8 1/4 axles

[JR_Charger]

How much power can the factory sure grip take? Dr Diff sells an 8 1/4 limited slip that is good for 350 hp. I'd like to go up to 500.

I purchased the LPW bracing kit, but it turns out the shocks on a B-body are in the way of the braces. Any thoughts on that?

 

[1STMP]

How much power can the factory sure grip take? Dr Diff sells an 8 1/4 limited slip that is good for 350 hp. I'd like to go up to 500.

I purchased the LPW bracing kit, but it turns out the shocks on a B-body are in the way of the braces. Any thoughts on that?

Properly set up, an 8-1/4 can handle
500 hp. A girdle with proper carrier
bearing support, "green bearings",
and shortening the axle shafts,
(shortens the moment arm forces
from the carrier to the outer bearings),
and reinforcing the welds from the
axle housing to the tubes.
Though purchasing an 8-3/4
(at almost twice the price) of an
8-1/4, make this a more viable
option. (a lot less work).
I use a 8-1/4 in my build. But I'm
a mechanical engineer who loves
playing with the numbers. I also
have a steady source for 8-1/4's
as they're everywhere.
These smaller axles were used in
thousands of trucks and vans.
They're much tougher than most
give them credit for.
What kills these axles is the rearward
force of hard acceleration on the
carrier bearings, thus transferring
that load to the outer bearings.
(hence, the girdle)
As with any lever, the longer the
moment arm, the greater the force.
(hence shortening the axle).
The engine in my build is 489
hp to the rear. So far, zero problems.
C clips are another weak point, but
there are kits out there to eliminate
this problem, or you can install rear
disc brakes, which will keep the
axle from vacating the housing
if a C clip should fail. That, in itself,
will require mods to your braking
system.
I get into this kinda stuff, but you
may not.
I built a tube chassis to fit under
the sheetmetal of a pre-war pickup
mainly just to see if I could do it.
It's been a fun and interesting
project.

 

[JR_Charger]

I can't do all the work myself, but I seem to be "into it." I'd like to keep things light. So far I've been better at that than keeping it cheap.

I've got this 8 1/4 rebuild kit from Doctor Diff - Link

Should I replace the Koyo bearings with Green Bearings? Doctor Diff has Green Bearings for 8 3/4, but I don't see any for 8 1/4.

Have you got pics of the reinforced axle housing/tube welds?

 

[1STMP]

They're not "green" bearings per se,
but they are a sealed bearing.
The part number for the repair bearing is RP-1563-TAV.
The axle tube welding is just to up
grade the factory welds, which
typically are of poor quality.
When shortening the axles, I cut 3"
off per side, and had them re-splined
and hardened.
The diff cover is a LPW-10C. I removed
the feet off of the load bolts and
ground the ends round and smooth,
and they now contact the center of the
bearing caps.

 

[Ceedawg]

They're not "green" bearings per se,
but they are a sealed bearing.
The part number for the repair bearing is RP-1563-TAV.
The axle tube welding is just to up
grade the factory welds, which
typically are of poor quality.
When shortening the axles, I cut 3"
off per side, and had them re-splined
and hardened.
The diff cover is a LPW-10C. I removed
the feet off of the load bolts and
ground the ends round and smooth,
and they now contact the center of the
bearing caps.
View attachment 1391954View attachment 1391955


View attachment 1391961

I would think even the 8-3/4 would benefit from jack bolts thru a reinforced back cover. All looks great there.

 

[JR_Charger]

View attachment 1391954

Wow, the way those feet sit looks terrible! Hard to believe LPW shipped that product!

Here's what Doctor Diff shows for the Koyo bearings -

And here's what Amazon shows for Timken's TRP1563TAV-

Would I be correct in assuming the Koyo bearings are unsealed, and the Timken is sealed?

 

[1STMP]

Wow, the way those feet sit looks terrible! Hard to believe LPW shipped that product!

Here's what Doctor Diff shows for the Koyo bearings -

View attachment 1392052

And here's what Amazon shows for Timken's TRP1563TAV-

View attachment 1392053

Would I be correct in assuming the Koyo bearings are unsealed, and the Timken is sealed?

It struck me as odd as to why they
designed the load bolts that way.
They're torqued to 10 in/lbs, and
those feet don't distribute the load
equally on the bearing cap.

Yes, the Timkin bearing is sealed.

