Weird grinding/scraping noise from rear wheels after new wheel install

[asdfshow1215]

Hello everyone, hope y'all are doing well. I got a new set of wheels & tires installed on my 2018 Mustang GT PP1. I noticed after putting them on that there is a weird noise from the rear wheels upon braking, like a scraping/griding noise. I let a shop install them and put them on. The rear size of the rims is 20x11 with 305/35/20 tires , American Racing TTF rims. I did not have that noise with the OEM wheels when braking, the sound only appeared after the new wheels were put on,l. I linked a video that shows the sound:




Someone suggested to check the lug nuts however I’m not sure how that would cause this sound.
Any advice or help would be much appreciated.

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[SheepDog]

Sounds to me like the backing plate/heat shield is scuffing a rotor. These are very easy to bend, and sometimes get tweaked when people are wrestling the wheels on and off. Take each wheel off one at a time, replace one lug nut onto a stud to keep the rotor flush against the hub, and rotate the hub

 

[Skye]

Rear wheel area, only under braking.

You can start by isolating the rear, so you can test a few things.

The shop that performed the work should have warrantied this project. Return to them, explain the situation and ask them to lift the rear of the car. Lift each side, rear, at the jack points, just enough for the wheels to clear the ground.

Once isolated, start by simply turning the wheels and performing a visual inspection. Later, have someone begin pressing down on the brake pedal while another is turning each wheel.

The checks explained above could be detailed further, with one wheel on on one side, one wheel off on the other, while the checks were made.

That it is only heard under braking is somewhat promising. The sound is linear or constant when the brakes are applied. I noticed the rim is a five-spoke. If I was hearing a clunking sound in the pattern of the spokes, I'd be worried about that.

https://www.americanracing.com/amer...MeK5bIYwrmTtCli1jH3hWq7E1KQEvKV1gFc4soOyJHocc

 

[asdfshow1215]

Rear wheel area, only under braking.

You can start by isolating the rear, so you can test a few things.

The shop that performed the work should have warrantied this project. Return to them, explain the situation and ask them to lift the rear of the car. Lift each side, rear, at the jack points, just enough for the wheels to clear the ground.

Once isolated, start by simply turning the wheels and performing a visual inspection. Later, have someone begin pressing down on the brake pedal while another is turning each wheel.

The checks explained above could be detailed further, with one wheel on on one side, one wheel off on the other, while the checks were made.

That it is only heard under braking is somewhat promising. The sound is linear or constant when the brakes are applied. I noticed the rim is a five-spoke. If I was hearing a clunking sound in the pattern of the spokes, I'd be worried about that.

https://www.americanracing.com/amer...MeK5bIYwrmTtCli1jH3hWq7E1KQEvKV1gFc4soOyJHocc

Thank you for the response Skye, going back to the shop today, hopefully they’ll figure it out.

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