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Hey guys I ordered an Absolute Black Oval 30t chain ring to replace my 30t round SRAM ring. I'm guessing since I am going 30 to 30 (with the "big" part of the oval being like a 32) that I wont need to do anything to my chain? But should I need to would I measure the chain on the bigger dimension of the oval the smaller?

Thanks
J-
 

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THe AB 30 tooth chainring varies from a "diameter" of 28 teeth to 32 teeth but the actual number is 30. So no, you don't need to change your chain length. The derailleur moves slightly when pedalling to acommodate the change in diameter as you pedal.
 

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The chain always goes 1/2 way around a ring and engages 1/2 the teeth, whether oval or round, irrespective of rotation. You can watch the derailleur cage as you turn a crank with an oval ring and you'll see it doesn't move. There's a very small effect due to the changing angles involved but it's much less than a tooth.
 

Slowohioboy
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How about if you go from a 32 to a 30, is that enough of a change to require a chain link to be removed? I was told that it wasn鈥檛 but figured this is a good chance to ask again.
 

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Chain goes 1/2 way around, so going from 32 to 30 means a change of one tooth for the chain. You can only change chain length in two tooth increments. Definitely check, but it's pretty unlikely you'll need to shorten the chain.
 

Slowohioboy
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Thanks LR! I tested it a bit on the workstand without issue and it seems ok. Just figured I鈥檇 ask since it rained all weekend and I didn鈥檛 get to put any load on it.
 

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From my experience sizing big to big you usually don't fall perfectly on the link - I usually size up. I also take into account full suspension chain growth by deflating the shock & watching movement.
 

NedwannaB
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Thanks LR! I tested it a bit on the workstand without issue and it seems ok. Just figured I'd ask since it rained all weekend and I didn't get to put any load on it.
Does kind of depend on whether chain was sized correctly in the first place. Easiest is to put ring on and check extra movement of derailleur when in the big cog and make sure it's(derailleur) is not collapses on the jockey wheels in final drive cog.
 
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