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Thread: Extending thule square bars

  1. #1
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    Default Extending thule square bars

    hi all,

    I have perused all the threads on extending roof bars so 2 canoes can sit side by side, and the best solution for temporarily but sturdily extending thule square bars seems to be adding some box section steel to each side - 4 sections in all?

    Either extending by sliding the box section inside the square bar, or outside the square bar and bolting together

    Just wondering if anyone has successfully done this and what size and length box section you used and fixing method worked best for you?

    thanks!

  2. #2
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    I have done it on other manufacturers square / rectangular bars. mine was an external sleeve, the important dimension being the vertical one where it has to be an interference fit. width isn't as important they are fixed by a single 6mm bolt and nylock horizontally through the bar and extension piece. I have some photos inf you pm me with an email address.

  3. #3
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    Chris_B may have an answer for that. Chris has looked into this sort of thing from and insurance point of view. But in the mean time we have to consider the insurance situation. An improvised adaption, although secure in our eyes may have bad implications in the event of an accident.

    You can buy Thule square bars in various lengths. You need to check that slots match your car. Thule Pro bars have slots on their full length.

    In the past I have used 50mm x 50mm timber bars to the width required strapped to the roof bars, they worked for carrying 2 and even 3 canoes. Although now I wouldn't recommend it.



    Carried over 200 miles like this.

    Doug
    When there's trouble on shore, there's peace on the wave,
    Afloat in the White Canoe.
    Alan Sullivan


  4. #4
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    Quote Originally Posted by nantcoly View Post
    I have done it on other manufacturers square / rectangular bars. mine was an external sleeve, the important dimension being the vertical one where it has to be an interference fit. width isn't as important they are fixed by a single 6mm bolt and nylock horizontally through the bar and extension piece. I have some photos inf you pm me with an email address.
    will pm you thankyou!

  5. #5
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    Quote Originally Posted by dougoutcanoe View Post
    Chris_B may have an answer for that. Chris has looked into this sort of thing from and insurance point of view. But in the mean time we have to consider the insurance situation. An improvised adaption, although secure in our eyes may have bad implications in the event of an accident.

    You can buy Thule square bars in various lengths. You need to check that slots match your car. Thule Pro bars have slots on their full length.

    In the past I have used 50mm x 50mm timber bars to the width required strapped to the roof bars, they worked for carrying 2 and even 3 canoes. Although now I wouldn't recommend it.



    Carried over 200 miles like this.

    Doug

    well thats the thing i guess - in an event of an accident to have an unapproved modification or whatever the terminology is would not be great

    the alternative is get some thule probars - they arent cheap and also i'd have to fit them solely for when i want to carry 2 canoes on a motorway/long trip, i'm happy to carry 2 boats for local journeys using the one canoe flat/one canoe angled up method - leaving on the long bars isnt practical for day to day car use, and changing the bars is a bit of a faff...

  6. #6
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    I have longer bars that I bolt on top of the standard ones. They are easy to remove and fit using cap head bolts and nyloc nuts. Very sturdy.

    The bars are narrower than my wing mirrors, but wide enough for two canoes.

    [/URL]


    The heads of the bolts are inside the top bar so don't interfere with loading the canoes.

    [/URL]



    The bolts are easily fittted using an allen key and ratchet spanner. The rubber spacers stay on the bolts when the extension bars are removed.

    [/URL]
    Last edited by Big Al.; 5th-March-2019 at 07:38 AM.
    Big Al.

    Only when the last tree has died
    and the last river been poisoned
    and the last fish been caught
    will we realise we cannot eat money.
    ~Cree Indian Proverb

  7. #7
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    I do pretty much what Big Al does except I have the square head bolts that slide into the channel in the lower bars. I would strongly recommend using two long bars fitted on top of your narrow bars rather than trying to add 4 short extensions as the failure points are far less and the loads on the joints far less.

    When strapping the canoes on I always make sure than on the inside at least the straps go under both bars so that the original bar mounts would need to fail for the canoes to be able to come off.
    John

  8. #8
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    I use a (I think) 25mm square steel from B&Q fixed to the top of the roof bar with exhaust pipe clamps. It means I am not drilling anything to make it weaker. I cut the bar to the width of the wing mirrors, about 6 feet and use pipe lagging to protect the ends and reduce sliding. I've done several 1500mile journeys like this without problem. There appears to be no flex.

