How To Replace Your Chainrings

Basic removal and installation instructions for 5-bolt chainrings on 3-sprocket systems.

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This tutorial will demonstrate how to remove and install chainrings. Since there are so many different crank and chainring sizing combinations, I’ll stick to the basics and give a general overview of the process based on a 5-bolt, 3-chainring system.

For this job, you’ll typically need a 5mm allen key, a chainring nut wrench, and some waterproof grease. On some bikes, you may find it easier to remove the right crank arm before you begin.

Chainring Removal

Before removing the largest two chainrings you’ll often have to remove the smallest one, which is often threaded directly into your crank arm. Use your allen key to loosen all of the bolts that hold the chainring in place, and then use a marker to make a note of the chainring’s position in relation to the crank before removing it completely. Some chainrings have a bump sticking out that should be lined up with your crank arm.

The largest two rings are usually bolted to each other with a nut and bolt. Here you’ll need to hold the nut in place with the special chainring wrench while you loosen the bolt with your allen key. Once again it’s a good idea to mark the chainring’s position in relation to your crank arm. The two largest outer rings often have a few spacers or washers in between, so be sure to note exactly how they came apart so they can be reinstalled correctly.

While it’s ok to install a new chainring that has a different number of teeth, you’ll want to make sure that your new chainrings have the same side profile as the old ones.

Chainring Installation

Before you reinstall the bolts, apply a thin layer of grease to the threads to keep out moisture. Now you can reassemble all of your chainrings the same way they came apart.

Make sure all of the bolts are finger tight and then begin tightening them evenly in a star pattern. Start by tightening the first bolt, and then every second bolt until you’ve gone all the way around. Repeat this process until all of the bolts are tight. Be careful not to over-tighten. Park Tools recommends 44-88 inch pounds of torque for aluminum bolts, and 70-95 inch pounds for steel bolts.

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27 Responses to “How To Replace Your Chainrings”

Greg Cox on May 26th, 2008 6:05 pm

I will be riding my Giant OCR C1 double crank bike (I believe the cranks are 52/34) from Phoenix to Seattle in June with my grandson.

My experience riding has been short but in that time I have done one cross country ride, a Pacific Coast ride and a number of century rides.

Nonetheless, I still “suck” on long hills and when climbing in the mountains.

Do you think I could gain something from different chain ring sets or simply work harder. I already ride about 150 miles per week.

Thanks
Alex on May 27th, 2008 7:55 pm

Smaller front chainrings will certainly help on hills. I like to have as small as possible a ‘Granny Gear’ so I can take my time and easily climb.
Joseph on July 31st, 2008 2:35 pm

Alex, your site has been absolutely invaluable while upgrading my bike. One question for this tutorial – if replacing the chainring with a larger, how much longer should my chain be? I have a single speed bike and I’m upgrading from a 38T to a 42T front chainring. The rear freewheel will still be 16T.

Thanks again for all your help so far!
Alex on August 2nd, 2008 10:49 am

Once you have the new chain on, check the chain length using this tutorial. Also, your rear derailleur cage should be horizontal when you are in the small/small gear combination.
Nick on August 10th, 2008 7:15 pm

Thanks for all the good info Alex.

I’ve got a TruVativ Rouleur triple crankset (52/42/30) and need to replace the large and middle ring.

Searches for TruVativ replacements have come up short. Will FSA and Shimano 5-bolt fit?

Thanks,

Nick
Alex on August 11th, 2008 3:18 am

I took a look around and it looks like the Truvativ is a standard size, so you should be ok with the Shimano 5-bolt. If in doubt you can always take some measurements and compare them. Sheldon made a 5-bolt compatibility chart which you might also find helpful.
adam on August 15th, 2008 6:45 am

Hi Alex,

How can I check if my chainrings are worn enough to replace them ?

Thanks
Alex on August 15th, 2008 11:49 am

Chainrings take a long time to wear. You’ll notice that the teeth start to get really sharp looking and the chain will start skipping teeth under pressure.
syed on August 19th, 2008 9:01 pm

hello,

I recently had a chain break on me. I replaced it with a chain from Walmart and it just snapped in. However the chain starts skipping under pressure. Do I need new chainrings? The bike is very old, and I’ve got a pic if interested.

Thanks
Alex on August 20th, 2008 10:27 am

Usually your chain and rear freewheel wear out together, so it sounds like you’ll need to replace the rear sprocket cluster as well. Here’s some tutorials for both freewheel and cassette replacement.
Chris Larsen on August 26th, 2008 1:13 pm

How can I tell if a chain ring needs replaced?

My grandson has a Diamondback mountain bike, and the chain rings outer and middle look like they have a small burr on the back side(toward the rear wheel) of some of the links, but not all. the bike seems to shift well, are the cogs on the chain links shaped in some way for smooth shifting under load conditions?

