Rear Cassette Replacement

A while back, I wrote about changing your chain. The best thing is to change your chain frequently, e.g every 1,000 miles. Though it is a little expensive and time consuming, it is worth it because you can lose power through a worn chain. Also, if you change your chain regularly, you will get greater use out of your rear cassette block.

However, as is often the case, I don’t follow my own advice. I’ve ridden 3,000 miles on my road bike since the last chain change. Yesterday, I changed the chain and when standing on the pedals the chain started to slip.

Since I’d started the ride, I didn’t want to turn round and put a new cassette on. But, I found if I rode in the big ring, the chain didn’t slip. However, I do need to change the rear cassette now.

Generally, if you leave your chain for a long time, you will need to change both cassette and chain at the same time. For a cheap groupset, this is probably best option as cassettes are not too expensive and it’s easiest to do it all together. If you use a top end groupset like Shimano Ultegra, Dura Ace then cassettes become quite expensive.

How to Know if A Cassette is Worn


The above cassette is quite worn, though I’ve seen a lot worse. Generally, the teeth become more pointed on a worn cassette. The best test is often to see whether the chain slips under pressure.

Note: If you really don’t want to spend money on a new cassette, you can sometimes wear in a new chain. i.e. it may slip for first 100 – 200 miles, but, then the chain stretches a little and it stops slipping. It depends on what kind of cycling your doing, if it its up steep hills, the last thing you want is a slipping chain.

Changing A Cassette


To undo a cassette, you need a chain whip tool which stops the cassette free wheeling. Turn the cassette tool anticlockwise to unscrew.

I’m not keen on bike maintenance as I have no natural ability for it. However, changing a chain and cassette is not too difficult. For a cassette you need two simple tools

  • A chain whip to stop freewheel spinning
  • A cassette tightening nut.

Neither are too expensive, and if you do a lot of cycling it is worth investing in.

5 Responses to Rear Cassette Replacement

  1. velocipede2288 September 26, 2010 at 11:30 am #

    To change mine,I remove wheel, then having put the cassette tool on the nut, I put it in the vice and turn the wheel untill it loosens.
    The cassette tool I have is a small affair, not like the one in the picture.

  2. James June 16, 2010 at 10:41 am #

    About to do my cassette and chain today too.

    Will you be doing any tips for chain length as there are so many articles/methodology varies.

    Keep up the good work!

    • wood September 16, 2012 at 1:08 am #

      Tejvan- you can tell this chap to run the chain around the largest front cog and the largest rear ignoring the rear mech and then add two links (Each link being a pair) sometimes you only have to add one link but shimano always say 2

  3. Chris October 7, 2009 at 8:36 am #

    Interesting article, thanks!


  1. Changing Chain on Bike | Cycling UK - September 25, 2010

    [...] Rear cassette Replacement [...]

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