THE BIG DASH: Sorting the tow tug

I’m conscious I’ve made some criticisms of the Kia Tasman, but I should clarify by saying I feel it’s actually pretty good in plenty of ways.

Cabin space, comfort and stowage, load box size, powertrain calibration, lightly-laden ride and handling are among the positives.

It’s just the specific towing demands being placed on our Tasman X-Pro have shown – like many one-tonne utes – it needs a bit of help.

So how to reinforce the rear-end to get the whole combination more level and therefore more stable and riding better when towing?

I had wanted to avoid modifications to the vehicle itself. The idea was to drive to Darwin standard and then think about what happens from there.

In part that plan was developed because this is not my car, it belongs to Kia and it’s the result of hundreds of millions of dollars of development. I wanted to respect that.

Modifying it would need Kia’s sign-off, which might not be something they’d be keen on.

So the first avenue investigated was a weight distribution hitch. Essentially, this uses spring arms to redistribute a heavy tongue weight forward into the tow vehicle and backward into the trailer.

To say WDHs have their proponents and opponents in the caravan world would be like saying Donald Trump has autocratic tendencies. Bit of an understatement.

The transfer of load to points in the ute and caravan not necessarily designed to take them is one argument against. Another is the need to remove the bars when manoeuvring or driving on corrugated roads.

The decision was taken away from me by the short A-arm on our MDC caravan. The popular Hayman Reese set-up simply wouldn’t fit.

So the next step was what I wanted to avoid: modifying the vehicle itself.

Air springs were a common suggestion and one that, judging by the forums, are quite a popular solution.

Air springs are bellows that mount between the axle and the chassis and are pumped up to level off the ride. Some experts warn against using them with leaf spring vehicles because they impose additional pressure on the frame at a point where it’s not designed for it.

The necessary pressure in the bellows to get to the right level also posed potential ride comfort issues.

In the end the solution that offered the best hope was to add an extra leaf spring to the rear-end. This suggestion was made by my caravan mechanic Dave and he referred me to Spicers Springs, a 90-year old family-owned Melbourne company that specialises in such things.

Brett the fourth-generation owner of Spicers confirmed it was a straight-forward job that would take one day. They’d done a couple of Tasmans already and knew what was required.

The cost? A relatively modest $1100.

Important to stress at this stage, it was not a GVM (Gross Vehicle Mass) upgrade being proposed, as such a thing didn’t exist for the Tasman as this was written (although some are imminent). That was fine because I didn’t need that.

The next step was to talk to Kia Australia about this plan, specifically product planning boss Roland Rivero.

Happily, Roland was agreeable. He saw the logic of a modification that improved driving behaviour.

So into Spicers in Knoxfield went the Tasman for the day and at the end of it all, it emerged with five leaf springs on each side at the rear instead of four.

The work was done by Sean Spicer the fifth generation of the family to be involved in the business.

These days Spicers doesn’t make its own springs, instead its work focusses on installing springs and GVM kits from suppliers such as West Coast and Lovells for utes and SUVs, either for tradies looking to uprate their work vehicle to carry more load, or caravanners like me.

The rule of leaf springs is the longer they are the more absorbent they are, and the more comfort-oriented. The short leaf springs at the bottom of the pack are the ones that engage when a heavy load is applied.

Sean’s plan was to insert a leaf spring – or plate - one-down from top, bumping up the spring rate for a higher unladen ride height and added weight-bearing capability.

Sean says – and I’m not arguing with him - many of the utes he uprates come from the factory with rear suspensions designed for everyday lightly laden SUV-like ride and handling to suit family duties.

“There’s nothing wrong with their spring from the factory, it’s just the rate of the suspension is wrong for what they [owners who come to him] want to do,” he says.

“It is a commercial vehicle at its core but it’s not being sold as a commercial vehicle. It’s being sold as a family vehicle.”

That’s despite most utes being rated at up to 3500kg braked towing and one-tonne payload, although not at the same time of course!

Sean’s not complaining about all this, people like me are a ready-made business. He admits the downside of uprating the leaf pack is potential impacts on ride.

“I’ll be honest with people, I can’t set a spring up to carry 500kg during the week and then take it out and have it ride like Commodore on the weekend,” he said.

In my case, with the tertiary spring in contact with the chassis rail when the unladen caravan was on the ball, it was unlikely to make it worse!

Sean selected a 17mm plate from the hundreds Spicers carry in stock to add to the pack.

He cut it down to size, drilled it to fit noise-quelling spring rubber inserts and then reset the other plates (apart from the lowest main leaf) in the pack to sit with the new plate properly by literally pounding them with what’s called a friction hammer.

In Spicers case the friction hammer is a 100-year old belt-driven device that looks like it came from industrial revolution England on a sailing boat.

Sean also adjusts plates by hitting them with what you and I would just call a bloody great hammer.

Sean selects the plate and does all this resetting based on his practical experience. It’s not a set-up fed into a computer that emerges on the other side of an algorithm. It’s one bloke hitting metal with metal. Something very primal about that.

The addition of the extra leaf is straight forward. The primary complication with the Tasman is a bolt that holds the leaf spring to the chassis on the passenger side is hard-up against the fuel tank, meaning it has to be cut and reversed to fit. It’s nothing major.

In the end our Tasman went up in ride height 30mm and added about 250kg in payload capacity.

“We’re trying to get you to have a nicer ride through the top-stage of the spring but be able to carry the weight of the van. That’s the goal,” said Sean.

Sounds good.

Next up, hook everything together and see whether it all adds up...

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