# Teeth on Ultegra crank



## e34john (May 31, 2010)

How uniform are the teeth supposed to be? The ones on my Ultegra SL seem to have some that are more rounded than others. Can't be wear since the bike probably doesn't even have a hundred miles on it. Aren't these things forged? Don't think the die would be tweaked that much. Or is that how they are supposed to be to even out chain wear? New at this and was just wondering.


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## PSC (Mar 10, 2004)

Teeth are that way to enhance shifting performance.


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## DaveT (Feb 12, 2004)

Shimano's chainring teeth are highly shaped to enhance the shifting. Even when brand new 'out of the box' the teeth look hooked, different shapes on different teeth, shark-finned and definitely not uniform. If you look on the backside of the chainring, you'll see machined cutouts and hollows that assist in shifting. Your chainring is perfectly normal.:thumbsup:


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## Clevor (Sep 8, 2005)

One of the reasons Shimano drivetrains shift so smoothly is the customized tooth profiles. You get the whole nine yards with Dura Ace stuff (see pic). That's a DA 7803 triple crank, which was the pinnacle of triple technology. Many who have ridden this setup say there is no deficit in shifting compared to double 7800 setups.

You don't get all that CNC machining on Campy or FSA cranks. The tooth profiles on them is so simplistic it's pitiful. I don't think Shimano went through all that trouble for nothing, to say nothing about the manufacturing expense. The tooth profiles are designed by computer and executed using CNC machines.


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