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Gravity light 7050?

Discussion in 'Downhill & Freeride' started by Sandwich, May 30, 2013.

  1. Sandwich

    Sandwich Pig my fish!
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    I know the 6000 series arms are made of cheese, but apparently they now have 7050 arms. They also come in a size with rings I need. Worth a shot?
     

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  2. Lelandjt

    Lelandjt Turbo Monkey

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    The old ones worked perfect for me for 3 seasons. The new ones are supposed to be stronger at about the same weight (which happens to be very light, only 200g heavier than carbon SixC).
     
    #2 -   Jun 1, 2013
  3. BmxConvert

    BmxConvert Monkey

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    A half pound is still pretty significant in a crankset. Especially one synonymous with failure. I'd skip it based on past issues. Yes, 7050 is supposed to be stronger but when Descendants are less expensive, lighter, come with a far better bottom bracket and are well proven it makes it hard to ignore them.
     
    #3 -   Jun 2, 2013
  4. dilzy

    dilzy Monkey

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    Why do people use cranks other than Shimano? Seriously.
     
    #4 -   Jun 2, 2013
  5. HardtailHack

    HardtailHack used an iron once

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    Other brands have better paint.
     
    #5 -   Jun 2, 2013
  6. Sandwich

    Sandwich Pig my fish!
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    Well, shimano cranks are obviously the best, but I can find gravity cranks for 150 on crc... with two rings that I could put on my trailbike...saving me money over buying a three ring setup or a single ring which I dont need. They're therefore 40 $ less than descendants and more useful. Slxs or xts are about the same cost, but dont appear to be any more functional for my needs...if the 7050s work. So I asked. I know people didnt like the 6061s, b7t that's likea no brainer. Otherwise ill have to buy cranks, buy rings, and try to get in around $100, which isnt easy.
     
    #6 -   Jun 2, 2013
  7. Udi

    Udi RM Chief Ornithologist: “I Brake for Birds”

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    FSA use the same design as Shimano for their external BB cranks (apart from a coarser spline), so they actually don't lose out in any respect when it comes to ease of installation and interface reliability / longevity. They're the only brand of crank apart from Shimano I'd run for precisely that reason.

    I'd pick Saints over even the 7050 version from a strength perspective, but I think as long as you aren't clipping things regularly they should hold up fine. They have a proper steel pedal insert and washer too which is always nice.
     
    #7 -   Jun 2, 2013
  8. Verskis

    Verskis Monkey

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    You took the words out of my mouth. If a crank doesn't have the pinch-bolted spline interface, I wouldn't buy them.
    One thing to consider is that the FSA BB is much worse sealed than Shimano. Luckily the Shimano BB is compatible with FSA, making it an easy upgrade when the original FSA BB seizes.
     
    #8 -   Jun 2, 2013
  9. BmxConvert

    BmxConvert Monkey

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    Just to keep in mind.
    At this years Tech Summit, FSA was telling us/teaching us that they've keep hearing that their bottom brackets are junk and so they wanted to show us that they have designed them to be "serviceable" and should be done on a regular basis... which requires a $30 tool.
    Even with service the FSA bb's are still a bit of junk. I won't even stock them anymore. The $21 Shimano BB has proven to hold up far better to our muddy PNW conditions.
     
    #9 -   Jun 2, 2013
  10. JustMtnB44

    JustMtnB44 Monkey

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    I have the original Gravity light cranks on my Highline and they have held up fine for 3.5 seasons of riding. If the new version is stronger for the same weight (which it should be using 7000 series AL instead of 6000) I would buy it. I will agree that the FSA bb's are not very good, but I have been able to keep mine going without replacement just yet.
     
  11. Lelandjt

    Lelandjt Turbo Monkey

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    i kept the sameFSA BB going for 3 years with occassional regreasing.
    Saints are strongest
    SixC is lightest
    Gravity Light and Descendant are middle weight and though Descendants had a better reputation than original G-Lights the new ones should be strong enough for all but the harshest parts thrashers. I'd pick between the two based on price.
     
  12. Dirk77

    Dirk77 Monkey

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    Is the gravity light axle, compatible with sram gxp/press fit bb?
     
  13. Lelandjt

    Lelandjt Turbo Monkey

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    Pretty sure no. Sram was always unique while Shimano, Raceface, and FSA (Gravity) were the same.
     
  14. Dirk77

    Dirk77 Monkey

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    Ya, pretty positive you are correct..

