Fender strut reinforcement idea...

Discussion in 'General Questions' started by RedBaronX, Aug 4, 2010.

  1. RedBaronX

    RedBaronX Member

    OK, I haven't been here long, but I've been here long enough to know that lots of people think that using the fenders is a recipe for disaster-- the struts weaken from the vibration, break, and jam into the spokes...

    some people have made steel struts for their fenders, but I don't have much of a workshop... I have a space in my dining room five feet from my computer desk and not much for tools besides basic hand tools and common power tools.

    So my idea for reinforcing the stock aluminum struts is-- since they are concave in cross-section, fill the concave area with metal epoxy, maybe even adding a steel bar down the center like rebar. Anyone try anything like this? I think it will be effective because epoxy is strong and generally doesn't get brittle.

    I like the way the fenders look, and I am going to mount electric lights on them, so I have reason to keep them (that, and I used the red loctite on the fasteners of the front ones without realizing that the red loctite can only be removed with heat...)

  2. kerf

    kerf Guest

    I may not be qualified to speak on this subject as all of my builds have been mountain bikes and have no fenders. I do commend you for being resourceful, in looking for solutions using what you have to work with. My question is just this, is it worth the risk, given the possible catastrophic results if a failure occurs? From what I've read, fender failure can result in some serious broken bones and head injuries.

    Just ask'n.
  3. motorpsycho

    motorpsycho Active Member

    yep, red loc-tite is permanent, unless you use heat to melt it (as you already found out).
    i have fenders on my 50 c.c., 20" lowrider with the stock fender braces and have never had a problem with them vibrating, coming loose or anything like that.
    been riding it for over a year now with no problems, and the fenders and braces are just fine.
  4. RedBaronX

    RedBaronX Member

    that's the thing... if they were as absolutely DEADLY as some people think, no one would use them EVER...

    The person who has been helping me, she uses fenders on her builds, and has been building MBs for four years. I happened to mention early in my creation process that I hadn't decided if I wanted to use fenders or not, she said "you will want them if you get caught in the rain..." so, while we didn't discuss it in depth, not once did she say "keeping them can be dangerous".
  5. srdavo

    srdavo Active Member

    yes, fenders are good.

    Any kind of reinforcement is good.

    That said.... The problem with the failed fenders has not been the struts. It has been the bracket holding the top of the fender to the fork crown.

    When this bracket breaks, the fender drops onto the tire & follows the tire around to the ground. Once the fender comes between the rubber & the road, it becomes an instant brake.
    Picture your bike flipping forward like a mousetrap slamming shut.
    the struts just get mangled in the process.
    I am not sure that reinforced struts can prevent this. I am not willing to bet my face (arms, ribs, collarbone, etc.) on it.

    It is this bracket that needs reinforced. (also)

    Note: the majority of failed fenders have been on Cranbrooks & Kulanas.
  6. motorpsycho

    motorpsycho Active Member

    My front fender has 2 struts that go to the front axle. the struts are bolted to the fender with 4 nuts, bolts and lock washers. one strut is in the center of the fender and one strut is at the rear of the fender. my front fender is not attached to the forks at all...just to the front axle. but the struts slide on the axle before the forks do. If i take my front wheel off, the fender comes off with the wheel.
    my rear fender has one strut that is bolted to the back of the fender which goes to the rear axle, and the center of the fender is bolted to the frame on a bracket (like a bracket for a hand brake).
    the only thing i did was to loc-tite the nuts & bolts that go into the fenders that hold the struts on, and loc-tite on the nut & bolt that attaches the rear fender to the frame.
    with 2 struts in the front, one strut in the rear and the rear fender bolted to the frame, my fenders are mounted very solid.
    Last edited: Aug 4, 2010
  7. RedBaronX

    RedBaronX Member

    in the one story over in the "Legal" portion of the forum, the description of what happened to the guy was that the struts broke and slipped in amongst the spokes. I don't know if that IS what happened, but that's what I assumed from the story.

    Googling "Cranbook bicycles" the first image I get has pretty meager fender support... googling some more photos, all examples have poor support... comparing my bike's fender supports to the Cranbrook supports, mine look bulletproof...

    If THOSE are what are failing, I'm going to worry a whole lot less...
  8. RedBaronX

    RedBaronX Member

    motorpsycho-- mine sound like yours.