986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Help - Need New Tire Advice

dr_gille · 02-25-2010, 06:39 AM

Thanks for the welcome gsrhoden - in regards to an earlier post. I appreciate it.

I honestly think I'm going to pursue this for a while.

The naked truth is, the job of a tire is to stay in contact with the road. Unless
one is on a billiard table smooth skid-pad, bigger wheel and tire combinations
(+1, +2) will negatively impact performance in every measurable category
EXCEPT braking, and only if the reason for the move up was to install larger
rotors.

And/Or/If one spends Cubic Dollars on very light wheels and carbon ceramic
rotors. There are some especially deep pocket folks out there that can drop
$10 to 20k on brakes and wheels, but my budget is a tenth of that.

Larger wheels and tires are heavier. They have a greater flywheel effect
which requires more energy to spin up to speed, and then stores more energy
that has to be scrubbed off when slowing down, meaning extended stopping
distances, and increased brake wear.

There's also the increased gyroscopic effect of those four flywheels spinning
(which you really can't feel on a car that easily, but if you've been on a
motorcycle, the effect is obvious).

This gyroscopic effect of stored energy provides a net resistance to the car
changing direction. That impacts the nimbleness of cornering.

No Spin - No Proof. In many ways.

I darn near spun it last week, hooking into a corner and downshifting, and I
hit very small pressure ridge in the pavement, which the hard sidewall low profile
tires skittered across and the rear end broke loose.

Almost pulled a Speed Racer, headlights/tailights/headlights move.

I was surprised, because that Never happens in my Electra 225 (haha, just
messin with you guys...)...

02-25-2010, 06:39 AM	#6
dr_gille Registered User Join Date: Feb 2010 Location: Arizona Posts: 7	Thanks for the welcome gsrhoden - in regards to an earlier post. I appreciate it. I honestly think I'm going to pursue this for a while. The naked truth is, the job of a tire is to stay in contact with the road. Unless one is on a billiard table smooth skid-pad, bigger wheel and tire combinations (+1, +2) will negatively impact performance in every measurable category EXCEPT braking, and only if the reason for the move up was to install larger rotors. And/Or/If one spends Cubic Dollars on very light wheels and carbon ceramic rotors. There are some especially deep pocket folks out there that can drop $10 to 20k on brakes and wheels, but my budget is a tenth of that. Larger wheels and tires are heavier. They have a greater flywheel effect which requires more energy to spin up to speed, and then stores more energy that has to be scrubbed off when slowing down, meaning extended stopping distances, and increased brake wear. There's also the increased gyroscopic effect of those four flywheels spinning (which you really can't feel on a car that easily, but if you've been on a motorcycle, the effect is obvious). This gyroscopic effect of stored energy provides a net resistance to the car changing direction. That impacts the nimbleness of cornering. No Spin - No Proof. In many ways. I darn near spun it last week, hooking into a corner and downshifting, and I hit very small pressure ridge in the pavement, which the hard sidewall low profile tires skittered across and the rear end broke loose. Almost pulled a Speed Racer, headlights/tailights/headlights move. I was surprised, because that Never happens in my Electra 225 (haha, just messin with you guys...)...