Front end 'wobble' Marin Muirwoods 2016

andUK
andUK Posts: 85
edited August 2016 in MTB workshop & tech
Brand new Marin Muirwoods 17" 2016 29er- rigid steel frame/forks trail bike.

Problem: when I take my hands off of the handlebars the bars start to shimmy/wobble/oscillate which becomes more and more pronounced in a matter of seconds until I'm obliged to grip the bars again. I've only done about 100 miles on it on roads and trails, and it's been like this from new.

Before you ask: everything is mechanically sound ie. the wheels are tyres are balanced, the wheels run true, the frame and forks are true, the wheels are centred and secure in the frame/forks AND the headset has no play in it whatsoever ... and anything else, all sound! I've checked, tested and re-checked.

This phenomenon is not speed wobble, as it occurs at slow, medium and fast speeds.

I have never experienced this before on a bike (funnily enough I also own and ride a 1996 Marin Muirwoods, rigid steel frame)

I wrote to Marin to query if this was anything to do with the materials and geometry of the bike and got a stock answer back listing possible mechanical causes despite my having told them all is mechanically sound.

Any suggestions?

Comments

  • The Rookie
    The Rookie Posts: 27,812
    It can happen, I get a wobble on one of my bikes (rigid) in a certain weighting condition, move my weight back or forwards and it goes, it didn't have it with the previous (same size and also slick for road use) tyre.

    Bent forks seems most likely given your description, a small bend on one leg so the wheel isnt tracking correctly and you have a loss of trail will cause it, it will be pretty hard to spot as well.

    Just changing the front tyre has been known to fix a wobble where there are no obvious 'faults' to one with different characteristics.

    Have two 1997 steel frame rigid MTB's so feeling your love for them!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.