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I have an old Shim 600 der -- will it fit a 32t?

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I have an old Shim 600 der -- will it fit a 32t?

Old 05-05-21, 03:11 PM
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JeffOYB
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I have an old Shim 600 der -- will it fit a 32t?

I have an old Shimano 600 Arabesque rear der w short cage. Can I jam a 32t cog in there? Or will the pulley hit the teeth? I know sometimes we can break the rules. Probably 28 is considered max. I have a 28 now and it has worked fine (it's acting up right now). The pulley ends up about an inch away from the cog. So maybe 32 can work? Has anyone done it? I don't care what the specs say. I want to know if you have tried, etc. Thanks!
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Old 05-05-21, 08:02 PM
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Other than a little bit of time, what do you have to lose by trying it yourself?
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Old 05-05-21, 08:05 PM
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Max cog size is dependent on, besides the manufacture's spec sheet, the bike's axle to der mount dimension. Horizontal drop outs can vary this with axle placement in the slot. Verticals not so. But all dropouts don't have the same range (horizontals) or single dimension (verticals). Then there's the aspect of the tab' stop rotational placement on the drop out. Where that "B" screw stop is controls the angle of the der's parallelogram links. Of course with most modern ders the B screw also influences this but IIRC the 600 der in question doesn't have a B strew. Next up is whether the cage spring is adjustable. Some cages have a couple of spring tail holes to vary the cage spring strength. This helps to balance the B spring and the cage spring. Lastly is the chain length. Shorter chains will wind out the cage and with the 600's upper pulley being off set (and behind) the cage pivot the pulley swings down and away from the cogs with shorter chains.

How all this comes together on any one bike is anyone's guess until actual trial is tried. Andy
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Old 05-07-21, 09:12 AM
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The 600 short cage derailleur has 2 limitations, chain capacity and maximum cog size. It was made to work with cassettes not exceeding 12-27 and chainrings not exceeding 53-39. That's 29 teeth of takeup. Your cassette alone has a 21t range, so even if you were to use a road link for clearance you don't have enough cage to take up the chain slack. Unless you're running half-step gearing up front. Which, I presume, defeats your purpose.
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Old 05-07-21, 09:52 AM
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If you have 1/2" gap between the jockey wheel and the 28t, I can't imagine there would be an issue with going to a 32t. This should give you an idea...

Table Of Radius Values For Bicycle Sprockets

Chain wrap can be a concern, but only in the small-small. If you have sized the chain correctly for the big-big, generally nothing catastrophic will happen even in the small-small. Unless it is so far beyond capacity that the chain literally sags in the small-small, typically the derailleur folds back onto itself and the chain rubs the against the chain inside the cage. And you can always avoid that gear, which can be difficult with a 5, 6 or even 7 speed freewheel, but only you know how much you use the small-small.

John
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