Hi. We just replaced the tires on our 12 passenger Ford E-350. We replaced them with brand new Michelin Defender LTX M/S Highway All-Season
Size: LT245/75R16 120/116R E

The first time I drove over 60 MPH on those tires was quite scary. I felt like the van was swerving back and forth and hard to keep control.

We took it back to the shop where we had done the alignment. They checked everything out and it all looked good. They recommended lowering the PSI to reduce the swerving.

Today I was driving. Swerving seems to be mostly gone, but when I get up to speeds of 75-80 mph I am still feeling it.

Any recommendations? Is this just how these tires handle? I never had a problem like this with my previous tires which were LT 225's.

Please advise.

Thanks.

 

Ironically, I just went through the same thing...same tires with front end work and alignment done at the same time. If you had alignment done with the tires, they should provide you a printout of the settings. As it turns out (the first two times, no printout) caster was off by 1.6deg on one side (which could be why they didn't give me a printout!). I had both upper and lower ball joints replaced to fix the wandering, and ended up taking it back to the shop three times before they finally got it right. They had to change bushings to get the camber correct on one side.

Edit - Original thread here for reference: https://www.ford-trucks.com/forums/1...lp-advice.html

 

is the front or rear wandering?

 

I think the front.

 

Get the printout
I'd bet it's not right
Low psi makes it looser, not tighter

 

What psi? Door sticker says 60/80 I believe. Less air isnt your friend in this case. Your caster sounds too low.