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Tech and Tools Axles and the Craigslisticon – With “30Pack” Matt
As we bust into Season 2 at Bower Power Hour we have decided to do something really fun and educational for tech and tool time. We’re going to work on our producer Gabe’s JK and turn it into what we’re going to call the Craigslisticon.
C: It sound’s to me like we are going to be talking about axles today, right?
M: Yes. We are going to get the stock Dana 30 Axle Shaft out of the front of the JK and upgrade it to a 44.
C: Let’s talk about all the different types of axle shafts. Why did you pick that size?
M: We are upgrading to the Dana 44 because Gabe had already purchased it. It’s a regular 44 out of a JK Rubicon. Then we are going to throw all this aftermarket stuff at it like a 35 spline RCV, an ARB air locker, an Artec Truss and make it as bulletproof as Gabe will need for moderate to above moderate wheeling.
C: Let’s go inside the axle. What are the common sizes?
M: The most common sizes you are going to see are, of course, 30s and 44s because they have come standard in Jeeps since the 80s. However, in order to accommodate for larger tires and overall weight you need to upgrade the axle shaft. The Dana sizes are 30,44, 60, 70, and 80. The gross weight ratio is the weight limit of the axle. A Dana 80 is great because it has an 11,000 lb gross weight rating versus the Dana 30, which has a 2,700 lb gross weight rating. The ring gear transfers all the power. A lot of the strength of the axle comes from where the power is transferred, so the stronger the ring gear the stronger the axle. These are the ring gear sizes for each Dana axle:
Dana 30 – 7 1/8 in
Dana 44 – 8 1/2 in
Dana 60 – 9 3/4 in
Dana 70 – 10 1/2 in
Dana 80 – 11 1/4 in
As you go up in the axle size, the following parts have to go up in size as well: pinions, shaft diameter, bearings, and the distance between the bearings. Pinions are what connect your drive shaft. They actually turn the ring gear, which then transfers all the rotational force to your axle. The distance between the bearings gets bigger because it is like having a bigger lever; the further you pull the bearings apart, the stronger they are going to be because they won’t want to deflect on their load.
C: With a Dana 70, what size tires would you put on that, and what kind of vehicle runs that?
M: A vehicle that runs a Dana 70 would have 40 or 42-inch tires. An example of a vehicle with that big of an axle would be a 4-door JK with all the bells and whistles, weighing about 6,000 lbs. Or, a buggy that you want to run a V8 in with 40 to 42-inch tires. To get reliability you need size. The further you are from the gross weight rating of your axle, the better.
C: A typical JK or Jeep owner probably has a Dana 30. Are you suggesting upgrading it to a 44 or would you want to upgrade it to a 60?
M: There are a lot of Dana 30s out there, and they work really well as long as you remember it’s a Dana 30. You don’t want to try to drive it like you stole it. You also want to stick to a 35-inch tire. Putting on larger tires will put too much stress on the axle. It’s helpful to have larger tires when you are rolling a vehicle up and over something, but it’s when the tire gets wedged that it’s going to take a lot of force to get it out. A Dana 30 isn’t really up for that challenge. A good upgrade would be a 44. At the end of the day you need to look at the final price. It depends on what your end goal it.
C: What kind of maintenance do we need to do on this particular part in our Jeep?
M: When you modify any vehicle it starts to put a lot of load on the steering and suspension components like ball joints, tie rod ends, even the suspension links with the track bar. The vehicle is higher so there’s more load on the joints. Jack it up once in a while to make sure nothing is coming loose.