new cassette, chain now jammed

[chipmonster]

I had my cassette changed on my racing bike by a LBS. They managed to put a 30 teeth cog (largest one) at the back from 23.

However, bought it home in my car on Friday assuming everything will be okay.

Took it for a ride today, never got far at all only a few yards as I changed the gears, it felt like the chain was jamming and eventually jammed up. I think its jammed up at the back mechanism bit ( I have sti shifter gears).

Any idea whats wrong with the bike?

 

[RedBike]

23 to 30 is a huge jump. I wouldn't of thought your rear mech was capable of clearing such a large sprocket or taking up enough chain slack.

Your existing chain would of also be the wrong size.

 

[mickle]

Your bike has been vandalized by an unqualified muppet. Take it to another shop, have them fix it and write a damage report and invoice the original shop for the total.

 

[Will1985]

That's a ridiculous jump - I'd have a 25 or 26 inbetween.
As Redbike says, mech capacity is probably exceeded and the chain won't be long enough.

 

[chipmonster]

Te LBS was going to fit a 27 cassette, but when I got their they had a 30 on (just what I needed i thought).

It seems to have all the same bits on except for the cassette.

It will be going back on Monday, just so angry its not working.

What do you think will need changing to have this 30 cog working properly?

 

[mickle]

Your bike has been vandalized by an unqualified muppet. Take it to another shop, have them fix it and write a damage report and invoice the original shop for the total.

 

[chipmonster]

Your bike has been vandalized by an unqualified muppet. Take it to another shop, have them fix it and write a damage report and invoice the original shop for the total.

I need to go in and give them grief, they have damaged my bike.

 

[RedBike]

What do you think will need changing to have this 30 cog working properly?

I'm not sure you can get a 30tooth cassette. You can get 32/34 MTB cassettes but these will only be 8 or 9 speed.
The largest shimano 10speed cassette I know off 'only' has a 27tooth outer sprocket.

edit..........
Correction, I've just realised shimano do an Alivio (MTB) 11-30 cassette,

 

[chipmonster]

I'm not sure you can get a 30tooth cassette. You can get 32/34 MTB cassettes but these will only be 8 or 9 speed.
The largest shimano 10speed cassette I know off 'only' has a 27tooth outer sprocket.

edit..........
Correction, I've just realised shimano do an Alivio (MTB) 11-30 cassette,

This cog is 8 speed.

Shall I ask for a 10 speed cog, with the larges number of teeth, be it 27 or 30.

Thanks.

 

[RedBike]

No wonder things have jammed. An 8 speed cassette needs a much wider chain. Not to mention the fact that your shifters wont change right.

If you've got 10 speed shifters (Originally had 20 gears) then you need a 10 speed cassette. In which case you're limited to a 27 tooth cassette. You will need a new chain and a bike shop that is capable of checking your rear mech is compatible.

If you originally had 18 gears (9speed shifters) then you can run a MTB cassette. However, you will need a new rear mech and chain.

 

[RedBike]

We are talking about an 18 / 20 speed road bike arn't we?

Not a 16 speed Sora groupset?

 

[chipmonster]

We are talking about an 18 / 20 speed road bike arn't we?

Not a 16 speed Sora groupset?

Let me go out and see what it has, will post in 5 mins.

 

[fossyant]

Oh bugger - if it's a short cage mech then 25/26 is about the biggest you'll get if it's an 8 speed..... I think the new 9-10's go to 27 for a short cage road mech...but 30...whoops...idiots.

You can get what ever cassette you want, although it will be from either road or MTB ranges..... I use Tiagra Road on my MTB (for commuting)

 

[chipmonster]

What a day, bikes in the shed tried to go in in the shed and the padlock is frozen solid (its about -3 degrees here). Cannot open it, not going to try and open it now.

I am going to get the bike shop to list the components on the bike so i know what I have on it.

Just so angry that the bike is out of commission at the moment.

 

[chipmonster]

Top of my head the back mechanism is a shimano 105.