# Middle chainring replacement



## jonj (Jun 18, 2015)

I am new to mountain biking and want to replace the middle chainring on my crankset. It is a Shimano Alivio, 22/32/44 teeth, and I just need to replace the middle 32T 104mm chainring. I want to find the cheapest chainring I can. I ordered one, but it didn't fit, even though the BCD, brand and teeth were the same, but it was a 9 speed chainring and mine is an 11 speed bike (so I'm guessing that was the problem).

Can someone please help me with what to look for so I get the right chainring when shopping around for a new middle chainring for this crankset? Does it have to be an 11 speed or can it be a 10 speed?


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## One Pivot (Nov 20, 2009)

You have an alivio crank on a 11 speed bike? That would be very unusual... 11s is the highest end drivetrain out there right now, usually paired with a similarly high end crank with only a single front chainring thats not 104 bcd. Are you sure you have 11 cogs on your rear cassette? What chainring did you buy that didnt fit?

A deore ring should fit. They're about 15 bucks. Any 104 ring should fit actually.


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## jonj (Jun 18, 2015)

Thanks for your reply. 
Maybe I am not accurate in my description. It's a stock 2001 trek fuel 80. There are 3 gears/rings in the front crank and 8 cogs on the rear for a total of 11. I know that it's more than 11 speeds, but I thought when looking for parts it was considered an 11 speed. 
I bought a supposed shimano deore 104mm 32t chainring that was for a 9 speed bike from bikewagon, but the middle is a tiny bit too small to fit onto the crank. The bolt holes line up right, but the metal below the bolt hole is just a tiny bit too long for it to sit onto the crank and the teeth seem to line up a little different too.

Any help out education is greatly appreciated.


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## jonj (Jun 18, 2015)

The exact part that didn't fit is listed as a shimano deore fc-m532 32 teeth 9 speed chainring


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## perttime (Aug 26, 2005)

jonj said:


> ... There are 3 gears/rings in the front crank and 8 cogs on the rear have a (3 * 8 = ) 24 gears -although only the rear 8 is often mentioned because people don't always use 3 chainrings.
> 
> it has been a while since I last replaced chainrings, and never for 8-speed but ...
> What cranks/bottom bracket do you have? I found this about the ring you bought:
> "Chainrings from Shimano HollowtechII & Octalink MTB cranksets have different length tabs & are not interchangable"


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## Misterg (Jul 17, 2014)

You have 8 sprockets on the rear which defines your transmission as an an '8 speed' (3 x 8 if you like), so you need an '8 speed' chainring.

The original chainring should have the shimano part number stamped on it - probably FC-M430-8 32T - which you can use to source a replacement.

You *may* be OK with a 9 speed chainring from the same series, but I'm not sure of this - it might not play well with the 8 speed rings.

You could probably change the complete crank to a 9 speed, though (if you needed a new bottom bracket, this could be chaper than buying the BB and the chainring separately if you look for sale offers). If you don't change the BB, you would need to make sure that the cranks suited the one that you already have (Octalink??).


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## *OneSpeed* (Oct 18, 2013)

Shimano Alivio M415 32T/104mm Silver, 7/8 Speed


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## Mr Pig (Jun 25, 2008)

The cheapest thing to do is buy a whole new chainset. They don't sell those rings individually. The good news is that most of the cheaper Shimano chainsets use the same steel rings so if you find someone selling just a right crank/rings you should be able to just swap them over. 

Although the hole spacing might be the same, they often make the mating surfaces around them a little different so rings from higher up the range don't fit. Yeah I know, pretty annoying.


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## *OneSpeed* (Oct 18, 2013)

is that ring i linked is no good?


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## AndrwSwitch (Nov 8, 2007)

This thread is hurting my head a little.

OP, if the ring you bought isn't damaged or anything, file it down.

You can also look for the Alivio ring, but maintenance parts at that level are sometimes hard to find.

Or, go to a shop and tell them what you're looking for. They should have rings in stock, and be able to test fit something. I experienced a really similar situation several years ago and ended up using a FSA ring that fit okay right out of the box.


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## JonathanGennick (Sep 15, 2006)

AndrwSwitch said:


> OP, if the ring you bought isn't damaged or anything, file it down.


I like Andrew's idea. The ring is a sunk cost, so it's worth seeing if the tabs can be ground down to fit.


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## Harold (Dec 23, 2003)

AndrwSwitch said:


> OP, if the ring you bought isn't damaged or anything, file it down.





JonathanGennick said:


> I like Andrew's idea. The ring is a sunk cost, so it's worth seeing if the tabs can be ground down to fit.


Simplest answer, since you already have a chainring. The differences between 8 and 9spd are subtle and lots of parts have cross compatibility. If you can file the mounting tabs to make it fit, it should shift just fine.

My wife's first mtb was an 8spd, but had 9spd derailleurs. When we upgraded it to a 9spd cassette/shifters, we kept the rear derailleur and crankset. Always worked fine.


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## smilinsteve (Jul 21, 2009)

Thanks for reminding me how despicable Shimano is. Making chainrings with different length tabs so they aren't interchangable? Sheesh. I've been hating on SRAM lately, but now I'm refocused.


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## AndrwSwitch (Nov 8, 2007)

I've done stuff like that with 8 and 9 mountain too. Also 9 and 10 road.


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## Harold (Dec 23, 2003)

smilinsteve said:


> Thanks for reminding me how despicable Shimano is. Making chainrings with different length tabs so they aren't interchangable? Sheesh. I've been hating on SRAM lately, but now I'm refocused.


I like Shimano brakes, but SRAM's drivetrain stuff is nice. Shimano has ALWAYS liked to futz with chainring compatibility on their cranksets. Infuriating. My wife's bike came with an XTR crankset. Not many chainring options there, because her crankset uses a funny BCD.