The cogs do not look to be excessively worn, but do look to be shaped differently than those on my 30 year old road bike.
Alex on August 26th, 2008 1:47 pm

Chainrings last a lot longer than chains/cassettes. Usually the first indication that they need replacing will be if the chain starts skipping under pressure. They will wear, but will likely function fine for quite a while…
Simon on October 20th, 2008 10:27 am

Hi Alex,

I want to swap out the chainrings on my 2006 Kona Sutra to lower the gearing from 52-42-30 to 48-38-26, but I have some concerns WRT the front derailleur setup.

I understand I will have to lower the FD to maintain the correct clearance with the new large chainring size. However this bike has a braze-on FD and it’s not clear to me what if any option there is for the significant adjustment required. Do I have any option here other than cutting off the braze-on mount and getting a new clamp-on FD?

Secondly, I read somewhere that the curve of the FD cage plate has to approximate the diameter of the large chainring in order to ensure correct shifting. How much of an issue is this, specifically with an indexed FD (Shimano 105) which cannot be manually trimmed?

Thanks,

Simon.
Alex on October 21st, 2008 10:23 am

Simon, if you can get the proper height adjustment with your front derailleur on the braze-on then it should be ok. Otherwise you’ll have to replace the derailleur. The curve of the derailleur should roughly match the curve of your largest derailleur, but it’s not always crucial. Try setting it up and see how it goes… there’s some more tips in the front derailleur adjustment video
Garrett on November 2nd, 2008 3:38 pm

Hi Alex,

I was wondering if you know of a online site or place that I can buy a Campagnolo chainring and cassette from. I need to replace my smaller chainring which is 39T and my 8 speed cassette. Also on the chainring is say “-39-AS-” and I was wondering what the “AS” means.

Thanks
Alex on November 5th, 2008 12:28 pm

Hi Garrett,

I’m drawing a blank about the “AS” and I can’t find anything on google. Hopefully someone who knows better will respond here.

I did find a chainring and cassette in the shop.
Alan Bell on November 23rd, 2008 3:20 pm

Hi Alex
Amazing site and extremely helpful. I repacked the bearings in the bottom bracket and reinstalled the assy making sure the longest end of the shaft is on the drive side. I then took apart the chain rings to clean and dress the burrs. I made sure the tabs aligned with the crank arm and reinstalled. Now the small chain ring rubs on the frame. Did I miss something ?

Thanks
Alex on November 23rd, 2008 11:51 pm

Thanks Alan… nice gravatar!

If everything was re-installed correctly, I’m thinking the small chainring is on backwards? Sometimes they have a different spacing depending on which way they are installed. I’d try flipping it over and see if that does it… let us know!
Alan Bell on November 24th, 2008 4:36 pm

Hi Alex,

Fixed the problem, the clearance is still not that great but it won’t move and won’t rub unless the ring gets bashed.

Keep up the good work, much appreciated
Cameron on January 15th, 2009 5:40 pm

I have three rings on my bike but I want to make it a single ring in the front. Is there anything I should know before i just take the other two off?
thanks
Alex on January 16th, 2009 3:30 pm

Hi Cameron,

The middle ring would be the best one to leave on, as the chainline in that position will still allow for smooth shifting on all of your rear cogs.
Graham on January 24th, 2009 8:39 pm

When i ride along on my 2nd chain ring, the chain slips. 1st and 3rd are fine but its only my middle chain ring. I’ve ridden close to 1500km on my bike. Should i just replace the chain ring if possible or should I grab get myself a new crankset. I recently replaced the chain and cassette after I bent my old chain. Could this be contributing to the problem?

Thanks Graham
Alex on January 25th, 2009 1:43 pm

Graham, considering your chain & cassette are new, it does sound like your middle chainring may be worn out. How do the teeth look? At the end of this video there’s a pic showing what a worn chainring looks like (shark teeth).
Graham on January 25th, 2009 6:24 pm

Thanks for the help Alex.
Some of the teeth are bent forwards and are sharp, however some of the other teeth are blunt and look quiet worn down.
I’ve phoned the local bike shop, and they will replace the chainring or the crankset if necessary.
G on February 7th, 2009 7:29 pm

I have a SR Suntour XCC-T102 42/34/24 on my ‘08 Trek 4300D, but want to turn the front into just a single chainring with a bashguard. How do I take measurements so that I can get a new chainring and bashguard that will fit me cranks?

thanks…
Alex on February 8th, 2009 9:13 pm

@G: Measure your chainring from the center of the bottom bracket to the outside edge. Then measure the prospective bashguard to make sure it is larger than that distance. These measurements will be different depending on which bashguard you want to buy, as they have different ways of mounting.
Constantine Tsardounis on March 4th, 2009 1:54 pm

OOOoooops!… I did not mark the chainrings’ position in relation to the crank. ((
What should I do now?