  9. #9
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    Modifying the roof bars could be a problem with insurance etc. but Adrian's solution I'm sure would be viewed as part of the load, not part of the roof rack.

    My reccommendation would be to think in terms of something that straps/ties onto the roof rack which is in itself stable as a load. If your bar positions are fixed, you might add one or more longitudinals to ensure that the transverse bars cannot slip off the roof bars, but do watch out for roof curvature which causes the bars to not be parallel. If your roof bars end up in a different position each time you fit them, fixing longitudinals will be more challenging. Also watch out for the total weight creeping up - the weight of the roof bars themselves detract from the weight of load available.

    How hard can it be?

  10. #10
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    I have recently created a roof rack extension by securing t section aluminium bars 2 1/2 inch x 2 1/2 inch x quarter inch thick to the underside of my roof bars using M8 U Bolts


    Zoelzer bars (https://www.whetmanequipment.com/roof-racks.html) are then secured to the T sections using M8 t nuts supplied by zoelzer

    This helps to keep the bars parallel to each other and allows me to posission them anywhere on the roof not being restricted to the length of the roof rails


    In time I make a post about constructing this right but I've still got the part of it to build positioning a roler extension mounted to the rear bar.

    Sent from my SM-G950F using Tapatalk

  11. #11
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    Zoelzer bars are also available in lengths to suit 2 boats and they make a version to fit Thule roof bar feet

    Sent from my SM-G950F using Tapatalk

  12. #12
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    thanks very much everyone for your advice and solutions !

    ok so I can see that a single bar over the top of the short bar makes sense, and i like the u-bolt / clamp fixing idea, super easy to get off and no drilling...

    so 25x25x3mm box section , 3m length x 2 is about 40 online , cut to required length also

    galvanised version - about 60

    Just noticed thule do a square bar @ 2m , with the plastic sleeve - 90

  13. #13
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    I have found that the originally titled u bolts R Us supplier very useful

    https://u-bolts-r-us.co.uk/

    Ewan

    Sent from my SM-G950F using Tapatalk

  14. #14
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    Quote Originally Posted by WaterHarmonics View Post

    25x25x3mm box section , 3m length x 2 is about 40 online
    That's expensive, 7.5/7.6m length is around 20-00 inc Vat

    https://www.fhbrundle.co.uk/products..._6m_Grade_S235

  15. #15
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    indeed! thanks for the link

  16. #16
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    Quote Originally Posted by E_McNeill View Post
    I have found that the originally titled u bolts R Us supplier very useful

    https://u-bolts-r-us.co.uk/

    Ewan

    Sent from my SM-G950F using Tapatalk

    Ewan, what internal diameter u bolt did you use that fits nicely like that around a thule square bar? 30mm?

  17. #17
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  18. #18
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    Ewan, did you check the weight of all the various bits a pieces? Probably ok but you might be close to exceeding the load rating of your bars / rails on your car? Also consider that with the overhang you won't be distributing the weight evenly between the front and back bars
    Last edited by smurf; 6th-March-2019 at 05:25 PM.

  19. #19
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    Quote Originally Posted by WaterHarmonics View Post
    Ewan, what internal diameter u bolt did you use that fits nicely like that around a thule square bar? 30mm?
    U-Bolt M8 x40 mm Thread, 32 mm Inside Diam, 61 mm Inside Height T316 Stainless Steel

    Used with

    Slotted backing plate for M8 U-bolt (22 - 36 mm ID) T316 Stainless Steel

    And extra penny washers

    They are a very good fit round Thule bars

    https://u246613.ct.sendgrid.net/mpss...S7JlS3s3mJg-3D

    Ewan

    P.s yes checked weight

    I've yet to make an additional modification to redistribute the wait support more evenly

    Sent from my SM-G950F using Tapatalk

  20. #20
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    great thanks

    KI metals on ebay are pretty cheap too, wasnt that keen on getting a 7.5m length of bar

    https://www.ebay.co.uk/itm/MILD-STEE...T1gL-6oSjezNBA

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