Why do freehub and cassette have only one position that matches?

When I'm installing cassette on my freehub, I need to make sure that the spaces align correctly. That is, there are 10 splines on the freehub and 10 corresponding splines on the cassette. My first attempt was just to put it in any of 10 positions but then I found out that one groove on the freehub is slightly bigger and the corresponding spline on the cassette matches it. So in fact, there is only one acceptable position. Why is this like this? Why aren't all of the splines the same size?
Naturally, I managed to replace the cassette, so I ask this out of pure curiosity because to me this "feature" seems annoying because I need to look closely to match corresponding splines, so I thought there must be some smart reason for this behaviour.
cassette freehub alignment
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When I'm installing cassette on my freehub, I need to make sure that the spaces align correctly. That is, there are 10 splines on the freehub and 10 corresponding splines on the cassette. My first attempt was just to put it in any of 10 positions but then I found out that one groove on the freehub is slightly bigger and the corresponding spline on the cassette matches it. So in fact, there is only one acceptable position. Why is this like this? Why aren't all of the splines the same size?
Naturally, I managed to replace the cassette, so I ask this out of pure curiosity because to me this "feature" seems annoying because I need to look closely to match corresponding splines, so I thought there must be some smart reason for this behaviour.
cassette freehub alignment
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user43286 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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When I'm installing cassette on my freehub, I need to make sure that the spaces align correctly. That is, there are 10 splines on the freehub and 10 corresponding splines on the cassette. My first attempt was just to put it in any of 10 positions but then I found out that one groove on the freehub is slightly bigger and the corresponding spline on the cassette matches it. So in fact, there is only one acceptable position. Why is this like this? Why aren't all of the splines the same size?
Naturally, I managed to replace the cassette, so I ask this out of pure curiosity because to me this "feature" seems annoying because I need to look closely to match corresponding splines, so I thought there must be some smart reason for this behaviour.
cassette freehub alignment
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user43286 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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When I'm installing cassette on my freehub, I need to make sure that the spaces align correctly. That is, there are 10 splines on the freehub and 10 corresponding splines on the cassette. My first attempt was just to put it in any of 10 positions but then I found out that one groove on the freehub is slightly bigger and the corresponding spline on the cassette matches it. So in fact, there is only one acceptable position. Why is this like this? Why aren't all of the splines the same size?
Naturally, I managed to replace the cassette, so I ask this out of pure curiosity because to me this "feature" seems annoying because I need to look closely to match corresponding splines, so I thought there must be some smart reason for this behaviour.
cassette freehub alignment
cassette freehub alignment
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edited 36 mins ago
Swifty
3,0871829
3,0871829
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asked 2 hours ago
user43286user43286
111
111
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1 Answer
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Early cassettes (Suntour Accushift and Shimano Uniglide being some commonly encountered examples) weren't like this. The splines were all the same and there was no hunting for the little spline or big gap.
To summarize a bunch of history, these cassettes were current at the same time as early indexed shifting. Accushift and early Shimano SIS both functioned, but not all that well by modern standards. The cog teeth on some of them had various thinned out or axially twisted bits to act as a primitive shift aid, but they were substantively like the freewheel cogs that came immediately before them.
Arguably the key innovation in Shimano's entire history, the first Hyperglide cassettes were released in 1989. Hyperglide uses a system of mapped-out chain exit and entry points (the different profiled teeth on modern cassettes) along with pickup ramping on the sides of the cogs to facilitate smooth shifts that demand a bare minimum of finesse on the part of the rider. It's the piece of the puzzle that made indexed shifting start working really well, and has been universally copied. But by nature, in order for it to work, the cogs have to be in an as-designed position relative to one another. Hence all modern cassettes only go on one way.
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Early cassettes (Suntour Accushift and Shimano Uniglide being some commonly encountered examples) weren't like this. The splines were all the same and there was no hunting for the little spline or big gap.
