Hi does any member know the legalities of under slinging van axles for insurance requirements Ive done mine correctly . I checked with the manufacture who said there was no problem but hesitated to put it in writing referring me to a blue plate man who wouldnt certify it as the Center of gravity is higher,I then rang transport who referred me to the same engineer I asked to certify it so Im going around in circles. Im concerned if I have an accident will the insurance company will knock back the claim Ill have to put it back to standard I guess unless any of you guys have had experience many thanks mark

I guess its rising body by 50mm ? Or thickness of axle ? If 50mm increases centre of gravity to cause instability? Theres other issues !! Do it TEST it !! With wiggle test fully loaded ! Btw they also have to prove it was the reason !! They cant just knock you back !!

It is not simply the thickness of the axle (say 50 mm) to consider. You also have the thickness of the spring pack - say 30 mm. So the caravan will be sitting 80 mm higher. The original ground clearance of the van may be about 400 mm. It will now be 480 mm - a 20% increase. The centre of gravity is not at this level - assume it is 500 mm above the floor, so the new C of G will be 980 instead of 900 mm - an increase of about 8%. This should not significantly affect the stability of the caravan, BUT caravans fall over all the time, and ANY increase in the height of C of G will only make things worse. Normal running - perfectly OK, abnormal situation (caravan swaying, strong cross winds etc) - who can tell. This may be the straw which breaks the camel's back. And your blue slip man is not going to risk his career/reputation or whatever by having someone sue him because he authorised the change. I don't blame him.

If you do flip the axle, check the toe-in of the wheels. This is my favourite hobbyhorse, having had 2 vans with toe-in on the wheels which wore out the tyres. Axle manufacturers have trouble getting the wheels to run perfectly straight and true. There is always some toe-in or toe-out because of the way the axles are made. They put a stub axle on the solid square piece of steel and weld one side. they then weld the other side, and as the weld cools, it shrinks, pulling the axle back, but never enough to get it true again. So if you flip the axle and you had some toe-in of the tyres, you will now have toe-out, which will wear your tyres much faster (my Jayco came from the factory with under-slung axle and toe-out - such was the quality control at the factory).

There is also a locator plate welded to the axle (to stop the axle sliding along the top or bottom of the springs). In fixing this plate, the manufacturer should have measured the distance from the tow ball to the centre of the axle and evened up the measurements on both sides. If you flip the axle and there is an offset of the axle relative to the caravan centerline (as was the case with mine), simply turning it over will maintain the original alignment, but the brake levers will be facing the wrong way. A quick way is to turn the axle around, but this then exascerbates any misalignment which was inherent in the original axle position. If you flip the axle, undo and refit the brakes so they are facing the correct way and you will eliminate one source of error.

My last van, a Jayco came from the factory with the axle under the spring. If you are changing an axle from on top of the spring pack to underneath do not turn the axle upside down for the locating plate to be at the top and rest against spring. Axles are not straight.

Remove the locating plate and reweld it to the other side (top) of the axle, this will keep the axle the same way up as before, any camber and toe in settings remain the same, handbrake still the same.

Barry

Will follow up all the advice many thanks from mark and Kerry

Ps I removed the axle and repositioning it under the spring after welding in new locator plates to accommodate the Center bolts van tows well no wobble my van is a 6.9 meter fithwheeler very stable after over taking etc thanks again for your input

Mark,
How's your wheel alignment (some axles are bent to correct the alignment)? If you kept the axle in the same position, there shouldn't be an issue.