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Shimano 105 36/46 to 34/50

by Albec1
Sat, Oct 08, 2016 16:34
6

Could someone confirm it’s OK and simple to switch from a 36/46 chainring to a 34/50?  Would I need to raise the front mech?  Any other considerations?

Existing components:

105 5800, 172.5 36/46, 11 sp, HG600 105 chain, 11-28 cassette, short cage

Very many thanks

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6 comments

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madcarew | 8 years ago
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As mentioned you will need to check your chain length to make sure it's not too short to go big to big (I know you're not supposed to do that, but if you do shift into it you stand to do damage to chain, rear mech and frame etc.) You will definitely need to raise the front mech too. It should clear the big chain ring teeth by about 2-3 mm.

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Albec1 replied to madcarew | 8 years ago
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madcarew wrote:

As mentioned you will need to check your chain length to make sure it's not too short to go big to big (I know you're not supposed to do that, but if you do shift into it you stand to do damage to chain, rear mech and frame etc.) You will definitely need to raise the front mech too. It should clear the big chain ring teeth by about 2-3 mm.

Good to know, thanks for the tip

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VeloUSA | 8 years ago
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Verify your chain length. Go here for sizing calculations.

http://www.parktool.com/blog/repair-help/chain-length-sizing#article-sec...

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Albec1 replied to VeloUSA | 8 years ago
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VeloUSA wrote:

Verify your chain length. Go here for sizing calculations.

http://www.parktool.com/blog/repair-help/chain-length-sizing#article-sec...

Many thanks

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kil0ran | 8 years ago
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That will work fine, and yes I would imagine you'll need to raise the front mech a tad which in turn will need a cable adjustment. Probably an hour's work tops.

Are you after more top speed or lower gearing for climbs? If the latter you could always swap the inner chainring from 36 to 34, no mech adjustment would be required then.

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Albec1 replied to kil0ran | 8 years ago
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kil0ran wrote:

That will work fine, and yes I would imagine you'll need to raise the front mech a tad which in turn will need a cable adjustment. Probably an hour's work tops.

Are you after more top speed or lower gearing for climbs? If the latter you could always swap the inner chainring from 36 to 34, no mech adjustment would be required then.

It's optimum speed I'm after.  Thanks for your feedback, that's good to know.  Regards,

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