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Partial Chainring Replacement with a Different Size Ring

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Partial Chainring Replacement with a Different Size Ring

Old 01-29-17, 06:04 PM
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game_player_s
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Partial Chainring Replacement with a Different Size Ring

I have a touring bike that I acquired used last year and have been slowly working on. Two of the chainring gears/cogs have some very worn teeth, likely from sandy area conditions and poor maintenance by the previous owner. For whatever reason I can not find a same tooth count replacement gear from the same maker model series and need to know if there would be any disadvantage in going with a slightly higher tooth count gear as a replacement.

Chainring set is Shimano SG (5 bolt), with D-28, D-38, D-48 gears. The 28t gear appears to be fine, but both the 38t and 48t gears are exceptionally worn. I can ride the bike as it is but the 38t ring feels way off with a notable traction issue, and the chain even makes a rather disconcerting sound when on that gear due to a few teeth being almost completely worn away.

So my question is simply must the replacement rings be "D" series or should they be interchangeable with any five-bolt pattern Shimano chain rings? Picture of the actual chainring in question.: http://www.tweeg.psoarchive.com/other/b/IMG_7966.JPG



Last edited by game_player_s; 01-29-17 at 06:36 PM. Reason: Image link
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Old 01-29-17, 06:31 PM
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dsbrantjr
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Are you sure that the "few teeth being almost completely worn away" are not the shift gates, which are put there intentionally and associated with the shift pickup pins? Typically teeth wear evenly all around the chain ring.
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Old 01-29-17, 06:33 PM
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Your pictures do not appear to be working, however--as long as the BCD (which you should measure to be sure) and number of chainring bolts match, you can use pretty much anything. Try to match the rings with the appropriate number of speeds (probably 7/8, given the product name you posted), but you aren't limited to Shimano. You may be able to find whole chainring sets from Vuelta, Sugino, Raceface, among others.
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Old 01-29-17, 06:38 PM
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Thanks for the quick replies, not sure why the picture didn't work before.
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Old 01-29-17, 09:23 PM
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game player s, In short, Shimano cuts the top of selected chain ring teeth to aid in shifting from a smaller to a larger chain ring. The smallest chain ring will have traditional looking teeth.

Look on the backside of the crank arms, there will be a model identification, perhaps starting with "FC". Use the model number to help you find the chain rings you want.

Brad
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