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-   -   Crank Ring sizes? (https://www.bikeforums.net/bicycle-mechanics/1299366-crank-ring-sizes.html)

joesch 08-28-24 06:41 AM

Crank Ring sizes?
 
I know that crank rings have gone from 3x and 2x to 1x (one by) and larger teeth counts like higher 50s to now higher 20s but are there different teeth widths than 1/8 and 3/32 like chains?

Curious since some rings are now termed 11 and 12 speed so was not sure if the widths have decreased from 3/32?

This question is based on SRAM NX crankset where each tooth's thickness is CNC machined to work seamlessly with the chain's inner and outer links making it a better 11/12 spd crank. This CNC machining must change the 3/32 width? Also these rings are only offered in 28T, 30T, 32T, 36T sizes.

Steel Monkey 08-28-24 06:55 AM

Just from what I've read, I think the 1/8 and 3/32 measurements refer to distance between inside plate surfaces. So, admittedly having no knowledge of the particular chains, I'd expect the measurements to still be 3/32. My limited understanding is that, as number of cogs has gone up and available cassette space has remained constant(?), chain plates have grown thinner.

Though I am just a small bear of limited brain. :)

grumpus 08-28-24 09:08 AM


Originally Posted by joesch (Post 23334048)
I know that crank rings have gone from 3x and 2x to 1x (one by) and larger teeth counts like higher 50s to now higher 20s but are there different teeth widths than 1/8 and 3/32 like chains?

Curious since some rings are now termed 11 and 12 speed so was not sure if the widths have decreased from 3/32?

This question is based on SRAM NX crankset where each tooth's thickness is CNC machined to work seamlessly with the chain's inner and outer links making it a better 11/12 spd crank. This CNC machining must change the 3/32 width? Also these rings are only offered in 28T, 30T, 32T, 36T sizes.

7 speed HG cassette sprockets are 1.85 mm wide, Shimano 10 speed sprockets are 1.6 mm wide, and the chain inner width has become slightly narrower to suit this, from 2.38 to 2.18 mm. The machining to suit inner and outer links is known as narrow-wide, the shoulder of each outer-link tooth is wider to better align the following inner link. Generic narrow-wide chainrings are readily available, I've used them on 1x7 and 1x10 bikes and they run smoothly. Obviously they only work in 1x systems with even-number chainring tooth counts.

joesch 08-28-24 12:42 PM

Only asking the one question this time:

Are there different teeth widths than 1/8 and 3/32 like chains?

Note that 1/8 are for SS and 3/32 for multi-gear bikes like the common road bike.

maddog34 08-28-24 03:22 PM


Originally Posted by joesch (Post 23334422)
Only asking the one question this time:

Are there different teeth widths than 1/8 and 3/32 like chains?

Note that 1/8 are for SS and 3/32 for multi-gear bikes like the common road bike.

yes.
add 11/128ths to the list.... 9 speed and up...
and OUTER plate/pin width comes into play too...

https://bike.bikegremlin.com/3555/bi...ion-standards/

joesch 08-28-24 04:16 PM


Originally Posted by maddog34 (Post 23334574)
yes.
add 11/128ths to the list.... 9 speed and up...
and OUTER plate/pin width comes into play too...

https://bike.bikegremlin.com/3555/bi...ion-standards/

The link claims: "Multi speed chains from 9 to 12 speeds have inner width of 11/128″ (2.18 mm)"

Does it also cover a different tooth/teeth on ring width to work better for these more narrow chains? I did not see but the link also mentions: Note how rollers of all the multispeed chains are of almost the same width, only single speed chain being significantly wider on the inside.

Pitch is the same for all the chains – they are aligned by length.

Maybe only SS rings need wider teeth on rings and not even required as many conversions use road bike chains and rings.

maddog34 08-28-24 04:29 PM

they even vary between brands of chains or gears, within the respective "gear counts".. I recall measuring a selection of KMC, SRAM, and Shimano 6-7-8 sp.chains once....they were all a tiny bit different, even between two different models of KMCs of that group... i went with the shimano to reduce occasional noise from an annoying cassette...
and then, there's Campagnolo.. they exist in a world of their own, but are still fairly similar.

Kontact 08-28-24 08:52 PM


Originally Posted by joesch (Post 23334624)
The link claims: "Multi speed chains from 9 to 12 speeds have inner width of 11/128″ (2.18 mm)"

Does it also cover a different tooth/teeth on ring width to work better for these more narrow chains? I did not see but the link also mentions: Note how rollers of all the multispeed chains are of almost the same width, only single speed chain being significantly wider on the inside.

Pitch is the same for all the chains – they are aligned by length.

Maybe only SS rings need wider teeth on rings and not even required as many conversions use road bike chains and rings.

That website is riddled with errors, and I have never heard that dimension. What is true is that 11 speed chains will run on even 5 speed sprocket teeth. Some 12 speed also will, but SRAM road chains are narrower inside and only work correctly with SRAM road 12 speed cassettes and chainrings, or products designed to be compatible. So we know some of that information is wrong.


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