MTB-MAG.COM - Mountain Bike Magazine | [Tech Corner] 1x Chain Ring Checkup

[Tech Corner] 1x Chain Ring Checkup

[Tech Corner] 1x Chain Ring Checkup

04/01/2016
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04/01/2016

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Chainrings are not particularly technical pieces of equipment, but with a prevalence of 1x systems the wear is concentrated to one single front ring compared to years gone by when wear was spread across two or three rings.  During one of our bike maintenance days we did a quick check of the front ring to evaluate it’s condition after about 9 months of continuous use.

Tools: Allen keys, 8mm + 5mm, chain ring bolt tool, cleaner.

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This one is a simple unit to undo and as it’s much easier to work on once it is off the bike, we remove the crank arm/chainring as a unit.

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A quick initial inspection before we remove the dirt allows us to see where the chain is making contact on the ring and where it is not. If we take a look before cleaning then it helps identify problems.

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We take a quick look at the width of the teeth on the ring. Very few brands give a recommended wear limit. So this has to be judged by common sense.  An incorrect chain-line can lead to excessive side wear; if you find the chainring is wearing more inboard or outboard, you may want to double check your bottom bracket spacing and adjust accordingly. 

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We are looking mainly on this drop stop ring at the width of the square teeth, here we can see that they are looking pretty good (worn evenly), and we can’t see any place where the teeth are distorted from an impact with a rock, tree or any other trailside nuisances.

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We now give clean the chainring at the teeth with some degreaser.  We try to remove all of the dirt, grease and grime.  If there is a build up between any surfaces where the ring contacts the spider, it’s best to take it a step further and remove the spider and ring, then clean the interface between crank and spider and ring.  Then simply apply a very thin layer of grease between the interfaces and re-assemble.  That should keep your bike nice and quiet.

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All wiped off, you would be surprised how hard it is to removed caked on mud and grease, sometimes it requires more than just a degreaser, now we can make a closer inspection.

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Now the grime has gone we get a closer look at the tooth surfaces, we can see here that the form of the tooth is pretty good, no excessive hooking on the tooth profile or wear patches at the base of the tooth.

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There is some side wear as we can see the anodised surface has disappeared, but nothing excessive.

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Chain ring bolts are essential but often over looked pieces of equipment on a bike. They can be the source of many creaks and groans. So we take our 5mm hex key and chainring tool and check for tightness.

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If anything has worked loose like this bolt here, tighten them up.  In some cases apply a small amount of loctite blue to the thread. Make sure the bolts are not too long and the bolt actually tightens (a common mistake).

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A final check on each bolt, depending on hardware, a certain recommend torque should be used, if you don’t have a torque meter then tighten firmly, not excessively hanging on chain ring bolt spanner as it will likely slip, and it will be harder to remove the bolt in future.

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Ready to go, clean and tight. Depending on the type of riding you do and how well you maintain your bike, this ring should be good for another 6 months. If you start to notice an increase in dropped chains sooner or an excessive rattling noise when descending coming from the front then likely it’s time to change the ring if everything else is in order. 

Things to remember: Check your chain line if you are getting excessive side wear on the ring.  If the chain ring bolts keep working loose, use some loctite blue, or change your bolts making sure to use the right length.  Always check your chain ring if you think it took a noticeable impact from a trail object.

Mechanic: Punta Ala Trail Center

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