Does anyone know what chain ring type, model, brand to get for the 2021 model Orbea FS M 2O?
I can't seem to find what is on the bike.
All I can find on the specs is that it has a PW EB04-NW32 G4 Crankset.
Is that what I need to match a chainring to?
Is that a Shimano type?
From the aftermarket chainrings that I have found I need to know
what the BCD is
tooth profile,
Being new to bikes this is all a bit confusing to me.
I have a 32 tooth chainring now and would like to go up to at least a 34 or 36 if possible.
Fitment
You need to check how the current chain ring is mounted to the motor, on some bikes they are mounted directly to the motor spindle, and on others the chain ring mounts onto a separate spider which mounts to the motor. You can tell if its the seperate spider by the fact it will have 4 bolts connecting the ring to the spider
All the wild fs that I have seen (including my own) the chain ring mounts onto a separate spider, so I would assume yours is like this , if it is then any 104bcd chainring will fit the spider as long as its not so large that it fouls the chainstay or other part of the frame, as the suspension moves.
If you dont have the separate spider then you need a direct mount chain ring suitable for a bosch cx gen 4 motor - I dont think wolf tooth make a direct mount chain ring for the bosch cx gen 4
Tooth profile
Your bike has 12 gears , therefore you need a chinaring that is compatible with 12 speed chains, The wolf tooth range of chain rings differentiates between shimano chains and sram chains, if you have a shimano 12 speed chain you should use their drop stop st range, if you have sram chain then their drop stop b range (more details here
Wolf Tooth renames narrow-wide chainrings Dropstop A, B & ST based on compatibility - Bikerumor). I think (but do check - read the markings on the links) you wild has a shimano chain, so you want drop stop ST.
In reality the tooth profile doesnt matter too much, I suspect a drop stop st ring would work just fine with an sram chain and vice versa. Just get a ring that states it is for 12 speed .
Elliptical or round
For an e bike you want a round ring, the motor is turning the chainring independently of the crank arm position, so there is no point going for an eliptical ring on an ebike .
On a normal bike you may like the feel of an eliptical ring - I do, they're nice, smooths out the pedal stroke a bit, and seems to feel easier grinding up a steep slope.
chain length
If you just went to a 34 tooth ring, you'd probably getaway with reusing the existing chain, going bigger than 34 tooth, then you'd have to suck it and see. you need to check that the derailluer isnt fully stretched out when in the biggest cog on the cassette with the suspension fully compressed.
