kawi825

Bought some new to me wheels and sneakers for the 78. the wheels came with Pzero's. They mention 51psi which i thought was high, but i pumped them to 45psi. Took them for a drive, and MAN WERE THEY NOISY!.
These things hum as loud as my old truck with 33" mud tires.

Are these tires normally that noisy? i can hear them over the motor at 60mph.. don't like this at all.

Any relation to my pressure? i'm ignorant to these high performance tires.
(205/17 fronts, 255/17 rears)

TIA

Bill Ball

Uh, 51 is probably the maximum pressure. Take them down to 36 and take another ride. They may still be noisy.

waynestrutt

Get them off quickly and ship them north wheels and all. Will send you a set of manhole covers with new snows in trade

linderpat

What Bill said. It is always best to follow the recommendations of the car mfg - look inside of your fuel door for the sticker with the tire pressure recommendations.

antlee928

Looks like 17" rims. If this is the case take pressures down to 36PSI as recommeneded by Porsche for tyres on 17" rims./

Cheers

kawi825

Thanks guys ill give it a shot. I understand 51 was the max, so I was thinking 45 would be OK.
I actually thought the opposite, thinking you should follow the actual tire recommendations.
Thank you.

Jadz928

205 on the front is a little shy on width. Typical minimum is 225.

Just be careful as you get to know how you car handles differently with narrower 205's and wider 255's

kawi825

Thanks Jim, I thought the same. I had 245/50/16 all the way around before. I actually thought these would turn a little easier, but not the case. Gonna do a re-torque, air down, and take it out today again... If I must

antlee928

Hi Matt, strongly suggest going with the 36psi. You are running a lower aspect ration tyre that will have stiffer sidewalls. One aspect of a car's suspension system is the tyre itself and its ability of the sidewall to flex. Wider and lower aspect ration tyres tend to have stiffer sidewalls and, therefore, offer less suspension compliance on the road. This means harsher ride quality and more transmitted tyre noise. Certainly try 45psi (this is still way above the Porsche recommendation for 17" rims) but also suggest you try 36psi all around. 45psi might be good for a track day though ;-)

Cheers

rexpontius

Check the tires for cupping, this is when the thread has a sort of jagged wear, you can also feel is by going over the tire thread with your hands.

The noise can be extreme, much like worn wheel bearings. The pzero's should not be very noisy.


Cheers

kawi825

thanks all, noise is definitely better. I ended up going with about 38psi all around

Bill Ball

There is no "actual tire recommendation". Like I said, 51 is the maximum cold inflation pressure you are not to exceed (take a look at the tire sidewall again), not the recommended pressure. That varies by car.

http://www.tirerack.com/tires/tirete...jsp?techid=196

Look at the PZero specs...
http://www.tirerack.com/tires/tires....reModel=P+Zero