Humming sound from brand new tires

[fergo84]

Good day to all, 

i just changed my wheels and tires. 20 inch wheels

front: 20x8.5 (255/45R20)

Rear: 20x9.5 (255/45R20) alittle stretch imo but online calculator suggest that its ok.

Tires: Scorpion Verde

Before the change, i did not noticed any weird humming noises. ( just the regular road noise from tires)

Immediately after changing, the car now produces a weird humming noise. It happens at all speeds. Particularly obvious and louder when i go over rough roads. Over new tarmac, it seem to be less. If i can best describe the sound, its kinda like going over drainage grills that produces that "wooh wooh" (if you know what i mean) the noise does not change in frequency given the different speeds that i drive. only change is the volume.

Awesome service from the shop, they actually try to trial and error. Remove rear wheel and put the stock on back to drive n vice versa. Seem to be more obvious from the rear. 

Kinda weird because im using back the same tires as stock. Could the slightly stretch fitment in the rear cause the noise? shop was saying that now the new wheels are more flush and can potentially cause this noise. 

What are your views? 

[6699]

What is the offset of your new rims? Your tyres may be rubbing against the wheel housing when the car is moving.

 

[fergo84]

cant remember the offset. but its sitting flush to the fenders. 

did quite a fair bit of trial and error with workshop. 

1. same wheels, different tires (same)

2. different wheels same tires (slightly lower in volume but still there)

Workshop claimed that its the road noise due to increased in tire width. (235 to 255) I still think its not. i could hear that the typical tire road noise was significantly reduced due to new tires. 

Anyone on 20 inch experience the same? The sound/noise seem like a hollow sound. (somewhat like overinflated tires) 

[6699]

You should check your wheel offset.

For 20”rims using 255/45R20 tyres, the MB recommended wheel offset is 40.

Also, for your rear 20x9.5 rims, you should be using 285/40R20 tyres. For this staggered config, the recommended rear wheel offset is 22. Front remains same as above.

[6699]

Just to add: 

Issues with wrong offset can lead to noise caused by rubbing on fender/wheel housing and also from stress on the wheel bearings

[fergo84]

On 23/12/2017 at 11:49 PM, 6699 said:

Just to add: 

Issues with wrong offset can lead to noise caused by rubbing on fender/wheel housing and also from stress on the wheel bearings

Thanks for the input. i have no knowledge of that. too technical. hahah... but im assuming the workshop should know? its a reputable shop that i went.