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Documenting Problems That Were Difficult To Find The Answer To

Learning to Drive Non-Synchromesh Heavy Rigid in Melbourne

You want to drive a truck and see that the most broad category of licence you can get in Victoria with a car licence is the Heavy Rigid category (you can’t just jump straight into a Heavy Combination or Multi Combination). Then you realise that you’ll have a condition (B) placed on your licence limiting you to synchromesh/automatic transmissions unless you pass your test in a non-synchromesh vehicle.

Right away you think you’ll do your course/test in a non-synchromesh vehicle. But what does this mean?

For the most part a non-synchromesh truck has what is called a “Roadranger“, “RR”, “Eaton Fuller“, or “crash box” transmission.

They will commonly have 13 or 18 forward gears. Pretty cool, huh? Yeah, well.

First thing my instructor told me was that whatever I thought I knew about driving manual, to forget it. Unfortunately I didn’t forget it. I spent the next two hours crunching gears and feeling like I did the first time, at the age of 16, I tried to shift gears in a car.

So what’s so hard about driving a Roadranger transmission?

The Clutch

The clutch has 4 (four) different positions!

They are:

Position Description
up neutral/driving
quarter down (light push) change gear
third down (heel on floor) vehicle stopped (e.g. at lights)
fully down (for at least 3 seconds) initial gear from neutral
Truck Non-Synchro Clutch Positions

Truck Non-Synchro Clutch Positions

This is pretty much the hardest thing to adapt to. I kept putting my foot to the floor which was wrong, wrong, wrong!

You start off by pushing the clutch “fully down”, counting to three, and then shifting into starting gear (3rd is a popular choice).

Then once moving you put the clutch down a quarter (light push) once the engine hits 1,500 RPM, pull the gear lever out of 3rd, lift the foot off the clutch, wait until the engine drops to 1,200 RPM (about a second), then put the clutch down a quarter (light push) again and slide the gear lever into 4th, lift the foot off the clutch.

That last paragraph is a hell of a lot to take in for an experienced manual vehicle driver. You don’t really need to use the clutch (“floating” gear change) – but you have to use the clutch to pass a driving test.

When you get to a set of traffic lights, once you’ve come to a complete stop, you put the clutch in about a third of the way (heel on the floor), and then change from whatever gear you’re in back into 3rd. Then wait until the lights change when you can pull the clutch out to let the engine bite the wheels and get them moving.

If you ever end up with the gear lever in neutral and come to a complete stop then you’ll have to push the clutch all the way in to the floor and count to 3 (three) before sliding the gear lever into a starting gear (e.g. 3rd).

Gears

Truck Non-Synchro Gear Shift Pattern

Truck Non-Synchro Gear Shift Pattern

That brings us to the easy part, the gears. Or, perhaps, better described by watch the tachometer!

Because you can’t afford to ever think about the gear alone. You get to pick a gear for a given road speed (Km/h) and engine speed (RPM). And there is usually one good choice and one or two poor choices.

Depending on the truck there is a magic range where the engine offers the maximum power – in my truck that was 1,200 – 1,500 RPM.

At the same road speed (in my truck) there is a difference of about 350 RPM between gears.

Upshifting

That means aiming for an engine drop of about 300 RPM when going up a gear (e.g. 5th to 6th) because by the time you’ve finished the shift the engine would have dropped another 50 RPM.

Thus the recommendation when shifting up (e.g. from 5th to 6th) is to take the gear lever out of 5th when the engine hits 1,500 RPM, and put the gear lever back in to 6th when the engine drops to 1,200 RPM.

Downshifting

Aim for an engine rise of about 400 RPM when going down a gear (e.g. 6th to 5th) because by the time you’ve finished the shift the engine would have dropped 50 RPM. This is achieved by revving the engine (it takes practice to do this smoothly without excessively revving) when the clutch is in the neutral (foot off the clutch) position.

Thus the recommendation when shifting down (e.g. from 6th to 5th) is to take the gear lever out of 6th when the engine hits 1,100 RPM, rev the engine up to 1,500 RPM, and put the gear lever back into 5th.

If you’re downshifting 2 (two) gears at once, e.g. when you’re slowing down for a turn from 7th to 5th, then aim for an engine rise of about 700 RPM.

Thus the recommendation when shifting down two gears (e.g. from 7th to 5th) is to take the gear lever out of 7th when the engine hits 800 RPM, rev the engine up to 1,500 RPM, and put the gear lever back into 5th.

Shift Summary

Direction Example RPM Change Out At Then In At
Up 1 gear 5th > 6th -300 1,500 wait one sec 1,200
Down 1 gear 6th > 5th +400 1,100 rev it 1,500
Down 2 gears 7th > 5th +700 800 really rev it 1,500

Like mathematics? You’re going to.

Rescue Points

You’re going to have some tough times. You’ll miss a gear because you got distracted. It might happen during your road test. It happened to me. When this happens you have to have memorised the trifectas mentioned earlier – remember, road speed – engine speed – gear.

This combination is different for every truck so get to know yours. They are called “rescue points”:

Road Speed Engine Speed Gear
20 Km/h 1,100 5th
25 Km/h 1,400 5th
35 Km/h 1,300 6th
45 Km/h 1,200 7th

What does this mean? You’ve forgotten what gear you need to be in. You look at the speedo. You see you’re doing 35 Km/h. So get the engine revs up to 1,300 (with the foot off the clutch pedal), then lightly tap the clutch and put the gear lever into 6th.

This necessarily means looking at the tacho when making gear changes.

13 or 18 Gears?

A 13 gear truck has the following gears:

Rev, Low, 1, 2, 3, 4, 5, 5 1/2, 6, 6 1/2, 7, 7 1/2, 8, 1/2

An 18 gear truck has the following gears:

Rev, Low, Low 1/2, 1, 1 1/2, 2, 2 1/2, 3, 3 1/2, 4, 4 1/2,
5, 5 1/2, 6, 6 1/2, 7, 7 1/2, 8, 8 1/2

Changing into a split gear involves half the rev change of a normal gear change (instead of 350 RPM difference a split gear only changes 175 RPM) and doesn’t involve any clutch use (usually). I’m not going into split gears here because you don’t need them to pass a driving test.

Review

The non-synchromesh transmission is no walk in the park. My instructor described students that were full of bravado going into the course but came out with tears on failing their tests.

You’re going to have to listen to the instructor intently, accept their criticism, accept more of their criticism, and accept even more of their criticism. Because otherwise you’re just not going to get it unless you’re naturally gifted at it.

I enjoyed the challenge – but it was a lot more difficult than I had expected it to be.

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