Changing cassettes - some advice for a novice

pulck

I have generally avoided bicycle repairs, other than adjusting brakes/gears and a clean every now and again. However, my gears started being a bit less responsive in the last few months (e.g. rattling and taking 10 secs to change) and I think I may need a cassette/chain replacement (last replacement was about 18 months ago). I cycle probably 40-50 miles per week on average and have an old, cheap GT hybrid. Nothing special but it does the job.

Instead of spending £100 and getting it done by someone else, this time I was thinking of changing the cassette myself. Is this something I should attempt with my limited knowledge?

If so, would anyone be kind enough to give me some pointers. For example:

- What details should I be looking for to make sure the new cassette will fit my bike?
- What tools will I need?
- What brands/models should I be looking at for robust and reliable gear-changing and durability for everyday commuting?

Many thanks.

singlespeedexplosif

depends on make and speed (number of cogs) eg no point getting a Shimano 8spd cassette if you need a Campag 10spd. Check out what you currently have!
tools - chain whip, cassette lockring tool, big adjustable spanner.

nicklouse

there is also a good chance you will need to replace the chain so a chain splitter will also be needed.

have a read of the how toos on Parktools.

jairaj

as nick says have a look on park tools website, it will show you how to replace it. but for advise on buying a new one:

if you're happy with the gearing then buy the same size cogs (it should have it printed on the cassette what size they are).

if using for commuting and you prefer durability over light weight then go for something made from steel. this will usually be at the lower end of the price range, higher models usually made from Alu and other more exotic materials.

Also check how many speeds it it is and but the same eg 8 / 9 or 10 speed.

Also good idea to replace chain with the cassette too.

Also SRAM and Shimano cassettes are cross compatible.

rally200

If the cassette's going in the bin you can use a cheapo (chain type) oil filter wrench, instead of a bike specific chain whip -

only a few quid in it but if you're as skint/tight as me.

when it comes to chains count the number of links on your existing chain - if it happens to be the same as a sram chain (which come with a no-tools required link) you can get away without buying a chain tool, just take some hefty snips/croppers to the old one

pulck

All useful stuff. Thanks, guys. I will start having a look round Wiggle.

How long does it normally take to change a cassette? I have been putting it off till now because I thought it would be a real PITA.

supersonic

About 2 minutes with the right tools! If that!

Chain whip, 4 quid:

http://www.allterraincycles.co.uk/product/8381.html

Cassette lockring tool, 4 quid:

http://www.allterraincycles.co.uk/product/10096.html

You are sure it is a cassette though? Not a freewheel/block?



http://www.sheldonbrown.com/free-k7.html

pulck

Ah, okay. I will have to check! I was unaware there was a distinction.

2 minutes sounds encouraging, though. Thanks.

Underscore

pulck wrote:

... However, my gears started being a bit less responsive in the last few months (e.g. rattling and taking 10 secs to change) and I think I may need a cassette/chain replacement (last replacement was about 18 months ago). I cycle probably 40-50 miles per week on average...

Just a small point. While there is a good chance that your chain/cassette do need changing, I've not normally found poor shifting to be down to that. I've had shifting problems due to going out of adjustment, because the cable needs replacing or (in the worst case) because of a damaged dérailleur after a plastic bag got tangled in it. Might be worth checking for those sort of things first, or at the same time...

HTH,

_

pulck

Thanks. I hadn't considered that.

How do I check that the dérailleur is damaged or that the cables need replacing? Is it worth my while changing my cables anyway? The bike is about 4 years old and I don't think they've ever been replaced.

nyanza

How long does it normally take to change a cassette? I have been putting it off till now because I thought it would be a real PITA.

These video tutorials are quite handy, if you can bear the monotone voice!
http://bicycletutor.com/replace-cassette-cluster/
There are lots of other tutorials on there if you fancy having a go other things. It makes you feel a little more confident about what you are doing if you have seen it all happen in a video beforehand.

A strong indicator that your cassette teeth and/or chain is worn is if your gears skip when putting them under pressure (ie. pushing down hard on the pedals in quite a big gear). But, as you say your gears are simply unresponsive or slow you could start by lubing your cables - perhaps they are not moving through the cable housings properly inhibiting the movement of the derailleur. When lubing them look for visible signs of wear, dryness and fraying of the cable, or any sharp bends or kinks in the cable - these things will increase friction inside the cable housings and make shifting slow and generally poor. Scrub clean (toothbrush? I use a small wire brush for cleaning sparkplugs) all the derailleur pivot points and lube them as well. Give it a really hard wiggle to get out dried up mud and grit. Then reindex (ie calibrate) your gears by turning that little adjusting barrel at the back of the derailleur a quarter turn until the chain slips onto the next ring when you use the shifter so that the chain runs quietly (it's a trial and error process). Clean your chain with a solvent, like white spirit or WD40 or GT85 degreaser (more expensive), but it is vital that you then relube thoroughly when the chain is dry with a good lube (eg Finish Line product such as Cross Country), and wipe off the excess. The solvent will have cleaned the chain, but will also have stripped it entirely of any lubricant, so get that lube back on there. The step costs next to nothing - just the cost of a few lubes and a quid for new cable.

If you still have problems then it's time to invest in a new chain and cassette, and the tools. If you buy a SRAM chain you won't need a chaintool, as SRAM chains have a special "powerlink" that is used to join and re-join the chain with just your fingers. It's very good. However, you will still have the problem of getting the original chain off. You could unscrew and remove derailleur's jockey wheels and squeeze the chain out of the cage that way, just as a one off event. Hope that helps.

wgwarburton

nyanza wrote:

..... However, you will still have the problem of getting the original chain off. You could unscrew and remove derailleur's jockey wheels and squeeze the chain out of the cage that way, just as a one off event. ...

That won't help, unfortunately- the chain will still be looped through the drive-side rear triangle.

If it's definitely a write-off then you can probably snap it by bending it laterally hard enough, but you'll need to make sure your bike shop can shorten your new chain to the right length for you.
A serviceable chain-tool isn't that expensive. I'd recommend buying one.

Cheers,
W.

bails87

I find it's useful to have a minitool with a chain breaker on it. In case the chain snaps while you're out. It only has to happen once to be a major PITA, even if you've got spare powerlinks, a few mangled links in the chain and no chain tool mean you're stuck.

The 'stand alone' workshop ones are easier to use, but I've got a lezyne mini one that works absolutely fine, and has saved my bacon on a couple of occasions.

From your mileage I'd say that if you change the cassette then the chain will need changing too. But try resetting the gears first, could save some unnecessary expense.

pulck

Thanks guys. This is all incredibly helpful.

There's actually quite a lot to digest here for a novice like me, so I will spend some time on the Park Tools website and try changing the cables and see if that makes a difference before I start dismantling the chain, cassette, etc.

ratherbeintobago

On a related note, and to aska stupid question, if I change my rear cassette from 12-32 (which gives an unusably low bottom gear) to 12-28, will I need to shorten my chain, & if so, by how much?

Andy

giant_man

I've never got on with chain whips must admit, they always slip and graze my knuckles or arms so I invested in one of these and life it a little sweeter since have to say:

http://www.chainreactioncycles.com/Mode ... elID=31344

ratherbeintobago

+1 for the Pedro's Vise Whip

Andy