Rear Tire's cupping - Page 2 - ZR-1 Net Registry Forums

lakemeadzmonster · 11-04-2013

To clarify, To get the best feel, I'm only talking around 100 pounds. If two adults in the car its not needed. Obviously the car was designed to have more weight in it than the driver.

The Goodyear Eagles had no cupping when I took them off a couple of years ago. I'm going to talk to Big O and see if they caught the issue with cupping and if the rear thrust angle was checked and if they forced balanced. Joel

csavaglio · 11-04-2013

Good luck. Let us know what they say.

Chris

batchman · 11-08-2013

If it's not worn parts, it's alignment.

Try more (rear) negative camber, bump it by 1/2 deg more negative or so.

Flip the tires on the rim so you can tell what the wear is doing.

A cheapie infrared pyrometer can tell you about what's happening after a 10 minute highway run.

Good luck,
- Jeff

lakemeadzmonster · 11-09-2013

The final word from Big-O Tire concerning what they did during the 4 wheel alignment.

The thrust angle I believe was off in rear according to the Tech who did it initially but I was not given the before and after findings the first day. So what I have is 2 Technician accounts verifying the rear was out of alignment when I brought it in which caused the cupping.

But minor enough the tire should wear back flat on outer treads. I had it checked and got a new baseline this time, with the correct setup the Z tracks great even on these bumpy freeways and I'm really happy with the NITTO Motivo front tires what a difference! Gas milage creeping back up.

Thank You to all of the forum members and Corvette enthusiasts who have Served our Country and helped keep our Country the Greatest so we can own cars like these.

11-04-2013	#11
lakemeadzmonster Join Date: Nov 2006 Location: Las Vegas, Nevada Posts: 137	Re: Rear Tire's cupping To clarify, To get the best feel, I'm only talking around 100 pounds. If two adults in the car its not needed. Obviously the car was designed to have more weight in it than the driver. The Goodyear Eagles had no cupping when I took them off a couple of years ago. I'm going to talk to Big O and see if they caught the issue with cupping and if the rear thrust angle was checked and if they forced balanced. Joel __________________ [SIGPIC][/SIGPIC]

11-04-2013	#12
csavaglio Join Date: Oct 2013 Location: Colorado Springs, CO Posts: 160	Re: Rear Tire's cupping Good luck. Let us know what they say. Chris

11-08-2013	#13
batchman Join Date: Jun 2009 Location: I live at Devens, one run at a time Posts: 455	Re: Rear Tire's cupping If it's not worn parts, it's alignment. Try more (rear) negative camber, bump it by 1/2 deg more negative or so. Flip the tires on the rim so you can tell what the wear is doing. A cheapie infrared pyrometer can tell you about what's happening after a 10 minute highway run. Good luck, - Jeff __________________ [I]91 ZR-1 #1840, autocrossing in SCCA BSP. FIC S/S's DRM chip/Watson/Borla/lid/LW batt&headlights, springs, shocks, pads & lines, quick rack & Turn One, camber brace, 32/22mm sways, A/C halfway deleted 17x11 & 12 CCW's, 315 & 335 Hoosier A6s [/I]

11-09-2013	#14
lakemeadzmonster Join Date: Nov 2006 Location: Las Vegas, Nevada Posts: 137	Re: Rear Tire's cupping The final word from Big-O Tire concerning what they did during the 4 wheel alignment. The thrust angle I believe was off in rear according to the Tech who did it initially but I was not given the before and after findings the first day. So what I have is 2 Technician accounts verifying the rear was out of alignment when I brought it in which caused the cupping. But minor enough the tire should wear back flat on outer treads. I had it checked and got a new baseline this time, with the correct setup the Z tracks great even on these bumpy freeways and I'm really happy with the NITTO Motivo front tires what a difference! Gas milage creeping back up. Thank You to all of the forum members and Corvette enthusiasts who have Served our Country and helped keep our Country the Greatest so we can own cars like these. __________________ [SIGPIC][/SIGPIC]