Do I need D tires?

I had changed from load range C tires to load range D tires because my tires were seven years old and I had put 18,000 miles on them plus whatever the original owner had on them.

While shopping for tires I noticed that some tire brands had a load rating of D at 65 psi and a load rating of C at 55 psi. The objective was to match the tire pressure to the load rating for the best performance.

I bought D rated tires and ran them at 65 psi but soon discovered that the trailer contents were being battered by the harsh ride. I now run them at 60 psi.

Some folks run at maximum pressure with no difficulty.

The week link in the system is the TT axel rating, you have to look at your TT axel rating and decide how much over that you want your tires rated for.

Agreed. Only reason to upgrade tires to a higher class is to add capacity if you're border line or have less tire than your axles capability. I've never been a fan of over classing tires more than needed and then deflating to less than full air pressure. By doing so, you create more heat and rolling resistance that also decreases gas mileage. Good that your examining it need but in your case, I'd stay where your at.

JIMNLIN wrote:
The advantage of the D tire over a C tire comes only at those higher pressures. Derating the D tire to 50 psi will make for a hotter running tire (50 vs 65) and more parasitic drag for the tow vehicle to over come. The D tire advantage is lost so may as well stick to a C tire in this case for a 4500 lb trailer with 1125 lb tire load requirements.

This ^^^^^^and like mentioned earlier, the D rated will be better on a much heavier trailer, using FULL PRESSURE to reach max rating of 2040.

Jerry

The advantage of the D tire over a C tire comes only at those higher pressures. Derating the D tire to 50 psi will make for a hotter running tire (50 vs 65) and more parasitic drag for the tow vehicle to over come. The D tire advantage is lost so may as well stick to a C tire in this case for a 4500 lb trailer with 1125 lb tire load requirements.

You can inflate load range D tires to match the load you are carrying. For the Goodyear Endurance load range D tires in your size at 50 PSI the load carrying is 1760. Here is a link to the table.

https://www.goodyearrvtires.com/pdfs/rv_inflation.pdf

A 4500 lb tandem axle trailer can have maybe 1125 lb load per tire.
Your OEM load C tires 1750 lbs at 50 psi = 7000 lbs and has plenty of reserve capacity.
Nothing is gained by over tiring the trailer such as a D tire in your trailers case other than a rougher ride for the inside of your trailer.
At some point a trailer can have too much tire and this would be a good example.

If it was my trailer I would stick with the load C tire as its has gobs of reserve capacity and will ride much better for your lightweight trailer.

The Load D tires work best on heavier trailers.

Wet and loaded I’m 5200 pounds and run with LR Ds. I don’t notice any additional bounce from the old LR Cs.

IMO, just a rougher ride, and a lighter wallet. The C-rated have plenty of margin, even at full GVWR load. The tongue/tow vehicle carries at least 10 percent, that is not even on your trailer tires.

Jerry

Can your rim handle 65 psi? I don't think you need them. It will just make for a bouncier ride that will shake everything in your trailer to death in that light of a trailer. The roads are bad enough for doing that with a LR "C". That's just my opinion.

My trailer is #5000 GVWR and weighs every bit of that..

It came with 13" LR "B" tires on it.

I upgraded to LR "D" tires in the same size many years ago and no issues..

I really didn't have any issues with the "B" tires, but I have gained more weight since then, so just want to be sure..

I pump them up to 60 psi and don't worry about it.

Never a blow out and the only reason I replace them is due to age..

17 year old trailer owned since new and have a lot of 13" old trailer tires and wheels stacked and don't know what to do with them.. ;)

Good luck!

Mitch