I have a Shimano Deore LX crankset. I would like to replace the outer chainring. What manufacturer chainrings are compatible with my crankset ? My outer chainring takes all of the abuse, due to logs and rocks.

  • 2
    If you don't use the big ring much you may consider a bash ring. It installs in place of the big ring but with no teeth and is strong enough to bounce off logs and rocks.
    – mikes
    Jun 11, 2013 at 19:50

2 Answers 2


Any chainring that has the same bolt circle diameter (BCD) and the same number of bolts as your crank is compatible with your crank. The ever helpful Sheldon Brown has a page describing how to measure your BCD. The way you do it is dependent on how many bolts you have so I won't go into the details here.

While a chainring may be compatible with your crank, there are other problems you can run into...

Depending on your chain, you may or may not be able to use a chainring that was designed for a different chain, e.g., a 9-speed chainring with an 8-speed chain. Many people do this with success while many others have problems. It's probably easiest to just get one that you're sure matches.

You also may have problems going bigger or smaller than your current chainring. Whether or not this is the case depends on your front derailleur and the width of your chainstays. Derailleurs have a minimum and maximum number of teeth they can accommodate. Check the specs on your derailleur to find out what these are. The chainstays are a bit more guesswork. Basically, the wider your chainstays, the smaller your biggest ring has to be. If you're dead set on a bigger ring, you can get a little wiggle room through spacers or a longer bottom bracket spindle but it's usually not enough to be worth the hassle.


Might need a little more information - Deore LX has been around about as long as Shimano, and I am not certain if the specs changed over that time.....

My belief is you will need a 104 PCD 4 bolt chain ring. If its 5 bolt - it will most likely be 110 PCD.

These are standard sizes. Any chain ring manufactured to fit will be suitable.

  • thanks for answering. hope to buy a replacement this week.
    – Dan Barber
    Jun 12, 2013 at 19:45

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