Can I Replace 235/80-16 Tires with 235/85-16 Tires on a Trailer


I have had blowouts on my 235/80/16 tires on my fifth wheel. I keep the pressure right and its not overloaded, the tires seem to last about two years before having problems. How do I know if I have the clearance to go to a 235/85/16 g rated tire and does it really make a difference, and if I dont have the clearance what tire do you recommend.


Expert Reply:

It is best to have at least 4-1/2 inches of clearance between your trailer tire's tread and the underside of the trailer/fender. Of this 4-1/2 inches, 3 inches is directly for tire clearance and the additional 1-1/2 inches is for defection of the suspension.

Typically, ST235/80-16 size tires have an overall diameter of 30.9 inches. For ST235/85-16 size tires, the overall diameter is increased to 31.6 inches. Moving up a tire size will bring your tire tread approximately 3/8 of an inch closer to the underside of the trailer. This increase is minimal so it is likely that if you have proper clearance with your existing ST235/80-16 size tires then the ST235/85-16 will work just fine for you.

If your existing ST235/80-16 trailer tires are Load Range E and you have a tandem axle trailer, these tires are offering you a maximum load capacity of around 14,000 pounds. Using 4 of the larger ST235/85-16 size tires with Load Range G capacities will give you around 16,000 pounds of capacity. Keep in mind that going with higher capacity tires will not increase the trailer's capacity.

Using higher rated tires can help the issue you are having with blowouts, but if there is a different issue causing the tires to blow, changing the tire size will not stop your tires from wearing out in a couple of years.

There are some things to keep in mind to try and help extend the life of your tires. Two of these things you have referenced, keeping the tires inflated to their maximum psi and ensuring that the tires are not overloaded for their weight capacity. The other aspect to keep in mind is the speed at which the tires are run. Most trailer tires have a speed rating of 65 miles per hour, but some newer tires, like the Taskmaster Provider ST235/85R16 Radial Trailer Tire, Load Range G # TTWPRG235R16, have higher speed ratings of 81 miles per hour. Running a trailer tire faster than its speed rating can cause the tire to run hotter, which in turn can lead to a blowout. A tire that runs cooler can have a longer life.

Additionally, you will want to keep the trailer hub and bearings properly lubricated. If there is not enough grease inside the hub, the bearings will run hot, which will heat up the hub, which will heat up the tire and cause it to run hot. Keeping the trailer properly maintained will also help the life of your tires.

I have linked all of our ST235/85-16 size tires in Load Range G for you. The # TTWPRG235R16 I referenced earlier is only the tire. But tire and wheel combos, like the Provider ST235/85R16 Radial Trailer Tire, 16" White Spoke Wheel, 8 on 6-1/2 inch, Load Range G # TTWA16RGWSHD, are also available.

If you decide you do not have the clearance needed to size up your trailer's tires, I have linked all of our ST235/80-16 size tires for you as well.

A help article that covers some frequently asked questions on trailer tires is linked for you.

expert reply by:
Victoria B

Products Referenced in This Question

Product Page this Question was Asked From

Follow up Questions

Similar Expert Q&A Pages

See More Q&A Expert Answers >>