New Tires

Yes. I think I need a "c" (my current load 1820) not a "d" (which is 2100ish).

I am thinking a radial is the way to go.

I think this is what I may get:

http://www.etrailer.com/Tires-and-Wheels/Taskmaster/TTWTRTM2057515C.html

st205/75d15

The D behind the 75 denotes a bias ply tire and not a load range D.

I am thinking of ordering this...

http://www.etrailer.com/Tires-and-Wheels/Taskmaster/TTWTRTM2057515C.html

I don't think I need a Load D?

http://www.etrailer.com/Tires-and-Wheels/Taskmaster/TTWAS15B45SM.html

Above is a "C". Did you find a "D" Grit Dog?

Get on etrailer.com. Good prices, get D rated 205/75 R15s.

The weight capacity on the tire for what I have now: f78-15st st205/75d15 is 1820. Now that I just looked on the tire it says: f78-15st (st205/75d15) NOTE that the last part is in parenthesis.

You may also use LT tires on your trailer as long as it has the proper load capacity. In fact many folks that have the usual ST tire problems, move on up to the LT tire.
Benefits are 7-10 years before replacement vs 3-5 years for the ST tire.
LT tires have no speed restrictions vs 65 mph for the ST if your a interstate traveler.
If you choose to use a ST tire be aware of warranty differences. Maxxis ST8008 has a 5 year warranty and other ST brands may have a 3 year warranty. Some don't bother with it....some do.

Depending on room in the wheel well and proper wheel pressure/wheel width requirements;
... the Goodyear Wrangler HT in a LT235/75-15 C (50 psi) at 1980 lb capacity. Most LT tire makers carry this size.

And a Wrangler HT in a LT215/75-15 D (65 psi) at 2090 lbs capacity.

Maxxis LT U-168 are a commercial grade tire with several 15" sizes and have became popular with all types of trailer owners.

I see the Yokohama RY215 in a 700R 15 D at 2040 lbs capacity is popular on some of the other RV websites.

Do your home work on the numbers for your particular trailers wheel well top and side clearances.

I'd just look for the numeric size and ignore the alpha. I know what you mean about replacing good looking tires. The ones I took off the trailer looked perfect, but were 4 years old. I always cover them when not in use.

The first set the tire store got were 18 months old and I said no way. They ordered several sets because they said they couldn't request certain date codes. The ones that came in were right at the 6 month mark, so I took them.

They do seem to track a little better than the el cheapie tires that came with the trailer.

Good luck!

jfkmk: yes that is the full code. DOT code says date of manufacture was 2006. Sadly they look like new....but a lot of commotion about tire life on another thread I posted. I bought camper a year ago and has not left the driveway cause I've done some repairs. The consensus is that I should get new. What - is now the question. I know the tire size and hear ST - which makes sense I guess.

BY the way - on a side note.....I just had 4 tires put on my truck. 2 are 6 months old and 2 are 2 years old. I'm pretty pissed about that. I have to confront Sears with this. But don't know if they will do anything. Last time I got tires I had no problem. They were recent. So I never thought to insist on DOT date. A little knowledge is good....but ya gotta remember to use it. I am gonna raise a stink tho.

Do the tires have both F-78-15 AND 205/75-15 on the same tire? The alpha sizing on the tires is pretty old. Basically, the numeric sizing has replaced the alpha sizing. I'd go with a good quality ST tire and watch tire pressures, not hitting curbs, etc. the tires mentioned seem to get good reviews. We bought Carlisle RH Radial tires and are very happy with them.