285/70R18 or 285/75R18 Toyo A/T III on stock Overtrail wheels? (1 Viewer)

[daubourg]

I have a 2025 GX 550 Overtrail with the factory 18×7.5 wheels and CBI front bumper. I’m looking at Toyo Open Country A/T III tires in either LT285/70R18 (about 33.7 inches) or LT285/75R18 (about 34.8 inches).

I understand both sizes are approved for a 7.5-inch-wide wheel. I’m trying to understand how they fit on the GX, especially with the 2025 Overtrail’s factory lift.

If you’ve run either size on the OEM wheels, could you share:

• Whether you get rubbing at full steering lock or during suspension travel
• Whether you needed trimming, a lift, or alignment changes
• How the spare fits, and whether you noticed speedometer or driving changes
• Whether the CBI bumper affected your clearance

Photos and details about your suspension or other modifications would be especially helpful. Thanks!

 

[Emergencymed]

As I’ve come to understand with stock 2025 Overtrail onwards LT285/70R18 is the largest size that you can put on the vehicle and still retain a full size spare under the vehicle.

I’m looking at doing the same thing once my current tires are worn.