I bought my 2010 hummer h3t back in 2015, noticed slight corrosion. It has got worse. Is it a case of the wheel balance peg causing it ?

 

most likely yes it is the lead balance weights reacting to the chrome finish especially in wet salty conditions

 

Thanks; bi-metal problem, a necessary evil . Or a shaky ride

 

Have your tire shop remove the outer lip mounted weights. Many better shops will not even try to put those on nicer wheels and will instead use tape on weights on the inside of the wheel instead. Depending on the balancing machine and how out of balance they might stick some as close to the outer face of the wheel while some might be towards the inside edge. They can generally get them in balance just using the stick on weights on the inside though.