FWD Streamliner differentials

[Richard Thomason]

WOW to John Burk. I like the looks of your new liner. We actually had a similar design at one point. As the Aussies say-Good on you mate. Go for it. Enjoy but remember that you can always tell the pioneers by thwe arrows in their backs.

Richard

[John Burk]

Sparky
If Corvette IRS rear hubs like item number: 200336146739 on Ebay could be bolted to production king knuckles you'd have non projecting hubs . The question is are the bearings good enough . On production 4wd pickups the engineers chose to have the wheel bearings above the tread and live with a few inches of scrub radius . Dodges and some Fords have closely spaced bearings which work fairly well . Custom wheels with negative offset to reduce the scrub radius put the bearings off center which is hard on them . Chevys have plenty of space between the bearings so they can handle the leverage . Dodges and some Fords have closely spaced bearings and would fail quickly . The Corvette hubs may be the same , especially if they don't have Timken bearings . Custom hubs can be made with zero scrub radius and centered bearings .
 

[SPARKY]

I am looking at '98 Exploder outer wheel stud assy with the bearings and female splines, earlier Jeep outer male shafts, GM inner shafts that use same Spicer u joints as the GMs---will respline the inner shafts to fit the GM 7.5" carriers.  Will require a machined outer brgs. hub to fit the GM outer steering knuckel and will have to mate the inner knuckel to the axel tubes on the GM 7.5 housing.---in process not done yet!!!!  pretty sure we can though.

[JimL]

I'll go out on a limb, here, and offer an opinion.... do not use late model "double row" angular bearing type knuckles and hubs.  These things allow more movement of the hub, on the spindle, than you'd expect.  The road racing FWD cars have to put springs behind the brake caliper pistons just to get the pads back to the disc, after hard cornering (the wheels stand back up on the straights, due to the angular design). 

There is so much rock in the "sealed double-row" bearings that the pads get knocked back during a turn....driver gets to the next turn (without springs behind the caliper pistons) and goes for the pedal and it hits the floor.  It'll pump up, of course, but if he's any good...he already ran out of room.

I'd be running hub/knuckles that use taper bearings (the old Timken style).  You can be sure you'll keep the wheels from getting into lateral vibration (especially if you wind up with near zero scrub).  I don't know what setup the parts you are looking at use....no experience with them. 

Getting the scrub inboard is strictly wheel back spacing (more).  If the bearings are good, and tapered/adjustable, I'm not worried about the load being out of line with original design.  We (hopefully) don't jump these cars, or hit giant potholes at low speed, kiss curbs, or all the other stuff that customers do to the cars/trucks. 

Hope I'm making sense....been welding a lot today, and I'm pretty foggy tonight.
Regards, JimL

[SPARKY]

Jim L, Thanks for your input. 

I will be the first to say that I have NO experience with performance FWD applications of any kind. 

But why would we be able to put any more loads on the salt, than a fully loaded Surbuan or Explorer on patchy ice in 4 wheel drive?

The 4x4 inner and outer 1/2 shafts both have thrust surfaces, and I am not understanding where the side loads are going to come from.

I have some research to do for I do not know exactly what the definition of several of the Eng. type terms you used. I have learned the hard way not to trust or assume my laymans understandings and term usage.

Thanks again Jim L,  I will be smarter by this time next week.

[Rex Schimmer]

Jiml,
When you say "late model douple row angular bearing" do you mean double row angular contact ball bearings? I would certainly think for a fwd application with big hp, like Sparky will be applying, you would want to go with either a pair of angular contact ball bearings that are preloaded against each other or with tapered roller bearings. It is very hard to set up tapered roller bearings (Timken) so that they are preloaded. They are so stiff in the axial direction that getting them properly preloaded usually requires some pretty close machining and if you get to much preload they will self destruct. This is why properly applied angular contact ball bearings are probably a better choice as they are a little more forgiving and will give you lower drag than the "Timken" bearing set up.


Rex

[JimL]

Correct...yes they are  angular contact to "self center" the wheel when driving straight.  Low friction, no maintenance, but the trade off is imperfect hub angle control on the spindle, under hard side loads.  They really work great for our daily drivers, and last a good long time without problems.

I never knew about this until I worked with the Celebrity cars for Long Beach Grand Prix.  It turns out StopTech (their brake supplier) new exactly what was going on, as soon as the problems were mentioned to them.  Those were brand new cars, zero miles, and the tires were not that wide and sticky (had to fit into stock fenders)..... that's some "give" to knock the pads back so far that the pedal goes to the floor at the next turn!

The people that run them really hard (track days and all)...they seem to give up much quicker than traditional tapered bearings.  I don't have any proof that they would be a problem at 300 mph...but I'm not sure. 

For me, "Not sure" doesn't measure up to "worked fine for the last 50 years". 
I get more and more Ludite, every day, don't I ?!  (probably spelled that wrong)

Regards, (old and stuck in the mud) JimL

[John Burk]

I've learned that Spicer u-joints are the weak point on Dana 44 front ends but there are way stronger u-joints available like CTM , Ox Joint , thanks to the offroad and rock crawler market .

One or the problems with non-serviceable production hubs with angular contact ball bearings is they aren't rated so for lsr it's trial and error .

[SPARKY]

Thanks John

[John Burk]

On high strength u-joints for Dana 44 hubs for four/front wheel drive . All the brands eliminate the needle bearings so the pins on the cross can be larger . Some have the crosses titanium coated and run against the caps metal to metal and might gall at high speed with slight steering input . CTM u-joints have thin bushings so they would be the ones to use .

[SPARKY]

Thanks John, My buddy Bill Ratliff  [ Arlington  4x4 ---  817 994 6085 c 817 790 0657 s ]          (set up my 7.5 GM with the 2.14 gears )
has a pull truck "Radical Rat". Those are the type of U-Joint he runs has 10 years on the non bearing U joints.  those are the type we are leaning towards.

[Blue]

This is all very useful information.  Keep it coming.

[SPARKY]

Update,

 Terry Mourer, Mourer Machine Co, called today,  It is going to be relatively easy to chuck the outer axel tube with the King and increase the inside diameter  to a be able to slide them over the outer tube of the 7.5 GM after they both have been cut to fit. Then we will cut and spline the GM 4x4 1/2 shafts for the 7.5 Torsen center section with the 2.14 ratio. We will also have to find a seal that will work with the ID of the 7.5 and we will have to machine a seal surface on the axel shafts. 

I understand we are in a HIGH RISK application, but I THINK we will be helped very much by the action of the Torsen, which virtually eliminates shock caused loads from wheelspin.

[John Burk]

Sparky several people make stronger custom alloy axles rather than modify the 1040 steel Danas .

[manta22]

John is right-- for example, my Porsche axles were made out of 4340 by the Summers Brothers. Others such as Strange Engineering can do similar work.

Regards, Neil  Tucson, AZ