 

[RJRENTON]

Wow, the way those feet sit looks terrible! Hard to believe LPW shipped that product!

Here's what Doctor Diff shows for the Koyo bearings -

View attachment 1392052

And here's what Amazon shows for Timken's TRP1563TAV-

View attachment 1392053

Would I be correct in assuming the Koyo bearings are unsealed, and the Timken is sealed?

Bear in mind that even though the bearing is branded TIMKEN, it is not a tapered roller bearing. It is a CYLINDRICAL ROLLER BEARING and must be retained either on the axle (rolling element) or in the breaing retainer (housing) to prevent axial movement while rotating. The bearing is capable of radial load and no axial load.....sealed construction not withstanding.......look before leaping.....why not use what Mopar origionally designed and installed? Just my opinion of course....
BOB RENTON

 

[1STMP]

Bear in mind that even though the bearing is branded TIMKEN, it is not a tapered roller bearing. It is a CYLINDRICAL ROLLER BEARING and must be retained either on the axle (rolling element) or in the breaing retainer (housing) to prevent axial movement while rotating. The bearing is capable of radial load and no axial load.....sealed construction not withstanding.......look before leaping.....why not use what Mopar origionally designed and installed? Just my opinion of course....
BOB RENTON

Agree somewhat with what you're
saying Bob, but the reason I chose the
sealed type is they're a lot less prone
to leaking, and if there is a leak, it's
much easier to change the seals.
Unless the car is being autocrossed,
the sealed bearings will hold up
OK for normal street use, or
drag racing.
Both my '79 360 v8 powered Jeep,
and my '65 289 v8 powered (dare I
say....Mustang) have sealed bearings.
Neither has had any bearing failures
or leaks.

 

[JR_Charger]

Bear in mind that even though the bearing is branded TIMKEN, it is not a tapered roller bearing. It is a CYLINDRICAL ROLLER BEARING and must be retained either on the axle (rolling element) or in the breaing retainer (housing) to prevent axial movement while rotating. The bearing is capable of radial load and no axial load.....sealed construction not withstanding.......look before leaping.....why not use what Mopar origionally designed and installed? Just my opinion of course....
BOB RENTON

Can you provide a link to the best tapered and sealed RP-1563-TAV bearing?

 

[JR_Charger]

Unless the car is being autocrossed,
the sealed bearings will hold up

Are the unsealed bearings better for autocross? Why do the sealed bearings have a problem with autocross?

 

[1STMP]

Are the unsealed bearings better for autocross? Why do the sealed bearings have a problem with autocross?

As Bob pointed out, there is no axial
(lateral or side to side) support for the
bearing. Where a tapered bearing is
used, the axle seal is typically placed
on the axle, then the bearing is
pressed on the axle with the race
installed in the housing.
With a sealed bearing,
the bearing is mounted in the
axle housing with the seal mounted
over the bearing. This method allows
for less labor intensive replacement
of the seal, and is prone to less
leaking. I wouldn't worry too much
about performance unless you plan
on running autocross or instances
where you're beating the snot out
of it. Even then, a sealed bearing holds up pretty well.
As mentioned though, this puts
more stress on the C clips that hold
the axle in the housing. Since no
one offers a C clip eliminator kit
for an 8.25, for piece of mind, I
opted for rear wheel disc brakes
to hold the axle in place in the
event of a C clip failure.
Both my Jeep, and M*****g
do not have rear disc brakes
and have C clips, and sealed
bearings.
It's been 40 years on the Jeep
with lots of lateral force. No
failures. Even longer on the
M*****g. On either of these two,
if the C clip fails, the axle is prone
to vacating the housing.
Both set-ups are prone to
failure if abused. And usually
a hard and sudden impact
on the sidewall of a tire is
what it takes to break a C clip.

