Cross bars flexing- Mtbr.com
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  1. #1
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    Cross bars flexing

    Added some aftermarket crossbars to my 19 crosstrek (brightlines I think), and then mounted a Rocky Mounts Tomahawk rack to it.

    I am concerned that after mounting a bike intot he rack i can see the crossbars flexing as I pull on the biked.

    Worried this is a safety issue and that the bars will crack under load when driving.

    Am I just being paranoid?
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  2. #2
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    What brand crossbars? Is Brightlines a brand?

  3. #3
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    Yes. Brightlines in the brand. Sold by ASG Auto Sports.
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  4. #4
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    Quote Originally Posted by skankingbiker View Post
    Yes. Brightlines in the brand. Sold by ASG Auto Sports.
    Here is how I think you’d get an answer. If someone on here has a Thule or Yakima aerobar setup, with a bike carrier, they could put the steed up there and see how much if any flex there is. I have some aerobars, but I carry my bikes on the hitch so I can’t do it for you. If I could I would!

  5. #5
    since 4/10/2009
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    I googled these things. The only retailers I saw selling them were places like Amazon and walmart.

    I would absolutely NOT put them anywhere near the same league as Thule or Yakima's aero bars. They MIGHT be an improvement on low end factory aero bars, but there's a chance they won't be.

    And when it comes to factory aero bars, they're mostly not good. I remember when I worked outdoor retail at a shop that did a robust business on roof racks and roof rack parts. I went through a lot of rack fit guidelines for a lot of different stuff. The issue with a lot of factory aero bars is exactly what you're seeing - they're flexy. In the fit guides, I often saw notes from Thule and Yakima NOT to put bike mounts on these kinds of crossbars, and in more than one phone conversation with those rack companies, the answer was that those types of aero crossbars are meant for relatively light loads pressing straight down. Things like cargo boxes/bags, canoes, etc. Vertical loads that press down, but also lean side-to-side like bike mounts, some kayak mounts, and such, put stresses on those kinds of bars that they're simply not built to handle.

    Of course, not all factory crossbars are created equally. So some of them were perfectly fine with a bike or a vertical kayak holder.

    But, if you're just standing next to the car in the driveway and a test wobble of the bike flexes the bars easily, no way in hell would I drive with that setup. My car has plain old Thule square bars. I have a 1upUSA roof tray and sometimes carry my bike up there. I can wobble my bike, and the rack doesn't move. The car rocks on its suspension. My wife has a crosstrek with square thule bars, too (different towers), and it's the same way when we carry bikes up there. My teardrop camper has a custom built square bar roof rack on it, and it's the exact same way.

  6. #6
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    Here is what the company says:

    Dear Customer,

    Thank you for contacting us. We are sorry you are having concerns with your product. With any crossbars, there will be some amount of flex. One way to avoid as much flexing is to distribute the load on evenly. If you are loading this item onto a direct point, that could be the cause of added flex. Because bike racks are particularly known to sit on two fixed points, this flexing can be common. We can assure you these crossbars will have no problem cracking or breaking as long as you continue to not exceed the 150 pound load capacity. We apologize for any inconvenience this may have caused you. If you have any further questions or concerns, please do not hesitate to contact us.
    Veni Vidi Biki

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  7. #7
    since 4/10/2009
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    Quote Originally Posted by skankingbiker View Post
    Here is what the company says:
    Uh-huh. Doesn't inspire confidence in the product. Maybe ask them about bikes on the roof PLUS a microburst crosswind on the freeway. BTW, I have encountered this exact scenario with bikes on the roof in the 1upUSA roof trays. Damn near thre the car off the road, but the bikes stayed put.

    Sent from my VS995 using Tapatalk

  8. #8
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    There will be flex with any crossbars?

    Pretty sure I can put another VW on top of my Thule crossbars and not worry about flexing.

    Ditch whatever you bought and get Thule or Yakima crossbars.
    Vermonter - bikes, beers and skis.

  9. #9
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    You need to pull the end cap off of one of your bars are see if it has crossmembers, or baffles for lack of a better word, in there. If it’s just a hollow bar it wouldn’t be very strong. The Thule and Yakima bars both have significant structure within the aero bar. Or swing by a store and look at them, as well as the thickness of the aluminum.

  10. #10
    since 4/10/2009
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    Quote Originally Posted by VTSession View Post
    There will be flex with any crossbars?
    Yeah, no.

    There's flex with shitty factory crossbars that are more aesthetic than functional.

    But functional crossbars? Nope. I can put my 65lb 16ft Royalex canoe on the roof of my Honda Fit (boat is bigger than the car) and the crossbars don't flex appreciably.


    DSCN0391 by Nate, on Flickr

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