Shimano Deor single to double chainring

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Johnmad86
Posts: 2
Joined: 1 Jun 2023, 1:03pm

Shimano Deor single to double chainring

Post by Johnmad86 »

Hi,

Having broken my stock Shimano Deor cranks (tripple chainring) that came with my 2017 Norco Hybrid commuter bike, I decided to buy a replacement set of cranks.

Due to cost, I bought the single chainring shimano fc-m5100. This is all well and good and fits my bottom bracket.
I nievely thought that I could use my existing chainrings on the cranks, but it seems that Shimano changed their Bolt spacing to be Asymmetrical, so my old chainrings are now useless.

I have been struggling to find out if I can add an additional ring to the current setup, or if I need to just replace the 32T ring attached with a larger 44T? ring.

does anyone know if I can add a chainring to the shimano fc-m5100 (providing I can source a chainring that fits the asymmetrical bolt spacing)? Or do I need to return the cranks and buy a double chainring set from the start?

Thanks
rareposter
Posts: 1964
Joined: 27 Aug 2014, 2:40pm

Re: Shimano Deor single to double chainring

Post by rareposter »

FC-M5100 is a single ring specific chainset for MTB running 1x11 or 1x12, it absolutely won't take a second ring on there. You may struggle to fit a replacement 44 - the 1x MTB system is simply not designed for rings that big.

Without knowing the exact chainset you had on the bike originally (and the BB arrangement), it's difficult to say what would fit on it now.

Check the Q-factor and chainline too (the distance between crank arms) cos single and double ring setups will differ from triple.
Johnmad86
Posts: 2
Joined: 1 Jun 2023, 1:03pm

Re: Shimano Deor single to double chainring

Post by Johnmad86 »

thanks for the confirmation, that answers that then!
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