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Help me build a 2x11 crankset with a 40t/42t big ring and bashguard

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Help me build a 2x11 crankset with a 40t/42t big ring and bashguard

Old 08-01-22, 10:18 AM
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alexk_il
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Help me build a 2x11 crankset with a 40t/42t big ring and bashguard

I have an old MTB TREK 650. It's currently on single chainring with a 38T narrow-wide chainring, 8 speed shifters and RD and 9 (didn't even know this is possible?!?!) speed original cassette. It somehow works, shifting down is smoother than up though.

I'd like to set it up with M8000 rear/front drivetrain that I already own, so I have exactly the the same question as here: Help me build a 2x11 crankset with a 40t/42t big ring and bashguard. The bike comes with the with what seems to be the 104/64 Claw crankset: https://www.aliexpress.com/i/1005002838105008.html if that helps. Ideally, I'd like to have sometihng like 42t or 44t on the front.

Unfortunately I can't find an outer 10-11 speed chainrings for 104, 4 arm cranks. Most if not all are coming at 8-9 speeds which are not ideal for 2x11. Also a bit confused about the answers in that thread that mention chainring spacers and filing chainrings to make them fit. Can anyone explain what options I have, ideally mentioning specific parts.

Priorities: making it work- first, bashguard would be a bonus.

Last edited by alexk_il; 08-01-22 at 03:35 PM.
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Old 08-02-22, 07:37 AM
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I finally understand where the problem is.

I finally understand where the problem is, it's all about the evolution of the modern drivetrains and availability of the new parts:
"SRAM abandoned the front derailleur long ago, and 1x drivetrains have since become the standard for modern mountain bikes. But Shimano has remained faithful and still offers 2x mountain bike drivetrains."

Also 40-44t/26-28t cranks are also gone long ago, therefore shopping with the latest google recommendations was not easy. Luckily browsing Shimano archives opened the whole new world of information and I managed to find the following chainring combination that will hopefully work.
  • Outer ring: Shimano XT FC-M785 40T, 104 BCD
  • Inner ring: Shimano FC-M6000 26T, 64 BCD
  • No bash-guard, never needed it anyway
Please feel free to stop me if you think I am missing something big time here.
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Old 08-02-22, 08:11 AM
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beanbag
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haha, the FC-M6000 chainring is asymmetric 4 bolt, so it won't fit.

Easiest thing to do is buy an older SRAM 2x crankset with 28/42 and 10 speeds. Yes, 10 speed cranksets work with 11 speed chains and rear cassettes, Zinn said so.

Last edited by beanbag; 08-02-22 at 08:17 AM.
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Old 08-02-22, 08:43 AM
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Originally Posted by beanbag
haha, the FC-M6000 chainring is asymmetric 4 bolt, so it won't fit.
​​​​​​🤦🏻🤦🏻🤦🏻🤦🏻😂😂😂😂

This is where my naive thinking that the newer M6000 is better than the old M785 backfired.

Thanks a lot. Will call the shop and ask for the original M785 inner ring instead if they have it.
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