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## jeffj (Jan 13, 2004)

Chainrings have become more and more complicated, especially the past five years. The more they do to fine tune the shifting for a particular groupset, the more specialized it becomes. If you look at pin placements, 2x or 3x, and all of the other subtle nuances they must account for, I think they have good reasons to try to get you to get the proper rings for your crankset. Maybe not always, but I don't see it as being as evil as some make it out to be.


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## Mr Pig (Jun 25, 2008)

smilinsteve said:


> Thanks for reminding me how despicable Shimano is. Making chainrings with different length tabs so they aren't interchangable? Sheesh. I've been hating on SRAM lately, but now I'm refocused.


I'd rep you for that but I can't yet :0)


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## AndrwSwitch (Nov 8, 2007)

I think Shimano does a great job with front shifting, and I think part of that is the machining on the sides of the rings.

But yeah, it can be frustrating. The four-bolt standard itself is already something they did, as I understand it.

I like that they're willing to try things, like biopace and more optimized spiders for XTR. Obviously the market rejects some of it. It is annoying when they do it across the board. I feel no pity for early adopters who have a few things not work out, but I think people who buy XT and lower expect fully developed products that are easy to own.

I did find it kind of ironic that the machining on the sides of Shimano's replacement rings meant I had to go elsewhere to maintain my Alivio crank, though, and their recent attitude about granny ring sizes got me to stick with SRAM last time I replaced a complete crank.


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## Mr Pig (Jun 25, 2008)

AndrwSwitch said:


> I did find it kind of ironic that the machining on the sides of Shimano's replacement rings meant I had to go elsewhere to maintain my Alivio crank..


Alivio cranks are so cheap it doesn't really make sense to replace the rings, you just buy a new crankset.


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## Guest (Jun 22, 2015)

Mr Pig said:


> Alivio cranks are so cheap it doesn't really make sense to replace the rings, you just buy a new crankset.


 <<This<< I won't even buy Shimano rings for XT Cranks, the crankset is cheaper than the rings normally. If you're going to better rings (like Raceface or similar) buying replacements might be a good idea, but not on Alivio cranks. That would be like installing Leather seats in your 1986 Yugo.


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## HEMIjer (Jul 17, 2008)

smilinsteve said:


> Thanks for reminding me how despicable Shimano is. Making chainrings with different length tabs so they aren't interchangable? Sheesh. I've been hating on SRAM lately, but now I'm refocused.


Seriously he is talking a lower end 8 speed crankset from 2001 and ordering rings 14 years later, things change. This isn't Shimano it is time pure and simple.

Original Poster if you are that much in a jam I have a deore level crankset with square taper bottom bracket I will send you cheap (or close to free) (you pay shipping and handling). PM if need it.


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## nightvisionmiami (Dec 29, 2014)

BENKD29 said:


> Shimano Alivio M415 32T/104mm Silver, 7/8 Speed


The above link states the product is out of stock. ChainReactionCycles and REI has it out of stock as well.

Shimano Alivio M415 found it on Amazon. But you are looking at $15 plus $4 s/h.

As it was mentioned before, might be hard to get your hands on the right part. I would file it down and see if it works. If you can't get it to work, then you have to evaluate if you spend $20 on 1 individual Chaingring or put that to a new Crank which might be a better investment.


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## AndrwSwitch (Nov 8, 2007)

Mr Pig said:


> Alivio cranks are so cheap it doesn't really make sense to replace the rings, you just buy a new crankset.


It's been a little while since I was that price driven in my bike maintenance choices. But I still dislike waste. It's pretty hard to replace a whole crankset for $30, and pretty easy to replace a chain ring for that. And since people sometimes kill their favorite rings twice as fast as less useful ones - why not. It's a perfectly good set of crank arms.

It's also as good an excuse as any to get something a little nicer if that's what a person wants. But I think it's really hard to make a money argument for replacing more than necessary.


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## RoadTire (Jan 6, 2014)

HEMIjer said:


> Original Poster if you are that much in a jam I have a deore level crankset with square taper bottom bracket I will send you cheap (or close to free) (you pay shipping and handling). PM if need it.


OP - If this crankset works for you, it's your best bet IMO, other than trying to mod the chainring as already suggested.

I had the same problem, needed to replace a chainring on my low-end 9 sp Octalink triple, and eventually just purchased a whole 9 sp square taper crankset just for the set of rings. I figured least likely to have shifting problems and worked out perfectly. The prices are so low it is hard to justify the risk of getting the wrong chainring.


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## jonj (Jun 18, 2015)

HEMIjer said:


> Seriously he is talking a lower end 8 speed crankset from 2001 and ordering rings 14 years later, things change. This isn't Shimano it is time pure and simple.
> 
> Original Poster if you are that much in a jam I have a deore level crankset with square taper bottom bracket I will send you cheap (or close to free) (you pay shipping and handling). PM if need it.


Thanks HEMIjer. I will try to file down the tabs and see if that works, if not I will definitely take you up on your offer.

I didn't realize how much work I needed to do on this bike when I bought it, because it is my first bike, but I am learning a lot from these forums and just trial and error of working on it.


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## jeffj (Jan 13, 2004)

AndrwSwitch said:


> The four-bolt standard itself is already something they did, as I understand it.


IIRC, the four bolt 64mm BCD was needed to accommodate the external cup bottom brackets.


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## AndrwSwitch (Nov 8, 2007)

Huh.

Is there a bottom bracket I don't know about?

I had a 104/64 crank fifteen years ago and think they've been out more than twenty years. Which puts them before nice bikes had two-piece cranks or external bottom brackets.


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