Front roof struts

[Jota27cole]

Hi everyone,
I have fixed the front roof struts to the pop up. How do you work out the fixing points to the van roof.

Cheers Russ.

 

[Bigsidavies]

This is a sort of guess, but surely it's related to the height of the canvas using pythagorus. You know the height of the canvas at the point where you've fixed the strut to the roof, and you know the fully extended length of the strut, so using pythagorus where a2 + b2 = c2, height of canvas is a, length of strut is c, so length along van roof from directly under the current mounting point should be (slightly less than) square root of b2, where b2 = c2 - a2.
So if canvas height is 90cm and strut is 120cm then length along roof from the directly below current mounting point (i.e. making a right angled triangle) would be 79cm.
anything longer than that and it won't extend enough to fully tension the canvas, anything less than that and the canvas will be under (maybe too much) tension.
It's not something I've ever done so that's just how I'd approach it.
Maybe someone who has got their roof up could take those measurements and see if the theory works out. I'd do it, but it's hoofing it down outside.

 

[Drive Wayne]

This is a sort of guess, but surely it's related to the height of the canvas using pythagorus. You know the height of the canvas at the point where you've fixed the strut to the roof, and you know the fully extended length of the strut, so using pythagorus where a2 + b2 = c2, height of canvas is a, length of strut is c, so length along van roof from directly under the current mounting point should be (slightly less than) square root of b2, where b2 = c2 - a2.
So if canvas height is 90cm and strut is 120cm then length along roof from the directly below current mounting point (i.e. making a right angled triangle) would be 79cm.
anything longer than that and it won't extend enough to fully tension the canvas, anything less than that and the canvas will be under (maybe too much) tension.
It's not something I've ever done so that's just how I'd approach it.
Maybe someone who has got their roof up could take those measurements and see if the theory works out. I'd do it, but it's hoofing it down outside.

Have you thought about teaching maths Si? Maths was never my thirté!

 

[Bigsidavies]

Have you thought about teaching maths Si? Maths was never my thirté!

The more I think about this, the more I think that may be wrong as the roof doesn’t go straight upwards, it describes a circle.
Anyway that’s basic triangle stuff. I can’t even remember most of my O-level maths let alone my A-level stuff. I can barely add up these days.

 

[Bav]

The more I think about this, the more I think that may be wrong as the roof doesn’t go straight upwards, it describes a circle.
Anyway that’s basic triangle stuff. I can’t even remember most of my O-level maths let alone my A-level stuff. I can barely add up these days.

I think it's right Si. The roof may scribe an arc (not sure ), but the maths of the final position can't work (I believe) unless it conforms to Pythagoras.

 

[Bigsidavies]

I think it's right Si. The roof may scribe an arc (not sure ), but the maths of the final position can't work (I believe) unless it conforms to Pythagoras.

Yeah, good point. I guess the calculation is based on the final resting position of the strut so the curve is irrelevant. Thanks.

 

[AJCConversions]

Make a note of the position the roof strut is on the body of the van when roof closed.
Measure strut total length when compressed Inc ends.
Add 40mm to this length.
Now measure this total length back from the position made on the van.
This should give the position for the bracket. And you know there is enough space for the strut to be compressed when the roof is shut.
Normally the roof manufacturer should provide this measurement, so i pressure its a cheap roof.
On a reimo when the roof is down the gas strut has around 40mm of compression left not used. Hence the reason for adding the 40mm.
Hope this helps and makes sense.

 

[AJCConversions]

This pic gives you an idea of location on a reimo on a SWB

 

[Jota27cole]

Hi,
Thanks for the reply. So I take the measurement from the threads that are the pop up. When the roof is shut on the body. Mark with masking tape and work from that?

Big cheers Russ.

 

[AJCConversions]

Sorry I should have said. The measurements should be from the ball ends

 

[Jota27cole]

Hi,
Thanks for your advice. It's very much appreciated. It did hurt me though when you said it was a cheap roof. Ha ha!

Cheers Russ

 

[Jota27cole]

Hi,
What's the best way to compress the struts? Plus how do you went to stop the compressing the strut.

 

[AJCConversions]

I attach the strut to the van ball end. Then Clamp up the pop top so fully open ( plaster board clamps work well )
Then compress strut just a little by hand and pop it on roof ball end at same time.

Hope that makes sense

 

[Jota27cole]

Hi,
What iam trying to do is. Find its shortest length so that I can work out the measurement. For the body bracket.