Can 5th Wheel Trailer Tire Size be Increased to Avoid Blowouts  

Question:

Expert Reply:

The root cause for most trailer tire blowouts, apart from a direct hit from road debris, is ultimately excess heat. Heat in a tire can become excessive if the tire is loaded beyond its weight capacity, driven at a speed beyond its rating or if it is improperly inflated, either too low or too high psi pressure.

For a 5th wheel trailer such as your tandem-axle Montana Mountaineer 356TBF that has a dry weight of 13,224-lbs plus a cargo capacity of another 2,776-lbs (GVWR of 16,000-lbs) each tire needs to be capable of handling up to a substantial 4000-lbs.

In your Montana's stock tire size ST235/80-16 the highest weight capacity per tire is 3520-lbs, Load Range E. These tires are linked for you, such as Taskmaster # TTWTRTM2358016E.

In the STST235/85R16 tire size we do indeed have 4400-lb-rated Load Range G tires such as the Taskmaster # TTWPRG235R16 that you referenced. These G-rated tires are linked too.

Both of these tire sizes fit on the same rim sizes: 16 x 6, 16 x 6-1/2, 16 x 7 and 16 x 7-1/2-inches, so you can certainly make this move to this larger diameter/higher load range tire so long as you have enough clearance in the wheel wells. The ST235/85R16 tire will have an overall diameter that is about 3/4-inch larger. In most instances this difference will be okay but it is worth checking with Keystone using your trailer VIN.

Several helpful articles on trailer tires are linked for your reference.

expert reply by: Adam R

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