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  1. #1
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    Replacing Acera FD with LX on Trek 4900

    I have a Shimano Acera as the Front Derailleur, and a LX in the rear. This is the stock configuration of my Trek 4900. I was thinking if I could get a performance boost by replacing the Acera with a new LX or XT derailleur in the front. What do you think?

    Also, can I just swap the Acera with a LX/XT? Or do I need to replace the cables and shifters too?

  2. #2
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    It's not an e-type derailleur clamp, is it?

  3. #3
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    Make sure when you get the front derrailleur you get the correct clamp size and whether to pick a top swing or down swing.

  4. #4
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    Easiest solution is to get a Shimano Deore mech - this is universal - comes with shims for different Seat-tube diameters, compatible for up or down pull and works with 7, 8 or 9 speed.

    You do not need to replace the shifter but very likely need a new inner cable only (you should be able to retain the outer cable unless it's in a bad shape).

    Not sure about the performance boost you're after, though the front would shift more precisely that's about all this upgrade will get you.

  5. #5
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    My two cents: Honestly, cable housing is so cheap that if you're replacing a cable, you should definitely replace the housing too. Actually, often the cable isn't that bad but the housing has grit / contaminants / kinks that put friction on the shifting / braking; sometimes housing is more important to replace than the cable. That said, replace both.

    I had a customer at the shop who had replaced a damaged GT Idrive frame with the same frame, so he figured it was okay to keep all the cables and housing. Then he couldn't figure out why nothing shifted very well. New cables and housing made his 'new bike' ride like a new bike. I told him, 'I sometimes replace my cables and housing when I'm bored, not just when it desperately needs it'. I think chains get neglected this way, too; save wear and tear on the rest of the drivetrain.

    I don't buy the most expensive cables and housing, either; I'm not very picky at all. I do use good crush-proof derailleur cable housing on my bikes, but nothing too spendy; it's just going to get dirty and need replacing anyway.

  6. #6
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    Quote Originally Posted by kenjihara
    My two cents: Honestly, cable housing is so cheap that if you're replacing a cable, you should definitely replace the housing too. Actually, often the cable isn't that bad but the housing has grit / contaminants / kinks that put friction on the shifting / braking; sometimes housing is more important to replace than the cable. That said, replace both.

    I had a customer at the shop who had replaced a damaged GT Idrive frame with the same frame, so he figured it was okay to keep all the cables and housing. Then he couldn't figure out why nothing shifted very well. New cables and housing made his 'new bike' ride like a new bike. I told him, 'I sometimes replace my cables and housing when I'm bored, not just when it desperately needs it'. I think chains get neglected this way, too; save wear and tear on the rest of the drivetrain.

    I don't buy the most expensive cables and housing, either; I'm not very picky at all. I do use good crush-proof derailleur cable housing on my bikes, but nothing too spendy; it's just going to get dirty and need replacing anyway.
    thats a good idea, replacing the housing would make sense, coz my bike has taken a couple of falls, and there are visible damage on the cables, although i havnt really noticed a decrease in the performance as yet. Maybe thats why im ignoring them...

  7. #7
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    I got another question--
    i have mechanical disc brakes right now. Im planning on upgrading them also to hydraulics. So can I use the same rotor that I have for hydraulics? Can I just buy a new brakeset (without the rotor), or do i need to get a new rotor also?

    I have seen one of my friends using the mechanical rotor for hydraulics, but I dont know how safe/efficient it is...

  8. #8
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    Regarding the FD... A few years back, i was in the same position. I upgraded from Acera to LX, and was very happy with the performance upgrade. The FD was all i replaced. Used the same cables and housing.

    Regarding the brakes... I have yet to see a shop sell the brake unit without the rotor.
    When under pressure, your level of performance will sink to your level of preparation.


    Shorthills Cycling Club

  9. #9
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    Most if not all brakesets come with the rotors. I do not believe there's a discernable efficiency difference between mech and hydro discs, definitely not a safety issue in any case.

  10. #10
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    Regarding the FD... A few years back, i was in the same position. I upgraded from Acera to LX, and was very happy with the performance upgrade. The FD was all i replaced. Used the same cables and housing.
    Just so we understand each other-- this is tantamount to replacing your brakes and then putting your old brake pads on. I don't know that you'd see a major 'performance enhancement' with the replacement of a front derailleur, but I know you're not getting the full performance out of it with old cable and housing. Of course, we wouldn't make such a big deal out of it if cable and housing wasn't so darn cheap!!

  11. #11
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    Quote Originally Posted by kenjihara
    Just so we understand each other-- this is tantamount to replacing your brakes and then putting your old brake pads on. I don't know that you'd see a major 'performance enhancement' with the replacement of a front derailleur, but I know you're not getting the full performance out of it with old cable and housing. Of course, we wouldn't make such a big deal out of it if cable and housing wasn't so darn cheap!!

    Sure, you're point is well taken. But if it ain't broke, don't fix it. I've also replaced just the broken FD when the cable was in fine shape.

    The question, I think, was whether an LX or XT would be better than an Acera. Mine was a Deore FD, which I replaced with an XT and the improvement was absolutely noticeable.

    However, while the old one still worked, I wouldn't have considered the $30 worthwhile. When parts wear out and break, replace them with better parts. Keep that philosophy in mind or you'll quickly find that you've spent more on upgrades than you did on your bike.

    -BD

  12. #12
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    Quote Originally Posted by Blue_Dooey
    Sure, you're point is well taken. But if it ain't broke, don't fix it. I've also replaced just the broken FD when the cable was in fine shape.

    The question, I think, was whether an LX or XT would be better than an Acera. Mine was a Deore FD, which I replaced with an XT and the improvement was absolutely noticeable.

    However, while the old one still worked, I wouldn't have considered the $30 worthwhile. When parts wear out and break, replace them with better parts. Keep that philosophy in mind or you'll quickly find that you've spent more on upgrades than you did on your bike.

    -BD
    So you believe that replacing the Acera FD with an XT is gonna make a noticable difference? Also, did u just swap the FDs, or did you have to go thru some extra procedures? Thanks for your post!

  13. #13
    work to ride to work
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    Yes, I believe you will notice the difference. It's easy. The new XT comes with adapters to different tube sizes, so you just have to make sure that you get the correct swing (top/bottom). But, even though I think you will notice the difference, I don't necessarily think that you should do it unless you are having problems with the existing one. I think it's a waste to throw perfectly good parts in the trash just for the sake of upgrading.

    -BD

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