275/65/18 too small?

[2015ChevySilverado]

I am looking to get my 2015 Chevy Silverado low as I can so I can get my pressure cleaner in the bed, I need to ramp it up in there as this is a very heavy unit, and the angle of the ramps are too steep. The dealer told me 'after purchase' that a lowering kit may void the warranty, and I have a pending claim since the truck shakes at 70-80mph which they cant fix???

 

What smaller tire size could I go to? I know a tire size wont lower it much but every bit helps. Thinking 275/60/18 ?.

I just cant understand why chevy makes the bed so high off the ground...sure make it harder for a contractor to work out of

[iancabanilla]

On 2013-02-11 at 7:03 PM, MS3DALE said:

Thanks,heres a few more with the same size 275/65R18 on the stock wheels...

 

 

 

I assumed the previous tires are 265? How's the rim flange on the stock wheels after you put the 275? Fits snugly? Not too tight? Need some input. Will buy a new set of tires soon. Thanks