Are you having issues understanding the various sizes of universal joints? Read on. This article demystifies the different u-joint sizes, the dimensions as well as the classification to ensure you know how to choose the actual size for your application.
What Are Universal Joints?
Another name for universal joints is U-joints. They permit the driveshaft to move to and fro with the suspension while the shaft is moving so that even when the driveshaft is not on a straight line between the transmission and the drive wheel there can be power transmission. In order words, universal joints connect rigid shafts in which axles are inclined together while still being able to rotate freely and move in different directions.
How Do Universal Joints Work
How Do Universal Joints WorkWorking mechanism of the universal joint might be simple, the physics behind this mechanism is rather complicated and interesting. The cross-pin is placed into the bearings in the yokes for rotation and swivel so that the shaft can rotate and move in relative to one another. It also permits the universal joints to tolerate changes in the relative orientation of both shafts while it transmits torque and gives room for rotation.
Understand U-joint dimensions
Having an in-depth understanding of u-joint dimensions is important for you if you are at the stage of choosing the precise u-joint for your application. No matter what you are working on either industrial machinery, automotive driveline, or if it’s equipment that requires transmission of torque between shafts at an angle. Refer to the breakdown below to understand u-joint dimensions:
- Cap diameter is the round bearing diameter that fits into the yoke ears.
- Lock-up type is used to secure the u-joints.
- Snap ring is used for retention in u-joints.
- The series or type typically correlates with actual dimension and torque characteristics.
- Understand and make sure the angles of operation of the u-joint you select will withstand your application operational angle without excessive wear or binding.
Categories Of Universal Joint Sizes
Categories Of Universal Joint SizesU Joint For Axles And Driveshaft
Different types of u-joint sizes are designed for driveshaft and axles to accommodate various vehicle types, applications, and torque capacities. You can identify their dimensions through their cap diameter and cross length to ensure they are compatible with your driveshaft and axle.
U Joint Angles And Binding
The purpose of u-joint angles is to ensure smooth power transmission in the driveshaft and axles. However, the normal angle range a universal joint should have is 1 to 3 degrees for minimal wear and optimal performance. When u-joint sizes exceed this range, especially when are above 7 degrees, there’s a high possibility of binding, thus making the universal joints go through difficulty in rotating smoothly, increased wear, vibrations, and potential drivetrain damage.
Front Axles U Joint (Wheel joint)
Front axle u-joints are specifically designed to transmit torque from the differential to the wheels, mostly in 4WD and AWD vehicles. They have different sizes that help to perfectly fit different types of vehicles, load requirements, and articulation angles. Normally, heavier-duty applications utilize larger U-joints to withstand greater forces, while lighter vehicles utilize smaller U-joints for efficiency and smooth performance. It’s important to note that the vehicle’s make, model, and intended use are what influence the exact size.
Drive Shaft U-Joint
Although driveshaft u-joints vary in type, here are some common sizes that you’ll find anywhere.
| Series | Max Angle | Max Speed | Continuous Tq. | Max. Cont. Tq | Yield Tq. |
| 1210 | 90 lbs-ft. | 560-ft. | 1,250 lbs-ft | ||
| 1310 | 30° | 6,000 RPM | 130 lbs-ft. | 800-ft. | 1,600 lbs-ft |
| 1330 | 20° | 5,000 RPM | 150 lbs-ft. | 890-ft. | 1,850 lbs-ft |
| 1350 | 20° | 5,000 RPM | 210 lbs-ft. | 1,240-ft. | 2,260 lbs-ft |
| 1410 | 35-7° | 5,000 RPM | 250 lbs-ft. | 1,500-ft. | 2,700 lbs-ft |
| 1480 | 5,000 RPM | 340 lbs-ft. | 2,200-ft. | 3,300 lbs-ft |
Different U Joint Models And Part Numbers
Different U Joint Models And Part NumbersDrive Shaft U Joint List
Over time, universal joint part numbers and models have been consistent, but there have been replacements in some types of joints because of some improvements. However, there’s the possibility of plenty of designs for the same u-joint model. Refer to the table below so that you can understand some types of popular automotive u-joints and their various part numbers.
