Northern Michigan to Florida across to Texas and New Mexico and back twice in the last two years. I did notice some unusual tire wear last year and replaced one tire because it was badly worn on one side. After reading some forum discussions here and examining my axles based on the forum information I had the axles replaced while we were in Texas. It made a big difference in tire wear with no unusual wear pattern and the trailer rides and pulls much better. I used to be a tire dealer and sold both bias ply and radial trailer tires as well as all of the other types including heavy truck and passenger car tires. I know it sounds old fashioned but bias ply trailer tires really ran and wore like iron. The reason being that trailer tire side walls and the tread area are stiffer than passenger car and light truck tires and the old bias ply tires did not flex as much as radials. This causes the tires to run a lot cooler because excess flex produces heat and over heating is what causes most tires to fail prematurely for example underinflation causes over flexing and heat leading to "blowouts". A blowout is nothing more than the tire disintegrating from the inside out being literally melted. Put only properly rated Trailer tires on your trailer put Light Truck tires on your pickup or suv, keep them properly inflated, check them regularly particularly before a long trip, loaded, on a hot day and you should not have any problems. It really isn't rocket science, there is a reason tire engineneers rate tires "P", "LT" and "ST" because each application has different handling characteristics and safety issues to deal with. Have fun with your Airstream we do.

SnoSheriff · 05-26-2009, 09:53 PM

I read many tire blowout threads here. If I were to switch to 16" wheels, would I have a wider selection of more reliable tires? If so, what 16" wheels and tires would I need?

Silverhobby · 05-27-2009, 07:13 AM

If your tire is difficult to install between the hub and the trailer body, you may be having a problem with your axle.
When changing tires, be sure to look at the clearance at the inside of the tire near the frame (backside of the tire) to make sure sidewall clearance is NOT an issue. If it is close enough to rub at a standstill, the tire will flex enough during travel to cause a failure if rubbing against the frame.

Mexray · 05-27-2009, 10:19 AM

I've been using bias ply tires on my various trailers for ages...nothing wrong with em', as posted above...

My tire guy set me up with some 7.00-15's for our AS a few months ago - only have about 500 miles, but everything's good to go, so far...

Yes, they're imported...what isn't...they are:

Hartland, EXP Highway, Load range D, 6 ply nylon tread, 4 ply nylon sidewall, max load 2040 lbs @ 60 PSI (D)...

They were 'fresh dated' stock from a local tire distributor, and my guy has used them without any know problems...he says, anyway...

Correct tire pressure and a quick check with your palm to check for excesive heat when you stop, go a long way to avoid tire problems...

Just my 5/64's tread depth opinion...

sander17 · 05-27-2009, 10:27 AM

Quote:

Originally Posted by SnoSheriff

I also read that the 225's are a bit smaller in diameter that the 7.00x15. Is that true and other than sitting lower what impact does that have on the trailer?

On our old '79, when we went from 7x15 to 225's, the aluminum tire clamps that act like chocks did not fit anymore. The difference in diameter of the tires put them out of the adjustment range.

Cos · 05-27-2009, 10:59 AM

I changed to a 16in rim and went with BF Goodrich commerical tires. I found there was a larger selection of tires at different load and speed ratings with the larger wheel.