Chassis Heeltoe Explains

Wheel Hub Spacers & Hub Adapters (w/ Video Content)

Why you want wheel hub spacers

Heeltoe has done the homework and found that there are three main reasons why you would want wheel spacers:

  • Looks
  • Handling
  • Brake Clearance

If you are trying to fit different bolt-pattern wheels on your car, you might be needing Hub Adapters instead, which we’ll explain a little further down.

That stance!

Bumping out the wheels on a car to widen the track is a great way to make the stance appear more aggressive. Car manufacturers leave ample room for wheels and tires to move and articulate to avoid rubbing in extreme situations, but this clearance can result in a “sunken-in” look to the wheels as they often sit far inside the fender arches with a fist-full of unsightly fender-gap; hardly a flattering stance for a dialed-in Heeltoe ride.

Getting the tire snuggled up to the fenders makes a car look a little lower and meaner. When sized properly, wheel spacers will complement the look of factory or aftermarket wheel and tire combos without much worry about rubbing. Of course, there is a tasteful limit to how far you push out the wheels, so act in moderation if you want to stay classy.

Flatter in the turns

Back in the 90s, Pontiac had a “Wider is Better” campaign promoting the wide-track design of their Grand Prix model. Contrary to the name, the Grand Prix is no “grand prize” of performance engineering, but the concept is true. A wider track–the distance between the left and right wheels, measured from the centerline of the wheel–will tend to improve the roll-resistance of the chassis. A little wider stance can help the car feel flatter and more stable in turns.

Brake clearance

Another main reason a car would need wheel spacers is to provide more space for aftermarket brake upgrades. Big Brake Kits sold by Heeltoe, or BBKs, often feature 4-, 6-, or more caliper pistons; a performance benefit with a side effect of to get much fatter than standard calipers. The additional size of aftermarket brakes oftentimes leaves little or no clearance to the backside of the wheel. Wheel spacers move the wheel away from the hub which makes for a more comfortable fit of larger brake calipers behind even a standard wheel.

So, how do they work?

This video helps you understand a little more about how these bolt-on spacers work.

You may have seen different kinds of wheel spacers and here we are explaining how the “bolt-on” kind work. Viable spacers below 10mm (0.4″) in thickness do not have studs in them and require extended studs to be installed to allow for enough thread engagement for the lug nut after the wheel is installed. There is no major rule of thumb for how thick is safe to go on a standard wheel spacer, but 5mm (0.2″) is the max that we would ever go, assuming you have even enough thread on the studs to begin with. If in doubt consult a technician.

Get Fitted

Getting the right size spacer for your needs is all about taking a simple measurement with a tape measure or ruler.

If you are trying to move the tire closer to the fender, measure the distance from the sidewall or tread blocks to the edge of the fender to approximate the width you need. Keep in mind that the tire will camber-in away from the fender as you drive so you may have a little more room than you think.

If you are trying to make clearance for brake calipers, the measuring can be a little more tricky. Ideally, you will have the brakes installed on the car’s hub & knuckle, and then put the wheel on over them. The risk here is that if there is contact between the spokes and the caliper, you can scratch the caliper, so first cover the caliper with blue painter’s tape. Then, add washers to the wheel studs to stand the wheel away from the hub until there is sufficient clearance to the calipers to spin the wheel without hitting the caliper, being sure you sung the wheel down onto the washers to get a true idea of the spacing needed.

Wheel spacers are available in fixed widths, so once you know how much space you approximately need, round out to the next size. Below are the most common widths of spacers you will find in millimeters with the approximate English unit conversions. For the most part, spacers of 15mm thick or greater will have studs in them already, where smaller ones will need longer studs installed in the hub, which, depending on the kit you get, may or may not be included.

Avail with Studs in Spacer? mm Size Approx Inch Size
w/o studs in spacer3mm1/8″
w/ or w/o studs in spacer15mm19/32″
w/ studs in spacer20mm3/4

There are more sizes than the above available, many with or without hub ring options. This chart just gives you an idea of how spacers are sized out. The difference between “rubbing” and “not rubbing” is as small as 1-2mm (1/16″) so don’t be afraid to get close but definitely round-up.

Spacer or Adapter

Spacers and Adapters are fundamentally the same thing, with one important difference. The difference between a spacer and an adapter is that a spacer moves the factory wheel out with the same bolt pattern. An adapter will act as a spacer but also change the bolt pattern, allowing you to use a 5×100 wheel on a 5×114 hub, for example. So if you have a 5×100 set of wheels that you truly love, you can put them on your 5×114 hub, provided you have room at your fenders for the extra 15mm-minimum spacing you’ll see.

Hub Centering

Hub-centricity is another frequent concern with wheel spacers. The wheel of the car has an inside bore designed to fit over the snout of the wheel hub. Some wheel spacers and adapters are very nicely designed and incorporate a hub centering feature. However, this design feature does increase the cost and also limits the supply of the exact, right spacer for you right when you need it. Plus you need to know the hub bore on you car as well as the bore diameter of your wheels, and in a wheel-fitting pinch, you probably don’t know this.

It’s often claimed that without hub centering rings to fit a mismatched wheel and hub size, a vibration will be present while driving. Heeltoe’s experience has disproved this claim without exception. While having a hub centering ring is ideal for the most support of the wheel on the hub, lug nut seat design will perfectly center the wheel on the hub and prevent any vibration. As always, even and proper torquing of the wheels is critical.

Billet or cast alloy?

Most spacers are machined from billet aluminum. You should always make sure you get good quality spacers because the studs need to be OE quality or better and the spacers themselves need to be strong. This stuff holds the wheel onto the car and having one break would be a catastrophe. Spending a little more money on quality or well-known brands is generally recommended. Some spacers that don’t have studs are made of cast aluminum, which is perfectly fine, as long as they aren’t too cheap and don’t deform with the wheel torqued down.

In Conclusion

The real reason you want spacers or adapters boils down to a personal need. You either put brakes on that won’t fit the wheels you have, or you put wheels on and they don’t look perfect against your fenders, or you want to improve the look and handling of the car a little without changing the wheels for different ones. Whatever the reason we hope you know a little more about how to select a spacer for your needs and always know that #HTinyourcorner!