| Model | Series | Snap Ring Spread | Cap Dia. | Greaseable | Previous PNs |
| 5-110X ⤴ | 1000 | 1.500” (Inside) | 0.938” | No | |
| 5-103X ⤴ | 1000 | 1.500” (Inside) | 0.938” | Yes (Body) | |
| 5-170X ⤴ | 1000 | 1.500” (Inside) | 0.938” | Yes (Body) | |
| 5-170-1X⤴ | 1000 | 1.500” (Inside) | 0.938” | Yes (Cap) | |
| 5-101X ⤴ | 1100 | 2.411” (Outside) | 0.938” | No | 5-102X |
| 5-105X | 1100 | 1.718” (Inside) | 1.000” | Yes (Body) | 5-100X |
| 5-443X ⤴ | 1200 | 2.438” (Outside) | 1.062” | Yes (Cap) | 5-315X |
| 5-554X | 1200 | 2.438” (Outside) | 1.062” | Yes (Cap) | |
| 5-1310X | 1310 | 3.219” (Outside) | 1.062” | No | 5-1201X |
| 5-153X ⤴ | 1310 | 3.219” (Outside) | 1.062” | Yes (Body) | 5-200X, 5-121X |
| 5-1310-1X | 1310 | 3.219” (Outside) | 1.062” | Yes (Cap) | 5-433-1X, 5-810X |
| 5-1330X ⤴ | 1330 | 3.625” (Outside) | 1.062” | No | 5-790X, 5-791X, 5-812X, 5-618X, |
| 5-213X ⤴ | 1330 | 3.625” (Outside) | 1.062” | Yes (Body) | 5-1203X |
| 5-3615X | 1350 | 3.625” (Outside) | 1.188” | No | 5-447X, 5-617X, 5-800X, 5-799X |
| 5-1350X ⤴ | 1350 | 3.625” (Outside) | 1.188” | No | 5-447x, 5-617X, 5-800X, 5-799X |
| 5-3208X ⤴ | 1355 | 3.612” (Outside) | 1.188” | No | |
| 5-1410 ⤴ | 1410 | 4.188” (Outside) | 1.188” | No | 5-801X, 5-641X, SPL36-1X |
| 5-1410 ⤴ | 1410 | 4.188” (Outside) | 1.188” | Yes (Body) | 5-801X, 5-641X, SPL36-1X |
| 5-160X ⤴ | 1410 | 4.188” (Outside) | 1.188” | Yes (Body) | |
| 5-481X | 1410 | 4.188” (Outside) | 1.188” | Yes (Body) | |
| 5-3207X⤴ | 1415 | 4.188” (Outside) | 1.188” | No | |
| SPL70X | 1550 | 4.964” (Outside) | 1.375” | No | |
| SPL70-1X | 1550 | 4.964” (Outside) | 1.375” | Yes (Body) |
Axle U Joint List
Here is a list of the popular wheel joints with their previous and/or part number.
| Model | Series | Snap Ring Spread | Cap Dia | Greaseable | Previous PNs |
| 5-260X⤴ | 1310WJ | 2.188” (Inside) | 1.062” | No | 5-260-1X / 5-74X |
| 5-760X⤴ | 1310WJ | 2.188” (Inside) | 1.188” | No | 5-997X |
| SPL55-3X⤴ | 1480WJ | 3.000” (Inside) | 1.375” | No | 5-332X / 5-88X / 5-806X |
| SPL55-4X⤴ | 1480WJ | 3.000” (Inside) | 1.375” | Yes (Body) | 5-807 |
| 5006813⤴ | 1485WJ | 2.90” (Inside) | 1.375” | No | |
| SPL70-4X⤴ | 1550WJ | 3.78” (Inside) | 1.375” | Yes (Body) | |
| CP750N | 750N | 4.747” (Outside) | 1.626” | Yes (Body) |
U Joint Grease
There are two major types of universal joint lubrication namely; greaseable and non-greaseable. Non-greaseable u-joints come preloaded with grease that is enough to last up to their expected lifespan i.e. there’s no external grease fitting for adding grease. Greaseable u-joints on the other hand come with external grease fitting or “zerk” which you can use to add grease to it. The reason for both types of lubrication methods is that lubricating u-joints brings out any contaminants or water that might have found their way past the seal.
How To Measure Universal Joint Sizes
You need to accurately measure universal joint sizes for them to fit your application correctly and give you optimal performance. Below is a simple guide:
- For easy measurement, remove the universal joint from your vehicle or machine if it’s possible.
- Measure the cap diameter by measuring the bearing diameter with a digital caliper.
- Use cross-measurement techniques I.e from one end to the other, to measure the length of the universal joint.
- Measure the distance from the groove of the snap ring to the opposite snap ring groove across the joint. This process applies to you only if your universal joint has snap rings.
Tips
- Ensure accurate measurements by measuring from different spots.
- Consider using digital calipers for you to get the actual measurements.
- Seek advice from experts if you are not sure about your measurements.
Conclusion
Having an in-depth understanding of the sizes of universal joint sizes is one important aspect that guarantees the smooth operation of your vehicle or machinery. When you accurately measure and match the u-joints to your actual needs, you will have optimal performance and minimize mechanical failure.