To summarize a bunch of history, these cassettes were current at the same time as early indexed shifting. Accushift and early Shimano SIS both functioned, but not all that well by modern standards. The cog teeth on some of them had various thinned out or axially twisted bits to act as a primitive shift aid, but they were substantively like the freewheel cogs that came immediately before them.
Arguably the key innovation in Shimano's entire history, the first Hyperglide cassettes were released in 1989. Hyperglide uses a system of mapped-out chain exit and entry points (the different profiled teeth on modern cassettes) along with pickup ramping on the sides of the cogs to facilitate smooth shifts that demand a bare minimum of finesse on the part of the rider. It's the piece of the puzzle that made indexed shifting start working really well, and has been universally copied. But by nature, in order for it to work, the cogs have to be in an as-designed position relative to one another. Hence all modern cassettes only go on one way.
add a comment |
Early cassettes (Suntour Accushift and Shimano Uniglide being some commonly encountered examples) weren't like this. The splines were all the same and there was no hunting for the little spline or big gap.
To summarize a bunch of history, these cassettes were current at the same time as early indexed shifting. Accushift and early Shimano SIS both functioned, but not all that well by modern standards. The cog teeth on some of them had various thinned out or axially twisted bits to act as a primitive shift aid, but they were substantively like the freewheel cogs that came immediately before them.
Arguably the key innovation in Shimano's entire history, the first Hyperglide cassettes were released in 1989. Hyperglide uses a system of mapped-out chain exit and entry points (the different profiled teeth on modern cassettes) along with pickup ramping on the sides of the cogs to facilitate smooth shifts that demand a bare minimum of finesse on the part of the rider. It's the piece of the puzzle that made indexed shifting start working really well, and has been universally copied. But by nature, in order for it to work, the cogs have to be in an as-designed position relative to one another. Hence all modern cassettes only go on one way.
add a comment |
Early cassettes (Suntour Accushift and Shimano Uniglide being some commonly encountered examples) weren't like this. The splines were all the same and there was no hunting for the little spline or big gap.
To summarize a bunch of history, these cassettes were current at the same time as early indexed shifting. Accushift and early Shimano SIS both functioned, but not all that well by modern standards. The cog teeth on some of them had various thinned out or axially twisted bits to act as a primitive shift aid, but they were substantively like the freewheel cogs that came immediately before them.
Arguably the key innovation in Shimano's entire history, the first Hyperglide cassettes were released in 1989. Hyperglide uses a system of mapped-out chain exit and entry points (the different profiled teeth on modern cassettes) along with pickup ramping on the sides of the cogs to facilitate smooth shifts that demand a bare minimum of finesse on the part of the rider. It's the piece of the puzzle that made indexed shifting start working really well, and has been universally copied. But by nature, in order for it to work, the cogs have to be in an as-designed position relative to one another. Hence all modern cassettes only go on one way.
Early cassettes (Suntour Accushift and Shimano Uniglide being some commonly encountered examples) weren't like this. The splines were all the same and there was no hunting for the little spline or big gap.
To summarize a bunch of history, these cassettes were current at the same time as early indexed shifting. Accushift and early Shimano SIS both functioned, but not all that well by modern standards. The cog teeth on some of them had various thinned out or axially twisted bits to act as a primitive shift aid, but they were substantively like the freewheel cogs that came immediately before them.
Arguably the key innovation in Shimano's entire history, the first Hyperglide cassettes were released in 1989. Hyperglide uses a system of mapped-out chain exit and entry points (the different profiled teeth on modern cassettes) along with pickup ramping on the sides of the cogs to facilitate smooth shifts that demand a bare minimum of finesse on the part of the rider. It's the piece of the puzzle that made indexed shifting start working really well, and has been universally copied. But by nature, in order for it to work, the cogs have to be in an as-designed position relative to one another. Hence all modern cassettes only go on one way.
answered 1 hour ago
Nathan KnutsonNathan Knutson
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