I bought alloy wheels from RT/GT model and installed barnd new Goodyear tires. Also purchased proper new lug nuts. Wheels been balanced multiple times. And I still have steering wheel vibration om high (70+ mphr) speed. 2015 Grand Carvan withn 155xxx miles.
I also have another set of wheels/tires (steellies) with 0 (zero) problems. 80+ on highway and no problem
Im really confused
Steering wheel sahking is kinda intermediate and extremely annoying
I weighed to compare steel wheel and alloy. Steel wheel + tire is 55lb, alloy is 47
My left front strut is leaking alittle bid, planning to replace it this summer and try alloy wheels again
other than that front suspension is tight. Brakes are good

wheel type, pic from interner

Im super confused and annoyed.
Please advise