Changing cassette advice

[Daninplymouth]

Hi, I have just took delivery of my new bike but I am planning on upgrading the wheels soon. Also at the same time I am thinking of swapping the cassette.
At the moment I have 50/34 and an 11-34 rear, I thought this might have been a bit easy on the gearing, and although the 1-1 gear is quite nice to spin up a few of the steeper climbs I’m not to struck on the bigger spacing at the harder end of the gears. Before I was running a 52/36 11-30, and I managed to get up everything locally on this, so a 34-30 should be fine really.
My plan would be to swap my new cassette to the same 11-30 would this simply be a case of swapping the cassette and maybe taking a link or 2 from the chain? Or will I have to look into a new rear derailleur too? I don’t quite fully understand the ins and outs of everything and will be getting my lbs to do the change, I don’t mind swapping the cassette and getting the gears indexed but if much else has to be done then il leave it as it is.
thanks

 

[Racing roadkill]

Hi, I have just took delivery of my new bike but I am planning on upgrading the wheels soon. Also at the same time I am thinking of swapping the cassette.
At the moment I have 50/34 and an 11-34 rear, I thought this might have been a bit easy on the gearing, and although the 1-1 gear is quite nice to spin up a few of the steeper climbs I’m not to struck on the bigger spacing at the harder end of the gears. Before I was running a 52/36 11-30, and I managed to get up everything locally on this, so a 34-30 should be fine really.
My plan would be to swap my new cassette to the same 11-30 would this simply be a case of swapping the cassette and maybe taking a link or 2 from the chain? Or will I have to look into a new rear derailleur too? I don’t quite fully understand the ins and outs of everything and will be getting my lbs to do the change, I don’t mind swapping the cassette and getting the gears indexed but if much else has to be done then il leave it as it is.
thanks

What’s the groupset?

 

[Daninplymouth]

What’s the groupset?

Shimano 105

 

[HLaB]

Hi, I have just took delivery of my new bike but I am planning on upgrading the wheels soon. Also at the same time I am thinking of swapping the cassette.
At the moment I have 50/34 and an 11-34 rear, I thought this might have been a bit easy on the gearing, and although the 1-1 gear is quite nice to spin up a few of the steeper climbs I’m not to struck on the bigger spacing at the harder end of the gears. Before I was running a 52/36 11-30, and I managed to get up everything locally on this, so a 34-30 should be fine really.
My plan would be to swap my new cassette to the same 11-30 would this simply be a case of swapping the cassette and maybe taking a link or 2 from the chain? Or will I have to look into a new rear derailleur too? I don’t quite fully understand the ins and outs of everything and will be getting my lbs to do the change, I don’t mind swapping the cassette and getting the gears indexed but if much else has to be done then il leave it as it is.
thanks

You're fitting a smaller cassette so you'll be fine with that, no new derailleur needed. You may have to adjust the 'b screw' to get optimum shifting but I'll let the lbs fix that if necessary. Its only if you are going from a quite small cassette to a far larger one that you may have needed a new cassette.

 

[Salty seadog]

As above, you'll be fine. A link out of the chain probably and some readjustment.

 

[Daninplymouth]

Ideal thank you both

 

[Racing roadkill]

You won’t need to adjust the chain length, just use the b screw to adjust the tension if you need to.

 

[Sharky]

A 50x11 is a massive gear. You may want to consider having a 13 upwards to give closer spacing on the gears you use more frequently.

 

[Daninplymouth]

A 50x11 is a massive gear. You may want to consider having a 13 upwards to give closer spacing on the gears you use more frequently.

Thanks but I do get onto the top gears quite often

 

[Ajax Bay]

You won't need to adjust the chain length.

Not because moving from an 11-34 to an 11-30 will not require a reduction (it will) but because the OP will be fitting a new chain at the same time as their new 11-30 cassette.
When they do this they'll pass the chain round large/large (not through the derailleur cage), allow an additional full link (one inch) and cut it.
If the current chain is the correct length, the new chain will be one (one inch) link shorter.
HTH

 

[Ajax Bay]

You may want to consider having a 13 upwards

Assume you mean a cassette with a 13t smallest sprocket. Do you use one? I'd be keen to see a link to a cassette with (say) 13-30, in 9/10/11 speed.

 

[Sharky]

Assume you mean a cassette with a 13t smallest sprocket. Do you use one? I'd be keen to see a link to a cassette with (say) 13-30, in 9/10/11 speed.

No dont have one myself. I always choose a close ratio cassette if possible, but I think mine go up to 26 or 28t.
On the front I have a single 40t.
Will have a search and see what's out there.

 

[Sharky]

Assume you mean a cassette with a 13t smallest sprocket. Do you use one? I'd be keen to see a link to a cassette with (say) 13-30, in 9/10/11 speed.

Miche seem to do one

 

[Daninplymouth]

Not because moving from an 11-34 to an 11-30 will not require a reduction (it will) but because the OP will be fitting a new chain at the same time as their new 11-30 cassette.
When they do this they'll pass the chain round large/large (not through the derailleur cage), allow an additional full link (one inch) and cut it.
If the current chain is the correct length, the new chain will be one (one inch) link shorter.
HTH

I wasn’t planning on getting a new chain as this one is brand new and by the time my wheels arrive would’ve only done a couple of hundred miles

 

[Ajax Bay]

@Daninplymouth
I misinterpreted your OP.
New bike = new 11-34 and new chain (say 56")
Old bike = worn 11-30 and worn chain
New wheels
"plan would be to swap my new cassette to the same 11-30 would this simply be a case of swapping the cassette "
So is the "same 11-30" the one you have currently on the old bike or is it 'new' (in which case what is it "the same" as)?
Either way, if the chain (on the new bike) is the right length for the 11-34 then it will be longer than required if you fitted an 11-30 cassette. Large/large the chain is engaged from 190o round to 352o on 16 of the the 34t (= 8") and on the 30t sprocket it'd be 7": one inch less chain required. Benefit: less 'slap' in small chainring and smaller sprockets on bumpy ground/roads eg the Plym Valley cycle path up to Yelverton