Shimano Chainring Compatibility
 

Hello all.

I have a Shimano FC M571 Mega 9 crankset and would like to replace the chainrings. This is an older model and am finding out that replacements are hard to find. I was able to get a new 22t ring, but the 32t, & 44t are hard to find.

My question is in regards to the operational compatibility with other Mega 9 chainrings. For example, will a FC M532 32t chainring be compatible with my existing crankset. Both are 4 bolt 104 BCD but will it operate smoothly being a different part number.

Thanks for your expertise.

A 4 bolt chainring, of same bolt circle diameter, from after market companies should work, It does not have to come from genuine Shimano spares.

Thanks for your reply. So would that mean I would have to buy the complete triple set or can I mix n match? I already have the original 22t for my crankset. With that said, can I mix n match Shimano mega 9 chainrings with the same bolt pattern and BCD??

So you could get 3 new chainrings and spend about $63 online for them to come to you. This is based on using FC M532 rings.

Or get a brand new crank with new rings and a new bottom bracket for $75 shipped. Shimano Deore M590 9 Speed Triple Chainset | Chain Reaction Cycles

Just thought itd be good to know that is an option.

I assume that this crank is for an indexed front shifting setup? Shimano's indexed triple shifting works best if the middle and large rings are "matched" so that the shifting aids (ramps, pins, tooth shapes) line up with each other.
I.e., the 44t ring is specific for 44/32 setups, and vice-versa on the 32t ring.
Small rings on triples are agnostic, so you can use any 74 BCD ring for the granny.

This could be another reason to consider buying the complete crankset...

If the OP currently has a 22T granny chainring it's safe to assume its bolt circle is not 74 mm.

Close, but no cigar.

A chainring doesn't care about the bigger one next to it. But the smaller chainring has to be the right number of teeth, AND those teeth have to be in the right position, in order for the shift gates and lift pins on the ring in question to work.

For instance, consider a road double using SRAM/Truvative rings. the small ring is worn, and is replaced with a Shimano one the same size. Suddenly the shifting bites - why? Because Shimano and SRAM don't put the teeth in the same place. Fortunately, if you hold one up against the other, it's apparent that you can just rotate the ring a couple of positions (at least with a 39t, IIRC).

Good catch. The OP's FC M571 is indeed 104/64 BCD.

You're right, although I think it's more important in double cranksets. The smallest ring on a triple doesn't seem as finicky.
Personally, I avoid indexed front shifting for triple cranks; I'm never satisfied with its performance or trim capability. My two bikes with triple cranks use friction bar-end shifters, which are fool-proof.

Thanks to all for your replies.

mstatglfr, Yeah I was looking into replacing the entire crankset as an option, but I had recently replaced the BB which is an octalink V2. (I know, I know, should've done the entire drivetrain at once instead of piece meal fashion like I'm doing now). So I'm kinda stuck going down this path.

Tim Iowa, yes the crankset if for indexed shifting. Its a Deore LX M571 crankset. Also, your right, I never looked at it before, but my small, 22t, chainring has no ramps or pins. Its pretty much a smooth cog. It is a 64mm BCD however. I've used indexed shifting on my mountain bikes for years and like your friction shifters, has been fool proof.

So this is where I'm at. I was able to locate a new Shimano exact replacement 22t and 32t chainring and so far I have $32 into it. Now I'm looking for a 44t chainring. So based on what Tim Iowa was saying about matched middle and outer chainrings, I should probably look for a M571 44t chainring.

Or maybe not. Are Mega 9 chainrings with 104mm BCD ramps and pins pretty much standard?

Setting up the FD properly is pretty crucial. But most MTB systems will have chain rub in small/small, middle/big, middle/small, and big/small. Less of an issue on newer and/or nicer stuff.
Shimano's flat bar road front shifters (for road drivetrains) are much nicer; they have the trim positions lacking on the MTB stuff.


Pretty much, AFAIK; your replacement ring just has to be designed to sit next to the other ring/s you have. Shimano has a letter system to differentiate between rings with the same number of teeth that are meant to sit next to different sized rings. Your 44t should be marked '44 A' or something - just make sure you get a ring with the same letter and you should be fine.

You know... shifting is more that just peddling along and blindly changing gears. It would be nice to get the perfect idiot proof chainrings, but it is not really necessary if you develop a little technique. It is not that tough even with indexed brifters and triggers.

John