Wheel bearings
 

I was going to re-pack the bearings in my 2007 kia spectra with 160k miles. Found out that the bearings are sealed. Does anybody know if putting new bearing assembly would decrease friction and resistance and help mpg?

Thanks in advance

Unless there is a defect or major flaw or maladjustment, the drag contributions of wheel bearings is so small as to be ignorable. Replacing bearings that aren't bad won't improve anything, except maybe the time interval for bearing replacement, which oftentimes never happens because the bearings outlive the rest of the vehicle.

As Frank says, it's a coin flip.

and someone was just telling me about some vw guy that was swapping out bearings in bugs with high end bearings... maybe scammin... :P

I like to think about these types of questions like this:

Friction = energy lost to heat

Suppose I am loosing 1hp of energy due to friction. That means I am loosing 746 watts of power in the form of heat. That is a lot of heat! I can't imagine bearings that are in decent shape heating up by any significant amount. Certainly not anywhere near 1hp, which itself is a very modest amount of power.

The pads on disc brakes remain in contact with the rotor even when the brake pedal is released. This constant friction is so low as to be negligible because the force of the caliper is not pressing the pads against the rotor.

I'm sure a brake system could be designed that retracts the pad away from the rotor and eliminates friction altogether, but the tiny savings would not justify the added complexity.

Where am I going with all this; if it ain't getting hot then it ain't reducing your MPGs.

Frank is dead on, sure on a bicycle you can get a tiny bit by switching to $300 ceramic bearings with lube that costs nearly that much as well, but it's not much and the bearings you can get for a car are not going to be that much different then OEM, so unless the current wheel bearings are bad they don't need to be replaced, good chance that they produce so little friction that they never get warm and bearings getting warm is a ok way to tell if there is something wrong with them.

wow...I quit reading after somebody said "frank lee was right........" :eek:






:thumbup:

I get to be right once in a while. Even a stopped clock is right twice a day.

Most modern disc brake systems use the seals as a means to retract the pads from the rotors, although very slightly.

You could use a laser thermometer to check the temp of the individual wheels to see if there was any wheel that produced higher temperatures than the others, which would indicate excess brake drag or a potential wheel bearing problem.

The newer sealed type bearings do have additional resistance compared to the older type that are precisely adjusted for lower resistance, but that is not the case here.

regards
Mech

Food for thought: Mazda sells blueprinted wheel bearings for Miatas that SM racers use. I've spun one by hand and was very impressed at the reduction in resistance compared to an OE bearing assembly. When you guys are talking about ~5-10hp of total energy use at ~50mph, I could certainly see a bearing like this having a measurable impact on economy.

That said, its unlikely that replacing an OE bearing with a new OE bearing would make any difference.

For GP it isn't worth it (as above). But for heavy vehicles -- big trucks -- it may be one way of improving rolling efficiency. Here, though, it is the duty cycle that makes the consideration worthwhile. On a commuter I'd put custom bearings out of mind.

I know this is a post that hasn't been commented on in 6 years and I skimmed through, but I was looking for some info on greasing sealed hubs. My guess is my wheel bearings on my explorer aren't great. 261k and not sure of any replacements. No significant movement when doing your tradition jack and wiggle. No real slop but would assume a bit dry. Have heard of living through abs. Was hoping for some suggestions and maybe some instructions.
Thanks in advance

The only sealed hubs I try to grease are those on my riding lawn mowers blade spindles.
I used to just run them till they failed, they last 2 years max.
Usually they would fail in the first part of the mowing season. Itwould appear that left over water causing corrosion over the winter does them in.
It all started when I thought I had a spindle going bad again earlier this year, so I took the old spindle off, put the new one on then I looked at the old one to determine failure, but it was fine.
So I pried the cover off the bearings, scooped out as much old grease as possible, put 3 drops of mobil1 85w-140 gear oil on the bearings then packed as much synthetic lithium complex grease as I could into the exposed side of the bearing. Reinstalled the covers.
Then I did the same to spindle on the other side, the other spindle, the good one was basically dry, if it didn't go out this year then probably first thing next year.
I noticed the spindle turned easier after doing this on both spindles.
When I put the mower away this fall I will do it again, to both spindles. If the bearings get fresh oil and grease just before I put the mower away for the winter they shouldn't be able to rust.
Replacementspindles are about $35 each from a local store, I can get them for nearly half that if I can wait a week for them to be snail mailed. But the quality of the no name fly by night Internet sourced blade spindle units is questionable.

So for a little time, a few drops of oil and about 2 to 3 CC of grease I can:
Save money
Reduce breakdowns
Reduce waste
Increase productivity and stay on schedule

I have no idea if this is even an option on ford exploder wheel bearings.
My old suburban and firebird have front spindles that I can take apart and service. Just because something is newer doesn't automatically mean it's better.

I believe they are all sealed on mine not positive. Would need a press to take them apart and don't have a friend with one I could use. Was just curious if anyone had any experience with greasing through the abs port. Would simplify things a bit

Bet it would screw up the abs wheel speed sensor/ring gear. For most of my cars 150-160,000 is when they start going bad (except my 1994 explorer much sooner but wasn't sealed bearing) Tried Ebay bearing on my Cobalt, 12,000 later replacing it with MOOG, other one was bad in a few more month.

On Cam's rogue one was bad, we just went ahead and replace both 2nd one is so much easier if you do it same day.

One mower I had, the spindles were aluminum, I never done it before but used a drill to drill the holes then run a tap in, 10 minutes grease zerts installed, sounded better afterwards. Current mower they are sealed. 54" Hustler for <1/4 acre of grass doesn't see much use since we've quit mowing for other people.