shimano ef51 shifters/ brake levers used with tiagra fd4403

[Part time cyclist]

Hi

I have been modding my specialized sirrus recently replaced the altus rear mech with a sora long cage and replaced the original crank for a tiagra tripple with hollowtech II bottom bracket as i wanted to get the bigger top chain ring and the deore only goes up to 48 teeth all good so far.... getting to the point... i replaced the front dérailleur with tiagra fd4403 but cant seem to get the indexing shifters to work properly it appears that when i change gear on the front chain ring it goes from 1st to 3rd and misses out second... it seems that the cable pull on the shifter for one gear change creates a large swing on the dérailleur.... is there anything i can do??????


thanks in advance

Richard

 

[RecordAceFromNew]

If the original front mech is an Altus (per Spesh link below), it is a mountain front mech which requires a lot more cable pull to traverse the same distance across the chainrings than the new Tiagra (which is a road front mech), hence your trouble is exactly what I would expect (see ctc link below).

A possible kludge (since your flat bar shifter is pulling too much, not too little cable), is to set the front cable tension in such a way that the front mech would line exactly in line with the middle ring when the shifter is on 2, then leave the cable tension alone and let the front mech L and H screws determine the mech position on rings 1 and 3. Generally what that would mean in this case is that the cable will be unusually loose on the small ring (which while not brilliant is not a huge deal), but extremely tensioned when on the big outer ring (which is NOT good for the shifter, if it can be achieved). I did say it is a kludge...

Since no Shimano flat bar front indexed shifter pulls the amount of cable for a road front mech and since mountain front mechs might have difficulties working with a road chainset chainline, the best solution is to get a flat bar road front mech (which requires the same cable pull as what Shimano's mountain/flat bar shifters deliver). For example if you have bought the FC4503 Tiagra chainset then the suitable front mech in your case is the FD-R453 (see page 2 of the last link below).

Hope it helps.


Spesh Sirrus example spec: http://www.specialized.com/us/en/bc/SBCBkModel.jsp?spid=45857&menuItemId=0

ctc on front mech compatibility: http://www.ctc.org.uk/desktopdefault.aspx?tabid=4068

Flat bar road compatibility: http://www.shimano.com/publish/cont...e.html/01) Drivetrain Compatability Chart.pdf