Highly recommend this product line, America's tire had them in 2 days
for about $70/side installed:

http://www.greenball.com/

Main short term advantage of the of the "T" rated tire is stiffer
sidewalls=less sway, which will enable higher speeds. Long term, much
greater life and less chance of deformation and degradation which can
lead to blowouts.

There is a 195/75/15 which is close to your needs, plus others in the
Greenball II line. I did not see a radial in your size, but note that
Bias will last and has stiffer sidewalls, although it might ride
rougher. My instruments incuding a Sage have survived just fine.

http://www.greenball.com/products.php?products_id=4

Check out the excellent calculators on the Tire Rack to get the actual
dimensions. You can also get the tires shaved at a quality shop if
they are a little big, but I doubt you will need to.

http://tires.tirerack.com/tires/Tire...r%20Calculator

Just like in cars, the right trailer tires can make a big difference
in handling. My setup ('95 Integra GS-R/SA box trailer, 2600lbs each)
is stable at 70 with only 8% on the tongue, and I get 22mpg at 55 mph
with the trailer tires at 50 psi. With the "P" tires, anything over
60 was marginal at best. The tires I have now (Greenball II,
ST205/65D14) are 8 YO with no sign of wear or degradation.


aerodyne
Cirrus "660"