As featured in June's edition of Owner Driver Magazine

Boosting your fuel efficiency, starting with the cost and performance benefits of crawler gears

By Matt Wood, Fuel Efficiency Manager – Volvo Trucks

In a cash flow-intensive business like trucking, fuel savings are the financial icing on the profitability cake. Fuel is one of the largest expenses incurred by a transport business, accounting for between 30 and 40 per cent of running costs. But it’s also something that can be managed.

My job with Volvo Trucks Australia is to work with customers, gain an insight into their operation and develop tailormade fuel efficiency strategies. I also get to spend quite a bit of time playing with Volvo’s Dynafleet telematics system, which turns out to be a very accurate and easy way of keeping tabs on fuel economy.

One of the more impressive developments I’ve come across in the Volvo Trucks universe recently is I-Shift with crawler gears. Crawler functions in some automated transmissions are nothing new. But with the Volvo they’re actual gears rather than a function that slips the clutch for low-speed manoeuvrability. I’ve always been a big fan of the standard I-Shift anyway, so what’s the big deal?

Because it means you can spec a highway truck with a taller final drive ratio without compromising low-speed performance – while also retaining start ability when taking off on a steep grade.

So we can now spec an FH16 with a very tall final drive to make the most of the green economy band when cruising down the highway. Big Euro engines love to lug along right in the middle of their long flat torque curve.

And, of course, lower cruising rpm means you can extract optimum fuel economy from the big 16-litre without compromising performance. We’re fuelling innovation … by burning less fuel.

The two crawler gears sit at the front of the transmission and provide a couple of very handy low-speed ratios. This adds 48kg to the weight of the I-Shift transmission.

Crawler gears not only make starting off on a big hill easier, they also mean that everyday exercises, like backing a B-double into a dock, are made easier as well. In low gear, a crawler-equipped Volvo will idle along at walking pace. No more juddering clutch engagements!

Manoeuvring a couple of trailers around on a concrete pad can really put an AMT’s clutch to the test. Excessive clutch actuations also result in more wear and tear on the clutch. That aside, it’s not a great deal of fun threading a loaded B-double backwards into a tight spot if the truck keeps jerking in and out of gear. Same goes for hooking up trailers; no one wants to be the person that rams a trailer king pin into the turntable jaws with an earth-shattering crash. That’s just a little embarrassing, not to mention the potential for damaging equipment.

With crawler gears you can idle along at low speed without taxing the clutch. Get some momentum and I-Shift will change up and get you on your way without any fuss.

I get that it may be a well-worn cliché, but flexibility really does sum up the crawler-equipped I-Shift. The ability to cater for both ends of the performance spectrum makes a crawler-equipped FH an agile beast with a dual personality.

It’s an innovation that delivers the best of both worlds – fuel and performance.

In a highway truck there’s clearly a fuel-efficiency advantage as well, but crawler gears aren’t just the domain of highway haulers, they’re also available on the FM and FMX models as well.

Down the track I’ll also elaborate more on the ultra-low crawler option as well, which caters for heavy-haulage applications of up to 325 tonnes. That’s got to be a whole lot easier and more efficient than wrestling with a couple of gear sticks!

Ultra-low crawler works on the same principle as the standard crawler I-Shift but uses a different combination of crawler and final drive ratios for big moves.

Now I could just sit here and preach away, but the idea of this column is to also answer any fuel-economy or Volvorelated questions you may have. I’m not saying I have all the answers, but I’ll do my best to find out the answers from the fine engineering minds at Volvo Trucks Australia.

Of course, any answers I may give will undoubtedly have a Volvo bias (they do pay me after all) but basically I don’t care what truck you drive, fire away on the email address: askmatt [at] volvo [dot] com