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  1. #1
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    Trying to fix my sons v brakes

    I'm somewhat new to wrenching on bikes, very experienced wrenching on cars.
    Anyway, I picked up a used Specialized hot rock 24 yesterday for my son.
    All looked well on the bike, rode it up and down the street, shifted and stopped fine. It has black rims that looked like they were new, tires are new. All is well.
    Get it home and he rides it a bit comes back in the house and says dad, there's a problem.
    So here's my problem. If he pulls the back brake hard to skid like kids love to do, the pads get stuck to the rim. After studying, checking, adjusting, more spring tension, etc....

    What it looks to me like is that the pad's left pad material on the rim and then when you hard stop, the pads are sticking to the material on the rim. I rode the bike myself and actually smelled the brakes being hot.
    I got some new pads from the local bike shop. I asked the guy about my problem and he looked at me like I had two heads and just said here's new pads.
    Thinking maybe these are cheap walmart pads or something, I got new ones. I've tried cleaning the rim with a rag and rubbing alcohol but it's not getting all the material off and I still have the same issue. Hitting the brakes with the wheel not rotating, everything moves and returns as it should as soon as I spin the wheel and hit the brakes with pressure, the pad sticks to the rim. It's not overlapping the edge of the rim, it's not hung up on the tire and it's not a cable because I can disconnect the cable and the pad is still stuck to the rim. Nothing is binding in the arm and the arm posts are lubed.
    Since the rims are shiny black I'm hesitant to hit the wheels with sandpaper or a scotch pad to try and take the material off. My next idea was to take the tire off and try some automotive brake cleaner. Hoping not to mess up the paint or whatever it is that makes the rim black.

    Any suggestions on fixing my problem.

    Thanks,
    Nick

  2. #2
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    Trying to fix my sons v brakes

    Pictures? Sounds like a cheap aftermarket wheel or a home paint job with a sticky rim surface.

  3. #3
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    I can take a pic and see if I can post it. It does not appear to be a home paint job, if it was, the rim was painted and then laced with spokes. Maybe a cheap rim? How do you tell what type or brand of rim it is?

  4. #4
    rebmem rbtm
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  5. #5
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    Not sure how well these will look, lighting is tough in the basement.
    The rear wheel after I tried cleaning it with a rag and rubbing alcohol


    The front that I haven't done anything to.


    The bike in question


    On the front wheel was a little pencil eraser sized dot sticker that said c2 or something like that.

    Thanks for taking the time to try and help me.
    Just blows to get your kid all wound up to ride his new bike and it doesn't work right...:-(

    Nick

  6. #6
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    A search reveals that at least some of the Hotrocks had black rims in the brake area. So, by deductive reasoning it must be one of the following three options:

    - The rims have become contaminated with something (or the black "paint" on the rims became sticky somehow).
    - The pads are contaminated.
    - It is not adjusted properly, in some weird way.

    Since you replaced the pads we can rule that out. And since you seem to understand adjusting the v-brakes it's probably option one. So I suggest you get something more pwerful like goop-off and try that. Be sure to clean the rims again with isopropyl alcohol afterwards. You may want to clean the new pads again since they may have become contaminated (or lightly sand them).

  7. #7
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    I was actually going to try a little goof off on the corner of a rag and went to the shelf looking for it, but I'm out of it.
    So I came here for suggestions. I think the rim is contaminated with pieces of the old crappy brake pad. The rims were completely smooth and clean when I picked the bike up.

  8. #8
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    Got to working on this last night. Well, I tried rubbing alcohol and that didn't do it, then I tried 2 kinds of citrus degreaser, that didn't work. Then I used goof off, followed by degreaser followed by a green scotch pad followed by rubbing alcohol.
    I put it all back together and it immediately started with crap building up on the rim. I can get one of the brake pads to stick while on the bike stand but not as bad as before. So I let Son ride it on the street and they are not sticking on him at the moment. He probably squeezes the brake with less force than me. I noticed when trying to clean the wheels that the black paint is coming off in places. So I can't tell if the guy painted the rims and it's the black paint coming off that's making the brakes stick or if they are crappy wheels or what's going on.
    He needs to ride the bike now and put some miles on it and the brakes and see what happens.
    If they have a sticking problem again with him riding it my next try is to sand the paint off the brake surface of the rim and sand down to a superfine grade of paper. If that doesn't work than it's new wheels I guess, although I'd rather not have to buy new wheels. But I'll approach that topic if I have to go that far.
    Thanks

  9. #9
    human dehumidifier
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    That's got to be a bummer for your son.

    I'd try some prep-sol or lacquer thinner on the rims. Since you're an auto mechanic you might already have some in the garage.

    I'd also look really close at the springs on the brakes and the cables to ensure it's really the pads that are sticking and not something else that just makes the pads stay on the rim. I would suggest making sure the pads aren't getting trapped by the bulge of the tire, but since you just installed new pads I presume you made sure there was plenty of gap there.

    I hope you can get this fixed so your son can get back the business of having fun on his new bike.
    NFL will punish America for its sins with Katy Perry as the Super Bowl halftime show.

  10. #10
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    I know for sure it's not the tire because I was testing the brakes on the stand with no tire on the rim and also it's not the cable because I disconnected the cable and the brakes still stuck to the rim. I didn't think about prep-sol, but I do have a can of that in the garage. I also adjusted the springs to the most tension slot and they appear to be ok. I also lubed the brake arm studs.

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