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12-speed Chainring & 8-speed chain?

Old 09-29-22, 05:45 AM
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anga
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12-speed Chainring & 8-speed chain?

SRAM Eagle X-SYNC 2 Chainring - 38t, 104 BCD, steel. 12-speed
Above chainring is available at a relatively low price.

Will it work well with an 8-speed chain, say SRAM PC830?

Single chainring, up-front.

Two possibilities at the rear.
1. Single 3/32” cog
2. 8-speed cassette

Last edited by anga; 09-29-22 at 08:31 AM. Reason: added info
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Old 09-29-22, 07:15 AM
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no. it could cause the chain to be thrown off/jam.
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Old 09-29-22, 08:30 AM
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anga
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Originally Posted by Troul View Post
no. it could cause the chain to be thrown off/jam.
Would you mind clarifying your response? Modified first post to add this info.

Single chainring, up-front.

Two possibilities at the rear.
1. Single 3/32 cog
2. 8-speed cassette
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Old 09-29-22, 08:56 AM
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You'd likely have chain slip as the 12 speed chain will not properly seat when used with am eight speed cassette.
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Old 09-29-22, 09:29 AM
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You can use an 8 speed chain with a 12 speed spec’d, well technically it is one speed, chainring.

I have not measured the inner width of different speed chains but it is really the inner width you want to be concerned about running a 3/32 rear cog.

Depending on the site, derailleur chains through 8 speed have a 3/32 inner width. 9 through 11 are 11/128, although I’m not sure that all 9’s have a narrower inner width. Not sure about 12 speed.

John
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Old 09-29-22, 09:53 AM
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IME with Shimano stuff: the 8 speed cogs are slightly thicker than the 12sp cogs.
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Old 09-29-22, 11:01 AM
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Using an 8 speed chain with a 12 speed chain ring (as anga proposed) should work as there is no front shifting and, as Troul mentioned, the 8 speed chain is wider than the 12 speed chain ring, so the two fit.

Theoretically, using a chain that is wider than the chain ring may allow some side-to-side play which may increase wear, but that is offset by using a steel chain ring.

Best practice (for a 1X and clutchless RD setup) would include a chain guide; I use this: Amazon.com : CyclingDeal Mountain MTB Road Bike Bicycle Chain Guide - Chain Drop Catcher - Chain Clamp Guard - Single Chain Guide - Size 31.8mm & 34.9mm : Sports & Outdoors
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Old 09-30-22, 08:46 PM
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A wide chain on a narrow cog might be noisy and might lead to excess wear on both the ring and the chain, but technically it should work. I never tried it. I would probably use this a temporary kludge but plan to replace it eventually with the correct ring.
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