11-34t cassette with Shimano Tiagra Groupset

sharding

Can anyone help me? I'm becoming desperate....

I recently read that you can fit a Shimano Deore 11-34t cassette to a road bike fitted with a Tiagra rear dérailleur. The bike is a Trek 1.5 triple (50-39-30) and the current fitted cassette is an SRAM 11-26. I have purchased a Shimano Deore 11-34 cassette and have fitted it to the free hub, no problem. I have also fitted a new SRAM chain, and I believe I have cut it to the right length. However, when I attempt to change down into the 30 and then the 34t sprockets, the upper jockey wheel "knocks" against the cogs. Adjusting the B screw has made no difference. Can anyone tell me what I am doing wrong? I'm so disappointed as I was looking forward to climbing some hills I'v not been able to manage. Any advice would be greatly appreciated. Thanks.

Monty Dog

Tiagra rear mech is only designed to accept a maximum rear sprocket of 27 according to the Shimano tech specs - you could probably get away with a 28. It's down to the distance between the mounting boss and the upper jockey wheel, otherwise, as you have noticed, the jockey wheel hit the sprocket.

sharding

Can I fix an alternative rear dérailleur mech, such as a Shimano Deore?

rothers_bikeo

yes

sharding

Many thanks, both. Is there a rear mech you would recommend? I'd been looking at the Deore XT, and the SRAM X9.

rothers_bikeo

I used a Deore XT, with your front triple you'll need the SGS long throw.

richa

sharding wrote:

fit a Shimano Deore 11-34t cassette to a road bike fitted with...triple (50-39-30)

What are you looking to climb with 34/30? At a cadence of 60 this is 4.1 mph.

______30____42____50
11 >__12.8___17.9___21.3
13 >__10.8___15.2___18.0
15 >___9.4___13.1___15.6
17 >___8.3___11.6___13.8
19 >___7.4___10.4___12.3
21 >___6.7____9.4___11.2
23 >___6.1____8.6___10.2
25 >___5.6____7.9____9.4
28 >___5.0____7.0____8.4
34 >___4.1____5.8____6.9

Monty Dog

Any Shimano MTB mech will be fine - Deore will be comparable in spec to Tiagra. FWIW SRAM rear mechs don't work with Shimano shifters.

sharding

Many thanks all. I will go for either the Shimano Deore LX or the XT, as it sounds like both will work. Thanks for the advice on the SRAM, as I now know to avoid them. To answer RichA's question, I particularly want this capability so I can attempt to climb the steeper lakeland passes. I'm not too bothered how slowly I'm going; I just don't want to have to stop and get off.

Last question: will I need a different derailleur hanger or will the one on the bike be ok?

Thanks again. I really do appreciate the advice.

Monty Dog

FWIW all bike rear mech hangers are the same thread fitting

sharding

Brilliant. Thank you very much indeed.

elcani

Hi - I think I've read that the new 10 speed Dyna Sys MTB mechs are not compatible with other Shimano stuff, so I'd check that. Any nine speed Shimano MTB mech will work fine.

mikenetic

FWIW I have a Kona Sutra and it's set up with the XT mech and I think an 11-34t cassette, which works very well.

As for the 4.1 mph speed thing, I can see where you might want that low a gear if you were doing loaded touring somewhere hilly. I did the JOGLE earlier in the year and Exmoor has some proper steeps if you're carrying much.

Mr Plum

mikenetic wrote:

FWIW I have a Kona Sutra and it's set up with the XT mech and I think an 11-34t cassette, which works very well.

As for the 4.1 mph speed thing, I can see where you might want that low a gear if you were doing loaded touring somewhere hilly. I did the JOGLE earlier in the year and Exmoor has some proper steeps if you're carrying much.

We tackled some 20%+ climbs on our LEJOG with loaded bikes (12kg ish of luggage on rack) and seriously struggled with 30 (front) 32 (rear).

sharding

Thank you all very much. All the comments have been very helpful. Hopefully see you on the road sometime? Hoping to do LEJOG in 2013........when I'll be 50!!

Mr Plum

sharding wrote:

Thank you all very much. All the comments have been very helpful. Hopefully see you on the road sometime? Hoping to do LEJOG in 2013........when I'll be 50!!

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