[CR]Shimano Cassette Compatability

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Date: Wed, 1 Dec 2004 08:10:47 -0800 (PST)
From: "Tom Dalton" <tom_s_dalton@yahoo.com>
To: classicrendezvous@bikelist.org
Subject: [CR]Shimano Cassette Compatability

For the gentleman in Switzerland with the Dura Ace hub question: I'm nearly certain that the cassette bodies from Dura Ace EX (EX) and New Dura Ace (7400) are not interchangeable. I reacall a tool for removing the older body that was similar if function to a crank extractor, suggesting that the body was pressed on to the hubshell. The 7400 body was threaded to the shell by an extension of the inner body through which the axle passed. There is a special splined remover to remove the body from the shell, similar in function and use to a splined freewheel remover.

On the other hand, I may be wrong... of course, and both bodies may be threaded to the shell. The best way to tell is to pull the axle on the EX and look for a set of splines just inside the edge of the bearing race at the end of the inner body. If the splines are there, the bodies may actually interchange. Then you just need to find that tool, which was used on hubs made through 1996 or so, and should still be available.

Regarding the lower level bodies (someone else asked about this), all the other Shimano cassette bodies were not like Dura Ace. They typically used a separate hollow bolt to hold the body to the shell. A 10mm allen wrench is used to remove the bolt, after you pull the axle (bacause that's where the wrench goes). I know there are exceptions, and the 600EX (first gen) was one of them. It was press fit and I think it used the extractor mentioned in the first paragraph. Bodies on some of the real cheap hubs were swaged in place and could not be removed.

Given all the variations above, it is easy to see why so many people complain about Shimano's lack of interchangeability. But consider this: All Shimano cassettes use the same splined cogs from the intro of the cassette with EX, to the intro of Hyperglide. I'd say that was roughly from 1978 to 1989. When they finally wised up and made cassette hubs, Campy made three different spline types (origial, EXA, and EXA2) in the span of about five years (1990-1995). So all the Shimano body wierdness aside, where it really matters (the cogs) they were pretty consistant. In addition, the different cassettte body on DA was built to be stronger (no just different) but was too expensive to a design to use on cheaper hubs. Eventually it seems that Shimano realized that the extra strength of the DA design was not needed (probably saw few failures of the cheaper, lighter design) and DA bodies from 9 and 10 speed groups are more like the cheaper hubs (though I don't know about compatibility).

Tom Dalton Bethlehem, PA

Tom Dalton Bethlehem, PA

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