Car Tire Tuning)))

[Vince F]

I have an 07' Subaru Impreza wagon that had an awful lot of road noise. I added more undercoating and sound insulation, and it helped a little, but not that much. On a Subaru Forum, I got replies to buy new tires, turn up the radio, or Dynamat the doors. All seemed stupid or like they weren't going to do much. Searching what tread designs make for more or less noise I came upon patents for designing tire treads for low noise. They said the tire forms a horn shape with the road and amplifies the sound made by the tread blocks vibrating and air being compressed and released in the grooves, as the weight of the car presses down on the tread on the road contact patch and then moves on. They had drawings of treads and complicated patterns to break up the grooves going around the tires, to spread the frequencies generated, and minimize peaks. It looked impossible to look for a tire with a tread pattern that would fit their theories, and reading reviews on Tire Rack, people would say the same tire was the quietest they ever had or the nosiest, and the ones I have had the same range of remarks, so that wasn't any help, and i wasn't going to buy new tires for a new car.

Since I have built a few horn loudspeakers, and found things that improved the sound, that I have later seen in patents, I figured I might be able to modify the tread pattern to break up the pressure pulses. I decided to just randomly apply black rubber cement to the grooves spaced close and wide apart in the grooves, and staggered sorta like I understood the patents, and it cut the noise dramatically. I have only done the front tires since they are easy to get to, but have to rotate the tires so will do the rears, and look at the front tires better, instead of having to move the car, to get to sections I hadn't treated.

I thought maybe treating some of the lateral grooves would really make them quiet, but it made them loud again, which i don't understand, so I removed the cement from them.

[Speedskater]

The major tire manufactures spend quite a bit of time and money on tire noise issues. They have anechoic chambers with treadmill like machines built into the floor to noise test tires while on a car. Tire design and manufacture is a trade-off of many factors. Like cost, life, ride comfort, ride performance and noise.

Nothing you can do at home will reduce noise and probably wont last more than a few miles.
High performance tires trade of tire noise and ride comfort for that performance.
Look for tires aimed at slow luxury sedans.

[Vince F]

well, maybe I degraded some traction, but the car is AWD, so shouldn't matter that much, but it has lasted 1500mi so far. Maybe what I did "Tuned" the tires for the car. The extra undercoating and sound insulation I added, which wasn't much, and mainly to the rear, cut down the noise from the rear, and made the sound, sound like it was just coming from the front, till I treated the front tires.

[Vince F]

sometimes subtle changes can make a lot of difference. In my other car the 6x9" speakers i changed to on the rear deck didn't sound good. I enclosed them with porous foam carpet padding, and they still didn't sound good. I opened the sides of the foam and they sounded great.

[llung]

Tires are a balance of many factors including performance (which in itself means a whole lot of different things to different people), cost, ride, wear, etc. Any change you make to it will have some affect be, it large or small. But if it were me, I would rather buy a set of tires with a certain set of desired characteristics (such as ride noise) than modify an existing tire.

When you make a change, you are most likely also changing some other characteristic and you would need to adjust your driving style to account for that change. Filling some gaps won't affect dry traction too much but you probably impacted water removal and wet traction; not to mention mud and snow traction. Also as your tire heats up, who knows what'll happen to the cement - they may melt and fall off?

Anyway, it it were me, I'd stick to buying a quiet tire to begin with. But bear in mind that there's limits to what can be done and there's always some tradeoffs. A quieter tire may have some other characteristic you find annoying.

As for making the car quieter, Dynamats in doors is a good idea. If you could get into the roof, it'd work there too. You want to dampen vibration and also isolate the passenger compartment from the road noise. Of course, the best bet is to have the car mfg do that at design time - luxury cars are quieter by design. Again, there's going to be a limit to what you can do without doing major surgery.

good luck

[Vince F]

Like I said, reviews by owners of the same tires were all over the place, as were ones for different tires that the mfg Claims are quiet, so I might be buying many sets to find one I found I thought was quiet. Back in the mid 80's I was interested in a Mustang, and at the time GY Gatorbacks had just come out on the Corvette, and sold as a direct copy of the Gran Prix Rain Tire, and in their ads they showed both. In a 10 tire test in Car & Driver, they came in 10th in all in wet weather traction, along with a softer rubber version GY had out, which came in 5th. They were put on all the US muscle cars, and in reviews of all of them it said, " Tricky in Wet Weather".

I don't think I changed wet weather traction much if at all, and the GY tires were one reason I didn't buy the Mustang, which the model was discontinued the next yr. I didn't completely fill up the grooves to the tread height, but affected the sound level a lot. I didn't think sound insulation would help as much as reducing the sound from the source. If I did change to a quieter tire, which ever that may be, I might loose traction, if I compromised it in mine, which made them quieter.