Do I have the wrong wheel and tire size on my 01 Prerunner or was Midas wrong?

I have a 2001 Prerunner 4CYL Automatic. I bought it about a month ago from a previous owner with 170K Miles on it and noticed it kind of rides hard over bumps. Originally I thought it was the shocks and struts but when I took it into Midas to have it checked out the gentleman told me that the wheels I have on it are to big and thats why it handles hard. He told me that though the shocks are the original ones they are not leaking and therefore its likely the larger wheels are the problem with the way it handles...

What do you guys say??? Do I need to get new wheels if I'm wanting a smooth ride

Do I absolutely need to have 15" wheels in order for it to ride smoothly? He also said I may be doing some damage to the truck as well with the current wheels...

Right now it has on it P235/70R16




He told me I need P225/75R15

 

tire size isnt the prob.
how much psi do you have in the tires???

 

26 psi front, 29 rear ... so it sounds like i need new shocks after all?? i have some sweet ones headed my way anyway so no sweat

 

Well then you midas well try that and see if it helps.