Road Noise 19" vs 21" Hard Numbers

[Muzzman1]

So I just replaced my 21" Arachnids with my 19" cyclones(with Pirelli P7's) for an upcoming trip to Lake Tahoe from LA.

I figured I'd take a dB noise measurement over a 5 mile road at exactly 50mph in the same lane and see what the average Decibel reading over the drive. (I used dB meter pro on the ios app store)
My 21" wheels came in at an average of 53dB ad the 19" at 52dB.

It's a measurable difference!

I'm not sure exactly how scientific my measurements are, but the numbers match my experience. The 19"'s are definitely less harsh and quieter.

 

[DIL]

But arachnids!

 

[Drewflux]

Its intresting the numbers are not that different. But it Feels quieter

 

[Ande]

dbm does not tell everything, frequency and spectrum is important too.
I did not measure, but my car with 22" wheels is quieter than a 19" loaner due to aftermarket noise proofing. I think that's the way to go.