Adjusting the PH springs

[boywonder]

Originally Posted by motoidiot

That looks great!

It's the way Sportsmobile should be doing it......from the factory IMO.....based on all the pivot bolt issues seen on this forum.


In the quantities that SMB uses it's about $6 worth of parts total. In quantity of one..it's about $8 in parts.

[Justgosurfin]

Originally Posted by boywonder

I'm not planning on machining anymore blocks.........but there should be enough info here to get to a solution if you've got the idea.


Also, it's worth noting here...that the gas spring force values, die springs and spring preload can all be tuned to whatever you have on your roof. The values I'm using reflect 3 solar panels and a pair of Yakima crossbars on my roof. I'm also 3 links tighter on the big extension spring chains.


Substituting 70lb or 60lb gas springs for the second stage (in my case) would likely slightly improve the roof action when lowering..but at this point the returns are diminishing.....



I updated the crossbar pivot joint today.....just because I think my latest config is cleaner and more robust....the old 5/16" shoulder screws and spacer were working fine; they have been in there since 2013.


Old Shoulder screws:





New crossbar pivot config: (needs 2 3/4" long shoulder screws) The new design gets the two outer wear points 1/4" in from either end of the shoulder screw.

Are the tubing spacers for 1" tubing? Looks like you counter sunk the head a bit? Could you share their respective widths if you still have it written somewhere?

Thanks again for all of your great ideas!

[boywonder]

Originally Posted by Justgosurfin

Are the tubing spacers for 1" tubing? Looks like you counter sunk the head a bit? Could you share their respective widths if you still have it written somewhere?

The nylon saddle spacers are from McMaster Carr:


for 1/4" holes in the spacers: P/N 92842A400


if you are using 5/16" pivot bolts: P/N 92842A500 or just drill out the above P/N to 5/16" holes.


A pack of 25 spacers is $8.32 today.



You will need to remove 1/8" of material off of each of the two spacers between the bars..they are 1/4" thick each and you need the pair between the bars to be 1/4" total. Using two unmolested spacers on the outside of each tube plus the above shaved spacers between tubes you get.....1/4" outside spacer + 1" tube +1/4" for pair of center spacers + 1" tube + 1/4" inside spacer for a total of 2 3/4"......


So if you are using shoulder screws ( recommended) you'll need 2 3/4" length shoulders.


I indeed countersunk the head of the shoulder screw a bit......that allowed the use of the metal washers with the 2 3/4" long shoulder screw.

[Justgosurfin]

Awesome, thanks for the info. I’ve got a fat McMaster car list going now. I couldn’t believe how quickly the chromoly tunes arrived.

[86Scotty]

Their processing and shipping speed is dizzying but careful, your shipping bill (not calculated at checkout) can be that way too, especially on odd sized stuff or if you aren't near a distribution center.

[Justgosurfin]

Originally Posted by 86Scotty

Their processing and shipping speed is dizzying but careful, your shipping bill (not calculated at checkout) can be that way too, especially on odd sized stuff or if you aren't near a distribution center.

Yea I was a little bummed when it came to $37 and not the $15 they suggested it might be on the phone. Either way I was happy I could find the tubes. I’m in south Florida which is basically one big city from Miami to west palm beach and couldn’t find a single metal supplier with them.