Free wheeling hubs? Aye or no?

[lambchop]

Hi Folks..

I'm in the process of writing out a long (and expensive) list of jobs that I want to carry out on my '94 y60 td42 Patrol.

I'm going to be covering long miles, only a tiny percentage of which will require 4x4.

There will be a roof rack and roof tent causing some additional drag.

Does any one have any thoughts or experience on the merits of fitting free wheeling hubs? I reckon it'll cost about £100 for parts and p&p. Money well spent, or spend it elsewhere?

Thanks in advance.

[farqhuar]

I had them on my Suzuki Sierra. Definitely made a big difference to fuel consumption.

[lambchop]

Thanks Farquhar. It defo makes sense so it's good to hear from someone with experience that it was a noticeable difference.

[moggy 1968]

In my experience on a variety of vehicles it made no difference whatsoever. You will certainly not recover the cost of the conversion and it's something else to go wrong. The only advantage is on my current vehicle oil is leaking from the front diff so having the hubs on free reduces the risk of excess wear due to low oil

[Tony LEE]

Friend who was in the Toyota Owners Club in Sydney for many years did many tests on fuel consumption in large 4WDs with freewheel and locked wheels when used on the bitumen (so in 2WD) and he reckoned there was not enough difference to be worth the hassles of getting out into a mud bog to lock the hubs. Wheels spend 99% of the time in the straight ahead position so diff and front drive shaft aren't working so how much energy is needed to spin the front axle.
Another friend with an OKA replaced his locking hubs with fixed hubs for the same reason and has never regretted it.
Once I get out where there are gravel roads, I lock the hubs and mostly drive in 4H to improve stability on loose surfaces.

On the other side of the equation - well, actually still arguing for locked hubs - are a couple of friends who have spent a considerable time searching back over a sandy track looking for all the bits and pieces that erupted when the locking mechanism let go


As for front diffs leaking out the axle seals, if you have dana axles then in some builds the front one is upside down which means the fill plug is about 2" higher than the back one so there is more oil pressure wanting to leak out. Leave the oil level way below the fill plug and there will be way less leakage.

[gren_t]

My experience comes from Landrovers with manual hubs and vaux/opel frontera's with both manual & auto hubs.
on the up side you do save a small amont of fuel..
In my experience fuel economy can be improved by leaving behind all the 5hit landrover owners carry.! - I'm one so i can say it..!

On the downside as only the wheels are turning you lose the splash lubrication effect on the top bushes of the wheel hubs.
With manual hubs once hubs are locked you are good to go however with auto hubs when engaged they take approx 1 revolution of the wheel to engage and lock so if you are stuck and need to rock back and forward to escape with auto hubs they constantly lock and unlock when you change direction.
So when stuck you engage reverse the wheel rotates once then engages with a shock load, then you go forward & the wheel rotates once then the hub engages again with a shock load.

Less components in a drive drain the bettter IMHO.

Regards All

[RogerM]

I'll preface this with "it happened in the 1980s" when I worked for Isuzu Trucks.


We had to do some fuel economy testing of a 4 tonne 4x4 truck that we hoped to sell to a rural fire brigades. Part of the testing included running the vehicle in 4x4 on dirt tracks and through a quarry for about half a shift, the other part of the testing was on a banked "speed loop" with the hubs in the free position and the locked position whilst in 4x2. The vehicle was fitted with fuel consumption gauges with a cross check by dipping/temperature check the tank before and after the tests and allowing the fuel to cool to the before test temp.


There was a marked difference between locked and free hubs - the figures escape me. When we won the contract I remember developing the driver training package which included having the hubs in free before driving on roads with a good surface - dirt or bitumen. The fuel consumption figures were significant enough that if they had to drive 100kms each way to a fire and then drive for six hours in rough terrain, they were pushing the limits of the vehicles safe fuel range.


I think there was also some engineering issues about the transfer case being "driven" by the front axle and not the engine. Probably no interaxle diff back in those days.