Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Page 1 of 2 12 LastLast
Results 1 to 15 of 16
  1. #1
    Join Date
    Dec 2010
    Location
    queensland
    Posts
    59

    Default Flat top car trailer

    Does anyone know where I can buy plans for this USA flat top car trailer ? I have checked most Aussie sites and none seem to have a clean flat top like this one

  2. #2
    Join Date
    Apr 2010
    Location
    Warwick QLD
    Age
    53
    Posts
    26

    Default

    If by "clean flat top" you mean "without the side & front barriers" keep in mind that local laws & regulations are different to those in the US.

    A bit more info as to what you want would be useful.

  3. #3
    Join Date
    Nov 2006
    Location
    Bendigo Victoria
    Age
    80
    Posts
    7,471

  4. #4
    Yonnee's Avatar
    Yonnee is offline Trailer Bloke & Mild Mannered Moderator
    Join Date
    May 2007
    Location
    Tooradin, Vic.
    Age
    52
    Posts
    1,318

    Default

    Two reasons we don't see many like that here in Australia is firstly the size of material required for the main chassis rail, and secondly, there's not much point. The main reason for eliminating the side rails is to allow the doors to open on a really low race car, but with the guards sitting up as high as they do, they are what's going to be in the way.

    The Master Plans & Designs kit shown requires a 5" channel for the main chassis... that 125mm! They need this sized material as there's no other support for the chassis. You can build a trailer with a deck 50mm lower to the ground by simply using 75 x 50 x 3mm RHS and then trussing it with smaller SHS up to the top of the guards.

    Whichever way you decide to go Jex, just make sure you document the build on here.
    Too many projects, so little time, even less money!
    Are you a registered member? Why not? click here to register. It's free and only takes 37 seconds! Doing work around the home? Wander over to our sister site, Renovate Forum, for all your renovation queries.

  5. #5
    Join Date
    Oct 2009
    Location
    Springfield NSW
    Age
    70
    Posts
    75

    Default

    ____________________________________________________________
    there are only 10 types of people in the world. Those that understand binary arithmetic and those that don't.

  6. #6
    Join Date
    Dec 2010
    Location
    queensland
    Posts
    59

    Default

    Thanks for your replies.
    I did not realise it would require 125mm side rails. I thought they would have been around 100mm.
    My previous car trailer had trussed sides and they were a pain in neck during entry/exit to a vehicle, especially a low vehicle. I agree, the mudguards are also a problem but with a higher trailer this would not be as pronounced.

    I have 2 x 12" electric brake axles & wheels rated at 4 tonne so a 3t load rated trailer to cover 4wd would be preferable. The car trailer plans on the web seem to be all 2.5T rated. A general purpose flat top would probably do the job as well. It could be used for vehicles or converted to a covered trailer if required

    John

  7. #7
    Join Date
    Dec 2011
    Location
    South East Queensland, Australia
    Posts
    355

    Default

    Here's a link to an interesting trailer USA. Something similar with the fold down mudguard might be a thought.
    Good tilt trailers make life easy, though the crook ones, and a couple of which I've been involved with, are a right PIA.
    The ones with high side rails are a real pain, I'm a bit less flexible than younger days to slide up out the window

    Tilt Trailer Plans For Towing Business

    Good luck with finding or working out a design that you like

    Cheers.

    If I'm not right, then I'm wrong, I'll just go bend some more bananas.

  8. #8
    Yonnee's Avatar
    Yonnee is offline Trailer Bloke & Mild Mannered Moderator
    Join Date
    May 2007
    Location
    Tooradin, Vic.
    Age
    52
    Posts
    1,318

    Default

    The thing about designing/building a car carrying trailer is getting the guard height you want. The wheel and tyre diameter of the trailer isn't going to change. You need suspension clearance from the trailer's tyres to the under side of the guards. So that can't change either. What you can then change, is the guard height to floor of trailer measurement. But this comes with a centre of gravity/floor height trade-off. You can have the floor level with the guards as a flat top trailer, but your floor height will be around 700mm. Drop the floor to between the guards, using straight axles, Slipper Springs, and a 75 x 50mm chassis rail (assuming a 600mm tyre diameter), your floor height will drop to around 500mm, and floor to guard height can be around 175mm. Using 4" drop axles, you floor height can drop to 400mm, but your floor to guard height increases to 275mm.
    Too many projects, so little time, even less money!
    Are you a registered member? Why not? click here to register. It's free and only takes 37 seconds! Doing work around the home? Wander over to our sister site, Renovate Forum, for all your renovation queries.

  9. #9
    Join Date
    Dec 2010
    Location
    queensland
    Posts
    59

    Default

    Yonnee, what wall thickness would you use for a 3T frame using 75mm rails? Would the draw bar be the same size & wall thickness?
    John

  10. #10
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    What are you planning to pull it with?
    A 3000Kg payload + mass of trailer (around 600-800kg wouldnt be unrealistic) will put it beyond the legal towing of pretty much every passenger car (4WD's included).

