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1330 myth?

9

96XJay

NAXJA Forum User
Location
Germantown, Ohio
Let me start by saying that I'm not the u-joint guru or anything. I just feel like passing on some info that was given to me so it can be discussed and a conclusion can be come to.

I was speaking with the owner of a local driveshaft shop and he claims that a 1330 is actually a weaker joint than a 1310. The reason he claims this is because they have the same size caps and bearing area diameter. The difference in the two joints is the cross width. The 1330 being longer. Now since they both have the same diameter in the cross shaft with the 1310 being shorter and the 1330 being longer the force applied on the body of the joint becomes a longer lever on the 1330 thus making it weaker than a 1310.

Anyone care to add or comment on this?
 
im not a guru either and that seems about right but dont we buy the longer u joints for other reasons....like being able to run more angle in the drive line because of clearance issuses?
 
96XJay said:
Let me start by saying that I'm not the u-joint guru or anything. I just feel like passing on some info that was given to me so it can be discussed and a conclusion can be come to.

I was speaking with the owner of a local driveshaft shop and he claims that a 1330 is actually a weaker joint than a 1310. The reason he claims this is because they have the same size caps and bearing area diameter. The difference in the two joints is the cross width. The 1330 being longer. Now since they both have the same diameter in the cross shaft with the 1310 being shorter and the 1330 being longer the force applied on the body of the joint becomes a longer lever on the 1330 thus making it weaker than a 1310.

Anyone care to add or comment on this?
Click to expand...

1330 has a larger cap size. Are you saying it has the same size trunion. If so wouldn/t that mean larger bearings?

I'll measure some tonight and reply.
 
Are you saying larger or wider? The 1330 is wider but does it have any more meat in it compared to the 1310? I wish I had two side by side so I could compare.
 
This thread would be a lot better with some side by side comparison pics!
 
If that were true then the 1410 would be weaker then the 1350 since the 1410 has the same size caps as the 1410 but a wider body.
 
I think your conclusion would be accurate IF the bodies of each joint, i.e. 1310 vs 1330, were the same but only with longer trunnions. However I think the main beef of the body..i.e. the main body before the trunnions stick out is larger on the 1330 joint than the 1310 joint. Since the bearings sit out farther they will experience less force from the driveshaft because of the increased leverage. Combine that with a larger joint main body and the entire joint itself is stronger.

Now, I'm not certain the main body is larger...so I could be totally wrong.
 
1310,1330,1350,1410,1480%20ujoints.jpg

Here are the most common u-joints in four wheeling. From Left to Right:



1310(also 297-x): The 1310 (shown) is a 1/2 ton u-joint used in driveshafts for many Jeep applications and is retained via external snap rings; the ones that slightly resemble a pretzel. The 297-x u-joint is effectively the same size but with internal snap rings used for steering knuckle joints on most Dana 44 and Corporate 10 bolt front axles.



1330: This is a 3/4 ton driveshaft u-joint most often found at the pinion yoke going into Dana 60 front or rear axles. The 1330 shares the same cap size as the 1310 but with a larger cross.



1350: Most 1 ton trucks of yester-year used these joints (middle joint in picture) in their driveshafts but could be found in 3/4 ton and 1/2 tons occasionally. Note the cross is the same size as the 1330 to its left but the bearing caps, and therefore the trunions that they pivot on are larger, i.e. more strength.



1410: In recent years, the Super Duty line from Ford, and Chevy and Dodge H.D. series are using even beefier joints in their driveshafts. The 1410 can be considered a 1.25 ton joint and is appropriate when behind the torque monster diesel engines from the Big Three.



1480: This joint (farthest right) is most commonly a steering knuckle joint rather than a driveshaft u-joint and resides inside the knuckles of Dana 60 and 70 front axles. In a driveshaft application, it could be considered as a 2 ton joint. Keep in mind that a steering knuckle joint sees 3-5 times as much torque as the driveshaft joints strictly from the ring and pinion reduction. It is further multiplied by having the steering turned to anything other than straight.
Click to expand...
 
Thanks for posting the pics.

I'm not personally saying it's fact or fiction. The concept was just brought up to me and I found it compelling. I figured it was at least worth a discussion of the minds here on NAXJA.

The 1330 joint does appear slightly meatier in the middle.
 
Wow,

BogHog1 to the rescue! Thanks for the pics.
 
Ok guys here is the engineering answer.
TORQUE = RADIUS X FORCE
OR FORCE=TORQUE/RADIUS
So if the caps and trunions are the same dimensions, but the trunion is farther away from the center of the ujoint the force from the torque on the trunion would be less (if the same torque were applied).

So lets say there is 100 ft-lbs of torque going through the drive shaft, and that the 1310 ujoint had a dimension of 1" from the center of the ujoint to the trunion. The force at that point would be:
FORCE=100/1 Or 100 LB

Now lets assume that the dim on a 1330 is 2" and the same torque is applied.
FORCE = 100/2 Or 50 LB.

Yes I know the dims and torque are not accurate, I did that for the easy math.

Any questions?
 
TORQUE = RADIUS X FORCE
Click to expand...

Sorry but (Torsional Shear Stress)= (Torque X Radius)/(Polar Moment of Inertia).
U joints dont really experience torision in the traditional sence, the drive shaft or axle shaft experience a torque loading, but a u joint experiences more of a bending load for each of the 4 trunions. Bending in this situaton is calcualted by (Bending Stress)= (Torque X Radius)/(Moment of Inertia) ...
gotta go more later.
 
You are just adding more shit to the equation, as the radius increases the force goes down, plain and simple.

IF you want to work through everything please do, but I was trying to keep it simple.
 
Sorry I had to pick up my Wife from the Emergency Room, but No I'm not adding more "stuff" just to make it more complicated, just trying to be correct with a complicated problem. I will try to keep it simple though.

(1310 u-joint) For example say the Torque applied is 100 in*lb and the radius of the ujoint is 1 in. and if the trunions are truely the same then the moment of inertia will be the same for both ujoints so we can use any number as it will effect both the same so we will choose 10 in^4 so the simplified problem will be
(100 in*lb X 1 in)/10 in^4 = 10 psi

So for the 1330 u-joint with all other things being equal except the radius is larger say 2 in. the the problem would look like this.
(100 in*lb X 2 in)/10 in^4 = 20 psi

You can see from this simple example that the stress is doubled by just the longer radius of the 1330 ujoint.
The real key comes in when you Look closely at the photo earlier you can see that the main body of the u-joint on the 1330 unit is actually bigger (more material) because where it meets the base of the trunion it is the as big as the diameter of the trunion but on the 1310 u-joint you can see how the main body has to be increased to match the diameter of the trunion, so thats where the difference is. The 1330 has a stronger and larger main body size which gives a much stronger base for the smallish diameter of the trunion giveing it more combined strength.

If you wanted to get complicated the calculating the actual moment of inertia for the main body section and adding on the moment of inertia of the trunion would need to be addressed and then remember that the final stress calculated would have to be divided by 2 as there are 2 trunions acting together while the other two are providing the reaction forces. But its too late to get into it much and its been a very long day.hasta
 
Okay, so, why'd spicer rate the 1330 as being for a 3/4 ton application while the 1310 is only a 1/4-1/2 ton application? I have a little faith in them to understand the physics behind the application of their products - in fact they employ many engineers for this purpose.


I'd rather give spicer the benefit of the doubt.
 
GroversXJ said:
The 1330 has a stronger and larger main body size which gives a much stronger base for the smallish diameter of the trunion giveing it more combined strength.
Click to expand...
 
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