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To Free Or Not to Free? That is the
Question…. Free wheeling hubs
were a common modification fitted to Series Land
Rovers. Since the introduction of Land Rovers full
time four wheel drive system on Defender, Discovery
and Range Rover these types of hubs were no longer
used. However many other 4wd vehicles
Free wheeling hubs
then; first let me dispel a few myths.
1. They do not engage 4wd; this is done in
the transfer case.
2. They do not lock the front differential.
What they do is engage and disengage the
half shaft or drive shaft from the hub of the wheel.
When the device is in the locked position
the shaft is engaged and when in the free position it is disengaged.
Why would you want to do this and why do
some vehicle manufacturers fit them as standard?
In theory when you have the hubs in the
free position and the vehicle in 2wd it takes less force to move the
vehicle over the ground because the front wheels are only being pushed
around and not the rest of the front half of the drive train.
Also in theory you are supposed to get less
tyre wear because you are decreasing the drag on the front wheels and
decreased wear on the moving parts in the front drive train.
In practice then, through my experience, it
doesn’t really make a lot of difference.
In fact, if you read through the
manufacturer’s handbook they will tell you to engage it to the lock
position and drive the vehicle around. This should be done every month to
ensure adequate splash lubrication to the moving parts to ensure that they
do not wear out prematurely!
There is a difference in fuel consumption
but it is negligible especially with a diesel engine. On trip say from
Kampala to Nairobi (650kms) you might save in the region of about 5-10
litres.
As to the wear and tear aspect I’ve seen
more damage caused by vehicles run in the free position than to the same
model vehicle with the hubs permanently locked!
Some aid organisations order their vehicles
with the hubs permanently locked to reduce the risk of damage by operator
misunderstanding or “mechanic” misunderstanding!
As a side note, I used to drive a Series 2
Land Rover with a petrol engine called Katie. She had Fairey free wheeling
hubs fitted by the previous owner. She was driven through some pretty bad
environments and in the end I decided to put the locks on full time. (Sick
and tired of getting out of the vehicle every time I wanted to put the
vehicle into 4wd) Even with a gas guzzling petrol engine, if the Katie was
driven with care and respect the fuel difference was negligible.
Just to recap then. If you do run with your
hubs free you have to lock them before you select 4wd.
Do not run one in free and one in lock. It’s
also a good idea to check them regularly to ensure that they haven’t
been tampered with! This could be costly.
In the end it’s up to personal preference
and, therefore, this debate will be going on until all the old part timers
are dead and the full timers have taken over for good!! Until then safe
and happy motoring.
by Mick
www.oncourse4wd.com
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