135 replies to this topic

[OrangeCrush86]

What is this SKF brand? I have never heard of them. Is there some specific place to buy them from?

[Jim Drago]

https://www.skf.com/...cing/index.html

 

SKF BR930143
 

 several sell, google that part number. I have never used them

[Bench Racer]

Jim, was reading back in the day front hub stuff. Karl was talking, he heard, never viewed 20 ball front hubs. ???

[Ron Alan]

Can anyone find the Jim Daniels free wheeling hub video from a bunch of years ago?

 

Did a quick search:

 

 

For all the newbies on here...think about this

[Steve Scheifler]

What, couldn’t find a video of him pulling the car with his fish scale?

Sure, there is some potential to reduce mechanical losses, and that little demonstration doesn’t even attempt to consider what hppens when the hubs are loaded with about 600 lbs. But, I’m not convinced that the only difference between those two is simply that one was REM treated. It smelled a lot like hype and a psych job at the time and still does. That said, I wouldn’t wager much either way. But let’s take it at face value for a moment. Although there is probably more to be lost/gained in hubs than the infamous half-shaft CVs, it’s still pretty small.

While tuning an H-prod car on the dyno just yesterday I was again reminded of how much heat is generated to dissipate HP through friction. We were having trouble matching our previous baseline from the end of last season before trying anything new. The power curve was right but we were still 2hp low at peak and a roughly equal percent low throughout the range. So I checked the rear brake rotors and sure enough, one was warmer than it should be and the other was too hot to touch. We freed up the pads and bang, the power curve was a near perfect overlay of the baseline. So right there I was observing a very accurate demonstration of the heat produced to dissipate 2hp. Wheel bearings are no different. If they are costing you power then they produce heat, period. And they do of course, no doubt about that, and a free spinning one will do that less (IF under load the oil film isn’t breached). I can’t use the dyno to test the non-driven fronts of course but the rears get only warm to the touch which tells me that total loss is low and potential improvement by any means is significantly less. So I’m not saying it’s nothing, I’m just trying to help put it into perspective before absurd numbers are thrown around as they were with the CV joints.

[Jim Drago]

For all the newbies on here...think about this

Rem as many hubs as you like.. None will do this  compared to same hub prepped same way The kind of post that starts all the BS 

[Dave D.]

Also Steve, it's difficult to get the point through to people about reducing the spinning friction by having freed-up bearings that were polished with unicorn sweat and magic low viscosity grease only to have a bearing that won't hold up to the on track loads and fail after a session. And as that bearing is tearing itself up when the magic grease fails, doesn't the friction/heat GO UP as the bearing surface breaks down??

  I just make sure the surfaces are clean with no pitting and use a good quality synthetic grease that I service regularly,maybe tighten up the lash by putting the inner races on the surface grinder and that's it. I replace a bearing due to noise maybe one every other season.

[Steve Scheifler]

They both sound like they were lubricated only with WD40.

Correct Dave, see my coment above about breaching the film. Back then some claimed to be using just gear oil or even motor oil. I don’t doubt it was tried but I can’t help wondering how long those lasted.

[Steve Scheifler]

BTW, my assumption was that the two hubs were not yet greased, just lightly lubricated so they could be spun freely to illustrate the difference. I don’t recall anyone claiming they were as-run.

[Bench Racer]

Steve, apparently you missed the my original post of the video. It was referenced to "heresy". No doubt the more perfect the balls and races less heat will be generated.  

[Steve Scheifler]

I didn’t miss anything Bench, not sure why you think I did. I am merely trying to add more useful information to your usual vague tease.

[gerglmuff2]

What, couldn’t find a video of him pulling the car with his fish scale?

Sure, there is some potential to reduce mechanical losses, and that little demonstration doesn’t even attempt to consider what hppens when the hubs are loaded with about 600 lbs. But, I’m not convinced that the only difference between those two is simply that one was REM treated. It smelled a lot like hype and a psych job at the time and still does. That said, I wouldn’t wager much either way. But let’s take it at face value for a moment. Although there is probably more to be lost/gained in hubs than the infamous half-shaft CVs, it’s still pretty small.

While tuning an H-prod car on the dyno just yesterday I was again reminded of how much heat is generated to dissipate HP through friction. We were having trouble matching our previous baseline from the end of last season before trying anything new. The power curve was right but we were still 2hp low at peak and a roughly equal percent low throughout the range. So I checked the rear brake rotors and sure enough, one was warmer than it should be and the other was too hot to touch. We freed up the pads and bang, the power curve was a near perfect overlay of the baseline. So right there I was observing a very accurate demonstration of the heat produced to dissipate 2hp. Wheel bearings are no different. If they are costing you power then they produce heat, period. And they do of course, no doubt about that, and a free spinning one will do that less (IF under load the oil film isn’t breached). I can’t use the dyno to test the non-driven fronts of course but the rears get only warm to the touch which tells me that total loss is low and potential improvement by any means is significantly less. So I’m not saying it’s nothing, I’m just trying to help put it into perspective before absurd numbers are thrown around as they were with the CV joints.

conservation of energy is a myth. 

this is racing. the laws of physics bend with how successful you are at runoffs. 

[Dave D.]

Guys, I still am not convinced of replacing with "better" quality balls is really an improvement....I found a while back a spec list from the OEM bearing supplier and the ABEC rating of the balls used originally are the same as the balls many are buying in bulk now( not sure, but I thought they were ABEC 3?, any better rating and the balls are listed as "AEROSPACE/AVIATION). I get that they will be better if the balls coming out are pitted......

       Do these bearings get "micro dented" over time and the races are still fine?

[Bench Racer]

Steve, it was not a vague tease, the video is a visual for anyone. There are many who race Spec Miata who don't truly understand words written by others as compared to viewing something. Just as someone posted asking questions about the SKF brand bearing. The company has been around since the early 1900's. people who have in their careers been involved in using bearings would know of many bearing companies, people who have not wouldn't have said knowledge. Now please find the fish scale video.

[Bench Racer]

Do these bearings get "micro dented" over time and the races are still fine?

 

If using grade 3 balls wouldn't it be the case hardened outer races which start the failure?             

[Steve Scheifler]

^ that. I suspect that most often the races fail regardless of ball smoothness, possibly from shock load rather than normal wear. But don’t take that to the bank, it’s just my best guess at the moment.

[Ron Alan]

Rem as many hubs as you like.. None will do this  compared to same hub prepped same way The kind of post that starts all the BS 

As in my post is BS or the video? If you think the video is entertaining we are on the same page

[Jim Drago]

As in my post is BS or the video? If you think the video is entertaining we are on the same page

Video is BS and implying anyone look at this as potential gain or benefit is a bad idea, many might not think its a joke

[granracing]

I didn't think it was a joke at first.

[Tom Sager]

For all the newbies on here...think about this

 

You can get that same free-wheeling low resistance roll if you only torque the hubs to 15 ft-lbs. Not for long though.