I have an ’86 Miyata Seven Ten on which I replaced the stock Suntour six speed 13-26 freewheel with a Shimano seven speed 11-28 freewheel. The seven speed freewheel is a bit wider than the six speed, but there is sufficient clearance for the freewheel to fit and for the chain to engage the 11t sprocket without having to mess with spacers/redishing, etc.
The stock Suntour Cyclone rear der can readily span the seven cogs, but does not have sufficient capacity for the 28t rear cog. So I purchased a Suntour VGT rear der to replace the Cyclone. The VGT accommodates the 28t cog just fine, but will not engage the 11t cog even with the high gear limit screw fully backed out.
So I made a shim to fit between the rear der and the hanger, and the VGT now spans all seven cogs just fine. But the B tension adjuster screw only barely engages the flange on the hanger. Is there a shim I can buy that addresses this problem, or am I better off just buying a newer rear der?