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  1. #1
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    Specialized S-Works Epic 29er – Lateral Crank Movement

    I have some lateral play in my crank. I can see this when I align my non-driveside crank arm with the chainstay and squeeze them together.

    Anyone else have this?

    I am using Specialized’s typical OSBB setup with 38/24t chainrings.

  2. #2
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    Unless this is more than a few mm's, this is normal. It's not lateral play, it is flex in the chainstays and BB. Quite normal. Every bike I've owned does it.

  3. #3
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    Skiwi, thanks for the reply. However, it is movement of the crank assembly. I can see the non-driveside alloy bearing cover, which receives the wave washer, move when I squeeze the crank arm and the chainstay together. The crank is setup exactly as Spec requires, so I can only assume that the BB shell is not quite 73 mm. I could fix this problem by installing a few 1 mm spacers, but I want to make sure that this float isn't supposed to be there.

  4. #4
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    Quote Originally Posted by SpryIP View Post
    Skiwi, thanks for the reply. However, it is movement of the crank assembly. I can see the non-driveside alloy bearing cover, which receives the wave washer, move when I squeeze the crank arm and the chainstay together. The crank is setup exactly as Spec requires, so I can only assume that the BB shell is not quite 73 mm. I could fix this problem by installing a few 1 mm spacers, but I want to make sure that this float isn't supposed to be there.
    What is your frame (alloy or carbon), and crank?

  5. #5
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    2011 S-Works 29er Epic frameset (full carbon)
    S-Works MTN crankset

  6. #6
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    Quote Originally Posted by SpryIP View Post
    2011 S-Works 29er Epic frameset (full carbon)
    S-Works MTN crankset
    In that case, yes you can pack the shaft to remove lateral movement. I have used the PF30 clear spacers (x3) between the spacer and the bearing which worked for me. Given that these bearings are not designed for lateral loading, they will wear fast if there is too much end-float. I replaced my RHS bearing after about 300kms. After repacking (I also replaced with the XX spider and rings & large 2-speed spacer), I've got 1500kms on the BB prior to replacement.

    Having said that, I plan to use the SRAM PF30 BB next time out. I'm only hearing good things about longevity with that BB.

  7. #7
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    Good info. Did you put the spacers (assume 1 mm) on the non-driveside? And, can you tell me exactly where you put the spacers? On the non-driveside, I could see adding spacers between the bearing cover (2) and the wave washer (3). On the driveside, I could see adding spacers between the bearing seal spacer (4) and the driveside alloy bearing spacer (9), but that would modify the chainline. All numbers taken from Spec's carbon MTB crankset document.

    Even 1500km is not very much distance on a set of bearings.

    Is SRAM's PF30 BB fully compatable with Spec's MTB carbon crank?

  8. #8
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    Quote Originally Posted by SpryIP View Post
    Good info. Did you put the spacers (assume 1 mm) on the non-driveside? And, can you tell me exactly where you put the spacers? On the non-driveside, I could see adding spacers between the bearing cover (2) and the wave washer (3). On the driveside, I could see adding spacers between the bearing seal spacer (4) and the driveside alloy bearing spacer (9), but that would modify the chainline. All numbers taken from Spec's carbon MTB crankset document.

    Even 1500km is not very much distance on a set of bearings.

    Is SRAM's PF30 BB fully compatable with Spec's MTB carbon crank?
    No, I put the spacers on the drive side. I was also trying to sort out a driveide crank arm clearance issue. The net was that I moved the RHS crank arm out about 1.5mm (3 x BB30 spacers) and reduced my crank arm strike issue significantly. If you look at the Specialized crank manual (first diagram), I fitted the spacers between "4" & "9" on the diagram. If I were to fit them outside "9" then I would be changing the chain line which isn't a good idea as it will affect front shifting.

    Hth

  9. #9
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    Spacers between 4 & 9 would be my preference, but I first want to understand why putting spacers anywhere on the driveside wouldn't change the chainline. It seems like it would.

    Also, besides the driveside crank arm clearance issue, did you also have lateral play? If no, 1.5 mm packed on the spindle would seem like enough to cause overloading on the bearings.

    Thanks for all you help!

  10. #10
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    Quote Originally Posted by SpryIP View Post
    Spacers between 4 & 9 would be my preference, but I first want to understand why putting spacers anywhere on the driveside wouldn't change the chainline. It seems like it would.

    Also, besides the driveside crank arm clearance issue, did you also have lateral play? If no, 1.5 mm packed on the spindle would seem like enough to cause overloading on the bearings.

    Thanks for all you help!
    I had lateral play so putting the spacers where i did removed the play without changing the chainline. Putting them outside of the large spacer didn't allow them to reduce the lateral spacing.

  11. #11
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    Have you tightened down the crankset? Remove the dust cap on the driveside crank and use the S Works mountain tool (A deep 35 Torx) to tighten it to spec. Only consider spacers after checking this.

  12. #12
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    Yes, that was the first think I checked. I am amazed that there was so much play in the crank, but I also didn't really notice it until the bike was about a year old. Maybe it isn't a big deal. Nonetheless, I have removed the play with two 1 mm spacers.

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