Tiagra front mech problem

The Spiderman

I have a Trek 1200 with a 2 x 9 set up,with a Tiagra bottom pull band on front mech.
Last week,whilst out on a ride,the front mech wouldn`t release from the outer to inner ring,and the action of the mech seemed very stiff.

I have removed the cable which was frayed and put a new one on,but the mech still doesn`t want to play.

The mech wants to stay put when flicking the small lever to release cable tension.The shifters seem fine as the cable is going slack,but the mech stays put over the big ring.

Any ideas?

John.T

It sounds as if it is seized up. Give the mech a good dose of easing oil or WD40 and work it by hand until it frees off. Follow this with a dose of thin oil or dry lub. After that keep it clean and lubed.

STEFANOS4784

I think John.T deserves some sort of bike radar medal for his continued endeavors with Tiagra shifting issues Top bloke

John.T

I don't just do Tiagra. It is the only one I have never used but for most problems they are all the same.

hamstrich

I had exactly the same thing happen with my Tiagra (triple) front mech a few months ago when I took took my bike off the train, just about to begin Land's End -> John o'Groats (bad timing!). It turned out that part of the mech which held the tensioning spring had actually sheared off.

If you have a good close look at the mech you should be able to see whether anything's sheared (i.e. rough edges). It may be that your tensioning spring has somehow disengaged and can be put right...but in my case it was definitely a replacement job

The Spiderman

I was thinking tension spring aswell,but I couldn`t see where anything had obviously sheared.....
I have been on to the Shimano website and looked at the tech docs,but can`t see any mention of the tension spring.
Is the Tiagra mech more prone to failure than others? Would it better to be replaced with a 105,assuming a 10 speed mech fits?

roger_merriman

not had a problem with the rear Tiagra shifter on my old bike, seems to shift fast and well. as ever millage varires

The Spiderman

OK seems the spring has definitley gone.Next question,its a Tiagra 4400 double,which is attached to a seperate clamp round the seat tube by a single allen bolt.Do I need a band on or braze on or could I use either?

John.T

Very unusual. You can use a braze-on with the existing clamp or get a clamp-on with the correct diameter clamp. Braze-on is probably easiest.