Installing a 2 8x170 wheel spacer is usually the first thing Ford Super Duty owners look into when they want to fix that "tucked-in" look their truck has from the factory. If you're driving an F-250 or F-350, you already know these trucks are massive, but the wheels often sit a little too deep in the wheel wells, especially if you've thrown on a leveling kit or a set of wider tires. It just looks a bit off, right?
That's where a 2-inch spacer comes in. It's that sweet spot where you get a noticeably wider stance without making the truck look like a dedicated "bro-lite" show rig that can't fit through a car wash. But beyond just the looks, there's a lot of technical stuff to consider before you start bolting things onto your hubs.
Breaking Down the 8x170 Bolt Pattern
Before we get into the thickness, let's talk about that 8x170 number. If you're shopping for a 2 8x170 wheel spacer, you're almost certainly a Ford guy. Ford switched to this specific metric bolt pattern for the Super Duty line back in 1999, and they've stuck with it ever since. It's a bit of an outlier compared to the 8x6.5 pattern you see on older rigs or Dodges and Chevys.
The 170mm measurement refers to the diameter of the circle formed by the centers of the eight lug holes. Because these trucks are meant for heavy hauling and high torque, the hardware has to be beefy. When you're adding a spacer to this setup, you aren't just moving the wheel out; you're adding a secondary set of studs that have to carry all that weight. This is why you can't just grab the cheapest thing you find on a random auction site. Quality is everything here.
Why the 2-Inch Size is Popular
You might be wondering why everyone seems to go for the 2-inch option rather than something smaller like a 1-inch or 1.5-inch spacer. It really comes down to the factory studs.
On most Ford Super Duties, the factory wheel studs are a little over an inch and a half long. If you try to use a 1.5-inch spacer, those factory studs might actually poke out past the face of the spacer. If your wheels don't have "pockets" on the back (those little indentations between the lug holes), the wheel won't sit flush against the spacer. That's a recipe for disaster.
By going with a 2 8x170 wheel spacer, you almost always guarantee that the factory studs stay tucked safely inside the spacer. It makes the installation a whole lot cleaner because you don't have to get out the angle grinder and start trimming your factory studs. Plus, two inches on each side gives you a total of four inches of added track width, which completely changes the silhouette of the truck.
Hub-Centric vs. Lug-Centric
This is the part where you really need to pay attention. If you're looking for a 2 8x170 wheel spacer, please, for the love of your suspension, make sure it's hub-centric.
A hub-centric spacer is designed with a center bore that fits perfectly over the lip on your truck's hub. It also has a matching lip on the outer face for the wheel to sit on. This means the weight of the truck is supported by the hub itself, not just the lug studs.
Cheap, lug-centric spacers rely entirely on the studs to center the wheel and carry the load. On a heavy truck that might be towing 10,000 pounds, that's a massive no-no. Lug-centric spacers are notorious for causing steering wheel vibrations that feel like your truck is trying to shake itself apart at 65 mph. A good hub-centric 8x170 spacer will keep things smooth and factory-feeling.
The Visual and Functional Benefits
Let's be real—most of us want spacers because they make the truck look mean. Pushing those tires out just past the fender flares gives the truck a planted, aggressive look that the factory setup just can't match. It fills out the wheel wells and makes the truck look wider and lower, even if it's lifted.
Functionally, a 2 8x170 wheel spacer can be a lifesaver if you've moved up to 35-inch or 37-inch tires. Big tires often rub on the radius arms or the inner fender liners when you're turning the wheel all the way. By pushing the wheels out two inches, you often gain just enough clearance to stop that annoying "rub-rub-rub" sound every time you try to park at the grocery store.
Just keep in mind that moving the wheels out changes your "scrub radius." This basically means the wheels swing in a wider arc when you turn. You might clear the radius arms only to find that the tire now wants to clip the bottom corner of your front bumper or the back of the fender well. It's a bit of a balancing act.
Installation Tips You Shouldn't Ignore
Installing a 2 8x170 wheel spacer isn't exactly rocket science, but you can't just zip them on with an impact wrench and call it a day.
- Clean the Hubs: Get a wire brush and some brake cleaner. Scrub those hubs until they're shiny. Any rust or grit trapped between the hub and the spacer can cause the spacer to sit slightly crooked, leading to wobbles.
- Use Loctite: Most people recommend a drop of red or blue thread locker on the factory studs before bolting the spacer down. You don't want those inner nuts backing off where you can't see them.
- Torque is King: Don't guess. Use a real torque wrench. For a Ford Super Duty, you're usually looking at around 150-165 lb-ft, but always check your specific year's manual.
- The 50-Mile Check: This is the one everyone skips, and it's the most important. After driving about 50 to 100 miles, take the wheels off and re-torque the spacers. Aluminum can compress slightly, and things can settle. Making sure those nuts are still tight is the difference between a great ride and losing a wheel on the highway.
Addressing the "Safety" Elephant in the Room
You've probably seen the forum posts where people claim wheel spacers are "death traps." Usually, those horror stories come from someone who used cheap, non-hub-centric spacers, didn't torque them correctly, or used a 4-inch spacer on a truck that wasn't built for it.
When you use a high-quality, forged aluminum 2 8x170 wheel spacer and install it properly, they are incredibly safe. Think about it: dually trucks use massive adapters from the factory to run their wheels. The physics is the same. As long as the material is strong (usually 6061-T6 aluminum) and the studs are high-grade steel, you're good to go.
Final Thoughts
Adding a 2 8x170 wheel spacer is a fantastic way to customize your truck without spending thousands on new wheels with a different offset. It gives you that wide, custom look and can help clear those beefy tires you've been eyeing.
Just remember to do your homework. Measure your studs, make sure you're buying hub-centric, and don't skimp on the installation process. If you take the time to do it right, your truck will look better, drive great, and you'll have the peace of mind knowing everything is solid under there. It's one of those small changes that makes a huge impact on the overall vibe of a Super Duty.