Can Larger Trailer Tire be Used to Reduce Risk of Blowout Failure

Updated 09/21/2017 | Published 09/20/2017

Products Featured in This Question

Kenda 215/60-8 Bias Trailer Tire with 8" Galvanized Wheel - 5 on 4-1/2 - Load Range D

(7292)

$91.70

Question:

I have a pretty old trailer and Im certain it doesnt have the stock wheels/tires on there. They look pretty tiny in the fenders. Im looking to give it a refresher as well as put some larger tires/wheels on there to decrease towing stress at highway speeds as most of my travel is fairly long distances at highway speeds. It currently has 5.7-8 on there, but looks like I could easily go bigger. How much bigger is the question. If I measure from the center hub to the fender I have about 12. Width also doesnt seem to be too much of an issue as it looks like theres plenty of room there too. I did a quick measurement and from the back of the hub to the frame of the trailer appears to be about 5. Any thoughts?

asked by: Christian

Expert Reply:

When the goal is reduction of tire heat stress so that chances of a blowout are reduced the best option is usually switching to a higher load range tire, rather than a larger size tire. That said, it is sometimes possible to do both at once.

In your tire size 5.70-8 we have tires in three weight load ranges. The maximum capacities for each are: B: 715-lbs at 50-psi; C: 910-lbs at 75-psi; and D: 1,075-lbs at 100-psi. If you happen to now have Load Range B tires on the trailer you could increase your tire load rating, and thereby reduce their operating temperature and risk of failure, by moving to a higher load range tire. All tires and wheel/tires in this size are shown on the linked page.

Since there are indeed wider tires with roughly the same overall diameter (yours are just over 18-inches when fully inflated) you could, for instance, use a wheel/tire in size ST215/60-8 (18.3-inches overall diameter) which is available with a weight rating of 1165-lbs at 70-psi. An example, is part # AM3H325. This tire size ST215/60-8 is about 8.4-inches wide and requires a wheel/rim that is 7-inches wide. This would give you a safety margin of 90 more pounds per tire. You can refer to the linked article on trailer tire sizing for more on tire dimensions and capacities.

The best ways to protect any trailer tire from a catastrophic failure are to 1) always inflate the tire to the cold psi pressure specified on its side wall; 2) operate the tire within its rated weight capacity; and 3) operate the tire within its speed rating.

Unless specifically stated otherwise, trailer tires are rated for 65-mph maximum. In your existing tire size 5.70-8 and in the wider size ST215/60-8 we have no tires rated for higher speeds.

We recommend that you have no less than 3-inches of space between the top of the tire tread surface and the interior of the fender or wheel well to allow for normal suspension travel.

expert reply by: Adam R