Full float rearends

[deuce_454]

x 4!

also mechanical engineer... and im getting a track9 from sc&c... although im leaning towards an aluminum williams centersection with GM12 bolt ring and pinion and 33 spline axles.. ..partly just to be different and partly to reduce loss..

[ccracin]

We went with the Strange aluminum center with a street aluminum daytona pinion bearing carrier and 31 spline Tru-Track with 3:89 gears. It looks really good and saves a bit of weight. We had a smooth back center housing mated to 3' axle tubes and Big Ford bearing ends. Add that to 31 Spline Moser axles and there you have it. Should be nice.

[another69]

Which semi-float housing ends (if purchasing an aftermarket housing) allow for tapered bearings, and how do you set the preload? Most of the SF aftermarket stuff I have seen uses the "cartridge ball" style which is not intended for alot of side loading. Thanks for everyone's input!

[chicane]

Originally Posted by tyoneal

To the best of your knowledge does anyone on this board drive their cars hard enough to justify the expense?

Yes.

Originally Posted by Silver69Camaro

I'll save the weight and put the cash somewhere else.

Save weight by... ?? Id love to hear your thoughts on this subject.

Originally Posted by Silver69Camaro

I'd be willing to bet a SF axle is slightly lighter, both in unsprung and rotating mass. AND you have all the brake kits you want that will bolt on.

With that mentality, you might was well go for a 4" driveshaft. But it's only money.

It would depend on the design. If you are referencing the typical BGN or wide five... Id say yes. But not with a cartridge bearing/sensor design... its less than half the rotational mass of a BGN/W5.

As for the subject of a 4" driveshaft... some of us need a 4" driveshaft because of the shaft speeds that we deal with. Safety and durability outweight the cost everytime.

Besides... $3k for something that will not break or that you will not have to fix or rebuild constantly... is a better mentality than a $10k paint job.

Originally Posted by another69

Which semi-float housing ends (if purchasing an aftermarket housing) allow for tapered bearings, and how do you set the preload? Most of the SF aftermarket stuff I have seen uses the "cartridge ball" style which is not intended for alot of side loading. Thanks for everyone's input!

If it were of any choice, I would be looking into the components from Mark Williams. Their 57/58, 66/67/68 series housing ends all use tapered rollers. But for what its worth... the typical 'Ford big bearing' ends are too large for 99% of the applications outside of drag racing. As are differential cases that have bearing registers larger than that of 3.062". Bearings... are subject to the very same limitations concerning critical speed. Most here will never see those limitations... but then again... there are those of us that do.

About the pre-load of tapered bearings... the difference in the bearing cup depth and the retainer plate is how this is accomplished. With the bearing pressed onto the axleshaft and inserted into the cup, the amount of the bearing race that protrudes past the end of the bearing cup (along with the axle seal) is clamped into the bearing cup with the loading of the retainer plate to the housing end.



If thought out well enough... you can build a stronger, more reliable, more efficient and lighter differential for well under $3... even while using a 9" type design. Although the the 9" is typically 3% less efficient... you can get that back and even a little more by choosing the right components.

[ccracin]

Originally Posted by chicane

About the pre-load of tapered bearings... the difference in the bearing cup depth and the retainer plate is how this is accomplished. With the bearing pressed onto the axleshaft and inserted into the cup, the amount of the bearing race that protrudes past the end of the bearing cup (along with the axle seal) is clamped into the bearing cup with the loading of the retainer plate to the housing end.

Chicane,

I am curious and would like to know a bit more about the SF taper roller bearing design. My question is, Is measuring the delta of the cup to cone the only way the "pre-load" is verified? We used quite a few tapered rollers in mass transit gear boxes and found through hours and hours of testing that we could not use this type of check to verify the proper initial clearance. Due to manufacturing tolerances of the cup to cone it was found that we needed to develop fixturing to measure the axial and radial clearance values. Based on those values and testing, a matrix was developed to determine the proper clearance for the application. I guess that brings me to a second question, you refered to pre-load. Our tapered rollers were always set with some amount of clearance, is "pre-load" just a generic term being used here? Thanks for any information you can provide.

Sorry to all the others for the book, but I'm curious.

Later,

[chicane]

Instead of falling suspect to any speculation I have called upon our resident bearing specialist... CarlC to address this subject. Hopefully he will reply shortly.

CC- Yes... that term being used is rather generic. But... Ill take a stab at a simple explaination as I under stand it.

Bearings with a tapered geometry, can be difficult to directly measure radial clearances. For this reason, radial clearances are commonly converted to axial clearances. (Radial clearance equals axial clearance times the cotangent of the bearing contact angle.)

The amount of clearance between bearing rollers and raceways measured in this axial direction is called endplay. The optimal initial endplay depends on a number of factors, including shaft and housing materials, bearing fits, and operating temperatures.

With this, endplay adjustments in tapered roller bearings are made during assembly or installation to compensate for the expected thermal expansion during operation and system deflections. Axial preload in tapered roller bearings is produced by displacing one bearing ring axially in relation to the other by an amount corresponding to the desired preload force. Generally, each bearing is individually and manually adjusted using shims or spacer sleeves, or by tightening torques from means likend to the bearing retainer.

In addition to manual methods, there are also several automated techniques. In the case of double-row tapered roller bearings, a preset assembly can be supplied, or the bearings can be adjusted manually at assembly by machining spacers.

Careful monitoring and observation of applications can sometimes reveal early warning signs of clearance and endplay-related problems. Vibration monitoring equipment, for example, can detect the excessive axial and radial shaft movements caused by too much endplay. Temperature sensors can detect-increases in heat associated with impending bearing failure. This may also be accomplished by reading the surface condition that may provide a picture of what the failure mode is... radially spalling, micro spalling, impact deformations etc etc.

CarlC... take it away.

[Silver69Camaro]

Originally Posted by chicane

As for the subject of a 4" driveshaft... some of us need a 4" driveshaft because of the shaft speeds that we deal with. Safety and durability outweight the cost everytime.

Besides... $3k for something that will not break or that you will not have to fix or rebuild constantly... is a better mentality than a $10k paint job.

Re-read my post:

Originally Posted by silver69camaro

That comment was within the context of this discussion, which is using equipment that isn't necessary for a particular application and is only purchased for a "cool factor" or otherwise (something other than a "need" basis).

If you NEED a 4" driveshaft, then you don't have a choice. Same goes for a FF axle. If you DON'T need a 4" shaft, than what's the point? You'll just spend more money on something that is oversized. Bigger isn't always better.

[chicane]

Don't need... and did not need to re-read your post. I read your comment's correctly the first time.

My reply was to educate the rest of the forum members that don't know any better and/or that do not understand shaft specifics. Even comments in generalization can mis-lead or mis-represent the point trying to be conveyed.

[another69]

My original question was if a FF axle can be used on the street, because I have never seen one on the street, and the answer was yes (thanks chicane). I may not NEED one now, but the direction my car is heading, I will most likely NEED one later. I will spend the extra few hundred now rather than a few thousand twice.

[CarlC]

Tom's on it.

Preload can be + or -. Often in the bearing industry, but mostly related to machine tool spindle bearings, clearance will be referred to as negative preload.

Due to the nature of the beast tapers are set using an axial endplay (bench endplay) value. On horizontal applications it can be a real bear to get the BEP set correctly since gravity is not your friend. On larger assemblies it is recommended to set the BEP in a vertical fixture. Trying to measure radially usually does not have good results due to trying to keep the system aligned, off-center housing mass loads, no access to both sides of the shaft, multi-piece rings, etc. It can be a very time consuming and arduous process.

Smaller TRB's like those used as discussed are great for the do-it-yourself'er since the preload is built in. There are very few self-contained TRB assemblies like these anywhere in the industrial field. I like them, and have proved very reliable for me.