I am wanting to upgrade my 5 speed freewheel with a 6 or 7 speed freewheel. Could someone please tell me the width (or stack height) of a shimano 6 and 7 speed freewheel? A over-all width dimention would be best. I have a old schwinn le tour with a 125mm hub width and I want to make sure there is enough clearance... and it has the nut on the inside of the dropout for the derailleur hanger. I would like to have a good acurrate measurement of a freewheel so I can make sure before I buy one! Thank you.