Updates & Errata

 In the caption under the photo on page 28 you point out that the front passenger side wheel is stationary, while the front driver side wheel is rotating fast. You then explain why this is occurring. In this explanation you state that, “the reason the driver’s wheel is easier to turn is because it has less of the car’s weight on it than the passenger side, and the more weight on a tyre, the greater the traction.”

I suggest that this could be made clearer if your explanation was ‘the reason the driver’s side front wheel is easier to turn is because it has less of the car’s weight on it than the passenger side front wheel, and the more weight on a tyre, the greater the traction.”

My reasoning behind this suggestion is that as the driver’s side is clearly down hill, gravitational force will result in more weight being on the driver’s side than the passenger ’s side. As you know, this doesn’t mean that more weight will be on the downside wheel (in this case the front driver ’s side front wheel) than the upside wheel (in this case the passenger’s side front wheel) as there are other factors to be taken into account. In your explanation, you have referred to the passenger side, not the passenger’s side front wheel.

The car in the photo is indeed at slight side angle and therefore the lower wheel, in this case the driver’s side, would normally have more weight on it than the higher wheel. However, the car is balanced such that the lower wheel has little weight on it, hence the wheelspin. Yes, I could have said “passenger’s side front wheel” to make it clearer.

On page 59, Automatics, 3rd dot point you state that automatics “can’t be towed for long, because the turbine is not designed to effectively “drive” the pump. While this is the case for automatics without a transfer case, if you have a 4WD Automatic (has low range) and put the transfer case in Neutral, and the transmission in Park, you can tow it for long distances. See the 4WD Action magazine No 164 page 83.

That depends on the design of the automatic. Some of them, such as the Jeep Grand Cherokee 2011 are designed for this operation and have a neutral. But it is a good point, worth clarifying.

Misprint.  I'll have the printer shot tomorrow morning without breakfast.

Correct.

Correct, good point.

On the same page under Parking on a Hill, 3rd line it says, “creep backwards”. I suggest that this be changed to “creep downhill”. This change is suitable whether the vehicle was facing down or up the hill. Correct, good point. In the 1st column on page 317, 13th and 12th line from the bottom, it says “…..rough for clutch-up speeds can be negotiated in a manual by holding the vehicle lightly on the brake ….” It took me a long time to work out the by “clutch-up speeds” speeds, you meant driving as normally while going as slowly as possible in the lowest gear possible with the clutch up (disengaged).

If my interpretation is correct, I suggest that in any future editions that “clutch-up speeds” be altered to something like “driving as slowly as possible in the lowest gear possible”. Even if you decide to leave is as it is, there needs to be a comma after speeds, and this terrain inserted after the comma and before “can be negotiated……..”

Your interpretation is correct.

You are correct, the answer should be 1066.6kg.  I don't know how I came up with the lower figure.

I have used the approach of using the Sine tables to obtain the 0.2756 rather than than radians. I am not sure a lot of 4wdrivers would understand the radian method of calculating the force due to the angle of the slope, including myself.

A simpler method is described in the book, slope in degrees x (weight / 60).  Radians are not required.

The coefficent figures on page 352 also, differ from those published by Ramsey Winches some years ago. Their rolling resistance figures are as follows
Smooth hardtop 1/25, 4%
Surface grass 1/7, 14%
Gravel 1/5, 20%
Sand 1/4, 25%.
Shallow mud 1/2, 50%
Deep mud to top of wheels =1x loaded weight of vehicle
Deep mud to top of mudguards= 2x loaded vehicle weight
Deep mud to top of cabin 3x loaded weight of vehicle

Thanks.  The figures quoted above are close to what are in the book which are an average of several sources and my own tests.  But "top of cabin" ???? 

I have checked this out.  The repair is actually more of a rebuild of the tyre where it is placed in a special jig and 'cooked' to more or less recreate the tyre, as opposed to a patch.  However  the basic premise of sidewall damage being legally repairable in some cases is correct, albeit with this specialised equipment.  So if you have a sidewall problem bring in to one of these guys to have a look at.  I can't recommend the work of either, but Grey's were significantly more helpful on the phone when I called to ask about the process, so I'd run with them.  Always be polite to callers as they may turn out to be bloggers!

On page 455 you state, “there are two basic types of battery, deep cycle and high-current discharge (starter)”. You then explain the difference between these. I was wondering why you haven’t included marine batteries, which have characteristics similar to starter and deep cycle batteries, and are designed to operate under adverse conditions and are suitable for 4WD use.

Marine batteries fall into either of the two categories depending on their design. Agree that they may be suitable for offroaders.