How to measure and install a new chain

Posted by Ed Brennan on

 How to measure and install a chain
(Click the link below for PDF)
https://cdn.shopify.com/s/files/1/1497/1072/files/news_letterchain_replacing_a_worn_chain.pdf?9489214432696249661
www.completecycles.co.uk 
Tools required.
1. Chain checker I use the super B (TB-3326) 2 in 1 chain checker and chain hook the best I have found so far,
2. Chain splitter I use Super b again depending on 8/9/10/11 speed each chain comes in different widths,
3.  Master link pliers Super B 2 in 1 master link pliers (these both remove and fit the master/quick link)
4. Chain (even though not a tool but very essential).
 
I do a complete package you can use for any chain job required.

www.completecycles.co.uk/products/chain-maintanance-tool-set

Let us remind ourselves on the components/parts that make up a chain, as this will help in understanding a lot of what is going to be spoken about. See the diagram to the left.


 
In my previous blog I spoke about chain maintenance, covering cleaning, lubrication and measuring for wear and tear,
Once your chain is worn the recommend wear is. 75 (please do not be mistaken like one customer who complained that when he had measured the worn chain I gave him after replacing it with a new one he wanted to know why his old chain was not 75% shorter than the new one.  There is being anal then there is being anal.
Chain wear and what is it? Lets begin by explaining what is meant by wear or chain stretch, the wear develops at each pivot, the accumulated wear over a group of pivots appears to the eye that the chain has stretched, however this is no the cast even though it looks and is slacker what has actually happened is the gap between the rollers has increase due to wear from the chain rings and the cassette teeth,  some people do suggest turning the chain round, this does not work firstly a shimano chain only works in one direction secondly the wear is on the rivet, so it will be the same no matter what way up it is. Wear accumulates as the chain moves over the sprocket teeth play then  begins to form and the distance between each rivet increases meaning that the chain will no longer sit fully down in the sprocket teeth causing slippage, this is because due to the increased distance the chain will ride up against the sprocket teeth then start to skip over them, this is not really apparent if the bike is in the stand but more so when force is put through the chain via force on the
 the pedals. It is at the point of roughly the wear of0.75 commonly said as 75% ( this is actually 0.75 of 1% wear from the ½ inch pitch point between the 2 rivets), when a chain should be changed. Changing at this point will preserve the life of the rest of the chain set.
Chain wear is measured using a tool such as chain checker. It is not only the chain that wears but the whole drive chain (chain rings, cassette, chain and jockey wheels). Getting the maximum use out of your chain and replacing it at the correct time is the most economical way to keep the bike riding and gears changing correctly, change the CHEAPEST PART FIRST. Fortunately for us the part that wears the most is also the cheapest. As parts wear together  if you have let the chain and cassette wear too much then the new chain will just jump (slip over the old cassette meaning that also will need to be changed).
Signs that that your chain may need changing
1. chain-suck (chain sticking to the small/middle front chain ring)
2. slow gear shifting function
3.    louder than normal noise level (dry rattling      chain)
4.    Squeaking noises from the chain or drive-train.
 
Choosing the correct chain, Depending on what group set you have? The common ones are campanology, Shimano and SRAM depends on what chain you need, please read my previous articles, I will always use KMC unless a customer asks otherwise as it works well on all 3 group sets.  They have a great guide to how to choose your chain please see the links below.
Is your bike fitted with a derailleur?
http://www.kmcchain.org/cms/media/chainchoice16EN_YES.pdf
your bike not fitted with a derailleur?
http://www.kmcchain.org/cms/media/chainchoice16EN_NO.pdf
Once the make has been chosen we than need to decide on coatings weight etc which will be determined by what you use your bike for and what weather you ride in and how many miles you do etc… lastly we need to think about length of the chain. All chains come in various lengths (amount of links), this is to accommodate the vast size of cassettes you can have anything from a 23tooth biggest rear sprocket to 34tooth sprocket and up. I always go for the longest I can get usually 114 link meaning it will never be too short, a long chain can always be shortened a short chain cannot and should never be lengthened.
Measuring the chain, Once we have covered the above it is now time to measure the new chain,
 
1. Drop the front  mech into the smallest chain ring likewise with the rear,
2. depending on what chain you have already fitted remove it via the quick link with  a set of master link pliers or any rivet using a chain rivet extractor.
you can use the old chain to measure against our new one for ease but I find it best practise to measure the chain yourself, there are various different ways but I will go through the way I fibnd the easiest and what works well for me every time.
 
 you can use the old chain to measure against our new one for ease), I find it best practise to measure the chain yourself, there are various different ways but I will go through the way I find the easiest and what works well for me every time. Everyone is different, this just works for me.
1. Remove the chain from the packaging it is always a good idea to have a clean piece of rag on the floor or work surface to put the chain on as it comes pre lubricated with a storage lubrication, we do not want to get it contaminated with any dirt or grit. There is no need to clean the lubrication off as this will suffice on the bike.
2. Wrap the chain around the 2 largest sprockets front and rear; do not put through the rear mech, but do thread it through the front mech. (this is only for sizing do not connect the chain like this).


3. Pull the chain tight ensuring it has not come off the largest sprockets, take a mental note or mark with tipex  the closest rivet could be joined, remember chains can only be joined together by connecting the inner and outer plates (male and female), if the 2 do not meet under tension move to the next closest. Where it can be joined (making the chain slightly longer not shorter)


4. Once we have noted where the chain could be joined by the 2 closest rivets lengthen the chain by an additional 2 rivets (yes lengthen not shorten)
5. Split the chain at this point remember if in doubt go longer.


Fitting the chain,
1. Shift the front and rear mech now to the smallest sprockets.

2. Feed one end of the chain through the front mech and around the small sprocket, Wrap the other end over the
smallest rear sprocket in the direction to the rear, let it drop down in front of the top pulley (jockey wheel) let it dangle free if possible. and the rear of the bottom pulley; ensure it stays inside the built in guys (it should look like a backward S)
3. Pull both loose ends together, (this is where the the super B (TB-3326) comes into its own), link the chain to the top
hooks of the chain checker, about 3 in either side, this makes it easier to connect, if using a quick link link the plates together and then click them together  the Master link pliers ( Super B 2 in 1 master link pliers) (if these are not available ensuring the chain tool if you used one to hold the chain In place is removed , pull the back brake and then put slight pressure on the pedal until you hear a small, click this will ensure the quick link is fitted and secure.
 
 

If using a chain with a rivet pin,
1. lubricate the connecting rivet, install the correct connecting rivet into the chain outer plate, tapered end first,

2. cradle the chain into the rivet extractor and then tighten the handle slowly pushing the connecting rivet into the chain and into the back plate, stop when the non tapered end is protruding about the same as the neighbouring rivets.

At this point ensure that the tapered end is seated correctly then unscrew and remove the chain tool. The rivet will now be tight with the chain not being able to twist, this is known as a tight link  to loosen hold the chain either side of the tight link and bend it slightly forwards and backwards this loosens it off,
 

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