    Bummer, you can get these gravity light 7050 cranks on eBay right now for cheap!
     
  15. Dirk77

    Dirk77 Monkey

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    So the 83mm version, should work with a Shimano press fit bb on my kona carbon operator?
     
  16. Lelandjt

    Lelandjt Turbo Monkey

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    I think so but maybe email FSA just to be sure.
     
  17. jonKranked

    jonKranked Press Button, Receive Stupid

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    i have an old pair of FSA road cranks that don't fit a shimano BB.
     
  18. rpet

    rpet Turbo Monkey

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    My OG (not the 7000 ones) Gravity Lights are like 85% compatible with Shimano BBs... the remaining 15% involves a razor blade and a rubber mallet IIRC.

    -R
     
  19. Dirk77

    Dirk77 Monkey

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    Ok i scored two pairs of brand new gravity light 7050 cranks. 68 and 62 bucks shipped each.. What a steal. Not sure why these are going for so cheap. I was in lbs the other day and they were like 265..

    My bb92 gxp is definitely not gonna work.

    So i should be able to use a Shimano press fit bb for a saint? This one:
    Shimano SM-BB71-41C Downhill Bottom Bracket Press-Fit

    Or it looks like fsa makes some press fit bottom brackets.
     
  20. troy

    troy Monkey

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    Dude... FSA axles are a little bit thicker than on Shimano cranks so it won't fit unless You will modify Shimano BB plastic bearing inserts.What is so hard to understand?
     
  21. Dirk77

    Dirk77 Monkey

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    Dude... your actually the only one who has described why and what needs to be done to a shimano bb to make it work... If I had a set of 300 dollar Saint cranks in my hand, to measure the difference in axle diameters and a saint bottom bracket to see if I can modify it to fit fsa cranks, Id feckn know this.. But I dont.. and if I did have these parts in hand I wouldnt be using feckn gravity light cranks from ebay.. Whats so hard to understand?
     
  22. troy

    troy Monkey

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    I'm sorry, I thought someone mentioned it earlier :D Anyway, difference is not that big. I don't have a micrometer. but difference between FSA BB and S-no is ~0,05-0,07 mm, so You dont have to shave off much of material.

    EDIT:
    1 more thing, FSA cups are ~0,5 mm wider too (each), so You will probably need a 1 mm spacer somewhere.
     
    #22 -   Nov 16, 2014
    Last edited: Nov 16, 2014
  23. Dirk77

    Dirk77 Monkey

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    Ha, it's all cool. You helped me greatly, thank you!
     
  24. Lelandjt

    Lelandjt Turbo Monkey

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    So the answer is a Shimano BB will work in a pinch but might as well make your life simple by ordering a FSA? For what it's worth I've got an FSA BB on my XC bike that's been working great for 5 years so you can probably trust their BBs to be as good as Shimano.
     
  25. Dirk77

    Dirk77 Monkey

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    Ya that's what i thought too, until i started looking for a fsa press fit bb that will work with their mega exo 24mm axle, that also has a shell width of 104.5mm to match the kona carbon operator. I don't think they make one. I'm also not sure if it matters. The fsa bb92 should work, it'll just be spread a little further apart.
     
  26. Lelandjt

    Lelandjt Turbo Monkey

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    Exactly. The BB is two parts and it doesn't need that seal/spacer between the cups anyway. The one meant for a 92mm shell will work fine in a DH width shell, just ditch the middle seal thing.
     
  27. jstuhlman

    jstuhlman We noticed.

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  28. Lelandjt

    Lelandjt Turbo Monkey

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    Yeah. You don't need him. And don't give me those puppy eyes!
     
  29. Dirk77

    Dirk77 Monkey

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    Got the cranks fitted. I used a wheels manufacturing bb92, aluminum cups, abec 5 angular bearings bb.

    I used a piece of metal electrical conduit, split fours ways to tap the old cups out. Then i just used a piece of 3/8" all thread with some washers to press the new cups in. Free tools. It went perfectly..

    Thanks for your help guys.
     
  30. Lelandjt

    Lelandjt Turbo Monkey

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    I saw a bunch of those Konas at the Fontana race today. Looked nice, especially for the price.
     
  31. troy

    troy Monkey

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    For the record:
    • FSA Gravity Light BB inner diameter is 24.02 mm.
    • Cup thickness is 10.30 mm.
    • 6805 - 2 RS bearings.
    • Crank spindle outer diameter is 24.06 mm.
    Will measure Shimano/RF bits some other time.
     
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