NSTimer在单独的线程上的行为不正确

-(void) startSpinner {
#ifdef DEBUG_MODE
    NSLog(@\"Starting Spinner...\");
#endif
    self.spinnerThread = [[[NSThread alloc] initWithTarget:self selector:@selector(scheduleSpinner) object:nil] autorelease];
    [spinnerThread start];
}

-(void) scheduleSpinner {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSTimer *_spinTimer = [NSTimer scheduledTimerWithTimeInterval:SPIN_FIRE_INTERVAL target:self selector:@selector(timerFireMethod:) userInfo:nil repeats:YES];
    NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
    [runLoop addTimer:_spinTimer forMode:NSRunLoopCommonModes];
    [runLoop addTimer:_spinTimer forMode:UITrackingRunLoopMode];
    [runLoop run];

    [pool release];
}