Tires: tire wear issue, chevy z71, spare tires

Question
QUESTION: I have a 2005 Chevy Z71 C1500 crew cab.  I replaced my front right tire with my spare (brand new OEM Bridgestone tire).  I had the front end alligned after having the new tire installed.  The tire now looks like chunks are missing or worn.  It is intermittant and is not in a regular wear pattern.  When I brake the front end feels like it shakes.  I pulled the tire off and inspected the brake wear on the rotor and the wear is uneven.  Only 60,000 miles on the vehicle.  What could be this issue??

ANSWER: I will try to answer this question, but it is recommended to have someone look at your tire to know for sure what is wrong.  
But first, I will need more info.  
Tire name, tire style and tire size on both front.
I know you said there is a Bridgestone tire on, I need to know about both sides.  Did you replace any tires?  How much trend is left on the tires on the left and right side ( 10/32, 2/32 )?  
Is the truck, 2WD, 4WD, full time 4WD, AWD?

I wait your reply,
John

---------- FOLLOW-UP ----------

QUESTION: John,
I have a Dunlop(Rover Touring LT) tire on the front left, same size as the Bridgeston(Dueller A/T 693 II) 265/70/17.  The tread is 10/32.  My truck is a 4WD Z71, I have not used the 4WD for over a year and not since the new spare tire has been installed.

Answer
Sorry to say, but it sounds like you have messed up the front axle or the area of.
When replacing tires, replace two at a time or at least stay with the same tire.
When you miss match, you are running two different tread patterns which will mess up the differential.  Spare tires are to be only used as a temp tire until a new one can be bought.
Since you have a 4WD, ( I understand you do not use the 4WD ) and if you run two different tires like you did, that will mess up or may mess up, your front axle.
When someone runs two different tread patterns, it voids there warranty on the tires.
So you should go get two brand new tires for the front and fix the brake.
This problem will not go away until you fix it.  If you do not take care of it, you may break the axle.
Best if you have someone look at the problem to make sure I am correct and make sure there is not anymore damage.
Sorry for the bad news,
John