pavman Posted June 20, 2008 Report Share Posted June 20, 2008 Anyone good at math? A nice calculation me thinks Guys, almost finished building a shooting platform that fits to my Towbar on the freelander and top rails are taken off the roof bar, I was fairly happy with progress until some bright spark pointed out that my 150 Kg rated towbar would have extra force exerted on it due to the extended platform How the heck do you work that out Quote Link to comment Share on other sites More sharing options...
MJN Posted June 20, 2008 Report Share Posted June 20, 2008 (edited) the towbar is designed to pull 2 tons or so, it is more a question of how will the car handle with more than 150 kgs on the back ! making the steering light or strain on the rear suspension. Edited June 20, 2008 by MGMan Quote Link to comment Share on other sites More sharing options...
Ice Posted June 20, 2008 Report Share Posted June 20, 2008 Ive got no idea, but looks bloody good though Quote Link to comment Share on other sites More sharing options...
al4x Posted June 20, 2008 Report Share Posted June 20, 2008 you'll be fine unless you're an absolute porker, the bars onto the roof rails will help to counter the forces though these are only designed really for downward forces so not ideal. Tow bar though only rated at 150kgs will be able to handle a lot more. Quote Link to comment Share on other sites More sharing options...
bob300w Posted June 20, 2008 Report Share Posted June 20, 2008 Don't worry about it, that's the towing limit, not weight limit. If you intend using it for rabbits, I would be more concerned with getting a hole in your roof with the guns so far back, and shooting downward and forwards, you would not be the first to have this happen! Quote Link to comment Share on other sites More sharing options...
al4x Posted June 20, 2008 Report Share Posted June 20, 2008 (edited) its the downward force on the towbar Bob towing limit will be a lot higher than that Edited June 20, 2008 by al4x Quote Link to comment Share on other sites More sharing options...
Dunkield Posted June 20, 2008 Report Share Posted June 20, 2008 you'll be fine unless you're an absolute porker, Post of the day for me Pav it's all to with leverage, I will get the boy to do the maths when he gets back from school. How long is the platform beyond the toe bar? and how heavy are you,exactly ? we need this for the calculation, don't be shy Great idea by the way. Quote Link to comment Share on other sites More sharing options...
pavman Posted June 20, 2008 Author Report Share Posted June 20, 2008 you'll be fine unless you're an absolute porker, Post of the day for me Pav it's all to with leverage, I will get the boy to do the maths when he gets back from school. How long is the platform beyond the toe bar? and how heavy are you,exactly ? we need this for the calculation, don't be shy Great idea by the way. Stu a modest 95 Kg and if we said 45 cm centres it would be around right, the bar is rated for a nose weight of 150 Kg and to be fair most of the time I will stand almost on top of it I am ofay with the lever bit but just cant work it out the roof bars really pull it together and its almost all quick release pins and R clips 20 mins to build up from scratch 10 to rip it down just got paitwork and foam to fit this W/E I have field tested the thing and jumped all over it with no problem Quote Link to comment Share on other sites More sharing options...
Dunkield Posted June 20, 2008 Report Share Posted June 20, 2008 A mere slip of a lad , I think you will be fine, I read this and it didn't help at all, someone must be able to work it out - where is Pin these days? http://en.wikipedia.org/wiki/lever Good use for decking as well, makes change from wooden skating rinks Quote Link to comment Share on other sites More sharing options...
pavman Posted June 20, 2008 Author Report Share Posted June 20, 2008 yep its all to do with my equilibrium, is that a bit like the equinox I think Twisted Preacher did a track on that in 97 Pin,,,, dunno, good point get your lad on it Stu dont want the bar droppin orf round the permission, make me look a right plonker Quote Link to comment Share on other sites More sharing options...
new to the flock Posted June 20, 2008 Report Share Posted June 20, 2008 95kg? Sure you didn't forget a 1 in front of that NTTF Quote Link to comment Share on other sites More sharing options...
starlight32 Posted June 20, 2008 Report Share Posted June 20, 2008 (edited) Anyone good at math? A nice calculation me thinks Guys, almost finished building a shooting platform that fits to my Towbar on the freelander and top rails are taken off the roof bar, I was fairly happy with progress until some bright spark pointed out that my 150 Kg rated towbar would have extra force exerted on it due to the extended platform How the heck do you work that out However, if you were to shorten the height of your uprights and then fully weld the top two braces directly to your roof rather than tying in to your roof rack- you would decrease the bending enertia upon the anchorage point. Therefore decreasing the downward force upon the the S.WL of the tow bar. Why are you going to all these trouble anyway when you have a perfectly good sunroof to stand out of? Trust me I won't see you wrong, if I'm not right we'll just air arc the welds out off your roof and put it back how you have it now, be alright providing we disconnect the battery Edited June 21, 2008 by starlight32 Quote Link to comment Share on other sites More sharing options...
lurcherboy Posted June 20, 2008 Report Share Posted June 20, 2008 you'll be fine unless you're an absolute porker, Post of the day for me Pav it's all to with leverage, I will get the boy to do the maths when he gets back from school. How long is the platform beyond the toe bar? and how heavy are you,exactly ? we need this for the calculation, don't be shy Great idea by the way. Stu a modest 95 Kg and if we said 45 cm centres it would be around right, the bar is rated for a nose weight of 150 Kg and to be fair most of the time I will stand almost on top of it I am ofay with the lever bit but just cant work it out the roof bars really pull it together and its almost all quick release pins and R clips 20 mins to build up from scratch 10 to rip it down just got paitwork and foam to fit this W/E I have field tested the thing and jumped all over it with no problem Yer right and whatever FBOY LB Quote Link to comment Share on other sites More sharing options...
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