Chevy feeling unstable

[stinkbelly]

I have a 2015 chevy 2500HD, 4x4 diesel and I just had 2 new tires put on the back end. They replaced the exact tire. All tires balances. Front tires are really new. Now it feels like the truck is unstable. It feels like it is swaying around. The back end feels like it slides sideways when I drive on a winding FM road at highways speeds. Also I had to lay on the brakes at 70mph and it started to fishtail. I had to keep turning into it to keep control.

What is going on?

[Smart]

Chevy feeling unstable

This was a long time ago, but I was told in high school by a tire guy to put new AT or MT rubber up front if you only buy two tires. Dad insisted the new rubber go on the back so that the drive tires had the better tread. Tire guy said ok. Whatever you want. I experienced the same thing when we did that. Slight fishtailing, unstable feeling. Like the back was walking driving straight down the road. We went back and flipped them and all was well. Guy said it had something to do with the softness of new tread versus tread that had some wear on it. Told me to always put new ATs up front. You might try that.

[alec73065]

This was a long time ago, but I was told in high school by a tire guy to put new AT or MT rubber up front if you only buy two tires. Dad insisted the new rubber go on the back so that the drive tires had the better tread. Tire guy said ok. Whatever you want. I experienced the same thing when we did that. Slight fishtailing, unstable feeling. Like the back was walking driving straight down the road. We went back and flipped them and all was well. Guy said it had something to do with the softness of new tread versus tread that had some wear on it. Told me to always put new ATs up front. You might try that.

This is what I have always been told as well and have done with no issues .

[Tbar]

Are they Michilens? In the past whenever I put on a new set it felt like that but got better over time. I don't know why.

[Johnny44]

Shocks ?

[eradicator]

This was a long time ago, but I was told in high school by a tire guy to put new AT or MT rubber up front if you only buy two tires. Dad insisted the new rubber go on the back so that the drive tires had the better tread. Tire guy said ok. Whatever you want. I experienced the same thing when we did that. Slight fishtailing, unstable feeling. Like the back was walking driving straight down the road. We went back and flipped them and all was well. Guy said it had something to do with the softness of new tread versus tread that had some wear on it. Told me to always put new ATs up front. You might try that.

My tire guy says this is true. He's been in business for many, many years.

[EarleyBird]

This was a long time ago, but I was told in high school by a tire guy to put new AT or MT rubber up front if you only buy two tires. Dad insisted the new rubber go on the back so that the drive tires had the better tread. Tire guy said ok. Whatever you want. I experienced the same thing when we did that. Slight fishtailing, unstable feeling. Like the back was walking driving straight down the road. We went back and flipped them and all was well. Guy said it had something to do with the softness of new tread versus tread that had some wear on it. Told me to always put new ATs up front. You might try that.

^This, exactly. Overinflating rear tires will do the same.

[SB09]

This is called tire squirm and is pretty common with brand new tires. Especially aggressive mud terrain types.

If it doesn't subside after a few hundred miles I'd take them back and see what can be done. It could be a manufacture defect judging by how pronounced it is for you.

[bbqfan5909]

Make sure new tires are E rated also.

[BlessedVeteran0305]

I always put new tread on the front no matter what vehicle if I'm only buying two. Was told about this in high school and always went with what worked.

[BRUTE 23]

Discount tire sold me an at tire a few years back for my 2015 2500 that was super sketchy. I had the back end try to slide out from under my twice in turns and they were down right scary on uneven roads or rain. I went back in after about 5K miles, one month for me, and talked to them. They said they had gotten a lot of complaints on them and were pulling them. Paid a couple hundred bucks to get my normal nittos put back on.

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[WItoTX]

This is called tire squirm and is pretty common with brand new tires. Especially aggressive mud terrain types.

If it doesn't subside after a few hundred miles I'd take them back and see what can be done. It could be a manufacture defect judging by how pronounced it is for you.

This. Had the same issue with Ridge Grapplers for about 200 miles.

[Deathrow Jethro]

This was a long time ago, but I was told in high school by a tire guy to put new AT or MT rubber up front if you only buy two tires. Dad insisted the new rubber go on the back so that the drive tires had the better tread. Tire guy said ok. Whatever you want. I experienced the same thing when we did that. Slight fishtailing, unstable feeling. Like the back was walking driving straight down the road. We went back and flipped them and all was well. Guy said it had something to do with the softness of new tread versus tread that had some wear on it. Told me to always put new ATs up front. You might try that.

This or under-inflated tires will feel squirmy.

[sasqy]

New tires always seem sloppy until they tighten up !

[stinkbelly]

These are cooper discoverers. I have had these on the truck since 2016 .

I jumped on the corners of the truck and the shocks seen fine.