Results 1 to 17 of 17
  1. #1
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462

    Alfine 501 skipping

    I have an Alfine 501, been using it off-road for a bit over a year now. Today I noticed some bad skipping but seemed to be only in gear number 2. In the past I had skipping because the cable came partially out of a stop in the frame, but today it was not that. I cleaned the cable and it's working fine, adjustment spot on, yet gear 2 still skips.

    I'm going to tear into the hub, clean, and lube it. The skipping is a loud crunch sound with the pedals falling forward. It doesn't do it all the time but when enough pressure is applied I get it.

    Is there anything I should specifically look at when I take it apart for this gear 2 skipping?

  2. #2
    mtbr member
    Reputation: Dover's Avatar
    Join Date
    Jan 2006
    Posts
    482
    it sounds like you've broken a tooth off the planetary gear. it should skip in seventh gear as well if this is the case.

  3. #3
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    Thanks for your input! I'll pay special attention to those gears and let you all know what I find out.

  4. #4
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    Well I tore it all apart and it's now back together. First thing I see was some water intrusion and a bit of corrosion on the outer races of the roller clutches. Cleaned that up with some 600 grit. Second thing was the pawl for gear two was slightly deformed and a couple of the teeth on the mating ring were marred as well. Touched those with a dremel, they look okay now.

    I even removed all the planetary gears to get to the mating ring and I found out the hard way that the rotation of the planetary gears upon reassembly is important. Whew, just gotta line up all the dots. The gears looked perfect.

    Slathered on some Shimano grease, no oil as it's not cold here, set the cone free play and put it on the bike. I'll give an update when I have a chance to ride it.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    107
    Just wondering, what size chainring and cog are you running?

  6. #6
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    I am running 32x20 on the gearing, 26" wheels, and I weigh 200 lbs. I had a chance to ride it around the neighborhood and it shifted great through all the gears and didn't skip.

    Maybe I will get to ride it again this weekend on singletrack. I had to repack my crank bearings as they were full of water too. And to top it off my Gravity Dropper developed a large crack on that same ride.

  7. #7
    mtbr member
    Reputation: Dover's Avatar
    Join Date
    Jan 2006
    Posts
    482
    Quote Originally Posted by presslab
    I am running 32x20 on the gearing, 26" wheels, and I weigh 200 lbs. I had a chance to ride it around the neighborhood and it shifted great through all the gears and didn't skip.

    Maybe I will get to ride it again this weekend on singletrack. I had to repack my crank bearings as they were full of water too. And to top it off my Gravity Dropper developed a large crack on that same ride.
    those hubs are designed to be run with a 2:1 primary drive. (Chain or belt system)
    32-20 might be a bit "torque-y" for the hub. try getting a 16 or 17 tooth cog or going up a bit in chain ring size and see what that does for the hub. the the 1.5:1 ratio you are running could be what coused the pawl gear damage.

  8. #8
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    Yeah I knew going into it that a 20t cog was beyond recommendations. The thing is that I screwed up my knee on the dirt bike a few years back and had two surgeries: ACLR and removed 1/3rd of the meniscus. I still have some PFS and it aches pretty good for the first few miles.

    I used to ride singlespeed.

  9. #9
    Frt Range, CO
    Reputation: pursuiter's Avatar
    Join Date
    May 2008
    Posts
    2,436
    Quote Originally Posted by Dover
    those hubs are designed to be run with a 2:1 primary drive. (Chain or belt system)
    32-20 might be a bit "torque-y" for the hub. try getting a 16 or 17 tooth cog or going up a bit in chain ring size and see what that does for the hub. the the 1.5:1 ratio you are running could be what coused the pawl gear damage.
    So if I'm 300lbs of rider/gear/bike and run a 32x23 on my Alfine, you're thinking I'm illegal? BTW, lots of people have a couple seasons running 32x22/23/24 with no issues. Don't know what happened to OP's hub, maybe he was standing while climbing and shifted?

  10. #10
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    Actually I think it was the water ingress as the clutch surfaces were slightly corroded. The messed up pawl was probably an effect and not the cause. There was nothing with the pawl that would make me think it would cause the hub to skip.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    107
    Did you do anything out of the ordinary to get water in there? Some people are routinely riding through streams without any intrusion. Maybe a bad seal?

  12. #12
    mtbr member
    Reputation: bikeny's Avatar
    Join Date
    Feb 2004
    Posts
    1,867
    Quote Originally Posted by Dover
    those hubs are designed to be run with a 2:1 primary drive. (Chain or belt system)
    32-20 might be a bit "torque-y" for the hub. try getting a 16 or 17 tooth cog or going up a bit in chain ring size and see what that does for the hub. the the 1.5:1 ratio you are running could be what coused the pawl gear damage.
    About the gear ratio thing. From all of the reading I have done, there is no official recommendation or limit to gear ratio from Shimano for the Alfine hub. There have supposedly been conversations with Shimano engineers etc. with that recommendation, but nothing official. I am currently running 30:24 on my Alfine, and so far so good(29" wheel). I know I am pushing it, but that is what I need to get my but up the steeps and get my low gear close to a der. system. I am acyually gettingready to mount a custom 28t ring on my crank to go even lower.

    I think the biggest cause of problems is not the actual gearing, but shifting under load. That is what really screws up the hub.

    Mark

  13. #13
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    The Alfine is on my winter bike so it does see a lot of wet weather. I ride through streams maybe 1-2' deep. The seals are nothing special, just a single standard lip seal on each side with some kind of dust cover.


    On my Alfine it doesn't generally shift under load, and knowing this I always ease up before I shift. This is because it needs to pull down one pawl and then raise another, if there is load it will not be able to pull down the pawl. Perhaps if there is light load it will be able to pull down the pawl and not properly engage the next one. There are a couple gears that don't pull down a pawl before raising the next one.


    I think a bigger problem would be misadjustment. This would cause the pawls to not be fully engaged.

  14. #14
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    Here are a couple pics I took when I rebuilt the hub. You can see the corrosion on the clutch and the slight nicks on the ring gear.
    Alfine 501 skipping-img_1329.jpg
    Alfine 501 skipping-img_1326.jpg

  15. #15
    mtbr member
    Reputation: rdhfreethought's Avatar
    Join Date
    Aug 2006
    Posts
    1,467
    Quote Originally Posted by presslab
    On my Alfine it doesn't generally shift under load, and knowing this I always ease up before I shift. This is because it needs to pull down one pawl and then raise another, if there is load it will not be able to pull down the pawl. Perhaps if there is light load it will be able to pull down the pawl and not properly engage the next one. There are a couple gears that don't pull down a pawl before raising the next one.
    I have noticed this as well. My hub has been strong enough, but the limited shifting under power is pretty annoying, especially considering that the Hammerschmidt has ZERO problems with this.

    I was wondering what was needed to 'pull up the pawl' as you mentioned. Would it be possible to get stronger springs to help with this?

    I think the Shimano engineers did us a disservice with the shifting performance. They apparently aimed for smooth, light shifting, and not durable shifting that takes a bit more effort. If anything, it should also have reverse shifting (from what it is now, i.e. like a conventional shifter), as it is much more important to downshift under power, than upshift.

    I have thought of replacing the bar shifter itself in hopes of improving the situation, as I had a crash early on that damaged the plastic (but I think all the innards were fine)

    Any advice?
    Regional Race Manager, Knolly Bikes
    Washington State, Australia, New Zealand, South Africa

  16. #16
    mtbr member
    Reputation:
    Join Date
    Feb 2007
    Posts
    107
    Quote Originally Posted by rdhfreethought
    I think the Shimano engineers did us a disservice with the shifting performance. They apparently aimed for smooth, light shifting, and not durable shifting that takes a bit more effort. If anything, it should also have reverse shifting (from what it is now, i.e. like a conventional shifter), as it is much more important to downshift under power, than upshift.
    I think they're making exactly those changes on the 11 speed.

  17. #17
    Master of None
    Reputation: presslab's Avatar
    Join Date
    Jan 2007
    Posts
    1,462
    The pawl springs lift it up, but I doubt they could be made stiffer. Maybe bending them but there isn't much room for modification.


    It turns out the small amount I ground off the tip of the pawl was too much. It would not always fully engage the gear. I took it apart again, removed the pawl, welded a little more material on top and ground it back into shape. Works good now, took it on a real ride.


    I don't think reversing the action of the shifter will help a whole lot. It doesn't really upshift *or* downshift under power.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •