3 tabbed sprockets for Hubs - How are they the same? How are they different?

[Oken]

Shimano makes a bunch of different 3 tabbed sprockets. Some dished like this 20T
View attachment 2196831

View attachment 2196835
You can orient the dish in or out and the tabs will always align, and you can use the dishing and spacers that come with your hub to adjust the chain line from the chain ring to the hub.

FYI Y'all: If you experience a loose-fitting (laterally) Shimano sprocket on a non-Shimano hub, it can be because the mounting width of the sprocket is a little bit narrower than a SA/F&S/SRAM version. In that case, it can sometimes help to use a Shimano square cross-section snapring (part number Y32520110 / Y32120100) instead of the normal round SA/Sachs/SRAM snapring to make the sprocket sit tight on the hub driver.

 

[Miq]

You mean sprockets meant for 1/8" vs 3/32" inside chain width?

Yes 3/32” inside width. I know the Sturmey Archer sprockets come in different thicknesses.

 

[Oken]

Strictly speaking off topic in regards to the thread title, but I will just quickly mention them here for reference:
The "Cannonball" SRAM 9/8 speed internally geared hubs (i-Motion 9, G9, G8) used proprietary four-tab sprockets with an inner diameter of 55 mm, produced in 18 to 22T sizes.

 

[Oken]

Who ordered Deep Dish?

Normally, sprockets smaller than 16 teeth are flat (non-dished/not offset), with a few exceptions. Here is a 15T oddball from my stash:

A full 7.5 mm of offset. The snapring would probably be a nightmare to get off again once installed in the deep recess.

 

[Oken]

Regarding the whole wide (1/8") and narrow (3/32") chain type and sprocket thickness: I measured at lot of sprockets and the results are:

• The plate thickness of narrow sprockets meant for 3/32" chains is typically between 2.1 and 2.2 mm
• The plate thickness of wide sprockets meant for 1/8" chains is typically between 2.9 and 3.0 mm
• The effective thickness of the sprocket where the snapring sits is 3.0 mm* on both wide and narrow sprockets

My naive, metric European brain then wanted to check if the effective mounting thickness matched @Old'n'Slow Bikes' stated use of "11 gauge stainless steel" for the custom 24 and 28 tooth rear cogs. It will be easy, they said. It will be fun, they said... Different Google searches started giving me different, contradicting answers. What's up with that? Then I found this...
Guys, we need to have a conversation about your (America's) units of measurements. Are you telling me that the thickness of sheet metal is different depending on the material for the same gauge number? And before you answer "it's because it's based on the mass/density/weight of the material", let me counter with the question "then why is 11 gauge brass and aluminum the same, but stainless different?"

*It probably could be a bit more than 3.0 mm and still achieve a good snapring fit, but it should not be thinner.

 

[Old'n'Slow Bikes]

Welcome to world of American measurements, where nothing makes sense! Typically, the 11gauge stainless that I use is .118" thick. Yeh, crazy, we mesh metric ( .118 of an inch??!!) with imperial measurements!

 

[Old'n'Slow Bikes]

Oh yeh, .118" is 2.9xx mm. And to keep in mind, .005" is a sheet of cheap paper

 

[Oken]

Welcome to world of American measurements, where nothing makes sense! Typically, the 11gauge stainless that I use is .118" thick. Yeh, crazy, we mesh metric ( .118 of an inch??!!) with imperial measurements!

Thank you for the clarification!
0.118 inches converts to 2.997 mm which is spot-on for my analog/vernier caliper measurement of 3.0 mm.

 

[Oken]

At some point we can talk about the 1/8" vs 3/32" chain width varieties...

According to this, this, this and this, Sun Race Sturmey-Archer produces flat 3/32'' sprockets in 13 to 22 teeth, dished 3/32'' in 17 to 19 teeth, flat 1/8'' in 13 to 22 teeth and dished 1/8'' in 17 to 24 teeth.

Extrapolated from what I have seen, it seems F&S/Sachs/SRAM produced flat sprockets in 14-20T in both 1/8" and 3/32", and dished sprockets in 16-24 in both 1/8" and 3/32" (although 21-22-24 probably only in 3/32").

 

[WillWork4Parts]

According to this, this, this and this, Sun Race Sturmey-Archer produces flat 3/32'' sprockets in 13 to 22 teeth, dished 3/32'' in 17 to 19 teeth, flat 1/8'' in 13 to 22 teeth and dished 1/8'' in 17 to 24 teeth.

Extrapolated from what I have seen, it seems F&S/Sachs/SRAM produced flat sprockets in 14-20T in both 1/8" and 3/32", and dished sprockets in 16-24 in both 1/8" and 3/32" (although 21-22-24 probably only in 3/32").

I just had a 22t on a 7sp Sachs in my hands last night. Now I wish I had measured thickness. It seems like the more gears these hubs have, the more teeth they have too.