Jump to content

Outrigger construction


Recommended Posts

did one of the posts recommened a further brace from the re-shaped outrigger / roll cage brace back to the chassis further back as it rises back up again, to add an additional element of rearward rigidity ?

Yep, the further back the better, from the point where the cage meets the outrigger diagonally back to the chassis.

Link to comment
Share on other sites

Thanks for your feedback so far Steve, it's appreciated to ensure we get to a suitable solution.

I suggested that if the brace had been taken from the top of the cage down to the centre of the bed then the outrigger would not have been required.

That would mean cage tubes in the middle of the load area, not very useful... No rear seats, as it's going to be pickup style so wanted to keep the maximum load area I could.

DVLA has stated any modification to the chassis = IVA but others will tell you that they have been known to deviate from that ruling. I was told even moving an engine mount was a chassis mod.

This type of change does not fit any of the MOT inspection criteria. They will only be inspecting that the chassis in that area is sound and is not cracked or rusty.

Chassis solid throughout so not worried at all about anyone with a hammer poking around.

If the cage had been fabricated as a separate structure a beam could be run right across at the height of the outrigger. Supports, with a 'shoe' at the base, could then have been welded under the beam to sit on the chassis without being welded to it.

The cage is totally separate and still is. Them main structure mounts on the existing body mounts. Maybe we will look at saddling the support as you suggest, but we were keen to add as much strength as possible in case of the horrible possibility of an accident ! Lateral support will help with impact strength.

Neil

Link to comment
Share on other sites

Hi Steve....

Just re-reading your posts.

If I were trying to be totally clean from an IVA perspective, is it your belief that if we bolted the roll-cage supports around the chassis rails this would not be altering the chassis, and not potentially altering it's structural support etc.

Do you believe it would it be seen differently if we were to bolt through the chassis to secure the roll cage mounts and saddle ? (Say 4 bolts per chassis rail ?)

I'm making an assumption that we could brace laterally using the rear body mounts already on the chassis.

Thanks in advance

Neil

Link to comment
Share on other sites

If I were trying to be totally clean from an IVA perspective, is it your belief that if we bolted the roll-cage supports around the chassis rails this would not be altering the chassis, and not potentially altering it's structural support etc.

As you say if you formed a saddle that sat on top of the chassis to take the load and locate your frame and then fitted a plate under the chassis with bolts down from above (either side of the chassis rail) you would not be modifying the chassis.

If someone challenged that loads were being applied to the chassis it was not designed for my response would be that the loads will only exist during a roll over or impact on the cage.

Do you believe it would it be seen differently if we were to bolt through the chassis to secure the roll cage mounts and saddle ? (Say 4 bolts per chassis rail ?)

If you drill the chassis you have altered its strength and therefore modified it. I agree this would not be a significant change in strength but that's not how rules work.

I'm making an assumption that we could brace laterally using the rear body mounts already on the chassis.

Yes you should make use of the existing body mounts but could also provide lateral bracing by forming the saddle as an up-turned U. It need only wrap down the side of the chassis by 40mm or so. A nice strip of 1/4" rubber between chassis and saddle should finish things off nicely.

Steve

Link to comment
Share on other sites

If you drill the chassis you have altered its strength and therefore modified it. I agree this would not be a significant change in strength but that's not how rules work.

Again, this depends on interpretation. The same rules that say a chassis frame should not be modified also say that modifying the bodyshell of a unitary bodied vehicle will lead to an IVA. Eurobox owners who have drilled a few holes in the sills to inject Waxoyl, or in the floorpan to fit an aftermarket tow bar, should be very worried.

At this rate half the country will be queuing up outside the IVA test stations :huh:

Link to comment
Share on other sites

with the fact that its open to interpretation, in theory isnt replacing a rear crosmember/welding plates over rust holes mods to the chassis-if you had a real pedantic/ridiculous tester. even if not, at what point do reapirs to the chassis count as modified? i know the strength of weld, or something in an mot, but hey.

just my thoughts!

Link to comment
Share on other sites

at what point do reapirs to the chassis count as modified?

When you get paranoid about doing the slightest bit of welding to your L/R. or perhaps when those that really don't know for sure, tell you that you have structurally altered it by drilling a hole, adding a bracket, plating over some rust, or (God forbid), adding an outrigger. You could waste almost £500 checking that you haven't weakened your chassis so much that it's about to snap in half/chuck you across a crowded playground/old folks home, or perhaps you should apply some common sense. I wouldn't even consider an IVA test by just adding a DIY outrigger or two - it is after all significantly less 'dangerous' than replacing a crossmember and doing a bad job of it. I think the IVA check of the chassis is that it is still safe to use on a public road after the alterations have been done (DIY being the monster that it is). I think the current website 'IVA Police' are putting people off asking questions concerning structural repairs to their L/R's - you can almost hear them zoning in whenever the subject is raised :(

Les.

Link to comment
Share on other sites

Repairing a chassis is just that 'a repair'. Replacing a rusted crossmember or outrigger with a repair panel or a hand fabricated alternative performing the same function is a repair.

Welding in a crossmember made of 6mm plate, carrying a winch and 100 ton (approx) recovery points is a modification.

Welding on an outrigger that was never there on the original is a modification.

Les...IVA police on not, you cannot claim this to be a repair.

Steve

Link to comment
Share on other sites

Well I've emailed VOSA as this would also affect me.

Slightly sick of the bickering TBH.

Better still ring 01792 454 203 which is the direct line into the VOSA technical support department. I have had nothing but good support from them and they seem more than happy to have a chat and discuss the finer points of your query.

In a phone conversation you have a far better chance of running a number of 'what ifs' or 'yes,but?' past them.

However, the decision as to whether your changes will require SVA/IVA lies with DVLA not VOSA. In that respect I've had very little help from a technical direction as each office seems to work their own rules and getting hold of the technical officer in your local office can be a nightmare. You can only deal with the office local to you so there is no scope for finding a LR friendly office.

Keep us posted as to what you find.

Steve

Link to comment
Share on other sites

Like he says. VOSA does the tests but the DVLA decides whether, or not, you need one.

My experience:

VOSA very helpful with a positive attitude.

DVLA alway refer you to your local office. When I've spoken to my local office they seem a bit vague and unwilling to commit themselves until they have looked at the vehicle. Which isn't much help if you haven't built it yet and are just trying to guage what is acceptable. I just decided that trying to avoid an IVA would lead to too many compromises in the design of the vehicle.

Link to comment
Share on other sites

There was an article in practical performance car about this a few months ago with an interview with the chaps at VOSA about what modifications would mean the car requires an IVA. One of the questions asked was if cutting off and welding on new engine mounts amounted to "structural modifications" and the answer was no.

I could scan the article in if you wanted?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy