Are you sure it's a 1.5" headtube and not an internal 1-1/8"? If you pop the cups out, the internal diameter would be 44mm for an internal 1-1/8". A 1.5" headtube would measure 49mm.
Edit: My money is on it being 1-1/8". There doesn't look to be a whole lot more room inside the headtube- the steerer seems to be filling it out nicely.
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Originally Posted by
sp00ki
Using a nicer sealed bearing headset vs a $10 set is like throwing a frisbee vs a dodgeball.