mcman56 Posted April 9, 2011 Report Share Posted April 9, 2011 Does someone sell rear sprockets on line? I'm told the wheel is from a 1971 Alpina. Chain size is 428. ID about 5.75, 6 bolts, 3 pins about 8mm, bolt/ pin circle about 6.375, shallow counter bore. The wheel is on a BSA C15 and I'm looking for a big sprocket up near 80 tooth. I could even do the ID and bolt circle machining if sprocket blanks were available in that size. Quote Link to comment Share on other sites More sharing options...
pschrauber Posted April 9, 2011 Report Share Posted April 9, 2011 (edited) Does someone sell rear sprockets on line? I'm told the wheel is from a 1971 Alpina. Chain size is 428. ID about 5.75, 6 bolts, 3 pins about 8mm, bolt/ pin circle about 6.375, shallow counter bore. The wheel is on a BSA C15 and I'm looking for a big sprocket up near 80 tooth. I could even do the ID and bolt circle machining if sprocket blanks were available in that size. You can look up here, they have sprockets front and rear, maybe they manufacture a special one on your request, but this will cost some money! Talon Edited April 9, 2011 by PSchrauber Quote Link to comment Share on other sites More sharing options...
feetupfun Posted April 10, 2011 Report Share Posted April 10, 2011 I think that for such a big 428 sprocket you will not find one ready-made for an early Alpina hub available on-line. The Aussie Talon importer sells 428 and 520 rear blanks made from aluminium alloy for reasonable prices so I imagine you should be able to get a blank from Talon direct or from someone nearer you who sells them. Quote Link to comment Share on other sites More sharing options...
monoped Posted April 10, 2011 Report Share Posted April 10, 2011 An 80 tooth rear sprocket seems extreme! Have you checked the primary gearing? It is probable that the duplex chain sprocket on the cranshaft (which drives the clutch basket)may be from a road bike. For trials use this sprocket should be 12 teeth, whilst you are at it check the size of the gear box sprocket as well. Quote Link to comment Share on other sites More sharing options...
motovita Posted April 10, 2011 Report Share Posted April 10, 2011 Does someone sell rear sprockets on line? I'm told the wheel is from a 1971 Alpina. Chain size is 428. ID about 5.75, 6 bolts, 3 pins about 8mm, bolt/ pin circle about 6.375, shallow counter bore. The wheel is on a BSA C15 and I'm looking for a big sprocket up near 80 tooth. I could even do the ID and bolt circle machining if sprocket blanks were available in that size. I would contact Sprocket Specialists in your state of CA. They can probably make one for you. Quote Link to comment Share on other sites More sharing options...
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