Viking Roof gas strut specs

[CJH]

Can anyone with a viking roof tell me what load rating your gas struts are? I need to replace mine, and the values of my existing struts don't match what I'm being told by one potential supplier.

My roof has two struts at each end, and none in the middle. The struts which end up more vertical when the roof is open are rated at 300N, while the struts that connect nearer to the roof hinge and finish up closer to horizontal are rated at 650N



The first supplier I've contacted has suggested that they would supply 250N struts for the vertical ones, and 450N for the horizontal ones. While my roof was working, the struts seemed about right - they gave a good amount of initial assistance and supported the roof in the open position. What's making me wonder about fitting lower rated struts is the fact that one of my upright 300N struts jammed open, so that when we tried to close the roof it pulled a couple of hinges out of the metal roof. This made me realise that the stronger that strut is the more tension it puts on the hinges, and I'm wondering if 300N is a bit too much.

I've also got a couple of brackets on the vertical struts, which I assume I'm supposed to use to lock them open, but with my existing struts there was never any danger of the roof closing by itself. That again makes me think that the 300N/650N combination is more than would have been fitted from new.

So does anyone know what the original values were, and do they seem 'right'?

[CJH]

*bump*

Anyone? The strut ratings will be printed on the struts themselves, so if this isn't the sort of information you keep in your head then is there any chance someone with a Viking roof could do me a favour and check the struts on your van?

Thanks
Chris

[vanisveryrusty]

http://www.sgs-engineering.com/gas-stru ... tAodqFcAuw" onclick="window.open(this.href);return false;

Here is where you can get your gas struts from, old ones can be used as a pattern.
The gas struts from SGS are OK.
I found SGS hard to deal with, emails slow to be answered, card machine not working when I arrived to pay, and gas struts not ready.
Half an hours perseverance sorted all that and the struts themselves are OK.
Made by SGS on the premisies so a solution is available if you can work around the customer service issues I experienced.
It may have just been a bad day for them of course.

[CJH]

Thanks Rusty

Yes, that's the (only) company I've spoken to - I live in Nottingham so a trip out to Derby would be quite convenient. I called on the phone and got through to a very helpful guy, and in fact he was the one who suggested the 250N/450N combination, but he did imply there was some uncertainty over the values. If he made yours to match your originals there's a chance that he matched your original values too, rather than just going for the 250N/450N combination. So do you happen to know what values you've got now? Do they work well, ie do they give a good initial lift when you open the roof, and do they support the roof adequately when it's open?

Thanks
Chris

[vanisveryrusty]

No they didnt replace my roof struts.
We had a long discussion about roof struts on a previous van that had struts missing.
There was some idea that if the weight of the roof could be given, then struts could be designed for the weight.
Or maybe adjustable struts that could be made stronger or weaker depending on how they perforemd.
Unfortunately the van was sold before I got around to that job.
The struts I bought were rear door struts.
They are not as strong as the ones I have bought in the past from Aircooled in cornwall, and they dont work very well, the door sinks after a while.
Aircooled ones never did that at all.
Not bad enough to warrant a trip back to complain, but I wish I had bought elsewhere because of the sagging.

I am sure the Derby company have the ability to provide good struts, if you can tell them what you want.
Other than that its a bit trial and error I found.
Best of luck.

[CJH]

Thanks Rusty.

[dbz864]

When I dealt with the same company they were spot on,quick and cheap as well.

[vanisveryrusty]

Unfortunately the gas struts I bought from them are now only holding the rear door at half height.
Will have to be be geting in touch for an exchange, or a refund or something.
Not a good result so far.

[CJH]

Just in case anybody should come looking for an answer to this question in the future I thought I'd post the details of the struts I've purchased, and I'll include my working for a few extra marks.

I weighed my viking roof by putting a pole under the edge that lifts and standing the pole on my bathroom scales. Since the roof was only lifted slightly this should tell me what half the weight is. Without the roof canvas attached, and without the luggage bar at the back, I estimated the roof to be about 45kg. To lift this bare weight I'd need two struts rated at 225N each (45kg x g / 2). So allowing a bit extra for the canvas weight and a bit of wind loading I figured the existing 300N upright struts were about right.

The struts that end up more horizontal are only there to provide an initial lift when you push the edge of the roof up, and they disengage once the roof goes past a certain angle (that's what the sliders are for). Once they disengage then the two upright struts have to do all the work of supporting the roof, which is why the upright struts need to be rated for the whole weight of the roof. The more horizontal struts are at a very shallow angle and therefore need to be rated much higher in order to do anything (cosine of the angle from the vertical, etc). I didn't really calculate this very accurately, but 650N seemed about right, and gave a good initial lift, so I just went for the same again.

I bought my struts from SGS in Derby - I just turned up at the counter and talked through my requirements with Scott, who was very helpful. He discussed the different types of 'ends' that I could fit on the struts, then went away to have them made up - took about 10 mins. I've ended up with two bespoke sets of struts which I'm sure will fit the existing fittings better than the ones I'm removing.

Scott also suggested that the two locking bars that were fitted to my old struts should not be used (they're bars that slot around the piston rod to lock the strut fully open), since they could scratch the piston rods and cause the seals to fail. I've no idea whether those bars were original or a bodge fitted by a previous owner to help with failing struts. Before my previous struts failed I never felt the need for these bars, since the old 300N struts held the roof open very securely.

So now I'm ready to start rebuilding my pop-top, since the new canvas arrived today too, but that's a topic for another thread.

[CJH]

I'm only posting this in case somebody finds this thread - the strut specs that I posted earlier weren't quite right.

The 650N struts are way too strong, so for the last few months I've been using the new 300N struts for the upright pair and the old 300N struts for the horizontal pair. Today I resolved to sort out the correct values so paid another visit to SGS.

They were incredibly helpful and swapped my 650N pair for a couple of adjustable struts, which they set to 400N for me as a starting point. After fitting all the new struts back into place, it seems that they're just about perfect, so cutting a long story short, here's the specs that work well for me:

1) for the struts that end up almost vertical with the roof open, I'm using a pair rated at 400N
2) for the struts that end up about 40 degrees up from horizontal with the roof open, I'm using a pair rated at 300N

[b-f-c]

Thanks. Bookmarked for future use.


Can I ask how much they cost in the end?

[CJH]

I don't remember for certain - just shy of £100 I think for the four. I think they did me a big favour by swapping the 650N struts for 400N adjustable ones. What I didn't realise was that conventional struts can have the pressure increased but not decreased, so there was no way to turn the 650N struts into 400N struts. The adjustable ones can be increased or decreased - I can let some gas out myself but have to take them back if I want the pressure increased. In the end they don't need adjusting now, but I suspect SGS were 'self insuring' in case I went back again! Whatever their motivation, I can't speak highly enough of their service.