Front derailleur question
Discussion
Just bought a pre owned mountain bike, and it's mostly hunky dory.
But the front derailleur, a Shimano Deore is sticking. It won't return to the smallest ring without a swift tap, and it doesn't seem to have enough movement to make it onto the largest ring either.
I've had it off the frame, given it a good WD40ing and tried to work it back and forth, but while better, it still won't work properly.
Should I get another unit off ebay, or will I be stuck with similar problems? Is there a better, but still cheap equivalent that'll work with my shifters? (They have a little indicator window on them, and two levers, one up, one down).
Sorry for the novice stuff, but I have no clue.
But the front derailleur, a Shimano Deore is sticking. It won't return to the smallest ring without a swift tap, and it doesn't seem to have enough movement to make it onto the largest ring either.
I've had it off the frame, given it a good WD40ing and tried to work it back and forth, but while better, it still won't work properly.
Should I get another unit off ebay, or will I be stuck with similar problems? Is there a better, but still cheap equivalent that'll work with my shifters? (They have a little indicator window on them, and two levers, one up, one down).
Sorry for the novice stuff, but I have no clue.
Have you cleaned up the gear cable where it runs inside the outer cable sections? You can do this by releasing the tension on the cables, just operate the shifters without pedalling. This should let you lift the outer cable out of the guides and slide it up and down the inner cable without having to take the cable off. Once you've got it free, set to with the WD40 and a rag on the inner cable, and flood plenty of it down through the outer cable. Once the cable stops cacking up the rag, apply some lube (chain lube or a light cycle specific grease) sparingly. Put the outer cable back into the guides, and use the shifters to re-introduce the cable tension. While the cable is slack, don't forget to clean the plastic cable guide under the bottom bracket, if your cable is routed that way. Dirt/corrosion on cables is one of the top causes of shifting problems. If it's too far gone, the cable may need replacing, but a basic cable kit shouldn't cost too much. To be honest, on a pre-owned bike I would check the cables thoroughly, and consider replacing them. While your at it, get the chain checked for wear, and if it is worn, budget for a replacement chain and rear cassette. The last time I replaced a MTB cassette it was a Shimano like-for-like replacement and cost about £24 from my local bike shop, and a chain can be had for about a tenner. Worst case, the dérailleur is borked. Once out of shape, incredibly difficult to fix, so you may need a new one http://www.wiggle.co.uk/cycle/mtb/front-derailleur... (from about £20 upwards)
Links, if they help (other online bike shops are available!)
http://www.wiggle.co.uk/mtb/gears-drivetrain/
http://www.wiggle.co.uk/mtb/chains/
http://www.wiggle.co.uk/mtb/cassettes-freewheels/
http://www.wiggle.co.uk/mtb/gear-cables/
http://www.wiggle.co.uk/lifeline-chain-wear-tool/
If you are a total newbie, then something here might help:
http://www.amazon.co.uk/s/ref=nb_sb_ss_i_4_4?url=s...
Links, if they help (other online bike shops are available!)
http://www.wiggle.co.uk/mtb/gears-drivetrain/
http://www.wiggle.co.uk/mtb/chains/
http://www.wiggle.co.uk/mtb/cassettes-freewheels/
http://www.wiggle.co.uk/mtb/gear-cables/
http://www.wiggle.co.uk/lifeline-chain-wear-tool/
If you are a total newbie, then something here might help:
http://www.amazon.co.uk/s/ref=nb_sb_ss_i_4_4?url=s...
Sorry, not made myself crystal clear.
From memory, (bike's in the shed) when I use the shifter to try and hit the largest ring, it won't quite engage.
Then if I try and shift down, the mech sticks and the cable goes loose.
As mentioned earlier, I think I ruled out cable stickiness by taking the mech off the frame and operating it by hand. It was still sticking.
It was pretty dirty, and I gave it a good clean and oil, but I reckon it's possible the spring has more dirt in between the coils which is inhibiting free movement.
If I was to dismantle the mech totally, is it likely the spring will be tricky to replace?
From memory, (bike's in the shed) when I use the shifter to try and hit the largest ring, it won't quite engage.
Then if I try and shift down, the mech sticks and the cable goes loose.
As mentioned earlier, I think I ruled out cable stickiness by taking the mech off the frame and operating it by hand. It was still sticking.
It was pretty dirty, and I gave it a good clean and oil, but I reckon it's possible the spring has more dirt in between the coils which is inhibiting free movement.
If I was to dismantle the mech totally, is it likely the spring will be tricky to replace?
Rather than go through the inevitable heartache of dismantling the mech, you could replace it for a shiny new one http://www.wiggle.co.uk/shimano-fd-m590-deore-atb-... for a score. If you want to fiddle with the old one, good luck. You're a braver man than I.
yellowjack said:
Rather than go through the inevitable heartache of dismantling the mech, you could replace it for a shiny new one http://www.wiggle.co.uk/shimano-fd-m590-deore-atb-... for a score. If you want to fiddle with the old one, good luck. You're a braver man than I.
Yeah, the only problem is my inner Yorkshireman is baulking at spending the same on a new mech as I paid for the whole bike.vladcjelli said:
Yeah, the only problem is my inner Yorkshireman is baulking at spending the same on a new mech as I paid for the whole bike.
Yup, I know that feeling. I bought a snotter as a barracks hack when I was posted up in Ripon, proper Motor Factor window dressing, bought from a mate who got posted and couldn't be bothered to ship it to NI. Rode it for about 2,000 miles, no maintenance to speak of. It's now virtually unrideable, hub bearings and bottom bracket shot, freewheel knackered, cables stuck, brakes won't release when applied, play in the headset. Even using the cheapest parts to fix it up, the cost is too high. Even if it worked, it'd still weigh about a ton, and be virtually valueless. Still, at £20 to buy the thing, it's cost me all of 1p per mile to ride it to destruction, and perversely it was kind of fun when compared to riding my (much) nicer GT Avalanche, or my fancy-schmansy road bike. A real leave it anywhere and not worry about it getting nicked machine, that really helped when part of my last job involved working away from the main barracks, in the middle of an old WW2 fighter station runway, riding 4 to 6 miles a day to and from the office and bunker. Good luck with the fix!Op, try adjusting the outer limit screw - think it's h, but put tension on the adjuster, turn and observe. If in doubt, just undo both l and h by 2 full turns, get the mech moving, then readjust as per youtube videos.
Losing tension in the cable - degrease the mech itself, see if you can free it up. Other people have blamed the cable, but imo if it goes slack, then the cable is free - it's the mech that is not.
Losing tension in the cable - degrease the mech itself, see if you can free it up. Other people have blamed the cable, but imo if it goes slack, then the cable is free - it's the mech that is not.
gradeA said:
Have you got a photo of the current front mech? I might have a working replacement you can have for the cost of postage.
A kind offer, and if, after a bit more tinkering I'm not making any headway, may well take you up on that.So, pictures:
On the bike:
Taken off to show stickiness:
No tension/smallest ring position
Fully tight/largest ring position. Guessing it shouldn't stay open like that with nothing holding it?
Easier to see in the first two pictures, but I think your mech is definitely BORKED. Just had a look in the garage, and on all 5 of the bikes in there, the top part of the mech cage is parallel with the floor, with the sides vertical. One of them is the current Deore mech, on my son's brand new GT Avalanche 1.0. It may be that the bike has been dropped, or badly handled/stored with it's weight on the dérailleur. It may be worth trying to straighten it up, as I don't think you could make it much worse, but I fear you would need to be some kind of wizard of metalsmithery to get it perfectly re-aligned.
ETA
If you're not happy about buying new bits, I would avoid used stuff off the 'bay, as you could end up with another problematic mech. You could try your local recycling centre, as ours often has a number of bikes in various states of disrepair stacked next to the scrap metal bin. You may be asked to pay for that, though, despite the fact that it's someone else's garbage. You never know, you might turn up a hidden gem there, and end up taking a whole bike home as a project. n+1 and all!
ETA
If you're not happy about buying new bits, I would avoid used stuff off the 'bay, as you could end up with another problematic mech. You could try your local recycling centre, as ours often has a number of bikes in various states of disrepair stacked next to the scrap metal bin. You may be asked to pay for that, though, despite the fact that it's someone else's garbage. You never know, you might turn up a hidden gem there, and end up taking a whole bike home as a project. n+1 and all!
Edited by yellowjack on Thursday 4th October 13:51
vladcjelli said:
Fully tight/largest ring position. Guessing it shouldn't stay open like that with nothing holding it?
No, it shouldn't, it relies on cable tension alone to pull it away from the frame. Agree with the above it's taken a knock, the top part of the cage is bent out of shape. A replacement will be about a tennerFirstly, the outer plate should only be 2-3mm about the outer chainring. Also, the plates should be perpendicular to the ground; I agree with everyone who's said it's taken a high energy impact to cause it's current predicament. While you're handing over that tenner for a new front mech; I'd seriously consider blowing a fiver on some degreaser for the chain and chainrings. Few things don't work better when they're clean. We're going crazy now so don't look back and blow £4 on a new cable (with outer). You'll wake up the next day wondering where that £19 went to but your bike will fly like never before 
yellowjack said:
Just had a look in the garage, and on all 5 of the bikes in there, the top part of the mech cage is parallel with the floor
itsnotarace said:
Agree with the above it's taken a knock
jrb43 said:
I agree with everyone who's said it's taken a high energy impact to cause it's current predicament.
Cheers for looking fellas.Had nothing to compare it to, but now you've mentioned it, the fact it's bent inwards a little bit would explain why it wouldn't engage the largest ring.
And I guess that knock/pressure that's bent it must have stiffened up something in the mechanism preventing free movement.
Wish I'd thought of hitting the recycling centre (is that what we call the tip nowadays?) as I drove past there just this morning.
Chain Reaction Cycles seem to be selling these at 11.99 inc P&P, so might just take the plunge.
Although the call of ebay is strong...
Gassing Station | Pedal Powered | Top of Page | What's New | My Stuff