LC 250 Premium - Highway instability after wheel/tire swap, seeking diagnosis
Replaced my 2013 GX 460 with a 2026 LC 250 Premium in December. Around 2,700 miles I swapped to GX 550 Overtrail OEM wheels (18x7.5, +50mm offset vs stock +60mm) and Falken Wildpeak AT4W 275/70/18 Load Range E at 40-42 PSI cold.
Had the vehicle aligned by an LC/GX specialist in SoCal. Despite that, the car drives terribly on highway - constant rightward drift, tramlining, left-right hunting on grooved pavement, and just generally exhausting and unsettled. Not harsh - just never planted.
What I've done:
- Road force balanced twice at America's Tire - discovered first shop balanced at 33 PSI door sticker pressure instead of correct 40-42 PSI for E load. Rebalanced correctly, all four corners now at 16-18 lbs
- Front tires swapped side to side as conicity diagnostic — pull didn't clearly reverse
- Alignment confirmed clean — thrust angle 0.00°, camber equal, minor caster split
Now at 6,000 miles with persistent issues.
My theories:
- +50mm vs +60mm offset increasing scrub radius
- 0.13° rear thrust angle from non-adjustable rear toe
- E load stiff sidewalls fighting the LC 250's EPS
- AT4W too aggressive for this platform — considering KO3 or Toyo AT3 as replacement
- Stock suspension underdamped — considering BP-51 install?
Coming from a GX 460 with hydraulic steering so the EPS adjustment is real, but this feels like more than adaptation. Anyone dealt with similar issues?
More info on Mud: https://forum.ih8mud.com/threads/lc-250-premium-persistent-highway-instability-after-wheel-tire-swap-seeking-diagnosis.1380900/