 

[Ceedawg]

As Bob pointed out, there is no axial
(lateral or side to side) support for the
bearing. Where a tapered bearing is
used, the axle seal is typically placed
on the axle, then the bearing is
pressed on the axle with the race
installed in the housing.
With a sealed bearing,
the bearing is mounted in the
axle housing with the seal mounted
over the bearing. This method allows
for less labor intensive replacement
of the seal, and is prone to less
leaking. I wouldn't worry too much
about performance unless you plan
on running autocross or instances
where you're beating the snot out
of it. Even then, a sealed bearing holds up pretty well.
As mentioned though, this puts
more stress on the C clips that hold
the axle in the housing. Since no
one offers a C clip eliminator kit
for an 8.25, for piece of mind, I
opted for rear wheel disc brakes
to hold the axle in place in the
event of a C clip failure.
Both my Jeep, and M*****g
do not have rear disc brakes
and have C clips, and sealed
bearings.
It's been 40 years on the Jeep
with lots of lateral force. No
failures. Even longer on the
M*****g. On either of these two,
if the C clip fails, the axle is prone
to vacating the housing.
Both set-ups are prone to
failure if abused. And usually
a hard and sudden impact
on the sidewall of a tire is
what it takes to break a C clip.

But an 8-1/4 axel rides on a straight bearing unlike an 8-3/4 or 9-3/4. The c-clip is the only thing holding that axel in place (unless a disc is used) so it doesn’t matter what race you run still a straight bearing, sealed or in sealed. Now if a bearing is pressed onto the axel with the lock ring like an 8-3/4 green bearing that would get around the c-clip but wouldn’t address the side loads like a tapered bearing.

 

[JR_Charger]

I've got the stuff to convert the rear to discs, so I'm not worried about c-clips.

So what I gather is there is no such thing as a tapered, sealed bearing - it is tapered bearing or sealed bearing.

These are tapered bearings?

Sorry if these questions seem dumb - it's new to me.

The main advantage of the sealed bearing is preventing leaks, or replacing seals when there is a leak? Do leaks develop often with tapered bearings?

 

[Ceedawg]

I've got the stuff to convert the rear to discs, so I'm not worried about c-clips.

So what I gather is there is no such thing as a tapered, sealed bearing - it is tapered bearing or sealed bearing.

These are tapered bearings?

View attachment 1392174

Sorry if these questions seem dumb - it's new to me.

The main advantage of the sealed bearing is preventing leaks, or replacing seals when there is a leak? Do leaks develop often with tapered bearings?

They look like the 8-3/4 bearings with the lock ring. Only thing is they wold need some block between the axel ends and an adjuster to set the preload, I’ll go back and look at kit again, might have missed it.

 

[33 IMP]

An 8 1/4 is just like a 9 1/4, 12 bolt, or 8.8 Ford. Bust a c-clip or axle, and the axle, wheel and tire exit the vehicle, not doing any favors to the quarter panel on the way by.
Best solution for any of them is a rear disc brake setup.

 

[RJRENTON]

Can you provide a link to the best tapered and sealed RP-1563-TAV bearing?

Suggest that you visit the Timken web site.....you will find the information you seek plus all you ever wanted to know about anti-friction bearings, in all configurations (tapered roller bearing, ball bearings, cylindrical roller bearings, spherical roller bearings, etc.), and the engineering information, drawings with dimensions, should you wish to experiment with different types.
 www.timken.com
BOB RENTON

 

[JR_Charger]

I feel like Timken is more interested in virtue signalling . . . but I know the difference between a tapered and cylindrical bearing now. Is there an automotive use for multiple row bearings? I don't see how multiple little bearings would be better than one big bearing.

 

[RJRENTON]

I feel like Timken is more interested in virtue signalling . . . but I know the difference between a tapered and cylindrical bearing now. Is there an automotive use for multiple row bearings? I don't see how multiple little bearings would be better than one big bearing.

Almost all FWD and AWD front drive axles use duplex angular contact bearing assemblies on the rotating spindle-drive assembly in addition to the R-Zeppa (spherical) and tri-pot assemblies that allow for angular and vertical movement of the suspension while rotating. Smaller bearings have less internal frictional losses and less moment of inertia due to less mass....but it depends on application and load. Look at the engineering by bearing type by use rather than virtue signalling. Also consider NTN bearings as well as RBC offering.....
BOB RENTON

 

[Backrd.Junkyard]

One thing I’m planning on doing since I’ve got another axle in a junk Durango is to find out if the 29 spline side gears will fit into a spare 27 spline factory sure grip I have that needs rebuilt. If it will, I may use the Durango axle (total stink bug stance with springs on top of the tubes!) and go with a retainer clip green bearing 8-3/4 / Dana 60 type axles and swap housing ends to match. It’s got to warm back up a little bit before I can finish pulling the axle, but I am also going to use the solid flange yoke from it that fits a 1330 universal joint. That with a chromoly 1350 transmission slip joint should be able stand whatever I can dish out.