Changing rear cassette

G1032

Changing rear cassette.......

I really need to get a new one as my 11/25 isn't really suitable for me for the harder climbs. I can get up them but there are a couple on my list to do that I think will be just too hard with the 25 on the back.

I have a standard chainring 52/39. What would be the most common combo to put with the 52/39? A 28 or 30 rear cassette??

Is changing the rear cassette difficult? I know I need a chain whip. Do I need any other specialist tools? Would watching a youtube video be lesson enough to learn how to do it? Do gears need adjusting after changing the cassette?

Thanks in advance for your help

quozl

It's easy to do. You'll need a chain-whip and a lock-ring tool (making sure to get Shimano or Campy depending on what you have). Videos on you-tube will show you how.

I got a tool set from http://www.chainreactioncycles.com/ie/en/x-tools-bike-tool-kit-18-piece/rp-prod40997 and it had everything I needed to build a bike except a star-nut installer for a headset.

You may not be able to use a 30 cassette depending on what your derailleur is. The last couple of years has seen road derailleurs with higher capacities so you may be ok. You'd want to google your derailleur model. If you can use a 30, then I'd put the 30 on - the 28 isn't really that massive a difference and if you're going to all this trouble you must want a noticable difference.

You'll also need a longer chain assuming your current chain is correctly cut to length for the 25.

It's the sort of thing that's easy enough and fun if you're into that sort of thing - I am - but if you're not then I'd honestly just bring it to your local bike shop and let them deal with it.

quozl

Oh yeah, another possibility is to swap your crank-set from a standard double to a compact.

If it turns out that you'll need a new derailleur and new cassette then swapping your crankset is going to be similar enough cost and a bigger difference than going to a 28 but less than the difference of going to a 30. You could even combine the two - compact and whatever the max your current derailleur will take on the back.

G1032

Thanks for the replies. Exactly the answers I needed. I'd never have thought of the longer chain!!

Koobcam

As others have said, this all depends on the equipment you're currently running. However, I would generally recommend getting a compact crankset (50/34 or maybe 52/36). 11-25 on the cassette is actually a nice ratio when combined with a compact as there are generally smaller gaps between the lower gears, which basically means you are more likely to find a gear that suits you on a given climb.

A new crankset will cost you more though than a new cassette, so if it is the cassette you decide to change, you need to know what your derailleur is. All campag 11-speed derailleurs will take a cassette up to a maximum of 29. SRAM and shimano 11-speed will take a max of 28, similar for ten speed I think. If you want to go higher than 28 on SRAM or Shimano, then you'll need a long cage derailleur, which should be able to take up to 36 in most instances.

For tools, I'd recommend getting a cassette unlocking tool with an adjustable spanner (as opposed to an unlocking tool with a handle attached) simply because the adjustable spanner can be used for other things, plus the cassette tool will then be cheaper. You do need a chain whip-be aware that chain whips come in different speeds, so for example if you have a 10-speed groupset, you'll need a 10-speed chain whip. You can use other speed chain whips, but they won't grip as well. Also, when taking off the cassette, no harm to clean the freehub and stick a bit of grease on it. Make sure also not to under-torque the cassette when putting back on, as it can come loose (this happened me in the wicklow 200 a couple of years back..).

Oryx

What is the correct torque?

Koobcam

Oryx wrote: »

What is the correct torque?

Correct torque on the cassettes I have had seems to max out at 35-40nm, but basically make sure it's tight enough that it won't pop off, not so tight that you'll never be able to take it off again. The correct torque will be written somewhere on the cassette lock ring

Tomfla

How do I figure out what arrangement I have on my road bike, where do you measure. Also what is the best arrangement for a casual road user. Doing the ROK in a few weeks and want to make sure I'm not doing anything unnecessary going over molls gap

quozl

Tomfla wrote: »

How do I figure out what arrangement I have on my road bike, where do you measure. Also what is the best arrangement for a casual road user. Doing the ROK in a few weeks and want to make sure I'm not doing anything unnecessary going over molls gap

Count the number of teeth on the smallest chain-ring of the 2 or 3 (depending) at the front. Typically 39 or 34 but if you have three rings at the front then it may even be 30 or 28.

Count the number of teeth on the largest ring at the back.

Those two combine to give you your lowest gear. The smaller the front one, the easier. The larger the back one, the easier.

The gearing you need depends on a few things but body-weight is the #1 thing IMO. Power (strength) to body weight being number 2.

G1032

I reckon I'm going to scrap this idea now and change to a compact chainset instead. Might cost a few euro more but the suggestion in this thread got me thinking and I'm probably better off with a compact.

Tomfla

quozl wrote: »

Count the number of teeth on the smallest chain-ring of the 2 or 3 (depending) at the front. Typically 39 or 34 but if you have three rings at the front then it may even be 30 or 28.

Count the number of teeth on the largest ring at the back.

Those two combine to give you your lowest gear. The smaller the front one, the easier. The larger the back one, the easier.

The gearing you need depends on a few things but body-weight is the #1 thing IMO. Power (strength) to body weight being number 2.

I've got 38 on the front and 26 on the back

G1032

Can I simply replace the small chainring with this?
http://www.chainreactioncycles.com/ie/en/shimano-105-fc5750-compact-chainring/rp-prod116086

Is it as simple as that? Could I keep the 52 ring and change the 39 to a 34?? The chain length could stay the same length then??

Or do I need to buy this instead??

http://www.chainreactioncycles.com/ie/en/shimano-105-5750-compact-10sp-chainset/rp-prod50444

nilhg

G1032 wrote: »

Can I simply replace the small chainring with this?
http://www.chainreactioncycles.com/ie/en/shimano-105-fc5750-compact-chainring/rp-prod116086

Is it as simple as that? Could I keep the 52 ring and change the 39 to a 34?? The chain length could stay the same length then??

Or do I need to buy this instead??

http://www.chainreactioncycles.com/ie/en/shimano-105-5750-compact-10sp-chainset/rp-prod50444

The bolt circle for compact and standard are different, the chainring you have linked above is 110mm, it wont fit your standard spider which is 130mm so you need to buy your last link above and make sure that the crank length is the same as your existing standard (165mm-170mm-172.5mm-175mm), that'll be stamped on the inside of the crank where the pedals fit.

G1032

nilhg wrote: »

The bolt circle for compact and standard are different, the chainring you have linked above is 110mm, it wont fit your standard spider which is 130mm so you need to buy your last link above and make sure that the crank length is the same as your existing standard (165mm-170mm-172.5mm-175mm), that'll be stamped on the inside of the crank where the pedals fit.

Cheers. Too good to be true

joxerjohn

G1032 wrote: »

I reckon I'm going to scrap this idea now and change to a compact chainset instead. Might cost a few euro more but the suggestion in this thread got me thinking and I'm probably better off with a compact.

I think Compact is the way to go. You can pick up good value second cranksets here in Cycling Adverts or else check out ebay lots to choose from.

G1032

Well

Called into the LBS yesterday evening to enquire about prices etc for changing either chainset or rear cassette.

Talked to the guy for about 20+ minutes about it!! He asked me about how I coped on climbs around us etc and what climbing I wanted to do in future.

To cut a long story short, he advised against getting the compact……..reckoned I’d get little if any use out of the 34 on the compact.

Bringing the bike in to him tomorrow and he’ll change the cassette while I wait and I’ll probably switch my 12/25 105 cassette for a 12/30 Tiagra.
Did the number crunching myself today – The 39/30 I’ll end up with as a lowest gear will be just under 20% easier than current setup. It’ll also be about 4.5% easier than if I switched to a compact and ended up with a 34/25

Fair dues to the LBS for not going for the bigger money job also. I went in hell bent on buying a compact chainset (105) and he more or less talked me into buying a 12/30 Tiagra cassette!!

Oryx

One thing you will notice is the jump between some gears on the bigger cassette. Its normal and doesn't mean anything is wrong, it just will be noticably less smooth when changing certain gears, than the 25-11.

G1032

Oryx wrote: »

One thing you will notice is the jump between some gears on the bigger cassette. Its normal and doesn't mean anything is wrong, it just will be noticably less smooth when changing certain gears, than the 25-11.

Ya. There will be a big jump between the 3 lowest gears - 24, 27 and 30. The 7 higher gears are basically the same.