Geez. Where did you buy this.
Good thing the fronts are the same. So someone was cluey.
Weird rules.
Get a wheel alignment at the very least after new tyres and keep an eye on it.
Hard to say if there is quick wear if you haven't had it for very long.
Is the car lowered?
Agree with Duncan. Inspections would have picked that up. RWC would not have happened with that tread.
How long was it between your purchase and noticing this?
Weeks or days?
Unless you've been doing burnouts or hard driving, it would have been very low to begin with.
A 275 will have a little stretch ie, placing the rim face down, it will hit rim and not tyre.
I have them on my 10.5
I have a 265 on another 10.5 but they're A050's so, not really a good comparison.
Like I said in the pm.
Come down on Saturday, anytime between 7am and 1:30pm and have a chat with the crew at ERD/EFI.
See what cars they've worked their magic on and ask anything you want to know face to face. A good start to a good relationship with a/your mechanic and tuner is always a good thing.
http://www.skylinesaustralia.com/forums/topic/398527-sau-qld-dyno-day-sat-may-12th/