Gear indexing for dummies: question 153

[CCS]

Sorry, me again....

Have just put some winter wheels on Champ (found in the garage - him indoors' old wheelset with very few miles on the clock and a new 11-28 cassette added). I naively headed out for a ride yesterday after just throwing on the wheels, but couldn't change up into the 28 (not too hilly a ride, so didn't really need to). Have just been messing around trying to index the gears, and no amount of messing around with the tensioning nut will make it change up into the 28.
Why, oh why, oh why?
Obviously, it is some sort of subtle message that I should just get some stronger legs - but shouldn't I just be able to swap wheels over just like that (works between Champ's summer wheels, and my race wheels, both of which also run an 11-28) - though I did notice these wheels are rather fatter than any of my others (the brakes are now incredibly shard - must loosen off the cables a bit). Do I just go back to very old grotty winter wheels with amazingly worn braking surface, or am I missing something obvious (should I have added a spacer when I put the cassette on or something like that)?

Promise that one day I will get the hang of this bike business and go away with all my dumb questions.

[Jimba]

I think the bike is faulty, so you know the advice......

[jonathon.e]

Did you run a 28 on the old wheels,?

Did you change the chain at the same time?

Should just be a couple of the turns of the screw,

Can you put the chain on the 28!by hand and will it stay there or slip off ?

[Tritans]

There are spacers between the cogs. But I have a feeling that would cause you more issues than simply missing a gear if it were missing.

[ris]

i wondered whether the spacer at the back of the cassette was needed, but you'd know that was missing by the cassette having play in it.

chain length could be culprit. whatever indexing you are doing now you will need to undo when you put your usual wheels on, so try to remember what you did, or take a photo, or something.

[CCS]

I think the bike is faulty, so you know the advice......

I couldn't do that to Champ!!!

Thanks to all for suggstions.
After a bit of experimentation (and the threat of having to put tubes & tyres back onto my really old wheels), I seem to have come upon the solution (and Ris wins the prize) - a spacer behind the cassette did the trick... I had foolishly assumed that as the wheels ran a 9 speed originally and I was putting on a 10 speed, that it wasn't needed... shows what I know...
More care & attention required next time I start messing around with kit!

Sadly, no time for test ride, as seem to be operating taxi service for various children

[Jack Hughes]

I'm too late.. But what I was going to say us that every wheel/hub is different... Dished differently, different size hubs etc.

So you invariably have to add or remove a space from between the hub and the cassette.

My cosmics need a spacer. My cheap wheels don't. For both the Shimano and campag bikes.

[andyb99]

its not a 'turn of the screw' its all about cable tension.....
so

disconnect the cable.
set the limiter screws moving the mech by hand...to each limit..
then attach the cable hand tight
and adjust the tension barrel...if the cable goes loose....tighten by hand and adjust the tension barrel.

patience is your only ally here!!!!

no short cuts to indexing!