  11. #11
    Join Date
    Dec 2011
    Location
    South East Queensland, Australia
    Posts
    355

    Default

    Quote Originally Posted by racingtadpole View Post
    What are you planning to pull it with?
    A 3000Kg payload + mass of trailer (around 600-800kg wouldnt be unrealistic) will put it beyond the legal towing of pretty much every passenger car (4WD's included).
    Even some of the fairly big 4WD vehicles don't have a very big load rating(vertical down) for the tow bar. Lets face it, modern 4WD's are more about luxury, nice ride and looks.

    Cheers.

    If I'm not right, then I'm wrong, I'll just go bend some more bananas.

  12. #12
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    Quote Originally Posted by Log View Post
    Even some of the fairly big 4WD vehicles don't have a very big load rating(vertical down) for the tow bar.
    The issue is not the point loading on the ball. The ball should have around 5-8% of GTM sitting on it. At 3000Kg that number should be closer to 5%. Most towbars are rated for 5-8% plus a safety margin. 5% of 3000kg is 150kg, thats only one and a bit people standing on the ball. A properly set up car with sufficient towing capacity shouldnt even notice that sort of point load on the ball.

    The main issue is Aggregate Trailer Mass. The new Mazda 4x4's are being advertised with a tow of 3500kg. Very unlikely you can make a trailer with a 3000kg payload that weighs 500kg or less to fit within the 3500kg tow of say a Mazda. Just the shear weight of the axles, wheels and springs are against you when you start wanting to pull those sort of weights.
    Pulling those sort of weights does wonders for your fuel economy too..

  13. #13
    Yonnee's Avatar
    Yonnee is offline Trailer Bloke & Mild Mannered Moderator
    Join Date
    May 2007
    Location
    Tooradin, Vic.
    Age
    52
    Posts
    1,318

    Default

    Quote Originally Posted by jex View Post
    I have 2 x 12" electric brake axles & wheels rated at 4 tonne so a 3t load rated trailer to cover 4wd would be preferable.
    I'm going to assume John means a 3000Kg ATM as opposed to a 3000Kg payload.

    Quote Originally Posted by racingtadpole
    The ball should have around 5-8% of GTM sitting on it.
    Actually, the figure generally bantered around the trailer industry is 10%, and you'll find most towbar's are rated with their ball weight rating of around this, but I don't quite agree... and never have. While 10% can be a rough guide as a generalisation, some tow vehicles just wont cope well with a 10% load on their rearend, particularly upwards of 1500Kg of trailer/Caravan.
    And a 20Kg towball weight for an unladen 6x4, for me is a little light.

    Quote Originally Posted by racingtadpole
    The main issue is Aggregate Trailer Mass. The new Mazda 4x4's are being advertised with a tow of 3500kg. Very unlikely you can make a trailer with a 3000kg payload that weighs 500kg or less to fit within the 3500kg tow of say a Mazda.
    The towing capacity of any car doesn't restrict you from towing a trailer that's rated higher. It just means you're not supposed to load the trailer beyond that tow vehicle's rating. So John can build himself a trailer rated to 4000Kg (as per his axles), and if he owned a BT50, he could still use the trailer, but only ever load it up to 3500Kg ATM.

    However, I would only rate the trailer at 3500Kg, as this the highest capacity you'll get in a 50mm towball and any 50mm coupling. This is also the cutoff point for the next level of safety chain required.
    Too many projects, so little time, even less money!
    Are you a registered member? Why not? click here to register. It's free and only takes 37 seconds! Doing work around the home? Wander over to our sister site, Renovate Forum, for all your renovation queries.

  14. #14
    Yonnee's Avatar
    Yonnee is offline Trailer Bloke & Mild Mannered Moderator
    Join Date
    May 2007
    Location
    Tooradin, Vic.
    Age
    52
    Posts
    1,318

    Default

    Quote Originally Posted by jex View Post
    Yonnee, what wall thickness would you use for a 3T frame using 75mm rails? Would the draw bar be the same size & wall thickness?
    John
    3mm as a bare minimum for the trailer frame.

    And I would not use anything smaller than 100 x 50 x 4mm for the drawbar.
    Too many projects, so little time, even less money!
    Are you a registered member? Why not? click here to register. It's free and only takes 37 seconds! Doing work around the home? Wander over to our sister site, Renovate Forum, for all your renovation queries.

  15. #15
    Join Date
    Dec 2010
    Location
    queensland
    Posts
    59

    Default

    Yes, 3000kg atm. I am towing with an Iveco 50c18 truck that I currently use to tow a 5T 5th wheel RV. 5th wheel or gooseneck trailer would be nice but that would be narrowing down the tow vehicle type. I thought the rails & drawbar would be 4mm, would that be over engineering ?

Page 1 of 2 12 LastLast

Similar Threads

  1. Flat Top Trailer for the Bush
    By rod1949 in forum TRAILERS & OTHER FABRICATED STUFF
    Replies: 18
    Last Post: 12th Jun 2012, 04:14 PM
  2. help me build a basic flat build bed trailer for my kayaks
    By gros21 in forum TRAILERS & OTHER FABRICATED STUFF
    Replies: 7
    Last Post: 13th Oct 2011, 08:47 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •