Wheel Bearings - rolling resistance question
 

Group,

I am still very new to this group so I am not sure if this question has been asked or covered befor or not. If it has, I have not been able to find it in searching the site.

My question is has anyone looked into repacking or replacing the bearings and races on the rear wheels of a front wheel drive vehicle (like my 2000 Honda Civic Coupe)?

I was discussing this today with a friend of mine today and we were trying to cover all of the areas that might impact rolling resistance. I thought that rolling resistance could be lowered if the wheel bearings were cleaned up or updated to roll more smoothly.

Has anyone looked into this or have any suggestions around what might work better i.e. specific grease or lubricant for the bearings, etc.

Let me know.

Scott in Tulsa

Don't you have sealed unit bearing? In theory, yes it would help some

Yes. Supposedly my (1991 CRX) bearings are sealed, but...

A year or two ago, after talking the matter over with my mechanic, we looked into the situation and discovered that the rear wheels could be drilled directly in the center (the area the small OEM hubcap covers), and this would allow the grease past the dust covers of the bearings (but without effecting the wheel structure, or hitting any critical structures of the wheels). Once this was done, we were able to tap that small hole (in the wheel), and screw in a grease fitting. Of course, once the grease fitting was in place, we used a grease gun to squirt in some high-tech synthetic grease (into that area that now had the exposed bearings), and spun the wheels with our hands (thereby starting the process of working that grease into the bearings themselves).

Yes, this means that we weren't able to clean out the old grease (as if there was much of it left, after 15 years on OEM sealed bearings), so we were just limited to putting new (much better than OEM) grease into the wheels. But even that (alone) made a very noticeable difference!

And while we didn't do any tests that quantified the difference, the effect was very noticeable (to both me and the mechanic doing the work). The first thing that we noticed was that the wheel just spun MUCH freer (the mechanic commented that it has been around 20 years since he saw wheels spin that freely, and the last time was on an almost new car), when up on the jack (and hand spinning the wheel). i.e. the wheel went from quickly slowing down (before this process), to spinning and spinning and spinning (almost as if we had lowered a huge amount of friction). And the effect translated very noticeably into longer/faster coasting when I got on the road. And as good as that was, the effect even got a little better over time (as the grease we injected into the wheels, worked its way around the bearings, to give them better lubrication). So yes, I think it was a "win".

NOTE:
If anyone is interested, the grease we ended up going with is the Amsoil "Series 2000 Racing Grease" ( https://www.amsoil.com/storefront/grg.aspx ). I picked that grease (even before I was registered as an Amsoil dealer), because it seemed like about as good of a grease as I could easily find on the market. It's not a waterproof grease (but also doesn't fall apart at the first sign of water), but that's not a concern for sealed areas like wheel bearings. And that grease otherwise seems to hold up very well, as well as being fairly slick (both properties you want in this application).

BTW: In the off chance that someone wants to check with me about Amsoil products, let me know. As an Amsoil dealer (at least on paper, I can often go months without having a client), I should be able to offer at least some discounts (off Amsoil retail) for gassavers members.

Draco- Good idea. I would have been worried about getting some metal shavings in the center of the bearing when the drill bit finally broke through.

How did you avoid this- magnetized drill bit?

I just squirt mine with moly grease and hope for the best. :D

So draco - you're saying you drilled a hole in the dust cover? You know you can just pry it off, right? That's how you get to the spindle nut so you can replace the bearing/hub assembly.
Also, if you pull the bearing/hub assembly off the axle, you can see into the sealed portion of the bearing between the inner races. Further, the races them selves aren't that tough to pull out of the bearing, and once they're out, you can remove the individual ball bearings and their retainer, clean everything with your preferred solvent, lube everything with whatever super-grease you come up with and reassemble. You can even get a new dust seal (which keeps dust and moisture out on the inboard side) from Honda and install it while you're in there.

[edit]
https://www.fuelly.com/attachments/fo...171076f1de.jpg
I've already done this one, that's why the grease is light blue.
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I would think that if the bearings are in good condition there is little you will do to improve them. Keep in mind that when the bearings warmup the grease will thin down some and turn easier. You would most likely gain more by adding even just 1-2 psi to the tires, that is where most all of the rolling resistance is.

My thoughts exactly!
 

I was thinking along the same lines as Draco, etc. that this would provide a benefit. I grew up on a farm and we replaced wheel bearings and races on machinery all the time. I haven't taken the time to take the wheel apart to see what type of bearings are being used. There are a lot of times where a bearing looks fine and you can clean it with solvent and then repack it to vastly boost the performance. In this case, the wheel should freely spin for quite some time when the car is jacked up and the tire is spun by hand.

There are also times where a bearing looks fine but the wheel won't spin well due to the fact that the bearing balls or cylinders are wearing down and rubbing more than they should. In this case the bearings (and preferably the races) should be replaced and repacked with good quality grease.

I know this makes a huge difference on farm machinery. I thought that it could make a big difference on cars too but might often be overlooked as an option. I am glad to see Draco's comments about the improved coasting ability of his vehicle. I would have expected the same results if the original bearings were dry or somewhat worn.

Scott in Tulsa

Rolling resistance comes on average 82% from tires, 12% from bearings and 6% from brake friction.

Self adjusting drums tend to drag for a while after you've backed up and braked.