Trying to find rear rack extension arms that are FLAT- Mtbr.com
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  1. #1
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    Trying to find rear rack extension arms that are FLAT

    Talking about the arms that come in pairs and attaches the rack to the seat stay. Looking on Ebay and called most bike shops and all they have are the arms that twist at one end. I have no clue why these arms are not flat. My LBS where I got my new Cannondale gave me a pair when I stopped by today. They're the right length and I'm thinking about hammering them flat. Wonder if that will work. Will try to heat it up first. Just don't want to weaken the metal.

  2. #2
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    Steel is pretty malleable and can be cold set without fatigue and cracks like aluminum. Rodar should comment. bssed on greater expertise, but I have reconfigured these before without an issue. A vice and adjustable crescent wrench took the twist out nicely. The right angle twist mates a set of seat stay rack bosses to the mounting points under the front of most racks.

    BrianMc

  3. #3
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    I have a Portland Design Works rack that has a pretty handy system for those supports. They are straight round bars and there's a sliding bracket underneath the rack's deck that allows you to adjust for fit on your particular frame. I have the aluminum rack, but there's a steel one for heavier loads, too.

    <a href="https://www.flickr.com/photos/[email protected]/6598619297/" title="On-One Pompetamine commuter by mtbikernate, on Flickr"><img src="https://farm8.staticflickr.com/7002/6598619297_402a5ec863.jpg" width="500" height="375" alt="On-One Pompetamine commuter"></a>

  4. #4
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    That is a sweet rack, Natehawk. The rack I have has support arms that would work perfectly for a bike like yours that has an inverted "Y" that links the seat tube to the seat stays. The support arms on this rack is actually a unit that can fortunately be removed. I was amazed at how heavy this part of the rack was. It's made of steel and believe it or not seems to weigh just as much as the entire rack itself! The rack is actually really light without this arm unit.

    BrianMC, thanks for the info. Gonna see if I can find a vice I can use. If not, will try the hammer against an iron piece.

  5. #5
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    Quote Originally Posted by NateHawk View Post
    I have a Portland Design Works rack that has a pretty handy system for those supports. They are straight round bars and there's a sliding bracket underneath the rack's deck that allows you to adjust for fit on your particular frame. I have the aluminum rack, but there's a steel one for heavier loads, too.

    <a href="https://www.flickr.com/photos/[email protected]/6598619297/" title="On-One Pompetamine commuter by mtbikernate, on Flickr"><img src="https://farm8.staticflickr.com/7002/6598619297_402a5ec863.jpg" width="500" height="375" alt="On-One Pompetamine commuter"></a>
    Nice rack! I have the same one. It's awesome sauce.
    Oh noes. I'm going to drink the Kool-Aid.

  6. #6
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    Quote Originally Posted by djork View Post
    That is a sweet rack, Natehawk. BrianMC, thanks for the info. Gonna see if I can find a vice I can use. If not, will try the hammer against an iron piece.
    Nate's PDW rack is a nice setup.

    In the absence of a bench vice, A short piece of wood on a concrete floor with the metal on top of that, and a hammer with a flat (not waffle) head or a sledge hammer can be used. A second wood 1 x 3 or smaller can be used as a punch to direct the hit to a specific point. You will learn how best to straighten it as you go. Learn to do by doing.

    Good luck.

    BrianMc

  7. #7
    weirdo
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    Quote Originally Posted by djork View Post
    Looking on Ebay and called most bike shops and all they have are the arms that twist at one end. I have no clue why these arms are not flat.
    They`re all twisted because most racks that use flat straps have holes or slots on the bottom of the horizontal platform to bolt onto and the other end of the strap usually goes either to designated rack bosses or to P-clips, either of which would be in a vertical position. I take it your rack has some different kind of setup? Curious what it looks like. BrianMc`s plans to straighten them out sound good to me. Remember that those straps (or tubes) only keep the rack from pivoting forward and back- the weight is all supported by the legs.

    EDIT: Whoops, sorry- Brian already said that too

  8. #8
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    rodar: I was surprised that some bike sops had no clue what I was talking about. A Performance shop told me he's never heard of what I described to him: extender arms, support arms, connects rack to seat stay, etc. Here's a link to my identical rack. Of course, I got mine from Bikewagon for $20 cheaper!

    The rack looks beefy but is really light. You can see the support arm unit underneath it. The arms are not flexible but the whole unit can move fore or aft and the arms swing up and down. Good thing it's removeable because it's useless on my frame and is heavy!

  9. #9
    weirdo
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    Thanks for the link, Djork- I hadn`t seen that rack before. So the rack is light and the block underneath is heavy? Taking it off doesn`t sound like a bad plan to me, but then won`t you need the half twist in the straps again?

  10. #10
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    If it was me, and the seat stay mounts are close making a parallel line with the rack top, to the rack mount points, so a straight bar would do, I'd get a 3' length of aluminum bar 1/8" x say 3/8" or 1/2", just wide enough to be 3 x the size of the holes you would drill in it. Cut and drill hoes to suit. If you need a bend in them, you could make a two piece with an angled and gusseted corner.

    BrianMc

  11. #11
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    Quote Originally Posted by rodar y rodar View Post
    Thanks for the link, Djork- I hadn`t seen that rack before. So the rack is light and the block underneath is heavy? Taking it off doesn`t sound like a bad plan to me, but then won`t you need the half twist in the straps again?
    The arm unit is held by two bolts that bolt on the side of the rack rather than under, hard to see in the photo. The unit can be moved for or aft, and using flat arms would work perfectly.

    BrianMC, I thought of that option and I'd prefer using aluminum arms, but I have no idea where one can buy aluminum pieces. I may do this down the line. For now I'll flatten the arms I have, which were free.

  12. #12
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    BrianMC, I thought of that option and I'd prefer using aluminum arms, but I have no idea where one can buy aluminum pieces. I may do this down the line. For now I'll flatten the arms I have, which were free.[/QUOTE]

    Free is good. My local Home Hardware and the big box home improvement stores have precut metal displays. If you have custom fabrication places nearby you might be able to buy a piece from the scrap bin.

    BrianMc

  13. #13
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    Just wanted to give a quick update. A week ago I was able to hammer the "twist" on the rack arms flat. It wasn't as hard as I had expected. Initially it was, but once the metal started to bend toward a flatten state it was easy from there. I put the part I wanted to flatten over a stove and got it red hot, and that helped (at least I think). It did discolor the arm and gave it a pretty cool chromish black color. I actually thought of putting the whole arm over fire to make the color uniform, but think I will paint it black or leave it as is. Overall, the arms were pretty flat when I was done with them. Turned out pretty nice and not beat up looking.

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