Free Wheeling Hubs: Why Have Them?

by Khalid Omar (Edit Entry)

Interesting article on free wheel hubs. There are two opposing camps about free wheel hubs, and never the twain shall meet. After many years driving a Willy’s jeep with permenantly locked hubs, I’ve never had a single problem with the front axles, or with mileage, loss of power etc.

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. This is 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 a 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!
>> Free Wheeling Hubs: Why Have Them?

Posted in Tech, June 14, 2005, by Khalid Omar

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Imad on June 15, 2005 6:34 PM (Edit)

I have driven with permanently locked drive flanges and also free wheel hubs, and the only thing I miss about drive flanges is the ability to pop into 4 hi without slowing down. Less drivetrain noise, less wear on that long, whippy CJ front driveshaft and u-joints, better acceleration, fewer torn oil pans on rogue speed bumps… what’s not to like about them? Yes, I am talking about FWHs in the real world of jeeps parts that wear out faster than you can replace them and of mechanics who re-cut your Toyota oil pan so that a spinning front u-joint goes through it like a hot knife through butter. Until I get a brand new driveshaft with spanking new u-joints, pinion bearings, oil seals, the works, I’ll just stick with FWHs.

FWHs are the bane of inexperienced drivers, who get stuck not knowing that 4 lo won’t do any good if the hubs aren’t locked, or those who never lock their hubs till the day they really need than and find out the damn things are jammed uo. Such people need not put themselves in such situations. It’s not so inconvenient to get out and lock your hubs before hitting the rough stuff. It’ll also give you a chance to spot anything wrong with the vehicle before you go ballistic on it.

I think the real argument is manual locking hubs vs. automatic hubs. Jeep and Ford came up with dreaded vacuum activated hubs in the late 80s, which failed more often than not. Now Japanese carmakers have jumped on the bandwagon too with their equally complicated, albeit more reliable, electric designs.

KO on June 18, 2005 4:14 PM (Edit)

In 2 wheel drive, only the rear drivetrain is under stress - so even if the front hubs are permemantly locked the front axles, driveshafts etc. will last much longer than the rear parts. I’ve replaced the rear driveshaft and crosses, but the front ones are still going strong. If you find that the front drivetrain components are wearing out as the same rate as the rear, than there is something wrong with the drivetrain geometry.

fewer torn oil pans on rogue speed bumps
Your front u-joint shouldn’t come into contact with the oil pan in the first place. Shape the oil pan upwards, put bumpstops for the front axle etc.

FWHs are the bane of inexperienced drivers
True, I seen quite a few people hopelessly stuck because they had no idea they had to ‘lock’ their front hubs.

Autolocking hubs are a pain - I’ve seen them fail first hand in a Kia, a Ford Bronco and a Toyota Landcruiser.

Imad on July 8, 2005 12:28 AM (Edit)

FWHs evoke extremely polarized opinions. Those who’ve never had problems running drive flanges will surely see no virtue in running FWHs, but those who had to deal with the things I mentioned above would much rather get out and lock the hubs.

You’d think twice about dismissing FWHs if you still had jeep hardware under your jeep. Your jeep has Daihatsu axles which have a much less intrusive profile than jeep axles. That helps keep the driveshaft yokes at a safe distance from the oil pan. By the same token, the front drivehaft is also made from larger diameter tubing and a longer slip yoke, all for a much less whippy shaft than the wimpy jeep original. Japanese diffs are also remarkably smooth, worlds more refined than 1950s American diffs.

I drove our old Willy’s with drive flanges for ages, and later on with FWHs. There was a night and day difference with unlocked hubs. It ran a lot quieter and acceleration was much better too. Then we got the CJ7 with all Landcruiser drivetrain, and in this vehicle you couldn’t tell if the hubs were locked or not. It was just as smooth and quiet either way, thanks to the beefy driveshafts and silky smooth diff operation.

As for oilpan-busting-u-joints, Toyota engines have pesky oil pickup tubes hanging out of the block limiting how much you can trim off the oil pan. You can’t go overboard hacking up the oil pan because it naturally won’t fit back on. Or you might think you ‘ve notched it deep enough, but then a bump will come along, compress your bumpstops you like never thought possible, and punch a nice little pin hole to slowly but surely bleed the engine dry (<- speaks from experience here).

Now what are you supposed to do if your engine is mounted so low that the oil pan will regularly rendezvous with the u-joints, no matter how big your bumpstops? Make sure the u-joint isn’t spinning when that happens. A stationary u-joint will only dent the oil pan and make room for itself. A spinning one will go right through.

BTW, auto locking hubs are torque sensing designs that lock up when the axle shaft starts spinning. Toyota doesn’t use them - you have to switch them on instead.

Emil on May 4, 2007 8:11 AM (Edit)

I just bought a 1963 Willys,how do i lock the hubs on the front wheels to use it in 4X4 they look different,any body can help please email me at emil@ bungeeco.com.
Thank you
Emil

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You are reading Free Wheeling Hubs: Why Have Them?, an entry made on June 12, 2007, filed under Tech. This entry is part of offroadpakistan.com.

There have been 4 comments on this entry. The most recent comment is by Emil.

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