Forum menu
front mech fitting ...
 

[Closed] front mech fitting stress

Posts: 4795
Full Member
Topic starter
 
[#2476699]

Building up a bike for a mate and getting wound up with the front mech.
It an Alivio dual pull with cable running along top and down seat tube.
I haven't fitted a front mech for a couple of years but never had this much hassle!!

I'm thinking that I've clamped the cable incorrectly and the mech is moving too much because when I shift from granny to middle it wants to go straight to big ring and when in big it wants to go straight to granny. I've tried adjusting the cable tension many times also.

Any ideas please.....?

I'll have another go at it tomorrow


 
Posted : 16/02/2011 9:34 pm
Posts: 0
Free Member
 

I feel your pain I had the same stress last week and gave up, a dmitted defeat and took it to my best but not nearest LBS and they sorted it all and tweaked the rear mech for £6. Not worth the frustration in my eyes.


 
Posted : 16/02/2011 9:37 pm
Posts: 4795
Full Member
Topic starter
 

Yeah thats plan B if no joy tomorrow lol


 
Posted : 16/02/2011 9:39 pm
Posts: 11630
Free Member
 

I haven't done one for ages but I think the cable should come down the seat tube, around a cam with a groove in it, and then back up towards the pinch bolt. If the cable were routed up from the BB it would go into the pinch bolt at the same angle.


 
Posted : 16/02/2011 9:44 pm
Posts: 8904
Free Member
 

My memory says it is the other way round. Straight to pinch bolt when coming from above, over the cam when coming from below.


 
Posted : 16/02/2011 9:51 pm
Posts: 8904
Free Member
 

Couldn't find the English version but the Japanese service instructions look to agree with me.


 
Posted : 16/02/2011 9:54 pm
 mmb
Posts: 0
Free Member
 

err if it's jumping from big to small and vice versa then the shifter may need lubricating as the ratchet inside might not be engaging properly, of course i may be wrong but that's how i cured it when i used gears.


 
Posted : 16/02/2011 10:05 pm
Posts: 4795
Full Member
Topic starter
 

Thanks all.

I've already lubed the shifters, I'll have a look again to see if if going round the cam is an option as well as straight to the pinch bolt.
Never had this much trouble fitting them a few years ago!

Will see what the morning brings, happiness or a trip in the car to the lbs.


 
Posted : 16/02/2011 11:20 pm
Posts: 0
Free Member
 

My 2p's worth (sorry if this is obvious) is seperate the shifter and mech - ie undo the cable cinch bolt.

Then but some tension on the cable and try the shifter for both up an down shifts. The cable should move equal amounts. From 1 - 2 - 3 and down.

By using your thumb the mech should shift from granny to middle to top whilst rotating the cranks.

The only similar problem I had was with the mech - it couldnt move past the mech mounting ring / mech due to a stupid problem that's too embarrasing to mention!


 
Posted : 16/02/2011 11:25 pm
Posts: 4795
Full Member
Topic starter
 

Ok cheers coulda I'll try that too


 
Posted : 16/02/2011 11:41 pm
Posts: 3351
Free Member
 

Front mechs are always a massive ball ache. If it's any help the sole Alivio geared bike in the PJM household never seems to want to jockey the chain to all three front cogs, it's a case of two out of three at best.

Can you budget a Deore front mech? The missus has one on her Marin and it's as well behaved as my XT.


 
Posted : 17/02/2011 12:02 am
Posts: 507
Free Member
 

There are a few different Alivio models, with different cable routings. An actual model no and a couple of pics of the mech in situ may help.


 
Posted : 17/02/2011 8:38 am
Posts: 4795
Full Member
Topic starter
 

Cheers coatsey

Had another look this morning in the old parts box and found an old 8 speed mech fitted that along with putting more lube in the shifter as it was still sticking a wee bit (as mmb suggested) and it's more or less there, still catching in some of the gears. my mate is going to take it to the lbs.

The Alivio mech is boxed up now but it's a FDM413X6 and I've just noticed that it got down swing marked on the box. For top tube cable routing shouldn't it be a top swing?


 
Posted : 17/02/2011 1:32 pm
Posts: 8904
Free Member
 

No, they are top and bottom pull compatible. The swing refers to the position of the cage in relation to the clamp band.

[img] [/img]

High band = conventional / bottom swing

Low band = top swing


 
Posted : 17/02/2011 1:36 pm