Trailer Tire Inflation Pressure and Speed Ratings and How Do They Affect Tire Performance

Updated 10/24/2017 | Published 10/23/2017

Products Featured in This Question

Kenda 5.30-12 Bias Trailer Tire with 12" White Wheel - 4 on 4 - Load Range C

(7697)

$89.95

Kenda 5.30-12 Bias Trailer Tire with 12" Galvanized Wheel - 4 on 4 - Load Range C

(7564)

$86.61

Question:

Hello from Tampa- Our camper was wearing out the inner edge cord on the smaller tires in 1996 and so in 1998 we started using the 5.30 X 12 load range C. These tires say max load range 1045 lbs at 80 psi cold. Does that mean to actually put 80 pounds of air which seems like a lot for a tire that size. My neighbor is a Firestone guy and said to run with about 65 lbs of air because the pressure will build on the road. This does not make sense to me because how do you know how much pressure will build up? When ever we stop for gas or something, I always check the air pressure and it stays right around 70 lbs. 1 - is this correct or should I start out with the full 80 pounds of air in each tire? 2- If that is the case, is it ok to run the tires at 75 or 85 mph? We have had no problems with these tires except on one trip while returning from North Carolina, we had a bubble develop in a sidewall while passing through Orlando. I changed the tire just in case. However, I would like to install larger tires so we can drive faster on the interstate. Can you recommend a better tire? Thanks-

asked by: JEFF B

Expert Reply:

All trailer tires, regardless of brand, size or construction, should ALWAYS have a cold tire pressure as is listed on the tire sidewall. This maximum cold psi pressure is required for the tire to meet its weight rating.

It is never appropriate to under- or over-inflate a trailer tire for any reason. There is no benefit to doing so and the incorrect pressure can lead to uneven tread wear, reduced capacity, excess heat and tire failure. Always start your travel day with your tires inflated to the maximum cold psi pressure indicated on the sidewall.

It is true that as you drive, and as the day's ambient temperature increases, your tires that were inflated to their rated psi early in the morning will indeed have higher pressure later in the day. This is normal and you do NOT need to reduce their pressure to compensate. After travel as the tires cool they will return to their rated temperature. Tires are made to handle this thermal cycling.

Trailer tires also have speed ratings. Unless a tire is specifically called out as having a particular speed rating you can presume it is rated for 65-mph. Our tires are rated for 65-mph unless we call out a different speed rating in the specs. All tires and wheel/tire items in your 5.30-12 size are shown on the linked page. These are available in load ranges B, C and D.

For example, Kenda # AM30790 is a 4-bolt wheel/bias tire in Load Range C that requires 80-psi pressure to meet its weight rating of 1045-lbs. This tire can also handle speeds up to 65-mph.

The key to long reliable tire life is avoiding heat. Heat comes from overloading the tire beyond its weight rating, incorrect inflation (too high OR too low) and from driving faster than the tire's speed rating. Avoiding these three issues will reduce chances for excessive heat in the tire and for heat-related tire failure. That will keep you on the road.

You can refer to the linked articles for more helpful tire information.