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  1.  
    I run a phil wood BB/Sugino 75 and i know the BB is specs right for the 75s.

    My concern is: On more than a few occasions upon getting my beloved samson NJS back from the shop i have noticed my drive side crank slip - almost feels as if the crank is slipping from the BB spindle or something..This has happened when there is lots of torque or stress pushed through the drive side crank.

    For example: A right side skid from brisk pedaling, a wheelie upon pushing down right after lifting the front end yesterday i felt the drive side slip again. It also happened rolling into a parking lot from speed to a track stand. Basically whenever there is a strong force or load being transfered through the drive side crank is slipping every once a while!

    Any thoughts or suggestions? I'm thinking worst case scenario my cranks square taper might be getting worn down, and the heavy loads are causing it too slip or maybe i just need to tighten all my crank bolts and chainring bolts but then again everything should be tight since i just got it from the shop last week?

    Bummed out and broke :)
  2.  
    Oh yea and anytime this happens it is very unnerving feeling like my cog or cranks are somehow slipping, i am riding very carefully now...
  3.  
    The shop mechanic could have been careless and forgot to tighten it him/herself. Do it yourself, you cant always trust those guys anyway :)
  4.  
    Are your lockring and cog tightened with the threads greased?
    • CommentAuthorwes m.
    • CommentTimeDec 14th 2009
     
    Every time someone says this it ends up being the cog. Bottom brackets dont slip. The crank arm may get loose on the spindle but that would cause more of a lateral wobble and less of a vertical feel. The odds that your "heavy loads" blew out a phil bottom bracket and 75 cranks are slim unless you did a lot of riding with loose crank arm bolts. This leaves the chainring and cog. Tighten the chainring and cog. Tighten the cog the right way, with a chainwhip and lockring tool.
  5.  
    Yeah, it's usually a loose lockring or cog. A crank arm cannot slip forward on a square spindle bottom bracket. If the cups were loose, your cranks would rattle around.
    • CommentAuthorthe rabbi
    • CommentTimeDec 14th 2009
     
    could also be your chainring bolts.
  6.  
    tell me your bb specs. this is interesting and i feel like i could help
  7.  
    no joke everyone thanks for the suggestions. i am almost positive it's not the cog/lockring. the reason i think the crank arm might be rounding off causing the slip since this aint the first time it has happened. i would never ride with loose crank arms, but who knows i guess the only mechanic one should trust is oneself.

    they charge me a god damn arm and a leg and i bet you they didnt bother to tighten the crank bolts... if ive been riding them loose, then this would cause the problem i presume.

    oh well i just took a spin and no slipping tonite, but like i said last time i cranked down a small wheely i defiently felt the slip which bums me out if i gotta get new crank arms shite! i used to skid 'alot' but like i said i always made sure everything was tightend down
    • CommentAuthorAaron C
    • CommentTimeDec 14th 2009
     
    honestly, i highly doubt it is anything other that a cog lockring issue (or possibly loose chainring bolts) . if your crankarms/spindle are indeed rounded out they will give you a "ca-chunky" back-and-forth feel. a loose cog/lockring/stripped hub thread will give you that smushy/gummy loss of power feel.
  8.  
    ya but they dont seem loose whatsoever. at worst i think the rounded out might be in its wee-early stage if anything.. the hubs are like new and same for the cog and l'ring.
  9.  
    Posted By: kleansupremeya but they dont seem loose whatsoever. at worst i think the rounded out might be in its wee-early stage if anything.. the hubs are like new and same for the cog and l'ring.
    Spend fifteen dollars on a square taper bb tool and take off the crank arms and check everything out. Chances are nothing will be wrong. Doing a few skids and wheelies won't ruin a phil wood bottom bracket and sugino 75 cranks. The sugino 75s are designed to be used by track racers who can exert more force on a crank arm than you and I put together ever could and those bottom brackets are tanks.

    Do you have a lockring tool and chain whip to check?
  10.  
    If you feel so confident that your BB and crank are to blame, take them to a shop and have them examined. But as wes said, if your parts fit together correctly and are tightened to spec, they're not going to slip, period. As far as things "seeming" tight, you really have to take things apart and put them back together to know a thing like that with any certainty.

