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  1. #1
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    Bonking ... not feelin' well Help! FD Replacement for 2002 Specialized Stumpjumper M4 Comp


    As others' reviews state, this Stumpy hardtail is a great bike and great value. Light, sturdy and responsive. Today I mainly use it for pulling my son on his Weehoo tagalong. Clydesdale Dad, 45 lb kid, 35 lb trailer bike, water bottles and stuff for the day--pushing 400lbs of total rolling weight on 20 mile + rides. Unfortunately the Deore LX FD sits right in the sweat drip zone, and it was the weak link to begin with. This weekend--one week before our vacation--it just froze up. Penetrating lube only helped a little.


    It was a Deore LX 3x9 bottom pull. Cranks are Specialized Strongarm 44-something-22 with an English BB. Shimano rear hub and sprocket and XT rear derailleur. I scrambled to find the closest thing available--a Deore M-590-6 9 spd FD, which looked like the right option (while Sheldon Brown says 9 and 10 SPD FDs are largely interchangeable, most of the 10s are designed for smaller chainrings and wanted to make sure it would fit the 44).


    Following all the classic FD alignment advice, even with the lower limit screw all the way out, it rubs the chain in the lowest 2 gears from the granny ring with no cable tension. It seems like the cage body opening does not flare out until further down than on the old LX, and it sits further from the seat tube. The other difference is that the pivot mechanism extends at least 1 cm further to the rear, which also pushes back the chain contact point. Iíve got it tuned so that it works in all gears on the middle and top chain rings, and tried every possible minor adustment, but the only way to eliminate the granny gear chain rub is to either raise it over 1 cm above the big chain ring so the chain is at the bottom of the cage in the granny gear or to angle it at least 5 degrees and then it rubs on the big gears and doesnít shift properly.


    Everything else works great, but I need the low gears for our combined wieght on hills. Any insights into this one? Is there another 9 speed triple FD option that is robust enough to handle our load and might better match the original chain angle needed?



    Thanks,

    Towiníkidz

  2. #2
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    Reputation: noapathy's Avatar
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    It's not the derailleur. If you're rotating it to favor the higher gears, you may want to re-think that strategy if it's primarily going to be used in the lower gears. Really, it shouldn't rub unless it's cross-chained.

  3. #3
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    I'm not rotating it, and I agree it shouldn't rub. I've done all my own bike work for over 40,000 miles of riding, and I've never had an issue like this. Right now it is set up in classic position, 2 mm above the the outside ring, outside edge of cage parallel to outside ring. With no cable tension or limit screw, from the granny gear the chain rubs not just on the inside cassette cog but on the second one as well. The only thing I can think of is that something about the standard geometry changed between 2000 and 2012 when the two Shimano derailleurs were probably designed--perhaps chainrings moved out a couple of mm or rear hub spacing changed?

  4. #4
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    Any chance of submitting a picture?
    If this is time critical, I'd just remove the FD and run the chain on the small ring to pull the kids and then go 1x with a more thorough plan after vacation.

  5. #5
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    Quote Originally Posted by towinkidz View Post
    I'm not rotating it...
    Why not? If you're not going to use the highest gears it's the easiest solution. Just a few degrees should do. It might rub on the high gears, but are you using them while on tow duty?

  6. #6
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    Thanks for the thoughts.

    I also reached out to the wise, experienced bike shop owner who sold it to me 15 years ago, and he suggested just carefully bending the cage to match the original. Current game plan is to combine some thin wooden pieces to wedge against the outer cage and upper cage down to the pivot point so they don't bend, clamp that wrapped in cloth, and then bend the inner cage wall so it flares a little higher like the original FD did. I'll take pics.

    We like to do 15+ mile rides on gravel or smooth dirt, and 20-30 miles on paved trails, so I use the outer ring far more than the granny. People hate it when they get passed by a not exactly slender guy on a 26'r with Conti Town and Countrys pulling his kid on a recumbent tagalong! The Weehoo is much easier and faster to pull than a child trailer--one wheel, much less drag, and he can pedal and help. It's much lower to the ground and tracks better than many of the cheap tagalongs where you see the kid bike leaning over at a 10 degree angle. He's strapped in to the recumbent bucket seat and not going to get bumped off. I'm big enough that even if he turns around to look back it doesn't make me wobble so we cruise a little faster than would be wise for say a 160 lb adult with a 60 lb kid. I may get by without needing the lowest two gears that rub during the trip, but last 4 days are in an area that does have some steep hills, and don't know what we will run into. The Weehoo is single speed, so on the steeper parts my son has too big a gear to help much, and I'm basically hauling an extra 80+ lbs uphill. I need the granny for stuff I could climb from the middle ring without the trailer bike.

  7. #7
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    I would bend the front to closely match the old one, I don't think it will work right if it's quite a bit different. Also look on ebay and just buy the same model you used to have; so many people are switching to 1x that there are a lot of spare front ders out there right now. If you are part of a bike club/community, chances are that someone has that same der in their parts drawer. That M4 is among the best 26ers ht out there, I had one for a while, I wish I'd kept that one.
    carry clippers! cut something off the trail every time you ride.

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