My 11400 lb 5er has tandem 5200 lb axles. The trailer came with ST225/75-15 D at 2540 lbs.
I upgraded to 16" trailer wheels and LT215/85-16 E at 2680 lbs
Another option for you is the LT225/75-16 E at 2680 lbs and is right at 29" diameter for your trailers 5200 lb axles.
Over tiring a trailer isn't the best idea such as a 4008 lb capacity tire on 5200 lb axle. 15-20 percent above axle rating is plenty.
Having pulled GN trailers for a living I found out the hard way the down side of too much tire on a trailer. As another poster mentioned is heat. These big heavy (60) lb tires will run hot when derated to pressures your trailer tires require.
This from our resident tire engineer Tireman9 tire blog for anything you need to know about tires for your trailer...
http://www.rvtiresafety.com/ Tireman9
rvtiresafety.com
The question of load capacity and Load Range gets asked a lot, so it seems to be a bit of a stumbling block for a number of RV owners. Here is an example:
"I need to replace the ST235/75R15 tires on my trailer. Currently have load range C tires which is sufficient for the maximum trailer weight when inflated to 50psi but allows almost no safety margin. I want to change to either load range D or E tires. My rims are only rated for 65 psi so if I went to the load range E tires I would only be able to inflate them to 65 psi. My question is this. Is there any advantage to a load range E tire used at 65 psi vs a load range D tire at 65 psi?"
Now just because he is asking about a 15" trailer application and considering a change from LR-C to LR-D it does not mean the general answer does not apply to others, even if they are considering a change from LR-G to LR-H on a Goodyear 295/75R22.5 Class-A tire.
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The answer to the question is;
He will gain a safety margin if he increases his inflation to 65psi with LR-D but if he stays at 65psi there is nothing further gained by going to LR-E as there is no difference in the capacity at 65psi.
The same thing would apply to the 22.5 example. When we look at the Goodyear tables we see that at 110psi both the LR-G and the LR-H are rated for 6,175# single or in dual application at 100psi they both are rated as 5,675#.
Special note: It is important that you look at the table on the web site of the manufacturer of your tires as not all companies give the exact same capacity number at every inflation level, even for the same size.
Now if you choose the those huge 4008 lb capacity tire over your trailers 2600 lb capacity requirements then this from
rvtiresafety.comrvsafety.com
Tire Load and Inflation Ratings
Note: Towable – Travel Trailer/ 5th Wheel owners Due to the severe use conditions experienced by tires when axles are very close together – tire industry experts recommend maximum (sidewall) inflation pressure for towable tires unless this causes a sever over-inflation situation (20psi+), often referred to as the ‘basketball effect’. If this is your situation allow a 10 – 15psi safety margin above the minimum required inflation pressure.