Hre is the parts list for my poptop shocks. the bottom bracket is drilled
into the van. the top one uses one of the mounting holes of an artificial
rain gutter, preferably yakima. I made an additional steel plate behind the
yakima gutter on the inside of the fiberglass to spread loads even more.
the weakest point in this setup is the bottom bracket, which bends if you
use shocks exceeding 100lb. McMaster sells a heavy duty bracket but that one
is too heavy duty. If someone finds a medium duty, please let me know.
However, it works just fine like that.
100lb springs will open the poptop by itself with roof rack and empty box.
Closing requires a bit of a pull.  If I add a canoe, opening the top
requires similar force as opening a stock poptop with no load, and it will
close without pulling, actually a little too fast.
I believe that 100lb is quite optimum if yoiu use the same mounting
locations like i did, obviously, if you move it foreward or backward, you
change the power dynamics.
all parts below are parts numbers from www.mcmaster.com   They have
excellent customer service and hassle free returns. I tried about four sets
of springs before coming up with this combo.   Changing the springs is very
very easy, so if you hav very varying loads like a heavy hangglider, you
might want two different sets.
Another way to do is is to just take one spring out if you have no load at
all and dont want to have to pull it down. I dont see this as necessary
though.
A pic of my van with the setup is at
http://good-times.webshots.com/photo/2234409180102149628orFyGu

19416K544<http://www.mcmaster.com/itm/find.asp?searchstring=9416K544&sesnextrep=786782370072955&tab=find&FastTrack=False&WRCntxt=OrdHist>2
EachGas Spring With Threaded Ends, 29.33" Extended Length, 13.77" Stroke,
100 Force34185T12<http://www.mcmaster.com/itm/find.asp?searchstring=4185T12&sesnextrep=786782370072955&tab=find&FastTrack=False&WRCntxt=OrdHist>2
EachGas Spring Seal Protector, For .87" Cylinder Diameter

39416K75<http://www.mcmaster.com/itm/find.asp?searchstring=9416K75&sesnextrep=786782370072955&tab=find&FastTrack=False&WRCntxt=OrdHist>2
Each13 Mm Steel Ball Socket For M8
Thread29416K79<http://www.mcmaster.com/itm/find.asp?searchstring=9416K79&sesnextrep=786782370072955&tab=find&FastTrack=False&WRCntxt=OrdHist>2
Each10 Mm Ball Socket, M8 Thread, Steel For, Gas Spring With Threaded Ends3
9512K99<http://www.mcmaster.com/itm/find.asp?searchstring=9512K99&sesnextrep=786782370072955&tab=find&FastTrack=False&WRCntxt=OrdHist>2
EachBall Mounting Hardware, 304 Stainless Steel 13 Mm Ball
Stud49512K95<http://www.mcmaster.com/itm/find.asp?searchstring=9512K95&sesnextrep=786782370072955&tab=find&FastTrack=False&WRCntxt=OrdHist>2
EachBall Mounting Hardware, Steel, 90 Deg Angle Inverted Ball Bracket

good luck

florian

On Thu, Jun 5, 2008 at 8:41 AM, Dug Smith <dug@dugbert.com> wrote:

> Hi Florian,
>
> I'm looking into the whole roof rack thing (to carry a hang glider), so
> could you send me the shock information?  Seems that would be most helpful
> :o)
>
> I'm hoping that the shocks make it almost neutral when the roof's empty,
> rather than having to pull it down :o)
>
> cheers,
> --
>       Dug Smith         | Terry Pratchett: It's almost
> (mailto:dug@dugbert.com) |  impossible to ride a rock and roll
> (http://www.dugbert.com) |  motorbike and stay on for three verses.
>
>