I fight the battle of the rattles with my 996tt, just like many other do. On some days, it's very quiet. On other days, one usual somewhat rough road brings out a nasty metallic rattle from the rear. I've put plenty of felt tape on the rear panel clips, but it's still there in just the right conditions.

So I've been reading some threads on tire pressures. I have the stock hollow wheels with OEM Conti's, and have always kept them at 36/44 -- just like it says in the manual and on the label under the hood. There's the occassional bad pothole, and I don't want to risk bending a wheel with low pressure in the tires. I decided to drop the pressures by 2 psi all around, and today the car has been relatively quiet.

Could it be the marginally softer inflation has eased some of the vibration frequency producing the rattle(s), or is it just my imagination combined with numerous other factors? I guess I'll know when the rattle(s) comes back!

 

2 psi could soften things a little, absolutely.

 

Joe is right but you have to remember your tire pressures certainly can vary 4 to 10 pounds between cold up to hot so that is a pretty big range. So I guess see if you notice a difference cold up to hot. the rears starting at 44 after spirited driving will certainly see 50psi and even above.

 

Joe and Tom -- Thanks for the replies. I'll keep an eye (and ears) on it. Maybe it's just the change in weather ....

 

When I use the factory pressure, the car is too stiff. I have it on 33/38 and it rides much smoother. I am sure the handling is affected, but not enough to notice on the road.

 

when I dialed in my ssupension I did it using 36 front and 40 rear. anymore the tires are getting to hot in the back. For street use 36/40 is ideal. IMO

-Suman

 

I run 44 PSI on the rears with PS2s. The car felt very loose and would want to spin in throttle off corners. I could literally feel the sidewall rolling under the rim and the car would start to oversteer. Pretty unnerving.

Just be careful in turns with that low of a rear tire pressure.