OK, so if you live around the corner from a bike shop, and you pay for all the repairs, you may not need any specialist tools. But for anyone with even the slightest ambitions to keep down costs and keep the bicycle drive train running smoothly, you will need to add these three basic items to your toolkits.
Chain whip
While it does look like a medieval torture instrument, this is the must-have tool to help you get the gear cassette off your rear wheel. The sole use of this device is to restrain the rear wheel cassette so that you can remove it. You will need to remove the cassette for one of three reasons: to change the gearing and mount to, say, a climbing cassette; to really clean the cassette well; or to replace a worn cassette. (If the cassette is worn, then you should always also replace the chain at the same time.)
Not everyone is convinced you need a chain whip. One guy at The Prologue swears that you can easily do without one, instead holding the cassette firmly enough to remove it by wrapping an old tea towel around the cogs and twisting hard.
Cassette remover
A Shimano cassette remover
This little fella fits onto the lock-ring that holds the cassette in place. It has a special shape, so you should never, ever try and use anything other than a remover specifically designed for the drive system you have. Your system will most likely be Shimano, or SRAM (these two are often, but not always interchangeable) or Campagnolo. Cassette removers don’t cost too much, and come either with a handle fitted or are made in the shape of a nut, so that a spanner will fit on it easily.
Chain splitter
Last, but definitely not least, is the chain splitter. This is essential if your chain does not have a special link (often known as a ‘quick link’). You will need a splitter to remove the chain in order to replace a worn one, to clean a dirty one, or to shorten/lengthen the chain when changing your gearing.
If you’ve never split a chain yourself before, we advise getting an old chain and practising several times following to the numerous self-help films on Youtube. You need to get the feel of this task, and learn how to avoid popping the rivets all the way out of the link—rivets will virtually never go back in again… Also, be sure to buy a splitter that fits your chain, as 9/10-speed cassettes have different chains than 11-speed transmissions.