When people are into hot rods, they always seem to go back to the simple things. After a long time of adapting different types of independent front suspensions to pre-1948 cars, rodders are once again going back to solid-axle, transverse leaf spring front suspensions. Many muscle cars from the 1950s and ’60s are now being made to look like Gassers again. Straight axles can be found under many of these cars.
What are the Best Spindles
People who are new to the hobby might have a lot of questions about old suspensions because so many people are interested in them now. It can even be hard for people who have been around for a long time. It’s a common problem to have to figure out which spindles to use on your early Ford-style front axle. Today, if you want to build a hot rod, you can look for original Ford spindles or buy reproductions of the same. Replica 1949-54 Chevy spindles can also be used on a tube axle. Given so many options, it can be a little hard to choose.
A little background on straight Axle Hot Rod Spindle History
You put a Ford spindle on a Ford axle in the early days of hot rodding because it was easy to figure out what to do. But even then, there was a lot of mixing and matching that had to be done. Some people used spindles from 1937 to 1948 on axles from before that. They could now use hydraulic drum brakes (also called “juice brakes”) instead of the mechanical drum brakes that they used to drive their cars. They later learned how to fit F-100 truck brakes and bigger Buick-finned drum brakes to these spindles.
The Spindle Identification Guide for Early Ford and Chevy is here.
Street rodding changed a lot in the late 1960s and early 1970s, and some hot rodders wanted better brakes so they used spindles from 1949-1954 Chevy passenger cars to fit on early Ford axles. Because the Chevy spindles used hubs that were separate from the brake drums, they had an advantage over the Ford spindles. As a result, you could remove the brake drum from the Chevy hub and slip a Corvette disc brake rotor into its place. This is because Corvettes used almost the same type of spindles through 1962. As a next step, you made caliper brackets out of a flat plate, and voila! You now had disc brakes on your hot rod!
All the spindles for GM passenger cars from 1949 to 1954
Chevy spindles had more benefits than just disc brakes. In the ’70s and ’80s, they were much more common in junkyards than early Ford parts were at the time. And unlike Ford spindles, Chevy parts had separate steering arms that could be bolted on. This made it easy to make custom dropped arms for dropped axles because the Chevy parts had separate steering arms. T-buckets also made it easier to flip their steering arms around and put the tie rod in front of the axle, which was common at the time. People who build straight-axle Gasser-style cars can put the steering arms on the tops of the spindles, making it easier to connect a steering system to these jacked-up cars.
To do the Chevy spindle swap on stock Ford beam axles, took a lot of work. This is how it worked: You had to make the axle kingpin bigger to fit the Chevy kingpin and then cut the ends off so they could fit. There were some differences between the Chevy spindles and the Ford spindles. The axle ends had to be heated up and bent to get the correct camber. As a way to avoid having to do this work, many manufacturers started making tube axles that were made to fit Chevy spindles.
There were more options for disc brakes for Chevy spindles as time went on. One option used Volvo parts. The spindles had to be machined to fit rotors and calipers from later GM cars. You need to figure out which spindle fits your straight axle best.
1932-1934 Straight Axle: Ford
Our traditional straight axle front suspension build starts with the axle itself. To figure out what spindles you’ll need, we need to start at the very beginning with the axle itself. To figure out if the straight axle you have is a Ford or Chevy version, you’ll need a lot of careful measuring (that is unless you bought a new axle of course). The main difference is in the area where the kingpin boss lives.
Ford and Chevy Straight Axle Kingpin Angles are different.
This is how you can find out if your axle is Ford or Chevy spec. You’ll need to measure the axle’s kingpin boss. All of the axles have different kingpin diameters and axle boss heights, but they all work the same. There is also a difference in the inclination of the kingpin, but it’s much more difficult to measure this one. The best way to take these measurements is with dial calipers or digital calipers. In our picture, the Ford axle is shown above the Chevy. This is how it looks. When you look at them with your eyes closed, you can see how different they are in angle.
1937-1948 Ford’s axles:
2.375-inch height of the axle boss
The diameter of the kingpin is 813 inches.
(36-41) and (6-inch) pin length: 5.5-inch pin length (42-48)
1949-1954 The Chevy Axles
2.125-inch-high axle boss
The diameter of the kingpin is 0.8767 inches.
Bearings vs. Bushings: Kingpins:
The original kingpin design used a bushing, and the newer design uses bearings to hold the kingpin in place. We wanted to briefly touch on this while we were talking about kingpins. The original kingpins used a bronze bushing that was pressed into the spindle and then reamed to the correct size, which is why they were so old. We have a standard set of kingpin bushings for the popular 1937-1941 Ford spindle that you can buy from us, too. The needle bearing is put into the spindle and then pressed into the kingpin in bearing style. The needle-bearing pivot is stronger and easier to turn than bushings. While the bearing style kingpin kit costs more, most think it is worth the extra money.
There are a lot of modern spindle options that will work with your straight axle
Forged Ford Spindle from 1928 to 1948 with a round-back design from 1937 to 1941 is what you’ll find.
Each style is made with a high-quality forging process and steel with a lot of nickel, making them very strong and durable. This is especially true for the Ford spindle, which was not forged and was weaker than its Chevy counterparts. They are also made with new designs that make them better than older parts. People who like to build hot rods can do a lot of different things without having to find old parts or pay for expensive machine work. So now that strength and availability aren’t important, how should you choose between Ford- and Chevy-style spindles when you need to?
Hot rodders who want their cars to look like they did in the past will naturally choose Ford-style spindles. Vendors make reproductions of the round-back, 1937-41 style. They can be used with bolt-on steering arms for more options. You can use them with drum brakes, like great-looking Buick-style finned drums for a look that’s right out of the movies. Some even have drum brake kits with Ford spindles that come with Buick-style finned drums. It’s also possible to choose from a wide range of disc brake kits, such as the 5 on 4-1/2 Ford bolt pattern or the 5 on 4-3/4 Chevy bolt pattern for more modern braking. Ford-style spindles are almost always the best choice if you’re using an original Ford axle or a beam axle that was made by another company.
Chevy-style spindles are a good choice for a lot of different applications where tube axles are used. This design is stronger than the Ford spindle because it has a shorter, thicker axle stub. This is a good idea for heavier street rods. If you want to use 9-1/4-inch Mustang II rotors or 11-inch rotors. Many versions of the spindle will work with them. You don’t need to do any machine work or adapters with this version. These cars also have better kingpin geometry so that they can work better with modern radial tires. There are two types of steering arms for these spindles that come in zinc and chrome. They can be used for traditional or cross steering, and they can be mounted to the top or bottom of the spindle. This makes them good for Gasser-style straight axles.