Front mech won't change down. How to fix?

sv1000dave

Hi everyone.

Been into cycling since June this year and now my Specialized Allez Elite - that was new in October - has let me down.
Out on a ride today the front mech decided that it would not drop the chain onto the smaller chain ring.
I'm not sure of the mechanics involved in the lever operating the cable and would like some advice as to what to check for before packing the bike off to a trained mechanic.
If it's likely to be something simple then I'm prepared to have a go at fixing it myself.
Basically the gear change lever does not have any resistance and therefore will not move the front mech.

Is it likely to be broken component or has the cable just dislodged itself from its seating do you think?

What screws do I need to extract to get at the workings? Any drawings anywhere on the web?

Any help greatly appreciated.

Thanks.

whyamihere

First of all, release the cable from the front mech. Once this is loose, it should spring back. If the mech doesn't shift down now, the spring's knackered.
Next, pull on the cable by hand and operate the shift levers. You should be able to feel the cable moving. If not, then check the cable seating in the shifter. If it's seated properly, the shifter's most probably broken, though your local bike shop would be able to confirm this.
If the mech springs back, and the lever operates correctly, then it's probably just a stiff dirty cable. Replacing the cable will probably sort the problem.

Monty Dog

I expect it's just got dirty - get in there with a toothbrush and scrub out any muck. Release the cable and work the cage in and out to try and get it moving - spray some WD40/GT85 on the pivot points / springs. Also check the cable under the BB and if it passes through the frame - it might be a bit clagged up there too. Front mechs generally last a long time IME - there's not a great deal to go wrong. www.parktool.com for the technical bits.

brucey72

+1 for www.parktool.com as Monty says.

I have no mechanical experience but have just used their website to help me replace my rear gear cable

sv1000dave

Big thanks to everyone who suggested some things to check.

Turns out to be a broken piece of aluminium inside the shifter body.

Now got to wait to get it repaired/replaced under the guarantee.

Expected more durability from a bike of this price though, although my routes are quite hilly.

Cheers,

rockmount

I'm guessing it's a 2008 with Tiagra shifters ? ... Seems to me like Tiagra shifters simply don't work (I got a set for my winter bike - they lasted about 5mins). I think the 2009 Allez Elite has got 105s.

Nasty little b*ggers ....

wilwil

sv1000dave wrote:

Big thanks to everyone who suggested some things to check.

Turns out to be a broken piece of aluminium inside the shifter body.

Now got to wait to get it repaired/replaced under the guarantee.

Expected more durability from a bike of this price though, although my routes are quite hilly.

Cheers,

Same happened on mine, same bike, same shifters. The bit of metal actually dropped out on the floor when I was trying to index the gears, I think its a broken ratchet tooth. Try not to push both levers at once when changing to the big ring. The LBS can get a replacement mechanism without the hood that cost me £60.00 otherwise its a pair of levers costing £120.00. The first option means not having to re tape the handle bars.

BTW: it shouldn't matter how hilly it is!

rockmount

I finished up fixing with these 105s for £99 ...


http://www.chainreactioncycles.com/Models.aspx?ModelID=13646

The unfortunate thing is this required going 10 speed, but I really didn't want another Tiagra shifter in my life !!

sv1000dave

I've got a 2009 model with the 105's fitted, so it looks like they can be just as troublesome. (just 600 miles of use)

I now have a small piece of broken toothed metal that's put my best bike out of action. (well unless I just ride on the flat)

I guess I'll have to un-hitch the old reliable Claud Butler from the trainer and use that again until I get it fixed.

Got some Christmas presents that need breaking in, like, overshoes and leggings etc, and got to make the most of the dry weather while I still got some free time left.

Not going to use it as an excuse to stay indoors.