    The only other thing to mention is that the Phil JIS BB fits in Sugino 75s better than the Phil ISO. Blah blah blah, Sugino does not machine it exactly to ISO standards. If your BB is ISO, I suppose it could have something to do with it. But plenty of people use both and I don't hear issues either way.
  11.  
    Posted By: proudxvxyouth
    Posted By: kleansupremeya but they dont seem loose whatsoever. at worst i think the rounded out might be in its wee-early stage if anything.. the hubs are like new and same for the cog and l'ring.
    Spend fifteen dollars on a square taper bb tool and take off the crank arms and check everything out. Chances are nothing will be wrong. Doing a few skids and wheelies won't ruin a phil wood bottom bracket and sugino 75 cranks. The sugino 75s are designed to be used by track racers who can exert more force on a crank arm than you and I put together ever could and those bottom brackets are tanks.

    Do you have a lockring tool and chain whip to check?


    well i dont know what to think right now, just got back from a brisk ride and had to 'pull' a few skids on the way, aok...lol get going later on again this time somewhat sprinting down then up a little slope hill street and just as im getting back to saddle 'chill mode' i felt the slip ... hopefully its just chainring or bolts or lockring.

    i would never and i repeat never-ever spin out on the road before making sure my cranks are tyte but at the same time i dont own the right tools as the bike alone has cost me out. im getting fed up with this shit.. you mentioned that 75s are for track racers and that 'you and i would never exert that much force' but to be honest with you i know and believe that riding in the streets for me at least is real demanding. specially on my drivetrain since all the gnarly skids i must pull to keep me going mang track racers dont be doin' that shit as tough as me.

    ok im not saying i can 'sprint as hardcore as a pro' but i unload plenty of heavy skids as it is. not too mention im fast as sin/njs is what it is..
  12.  
    Your NJS is broken
    • CommentAuthorwes m.
    • CommentTimeDec 16th 2009
     
    Skidding doesnt put as much force on the cranks/bottom brackets as a track racer does during a moderate acceleration. You dont even have to get out of the saddle to skid.



    example: Jody Cundy snaps a legit track chain from a dead stop with 1.5 legs.
    • CommentAuthorFlat Four
    • CommentTimeDec 16th 2009
     
    Kleansupreme, the EXACT same thing was happening to me a few weeks ago when I'd attempt a wheelie or skid. I was a bit concernicus about my crank/bottom bracket also. Turns out it WAS just the lockring. I'd put money on that being the culprit...easy fix.
  13.  
    Posted By: kleansupreme


    well i dont know what to think right now, just got back from a brisk ride and had to 'pull' a few skids on the way, aok...lol get going later on again this time somewhat sprinting down then up a little slope hill street and just as im getting back to saddle 'chill mode' i felt the slip ... hopefully its just chainring or bolts or lockring.

    i would never and i repeat never-ever spin out on the road before making sure my cranks are tyte but at the same time i dont own the right tools as the bike alone has cost me out. im getting fed up with this shit.. you mentioned that 75s are for track racers and that 'you and i would never exert that much force' but to be honest with you i know and believe that riding in the streets for me at least is real demanding. specially on my drivetrain since all the gnarly skids i must pull to keep me going mang track racers dont be doin' that shit as tough as me.

    ok im not saying i can 'sprint as hardcore as a pro' but i unload plenty of heavy skids as it is. not too mention im fast as sin/njs is what it is..

    Unless you are skidding while going 45 mph with a 56/12 gear ratio with clipless pedals, you do not put anywhere near as much stress on the drivetrain as a track racer. Even then it would be questionable. Have you seen pictures of japanese keirin racers' legs? You are not that strong. If you were, you wouldn't be paying for your bike or having it worked on at a local shop.
    Your chain would break long before you ruined a square taper crank and bottom bracket in this manner.
    If you were running a dura ace octalink crank and bb I would believe you because improper installation and skidding can create that issue.
  14.  
    Posted By: kleansupremesince all the gnarly skids i must pull to keep me going mang track racers dont be doin' that shit as tough as me.


    Ugh.



    Okay so, your chainring CANNOT be slipping. It's physically impossible. It has five bolts in it, and is secured to a solid spider on the crank arm. Unless ALL the holes are ovaled out in shape, it cannot be moving in that direction.

    As a fixed gear rider, two of the most important tools I suggest buying are a lock ring tool and a 1/8 chain whip for your cog. Also of course the correct size wrench for your wheel nuts and a set of alan wrenches. You should be set with that stuff.
  15.  
    Tell us......Have you taken your bike to the bike shop yet and had it looked at, and had them tighten your lockring and cog?
 
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