Nope, it actually balances the wheel for you!

seeing as its a thick liquid, bordering on being a gel it works the same way as these things - http://www.magnumbalance.com/index.htm

i've had my Ten at over 85mph with 'Seal A Wheel' sealant (similar to slime/ultraseal ) and have no issues whatsoever with balance. and come to think of it wahen i fitted the TKC's i didnt even take off the original balance weights from the Tourances - so the balance is even further out!