re-plating, how do you know if a vehicle is suitable?

[birdybiker66]

I'm looking for a MH to carry a 150kg bike (in a garage) and have found a few suitable ones, Bessacarr E480, Swift sundance 630G, and others. These are 4 tonners but what if i see something like a Burstner Quadro 674G (3.5T) Where do i look or ask if its suitable to up-plate, expensive or impossible? Thanks, Dave

[lennyhb]

As a rough guide if its a 3.5t and its on the light chassis the give away will be 15" wheels should be able to re-plate to 3850. The tyres will probably limit the rear axle to 2060kg which will not allow you to take full advance of the increased payload.

Carring that sort of weight in the rear you really are better off looking for at least a 4000kg chassis.

[Brian Kirby]

birdybiker66 - 2013-07-27 9:33 AM

 

I'm looking for a MH to carry a 150kg bike (in a garage) and have found a few suitable ones, Bessacarr E480, Swift sundance 630G, and others. These are 4 tonners but what if i see something like a Burstner Quadro 674G (3.5T) Where do i look or ask if its suitable to up-plate, expensive or impossible? Thanks, Dave

To start, you will need a van with the shortest possible rear overhang. You will also need to check the load limit in the "garage" (they all have one), and (more difficult) if that limit includes any single item limit (possible, if in designing the floor it has been assumed that any load will be spread more or less evenly).

You will need to find out what the vehicle weight, and the rear axle load are, with the vehicle in its unladen state, which means a trip to a weighbridge.

You will need to find the maximum permissible rear axle load from the vehicle VIN plate, and then calculate the load the bike alone will transfer to the rear axle, as this will exceed the self-weight of the bike alone due to leverage (hence the need for a short rear overhang).

You will need to know the weight of everything you would intend taking with you in addition to the bike, including all passengers and driver.

You will need to make assumptions on where these things would go, so that you can estimate how that load will be shared between the axles.

All of this is possible, but it will not be quick or particularly easy to achieve.

I'd be very cautious regarding the idea of re-plating to accommodate the bike, if that is your thinking. First, most re-plating exercises only exploit the fact that all vehicles have individual axle limits that exceed the plated MAM. So, all that is done is to add together the axle limits and, taking account of the "chassis" characteristics, increase the MAM to that total, or more frequently, slightly less. This means that the MAM increases, but neither axle limit is increased. As most motorhomes hit an axle limit (usually at the rear) before they run out of MAM, the re-plating is liable to be of little, to no, use. With a 150kg bike behind the rear xale, this is highly likely to be what would happen in your case.

It is possible in some cases to increase the rear axle limit, most easily where a van has been built on a "heavy" chassis, but down-plated during conversion. This can sometimes be achieved by adding supplementary springs, often air assisters, but this is likely to also involve changing the tyres, at least at the rear. Brakes and overall chassis suitability will also influence what can be done, and at what cost. IMO, it is a better solution to apply to a van one already owns, where its actual laden weight can be measured, than to try to calculate based on assumption. If the assumptions prove wrong and the van can't be adapted, you will either have to solve the bike problem a different way, or change the van.

There is also the affect of that relatively heavy bike at the rear, in combination with the other stuff you will carry, on the van's handling, and on its ability to maintain traction in slippery conditions if it is a FWD chassis.

I'd be inclined to look for vans of two types. First, either a tandem axle with a high rear axle capacity or, IMO better, for a rear wheel drive Merc or Iveco base (eliminating the potential traction problem) with a much heavier chassis, that can more readily be up-plated again if necessary. Can't advise which models would suit, but you will inevitably be fishing in a very small pond. However, FWIW, that would be the route I would take as being the most likely to gain a satisfactory outcome. If you like, just go for overkill to eliminate the downside risks.

[birdybiker66]

Wow, thankyou for taking the time to put all that down, I was hoping someone would say "I've done that with this etc" but everything you say makes sense, I even understand mostly all of it! I did see somewhere or have been told that there is one with a garage limit of 200kg, maybe it's the swift 630g but I'll check on that. I was hoping to expand my list of choices but I'll stick to what is already on a maxi 4t chassis,

Thankyou, Dave

 

ps, thanks to Lenny for the reply as well, cheers