Specialized stumpjumper, front End knock help.

Forums Mountain Bike Forum Specialized stumpjumper, front End knock help.

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    • #262759

      Hi Guys,

      I have a 2017 Specialized Stumpjumper 650b Comp alloy.

      since new i have had this front end knock which when i ride makes it feel like the headset is loose, i have made sure that the headset correctly adjusted, but this has not improved any ideas and help is greatly appreciated.

      as you can imagine its not very confidence inspiring or fun when you feel like something is loose or knocking so really want this fixed.

      i have also made sure the for is set up to my weight and the rebound is set properly


    • #262769

      I find headsets tricky myself. The headset is probably fine, but the fork/stem might not be tight.

      Try loosening the stem bolts at the steerer, and also the top cap bolt. Jiggle the front end of the bike a bit to get everything settled in, then tighten the top bolt. Next, do the same for the stem bolts.

      If that doesn’t help, you might need to add another small spacer to the steerer to get everything tight.

      • #262818

        Thanks for that i will try that as my next step.

        One thing i did forget to mention was there is no in between on the adjustment meaning it either is to tight or to loose.

        i will adjust so the wheel moves freely side to side but to do this the headset is slightly loose but then i will tighten the bolt ever so slightly not even a quarter turn and then its to tight and wont move freely, any advice

      • #262941

        I actually had a similar problem recently with my daughter’s bike. I tried everything (or so I thought), then took it to my LBS. I think there ended up being a washer or some kind of facer plate in the stack that didn’t need to be there. Once that was out, the fork was tight and the wheel was able to turn freely.

      • #263083

        So i tried the above i also decided to move all th spacers below the stem which is now a more comfortable position and has improved my speed on the decents and went for a ride.

        i really payed attention to what was going on with the knock and noticed that at the start of the run the knock is none existent but when the trail gets rough or when the run has taken a while it starts to occur ( feels like a loose headset)

        when i stop to start the climb again i checked the headset and there was a little moment not a lot but more than there was before so seems to be coming loose but when you do the letting the wheel fall to one side trick it still doesn’t do this so that tells you that its tight right?

        should i over tighten the top nut to compensate for it coming loose i use to work at a bike shop and have never had this issue before i am truthfully baffled and have stripped the headset down numerous times and have really analyzed every part and am stumped any suggestions?


      • #266084

        You need to replace the bearings.  Get a new headset and you’ll be good to go.

    • #266154

      Sometimes a sound or a knock seems to be coming from one place but is coming from someplace else.  I recently had a knock that I thought was coming from my headset and discovered that some rear suspension linkage bolts had come loose.   I would go over the whole bike and check to see that every bolt is correctly torqued.  I would also follow JB’s advice above regarding your how to retighten your headset.  Also check that your  washer stack and stem is taller than your steerer tube by about 1-2mm.  If the stem/washer stack is shorter than your steerer tube the headset will never get tight.  If need be, add another thin washer.

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