wheels on the bike go round and round

so i bought some new race wheels for my bike.nothing brilliant  but will keep them for racing.........so i remmebered to get some new tyres and inner tubes.............

so my problem is.....

the back wheel.......

if i change the wheel do i have to take the cog set thingies off and attach to the new wheel or do i have to buy another cog set to fit to the new wheel..........

sorry any answers need to be really simple as i'm crap at these things

If you was clever (note the if !!) you would buy a new cassette for the new wheel, but get different ratios (I can say this coz FB told me to do the same!) On my normal wheel I have 11-25 for flatish races, then I bought a 12- 27 for the race wheels to get me round Lanza. Or I can swap them round

Just to add to the confusion

If you do put a new cassette on then you are as well buying a new chain to go with the new cassette, as the chain and the cassettes wear a different rates!

So, old chain and new cassette may lead to shifting issues, new chain and cassette generally run smoother

Chris

Just 

thing is i have 2 bikes now.........and although i'm using the new one for IMW......i was thinking of keeping the old one for outlaw and TT as it has the tri bars on and set up for tribars...............

but both have different cogs on the back.........and i don't know how to change a chain.......

i think i would have to go to a shop before the race to get the wheels changed....

i really should learn about bikes......I need a course

 Dave we ahve a sctott that lives on the turbo which hasn't been outdoors

"If you do put a new cassette on then you are as well buying a new chain to go with the new cassette, as the chain and the cassettes wear a different rates!"

but I woud suggest for most that's a marginal issue although I would agree that it can cause issues if there is significant wear on one or t'other and also depends on how well you've looked after them.

seren - I'm confused - does the new wheel have a cassette (cog set thingy in Caerphilly speak ) on it or not??   your posts seem to indicate yes in one post, but no in another!!

I have the same cassettes on all my rear wheels, then you can just swap them around as you see fit.

If they have different cassetted on them, hmmm why?  Do you have different sized chain rings on the front on each bike, (ie 50/34 compact or 53/39 standard).  That might mean different sized rear cassettes. 
If its all close then you can keep the same chain length and just swap wheels.......

Why are you not using your new bike for Outlaw? - t/f the tri bars a month or two out and train / ride your swanky new bike at outlaw.

You will never catch me (on the run) if you are on your old bike

Sorry FB.the rcae wheels have no cassette ( see i'm learning ) on them.......both bikes are compacts but the new one has different gearings that should get me up the hills at wales easier..........

if i use my new bike for outlaw i would have to swap the tribars and the seatposts.........and the little front stem, thingy......and i think that i could do those things without too much problems......... i need to look again at the different sizes

O.rangeCannon - 7 hr marathons are cool..... wrote (see)

I have the same cassettes on all my rear wheels, then you can just swap them around as you see fit.

If they have different cassetted on them, hmmm why? 

Well, I have one set of wheels with deep rims that I use for races, and another lighter but less aero set that I'll use on hilly courses (IMW, Surrey hills, that sort of thing) and general rides.  The cassette on the second set is 12-25, the first one is a 23 - I doubt I'll ever use those wheels where I need a 25.  Obviously I can change them over if I ever need to.  As you say though, they're close enough that I don't need to worry about chain length between the two.

O.rangeCannon - 7 hr marathons are cool..... wrote (see)

I have the same cassettes on all my rear wheels, then you can just swap them around as you see fit.

If they have different cassetted on them, hmmm why?  Do you have different sized chain rings on the front on each bike, (ie 50/34 compact or 53/39 standard).  That might mean different sized rear cassettes. 
If its all close then you can keep the same chain length and just swap wheels.......

I'd normally stick a harder cassette (11-21, 11-23 or something like that) on race wheels because if you are racing you are going fast so don't need a 25 or 27 on there.  

Training wheels you might end up riding up a 1 in 4 after 100 miles so I'd stick an easier cassette on them.   The only time I've found chain length maybe needed changing was going for a very big cassette - maybe a 12-29 for the Alps or Fred Whitton in the Lakes or something like that.   

nope - still confused

the new bike has a full set of kit yes??  as you say the gearing is set up differently for IMW which would imply you have wheels, cassette etc already on that.

so the race wheels are for the old bike yes??  which I get the impression you will use as Outlaw?

am I getting closer?? 

I make mike life just a little bit easier.  All my wheel shave the same cassette, so if I swap wheels, chain length is fine, everything feels the same, except the wheels.

Set your chain length so it's OK on a 25 - even being conservative you'll certainly be OK on a 23 or a 27 with that - it's only really if you are going to extremes that it becomes an issue.   .

popsider wrote (see)

Set your chain length so it's OK on a 25 - even being conservative you'll certainly be OK on a 23 or a 27 with that - it's only really if you are going to extremes that it becomes an issue.   .

27 is a bit lumpy on mine, especially with in the big ring (sorry!). the 25 makes the bike a whole nicer beast. For some reasin I have a 26 too. Could do with a 21 or 23 for Dorney.

Are you sure you don' t just need to adjust the B screw on the mech ?   You can do a visual check of whether your chain is too short by looking at the cage when you are in big/big - 25 to 27 shouldn't make much difference unless you have it so it's right on the limit in 25.