Spritekit drastic frame rate drop - ios

Question

I have tried my best to boil this question down as simple as possible. I have a coin object in my game:
#implementation
-(CollectableCoin*)initWithLocation:(CGPoint) Location andValue: (int) val
{
self = [super initWithImageNamed:#"coin"];
[self setScale:.35];
_value = val;
_collected = false;
self.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.size];
self.physicsBody.categoryBitMask = APAColliderTypeCoin;
self.physicsBody.collisionBitMask = APAColliderTypeBall;
self.physicsBody.mass = 0.00009;
self.physicsBody.restitution = .35;
self.position = Location;
self.name = #"collectableCoin";
return self;
}
#end
I also have a shelf object:
#implementation Shelf
-(Shelf*)initWithLocation:(CGPoint) location andWidth:(NSInteger) width
{
self = [super initWithImageNamed:#"shelf"];
if(self)
{
self.size = CGSizeMake(width, HEIGHT);
self.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:self.size];
self.physicsBody.dynamic = false;
self.physicsBody.restitution = 0;
self.position = location;
self.name = #"shelf";
SKSpriteNode* topOfShelf;
if(width > 5)
topOfShelf = [[SKSpriteNode alloc] initWithColor:[UIColor yellowColor] size:CGSizeMake(width-2, 1)];
else
topOfShelf = [[SKSpriteNode alloc] initWithColor:[UIColor yellowColor] size:CGSizeMake(width, 1)];
topOfShelf.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:topOfShelf.size];
topOfShelf.physicsBody.restitution = 1;
topOfShelf.physicsBody.dynamic = false;
topOfShelf.position = CGPointMake(0, location.y + self.size.height/2);
NSLog([NSString stringWithFormat:#"%f", location.y + self.size.height/2]);
NSLog([NSString stringWithFormat:#"%f", location.y]);
topOfShelf.name = #"shelf";
[self addChild:topOfShelf];
}
return self;
}
#end
I create a scene like so:
-(id)initWithSizeTest:(CGSize)size
{
self.physicsWorld.gravity = CGVectorMake(0, 0);
_gameState = READYTOSTART;
self.physicsWorld.contactDelegate = self;
if (self = [super initWithSize:size])
{
self.physicsWorld.gravity = CGVectorMake(0, 0);
for(int i = 0; i < 25; i++)
{
CollectableCoin* orb = [[CollectableCoin alloc] initWithLocation:CGPointMake(i*10, self.size.height*.75) andValue:1];
[self addChild:orb];
}
Shelf* shelf = [[Shelf alloc] initWithLocation:CGPointMake(self.size.width/2, self.size.height/2) andWidth:self.size.width];
[self addChild:shelf];
}
return self;
}
Here is the touchesBegan method:
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */
if(_gameState == READYTOSTART)
{
self.physicsWorld.gravity = CGVectorMake(0, -2.0);
_gameState = PLAYING;
[[self childNodeWithName:#"taptostart"] removeFromParent];
}
When the scene starts, I have a row of coins hovering above a shelf, gravity is disabled, and I have a solid 60fps. When I tap the screen, the touchesbegan function enables gravity and the coins fall on the shelf, and the frame rate drops to 5fps. The didBeginContact function is not being called because the shelf object is not dynamic nor does it have contact or collision bitmasks, so I am fairly sure that it is not being overloaded by extraneous calls to didBeginContact. This happens on an iPad mini and an iPhone 4s, but not in any of the simulators. This is a very simple example of the actual problem that I am having. Anyone have any insights?