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[Closed] Longer chain for oval chain ring?

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[#10528111]

Thinking of trying an oval chain ring, same teeth as current round one - have seen some places suggest extra 4 links, rather than 2 that I would normally do


 
Posted : 11/03/2019 2:41 pm
 rone
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I think it actually would depend on the width of the chain ring. Tooth to Tooth.

Can't say I've done four links.

All mine are oval and I've used the same process - two links, that is one inner and one outer. Even on FS.


 
Posted : 11/03/2019 2:46 pm
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I think the overall tooth count is the same as your round chainring, so you should use the same chain length.


 
Posted : 11/03/2019 2:49 pm
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I used the same length as I did with the round one. Works fine.

Surely if its the same teeth on the ring, the 'effective' diameter will be the same? When the bulge is horizontal there is less vertical ring to have to stretch around.

More difficult to explain in text than I thought. I can see it in my mind though.


 
Posted : 11/03/2019 2:50 pm
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No, the chain length remains the same. The radius gain across one axis is cancelled out by the radius loss on the other axis. So no effect on chain length, no issues with clutch mechs and movement of the rear duralieur cage etc.


 
Posted : 11/03/2019 2:56 pm
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It doesn't exactly cancel out because of the changes in the angles at which the chain meets the ring (which depend on what cog you are in at the back). Very slight to-ing and fro-ing of the derailleur can be observed with an oval ring. But not enough to worry about, so peeps can run singlespeeds with oval rings, for example.


 
Posted : 11/03/2019 3:47 pm
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@greyspoke
I find the same. I run two single speeds with oval rings. There is a slight difference in chain tension as you rotate the cranks. I set up chain tension using an eccentric BB to the tightest spot on rotation, which means there is a bit of slack at the lowest spot.


 
Posted : 11/03/2019 4:03 pm
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Thanks all, will stay with same length.


 
Posted : 11/03/2019 4:33 pm