Quick rear derailleur question :-)

[Pat "5mph"]

Hi all!
Will my Tiagra rear take a 11/34 cassette, fitted now is an 11/30, triple set up.
Don't want to click "buy" before consulting CC. £ 12.95 from Wiggle is ok, isn't it?
I'll be away from the computer for a bit, so thanks in advance for the answers

 

[lutonloony]

Think it depends on cage size, but sure the experts will give proper answers

 

[potsy]

Yes, No, maybe.. buy it, try it and see

 

[Andy_R]

As you're running 30 on the back already, you've either gor a medium or long cage mech on there, so a 34 will be ok. You will need a longer chain though.

 

[lutonloony]

As you're running 30 on the back already, you've either gor a medium or long cage mech on there, so a 34 will be ok. You will need a longer chain though.

Would question that as shimano 105 can be "squeezed" to 30 even though spec'd at 28. ( but in fairness haven't checked Tiagra spec)

 

[fossyant]

You might be pushing it. Can you get the model number off the back of the mech body.

 

[steve50]

What are you planning to climb @Pat "5mph" , a 34T with a triple chain wheels will let you climb a vertical wall but it will be very very slow, you might be better going for a 32T, I have 11-32 with double chain wheels and it is more than adequate for the very hilly terrain round these parts.

 

[Andy_R]

Would question that as shimano 105 can be "squeezed" to 30 even though spec'd at 28. ( but in fairness haven't checked Tiagra spec)

SS - Short Cage Road Double - Maximum Cassette Cog is 27 and Total Capacity is 29

GS - Medium Cage MTB/Road Triple - Maximum Cassette Cog is 34(MTB)/27(Road) and Total Capacity is 33(MTB)/37(Road)

SGS - Long MTB - Maximum Cassette Cog is 34 and Total Capacity is 45

from here

 

[fossyant]

The RD-4700-GS will take a 34. That's the latest mech.

 

[S-Express]

If you're already running a triple, then the rear mech is most likely medium or long cage anyway - so yes.

 

[fossyant]

Shimano have made the mechs cope with more teeth as the models have progressed.

With a triple you are going to need a long cage. What's the front granny ring size.

 

[lutonloony]

SS - Short Cage Road Double - Maximum Cassette Cog is 27 and Total Capacity is 29

GS - Medium Cage MTB/Road Triple - Maximum Cassette Cog is 34(MTB)/27(Road) and Total Capacity is 33(MTB)/37(Road)

SGS - Long MTB - Maximum Cassette Cog is 34 and Total Capacity is 45

from here

Shimano ss 27? I am running 28 ( as fitted from new, and many posts reckon I can do 30. Maybe I missed the specific on post about it being Tiagra?

 

[lutonloony]

If you're already running a triple, then the rear mech is most likely medium or long cage anyway - so yes.

I knew there would be somebody that knew what they were talking about

 

[Pat "5mph"]

As you're running 30 on the back already, you've either gor a medium or long cage mech on there, so a 34 will be ok. You will need a longer chain though.

Cheers amore bello, I have 6 new extra chain links already, buy will buy another chain just in case.
Fitted a new chain yesterday, but on today's commute it was skipping allover the low gears so will stop using this bike until I get the new cassette.
Or I could use one of @potsy's bikes, they are all brand new
Thanks very much for the info @Andy_R.

What are you planning to climb @Pat "5mph" , a 34T with a triple chain wheels will let you climb a vertical wall but it will be very very slow, you might be better going for a 32T, I have 11-32 with double chain wheels and it is more than adequate for the very hilly terrain round these parts.

Shimano have made the mechs cope with more teeth as the models have progressed.

With a triple you are going to need a long cage. What's the front granny ring size.

Model: RD 4601 H1
Chain rings: 26/36/48

 

[potsy]

26x34 you'll be doing 1mph up those hills