105 Front Mech Capacity?

[HLaB]

Am I right in thinking that as a 105 front mech can handle a 16t change between 50t and 34t rings; it could handle a 16t change between 52t and 36t rings? I've got the latter and I'm thinking about swapping out the 38t for a 36t before I head to the Alps. TIA

 

[TheDoctor]

If that's a standard double you'll not get a 36T in 130mm BCD. 38T is as low as it goes.
If it's a compact (110 mm BCD) then I'd be surprised if it doesn't work.

 

[HLaB]

If that's a standard double you'll not get a 36T in 130mm BCD. 38T is as low as it goes.
If it's a compact (110 mm BCD) then I'd be surprised if it doesn't work.

Its a compact (110mm), Thanks

 

[slowmotion]

Which 105 front mech have you got? I think that most 105 two ring front mechs have an "official" 15T max difference. Judging by my limited experience of stretching the rear mech rules, my uninformed guess is that you will be absolutely fine. I would have thought that any minor front shifting problems could easily be sorted by sliding the front mech fixing a little lower. The shimano techdocs site gives tooth rules for front and rear tooth combinations. They are extremely conservative for a triple. I suspect that they might also be for a compact/double.

 

[HLaB]

Iirc its a 5600, I'll check it out

 

[slowmotion]

http://techdocs.shimano.com/media/t...600/SI_5JM0C_001_EN_v1_m56577569830621301.PDF

 

[slowmotion]

If you have a 5600 rear mech, here are Shimano's guidelines about total capacity etc. Sheldon Brown told me what that means, but I forgot. Anyway, it looks like the rules can be bent unless you are a professional racer. Good luck!
http://techdocs.shimano.com/media/t...01/SI-5VN0B-001-ENG_v1_m56577569830683908.pdf