2018 Sierra Handling Issue Post Leveling Kit

[Auhunter]

I’ve got a question for the group. Someone else has probably already posted so if there’s a thread someone can direct me to, that would be great as well.

 

I installed a 2” motofab leveling kit with 285/55R20 Toyo Open Country LT tires. I’ve had an alignment done and even checked again. Something with the handling of the truck just doesn’t seem right. It almost feels like the steering is over compensating to a small degree or just a little sloppy for a new truck at speeds above 60 or 70 mph. Is there something else that should be checked besides the alignment or corrected? 

[300 Blackout]

If you are experiencing steering that feels loose (i.e. you have to turn the wheel more to get the same effect as before and you find yourself making steering corrections more often) these symptoms, in my experience, are to be expected when installing a larger and heavier tire.

The stock tires on my Sierra All Terrain weighed 40 pounds each. My New tires are 60 pounds each. I also went from a 31.8” to a 34.5” diameter. If you upgraded to Open Country All Terrain IIs, then you also are running 60 pound tires which are a little taller and wider than your stock tires. All those factors contribute to a “sloppy/loose” feeling. The rubber compound can also have an effect on handling.

I run my Cooper STT Pros at 50psi. The ride is stiff but I like the way it handles at that pressure. Your Toyos, assuming they are the ATIIs, can go up to 80psi. You might want to try 50 and see if it feels any better.




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[Auhunter]

Thanks. That’s good info. You are correct about the tires. They are wider, taller, and heavier than the factory tires.


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[Z45]

Larger tires (more unsprung weight) means higher inertia. Higher inertia means more workload for suspension to keep tires on the ground. If unsprung wheels and tires have a higher mass they are harder to accelerate/decelerate and it is more difficult for the suspension to maintain a consistent tire load.