Shimano road chains...
 

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[Closed] Shimano road chainsets designed for 135mm/disc brakes

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Does anyone know any more about this?

I keep eyeing up some Dura Ace cranks for my nice bike, the alternative being Praxis Zayante Carbon.

Shimano state that the new Dura Ace cranks are designed for 135mm OLD hubs/Disc brake systems, which makes me think they have a wider chainline? Doesn't sound great for the chain angle, my current Ultegra setup works great but gets a little noisy in the biggest couple of sprockets in the big ring, add 5mm to the chainline and it's going to be even worse! I could live without big-big, I never deliberately use it anyway.


 
Posted : 21/05/2020 12:39 pm
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All road Shimano DA and Ultegra (9100, 9000, 8000, 6800) chain lines remain at 43.5mm. Only GRX has got wider at 46.9mm, so no problem.


 
Posted : 21/05/2020 12:53 pm
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Doesn’t sound great for the chain angle, my current Ultegra setup works great but gets a little noisy in the biggest couple of sprockets in the big ring,

- they always will be in the 2 cross-chain extremes gears.

add 5mm to the chainline and it’s going to be even worse! I could live without big-big, I never deliberately use it anyway.

It would only add 2.5mm to the rear chainline if the back end went out 5mm overall so it's within a bit of FD adjustment or accepting some crossed gears are best avoided. If anything your big-big gears will be a touch better if the cassette moves outboard relative to a chainset that stays in the same place. Small-small ratio will be a bit worse.

designed for 135mm OLD hubs/Disc brake systems, which makes me think they have a wider chainline?

It was more about how the chain is able to leave the small ring at a greater angle without catching on the shift ramps of the big ring. Older doubles can be more prone to snag there in small-small gears.


 
Posted : 21/05/2020 1:35 pm
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Seen as there are so many disc bikes on the market and have been for years with shimano cranksets, surely there is no issue??


 
Posted : 21/05/2020 10:06 pm

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