Single Axle Boat Trailer Tire Load Rating Suggestions

Question:

Hello! I have boat single axle trailer with st215 / 75 / d14 C rating. If I buy a category d tire instead of a c tire, then a category D tire has a stiffer tire wall and also a higher tire pressure of 50psi vs 65psi. Now that my boat and trolley are too light for a category D tire, can the trailer start jumping on the road? I mean maybe the D tire is too much ? What is your experience and suggestions? Second question. C and D tires recommend a cold pressure is. 50psi or 65. if the trailer is left in direct sunlight temp 90F for a day with max tire pressure, the air will expand, should I drive at a lower pressure or is it not a problem. Thank you!

asked by: Kaido S

Expert Reply:

The Provider ST215/75R14 Radial Trailer Tire - Load Range D # TTWTRTM2157514D will have a more stiff and less forgiving sidewall on your boat trailer than the Provider ST215/75R14 Radial Trailer Tire - Load Range C # TTWTR21514. It will truly be hard for you to notice an actual difference though when driving.

When it comes to which tire I recommend that will vary based on the different scenario. If you pushing close to the maximum weight rating I will recommend going to a higher load range. Yes the load range D tire will allow for a higher PSI and more weight but this does not mean that it will last any longer than the comparable load range C tire.

As far as pressures go I recommend using the pressures that are recommended from the trailer manufacturer. They give them these ratings to balance the amount that a tire will flex while still having the tire ride with the proper tread contact. The tire manufacturer gives their rating for a maximum amount of pressure the tire can hold without risking a blowout.

On a day as you described with the high temperatures the air pressure may rise a few PSI in the tire while it is sitting. This is okay and I generally would not get to overly concerned with such a small discrepancy in pressure. I have seen tire gauges that have a higher discrepancy than that.

expert reply by: Bud M