Joined: May 2008
Posts: 10,111
Likes: 2,753
From: Fredericksburg, Va
Bikes: ? Proteous, '65 Frejus TDF, '73 Bottecchia Giro d'Italia, '83 Colnago Superissimo, '84 Trek 610, '84 Trek 760, '88 Pinarello Veneto, '88 De Rosa Pro, '89 Pinarello Montello, 'Litespeed Catalyst'94 Burley Duet, 97 Specialized RockHopper, 2010 Langster
disassemble the axle and take it to your local machine shop. Have them duplicate it with 4mm longer. Specify how much on which end and where. You need to know where the Hub needs to be with the longer axle. For an 8 speed you may only need to split evenly, 2mm per side. I don't know how much more is needed to accomidate the extra sprocket. From the pictures I posted, you can tell that the 7 speed freewheel easily fit in the 126 spacing for what was a 6 speed freewheel.
I saw a chart of thickness' of freewheels but don't recall where it is. I looked on Harris, but no.