Front Derailleur woes

[antcox78]

Please help me before this front derailleur gets launched through the window.

Trying to fit a Shimano Deore m590 front derailleur to replace my original one for my Kona Dew hybrid cycle (full spec below)

Followed every guide to the letter and when it comes from trying to get it out the smallest cog into the other front cogs, the derailleur seems to hardly move where it ends up that I am in gear 3 on the shifter and the chain is whirling away stuck between the low and mid gear. I have tried to tighten the cable as much as possible to the point where its really stiff to get it to move up.

Wondering if it could be that halfrauds have misadvised me as i got the spare part from there. Took the original derailleur and told them my crank setup.

Please, any help would be much appreciated

Frame:Kona 7005 Aluminum ButtedFork:Kona P2 700c DiscFront Derailleur:Shimano C SeriesRear Derailleur:Shimano DeoreShifters:Shimano EZ Fire IntegratedChainset:FSA Dyna DriveChainrings:48/38/28 tooth chainringsBottom Bracket:RPM 7420Cassette:Shimano C Series (11-34 tooth range, 8 speed)Chain:KMC Z-72Pedals:Xerama SP-941SFront Brake:Hayes MX4 MechanicalRear Brake:Hayes MX4 MechanicalBrake Levers:Shimano EZ Fire IntegratedHandlebars:Kona RiserStem:Kona ControlHeadset:Ritchey LB-PlusGrips:Kona Race LightRims:Rigida ZAC-19SLFront Hub:Formula DiscRear Hub:Shimano M475 discSpokes:Sandvik Stainless 15g fr/14g rrFront Tyre:Continental CountryRide 700×42CRear Tyre:Continental CountryRide 700×42CSaddle:Kona ComfortSeatpost:Kona ThumbSeat Binder:Kona QR

 

[sidevalve]

Not sure of the spec of the shifter but you could just try a "seat of the pants" adjustment. 1 - diss the cable and slacken off any stop screws then check that the shifter will move far enough to do it's job by moving it by hand.
2 - replace the "inward" stop screw and adjust 'till the derailer is in the middle of the chain on the inner sprocket, [use which ever is the "slackest" position on your setup, it's usually the inner]
3 - set the handlebar shifter to the correct position and replace the cable on the derailer [keep it tight but not so tight it moves the mechanism].
4 - move the shifter and watch what happens, either all is now well, in which case adjust the stop screws to stop the chain being pushed too far and joy all round, or nothing happens meaning it's not the derailer, either the cable has slipped or it's become detatched at the shifter or the shifter is duff.
PS just make sure you have the derailer "square on" to the chain, it's easy to miss that one.

 

[antcox78]

When i pull the derailleur it goes as far as the outer edge of the cage being level with the teeth of the largest cog. Shouldnt it go so the centre of the cage where the chain runs is in line. The other issue is that the cage moves only slightly no matter how tight the cable tension is.

 

[sidevalve]

Yes. Try the complete undoing of the limit screws and move it by hand, if it still won't move over far enough then it's the wrong one for your set up.

 

[RecordAceFromNew]

It is somewhat unlikely for the front mech to be wrong for the setup, because Deore front mechs are designed for 50mm chainline (distance from centre of frame to middle ring), which is pretty much as far as normal chainsets are supposed to go.

The most probable reasons for that front mech to not work for the outer ring are: a) the H limit screw is not let out far enough (try turning it anticlockwise), or b) the chainset has the wrong BB so chainline is beyond 50mm.

ps I assume the cable is not completely slack when the shifter is on 1st gear

 

[boydj]

I'd check the cable is running freely. Put the bike in the low gear at the front, detach the cable from the shifter and hold it with pliers or fingers and move the shifter to see if the cable is moving freely. If the mech is the correct one, the symptoms sound like the cable is wrongly routed or obstructed somewhere.

 

[antcox78]

Tried letting both screws out and the cage move out same distance. Then screwed both fully in and moves the same distance. the cable is removed during all this. Does this mean the h screw is having no effect whatsoever.

Don't want to go to my LBS as won't ever get to be able to do these jobs myself but its looking inevitable.

 

[BimblingBee]

I think a picture would really help!

 

[RecordAceFromNew]

Tried letting both screws out and the cage move out same distance. Then screwed both fully in and moves the same distance. the cable is removed during all this. Does this mean the h screw is having no effect whatsoever.

Don't want to go to my LBS as won't ever get to be able to do these jobs myself but its looking inevitable.

Is the mech new? What is the distance roughly? Have you measured the chainline?

 

[antcox78]

Looked at it again. When the mech is off the bike, I can fully extend the cage until it hits the bottom of the h screw. Put it back on the frame away from the chain and chain rings and it stops before it hits the screw. Can't work what is stopping it, is it the fact I can't apply enough brute force to pull it that far. Even more confused now.

Could the angle of the chain stay affect this.