need help tire vibration/ very slight bouncing
 

2010 Grand Sport convertible front tires with 8000 miles on them. I"m getting vibrations/ tire bouncing at 70mph +. I rebalanced the tires, replaced front air dam and front splitter which did have very small gap getting air through the splitter and repaired. Anyone else have this experience ? Posted this last week and accidently deleted the thread.

have the tires/wheels spun on a balancer to see if they wobble (laterally). They can usually easily be repaired by a specialty shop, inexpensively.
Been there

PS...or, it could be the actual tire

Are those original 13 year old tires with only 8000 miles on them?

When I bought my Z, I had a similar issue. Turns out the wheels had a few slight bends. Had them straightened and new tires installed (non run flats), and all is well! Check the date codes on your tires and have the wheels themselves checked for straightness

As was previously said: How old are the tires? What type of balancing was used for the wheels and tires? It should be road force balancing. Some aftermarket wheels will need wheel hub centrics to make sure the wheel is absolutely centered on the hub. Were the wheels ever checked for being out of round? All of these can obviously affect the proper function of the wheels and tires. Good luck.

2 years old with 8k miles

Make sure rims are true and not bent.