Fsa VERO & SORA - compact to triple

Maquerade

New Member
My wife has a Bianchi fitted with a Sora ST3400 / FD3400 combination with an Fsa VERO compact crankset. She wants to change this for a triple to help with the hills having already swapped the 12-25t cassette for a 12-28t.
I understand that the ST3400 will not need changing but that she'll need to swap the FD3400 for an FD3403. Do I just then need to swap the crankset or will I also need a new bottom bracket? Do I need new pedal cranks or will the old ones still fit?

Would a different setup be recommended - for example a pure SORA solution?
 
OP
M

Maquerade

New Member
Whoops - chain set and crank set - confused <grin>.
 
Hi - Chainset normally equals cranks in old money, so no mix up worth taking the mickey out of ;)

Your left 'pedal arm''crank', 'whatever' comes with the right one which is joined to the chain wheels. These are part of a chain SET. Which if I haven't mentioned normally come with chain ringswheels.

Sounds like you may need to change the front mech andor shifters to work with 3 rings rather than the 2 it came with. (Scratch that, Google says you can use your front mech, but must change the front shifter so it works with 3 clicks instead of two...Google may be wrong though. Hopefully someone will confirm.)

The Chainset you use must match the bottom bracket in the way it is fixed - there are a few different fittings in use nowadays, where the Bottom Bracket (BB) must fit the cranks. Most of the older ones are square taper - the axle sticking out of the BB is square shaped and matches a square hole in each of the cranks. More recent (Shimano) ones include Octalink. More recently they have external BB's, where the bearings sit outside the frame, but these are essentially part of the chainset itself, rather than a seperate BB.

A triple chainset has a slightly wider aspect than a double as you would expect, so the length of that BB axle MAY need to be changed, or it would make the chainline less than ideal, resulting in excess chain wear (and more effort).

There are so many variables now, that short of reading a great deal, it is probably more cost effective to take it to the LBS. Tell 'em what you want and see what they can do.

Hint: Chainset model and BB diameter normally dictate the length of the BB axle, rather than the bike itself.
 
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Maquerade

New Member
2Loose said:
Sounds like you may need to change the front mech andor shifters to work with 3 rings rather than the 2 it came with.
Many thanks. According to the Shimano web-site - the ST3400 is common between the triple and double solutions and all I need to change is the derailleur from an FD3400 to an FD3403. I know I will also need to change the chain-set from the FSA VERO, but don't know what the triple equivalent is. I guess that I'll also need to change the bottom bracket (BB).

While I'd be happy to do most of it myself - I understand that it would be less risky to have the LBS do it.

So my questions are:
1) If I stay with FSA then what is the triple replacement and do I need to change the BB as well?
2) Should I take the opportunity to go for another chainset - eg. the Shimano one?
 

PpPete

Guru
Location
Chandler's Ford
I don't know what the triple equiv of a Vero is, but I'd suggest one of these
a) because it's a low cost option
;) gears just a little lower than Shimano's idea of what a triple should be.

Are the old cranks splined or Square taper?
If square taper you might get away without changing the BB. Measure the existing spindle length.

If you need a new BB I would suggest a 110 mm UN53/UN54 bottom bracket - better than the JP400 Spa suggest, and no more expensive if you shop around.

As you've a Bianchi I guess the BB shells may be Italian threaded ? You need to check that before buying a replacement BB, because an "English threaded" BB is NOT compatible.
 
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Maquerade

New Member
porkypete said:
I don't know what the triple equiv of a Vero is, but I'd suggest one of these .
Great suggestion - thank you. I need to check the BB - especially as to the thread. I do like to understand what I've got - even if I don't change the BB myself.
 

PpPete

Guru
Location
Chandler's Ford
porkypete said:
I don't know what the triple equiv of a Vero is, but I'd suggest one of these .
Great suggestion - thank you. I need to check the BB - especially as to the thread. I do like to understand what I've got - even if I don't change the BB myself.
Measure the width BB shell on the frame... gives a very good clue as to the thread. Check out Sheldon on BB threads. Many possibilities but realistically only likely to be one of:

68 mm wide = English Thread
70 mm wide = Italian Thread
 
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