Free Wheeling Hubs - Do they really save fuel?

[Dadz Toy BFI]

My Lady recently ate her way through a tank a fuel at an alarming rate :!:

I couldn't understand it as she's just been serviced as is running better than ever

I lost approx 60Kms less on a tank, I usually clock up +/-280Kms per tank.

Then, whilst I was filling up and checking my tyre pressures I noticed that I'd forgotten to unlock the front hubs, since my Christmas Camping Trip to Tulbagh

I understand that Toyota were the first to introduce free wheeling hubs as a fuel saving device and often wondered if it actually made any difference - now I know :o

Shame that they dropped the idea, apparantly due to none of their competitors maintaining suite, then they dropped them also to be more price competitive.

Whilst I know it's absolutely fine to drive around with them locked, (most 4x4 owners don't have any choice :!: ) I was still shocked to see the effect of a little extra friction :!:

Any body else noticed such a significant difference

Cheers

Rich 8)

[JBurger]

Rich
At 280km/tank, why worry about fuel consumption!! Just joking, but I must say, I am a bit shocked. I will have to hang on to my KZ, I feel unhappy if I get less than 600, but except 550 when I know I have been up to mischief. I have at times forgotten the hubs locked, but did not notice a change in the consumption.
Not trying to hijack your thread, I think it is valid especially for someone else that may be looking at the various vehicles with a mind to buy.

[Scooter]

I usually get round 6.4k/L with hubs unlocked and never really checked with them locked around town but did do alot of driving in Moz recently and I can say that with hubs locked, 4H engaged, tyre pressure dropped, I didnt really notice any difference in consumption. Maybe it was just my imagination but it seemed to give the same consumption. M2cW

[Bfreesani]

I like keeping my hub in the free position as I have noticed a slight vibration at higher speeds when they are locked and turning the drive train but not engaged in the transfer box. There is obviously some friction in the system that would affect fuel consumption I would think. But I feel the biggest saving is on the CV joints and part that could be waring out just through it's running free on the road surface even if not being needed. When in the free position it stands totally still with no ware and tare on anything else but the slip joint on the prop shaft.

2 cents for free

[Martin K]

I get around 650 km per tank with hubs free and 600 locked when driving on road. 2.7i

[Bfreesani]

WOW, did not think it would make that much of a difference. I have never done that exercise as we are off road every weekend somewhere. While in the bush, I never even switch the engine off while the convoy goes through an obstacle. So some days, from around 10am till nearly 4pm the engine will be running or we will be crawling around in low range.

Average however when I get to check my 2.7TD is around 9Km/l with a peak now and then at nearly 9.5.

[DOELLOOS]

At 180 kmh plus, there is definite vibration when the hubs are locked, even from 160 kmh and up. Also, unlocked the lux is definitely faster.

[BenHur]

David

That is not uncommon. With many 4x4s you will start noticing a vibration at high speed, some from 100 km/h some higher. It is nothing to worry about, as these axles were not designed for high speed and they are not that finely balanced.

[Cookie Monster]

I try not to forget to unlock mine as it vibrates a little as my front prop is a little worn

[BenHur]

Are you sure its the prop. I have the same thing but they checked the prop when the rear one was serviced. The guy at the propshop recons it is most probably one of the side shafts. He says he sees this regularly but since you are not suppose to use it at high speed you should not worry.

[Family_Dog]

Bulldog has the same problem, and it is not the front prop! After I installed the OEM, I had a new prop made because Bulldog did not have sufficient grip on the new contact area in the existing splines. Propshaft Centre in Klerksdorp confirmed the vibration does come from the side shafts at speed.


-F_D
Control Freak