Glad Allan dropped in!

I was saying if you up the GVM then the CGM would go up but what Allan has said and found out from his experience that’s is not the case the CGM stays as is.

Makes sense as the vehicle ability to tow has not changed only the vehicle ability to carry more load has changed and the more load you have in the vehicle the less van ATM you can tow.

JR

Yes, if the GCM is actually specified by the manufacturer then you are stuck with it. If it is not then technically you could get away with it so long as you don’t exceed say the max 3500 kg and 350 download on the tow ball (in the LC200 case, where “some say” the GCM is not specified by Toyota) but get it from the horse’s mouth and in writing as you may need to produce it one day.
Cheers,
ALLAN

Thanks everyone for your help.

We have spoken to Vehicle Standards and they were very helpful and we now understand where we are at factoring in the TBW in the GVM and adding the GTM etc

The GVM upgrade was only to allow us to carry slightly more in the vehicle because loaded we were likely to be about 50kg over, we were aware that it didn’t up our GCM.

Its staggering how many people have no idea about weights (we were included in that category) but its such an important factor. I believe that both car and caravan manufacturers are misleading and somewhat negligent in not explaining it all correctly at time of purchase. Especially what the real meaning of 3.5 towing is. We were told when ordering our van that yes, our DMax would pull the van no worries and when ordering the DMax yes you can pull 3.5 ton but nobody stops and carefully explains that you have to factor in GVM and GCM etc.

But, in our case we are now confident we will be pulling out onto the open road legal and safe

Hi again Macs,
So as you and Allan pointed out the GCM is set and changing your GVM will not increase the GCM.

As your van ATM is rated at 3400Kgs you are left with (GCM 5950Kgs – Van ATM 3400Kgs = 2550Kgs.) an allowable total weight for the D-Max of 2550Kgs, so where to from hear?

Might have to leave the kayaks at home!

JR

Allan is correct, GCM does NOT change with a GVM upgrade of the tow vehicle. The only way that I’m aware of to have the GCM uprated is a major modification such as a 6 wheeler conversion.

Also, don’t forget that the ball weight of the van adds to the load applied to the car. So, you really need to have an accurate ball weight to work it all out. Remember also that it’s the ACTUAL weight of the van that matters if you get checked over and not the stamped ATM.

Hi Macs, have a read of my blog page about weights. Not all my work, but you may find something worthwhile.

https://chrisanddiannesultimaadventure. … explained/

Depends on the engineer signing it off.

At my previous workplace we had about 30 landcruiser troop carriers that had both a GVM and GCM upgrade.

The GVM of the vehicle was lifted to the sum of the maximum axle loadings, and then the GCM was bumped up by the same amount so that we could still tow 3500KG whilst loaded up to the increased GVM.

The vehicles had a aftermarket leaf springs, and a set of air bags in the rear (none have ever cracked a chassis)

The only other modification the engineer wanted was a plaque that stated something along the lines of “vehicle may only tow braked trailers when loaded above factory GVM” affixed to the towbar.

The only downside was that if we loaded the troopies right up, we couldn’t tow an unbraked trailer.

Rules in your jurisdiction may be different, these were all modified and registered in SA