Quick Release: a Complete Guide to QR Hubs for Sim Racing

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Featured image: Cube Controls F-Pro with SQR QR Hub

I fit a new wheel to a QR hub on a near weekly basis – that’s not a flex, it’s the job. Reviewing sim racing wheels as a hobby means that I’ve fitted a lot of sim racing wheels, with QR hubs, ready to mount on whatever wheelbase I’m working with at that moment.

Today I’m going to cover what you need to know to demystify the subject, so that you can find a compatible QR hub for your wheel / wheelbase combination.

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It’s wise to do some pre-purchase research because there are different fitments depending on your wheelbase. Some, like Fanatec and Asetek have a proprietary or very unique way of mounting a QR hub to the wheelbase side. Compatibility, then, is key.

How will you mount your “6 x 70mm” PCD QR hub to your Simagic Alpha? And how does the Simucube 2 Pro work?

I’m covering off QR hub compatibility based on my experience with the direct drive wheels featured in my buyer’s guide. Here’s a list of the steering wheels I’ve worked with, which almost all feature a 70mm PCD fitment – I’ll cover what “PCD” means, too.

Contents:

• What does “6 x 70mm” PCD mean?
• How to fit a QR hub to a sim racing wheel
• Fanatec QR1 and QR2
• Simucube
• Asetek
• SIMAGIC
• Moza

By the time you’ve read this article you’ll know which adapter fitment (size) will match your sim racing wheel and wheelbase.

What does “6 x 70mm” PCD mean?

“PCD measurement” is the way a steering wheel fitment is described. There are usually 6 bolts mounting your steering wheel and most commonly they are arranged on a diameter of 50.8mm or 70mm PCD.

PCD stands for Pitch Circle Diameter and it’s the common way to describe a stud pattern:

So in the case of 6 x 70mm PCD, we’re saying there are 6 bolts placed on a diameter of 70mm. And just so you know, most of the time those are M5 (5mm) bolts. In almost all cases, there is a 70mm PCD drilled fitment arrangement on the back of your sim racing wheel.

How to Mount a QR Hub to a Sim Racing Wheel

When you’re mounting a brand new rim or sim racing wheel, you will most likely come across a hub that is pre-drilled for 6 x 70mm bolt patterns. But you might also find that the hub is 6 x 70mm (wheel end) to 3 x 50.8mm (wheelbase end).

Take a look at the image above – this is how a QR hub arrangement looks between your steering wheel and the wheelbase:

Steering Wheel > Hub > Adapter > Wheelbase

With some careful thought, it’s easy to match one end to the other: match the wheel to the hub, match the hub to the adapter. The adapter fits the wheelbase and you can get going!

I’m going to demonstrate fitting a Simucube SQR hub to the Cube Controls Mercedes-AMG – GT Edition sim racing wheel.

To get started, follow these steps:

1. Decide which Fixtures You’re Going to Use:

Take a look in the box and decide on how you’re going to attach the wheel to your hub. I find laying out the individual pieces I’ll need very useful. Most large manufacturers supply these; otherwise, you’ll need to know the bolt size.

The bolts pictured are M5, the black bolts use a Torx head and the silver ones are plain M5 nuts and bolts. I’m going to use the Torx bolts supplied and my own Hex (Allen) bolts when fitting the SQR hub.

2. Prepare the QR Hub Adapter

Find the hub adapter supplied with the wheel, if it isn’t already fitted:

This was the first time I’d received a Cube Controls wheel without the Universal Adapter already attached. It took me a little while to realise it was supplied in the box (but that’s a story for the review).

Note from the image above that I’ve already threaded the bolts into the wheel side of the hub adapter. If you look closely, you’ll see that I’ve allowed the bolt threads to poke out of the other side, just a little. This will help me index the wheel side when it comes to fitting it to the wheel, which we do next.

3. Place the Hub Adapter on the Rear of the Wheel Body

Using those little threaded ends, you can place the hub very quickly. Here’s the rear of the AMG wheel with the threaded holes and pillars visible. This is what you’ll be mounting the adapter to:

If you gently place the hub in roughly the right place you’ll feel the ends of the bolts index themselves ready for tightening:

Note that the “wheel side” of the Cube Controls hub adapter is 50.8mm PCD and the QR hub side end of the adapter is 70mm PCD.

I’m perfectly happy using 3 of the supplied bolts to make a triangle as, from experience, 3 bolts is enough. But you can go further if you’re planning on leaving the wheel mounted for a long time, there’s no harm in using a tiny amount of screw lock compound to be extra certain they can’t loosen with time.

Work methodically around the fitting, at first get the bolts “finger tight” and then tighten the M5 bolts down as best you can. It’s doubtful you’ll over-tighten them with your fingers – don’t be afraid to use a decent amount of torque.

Work your way back around the bolts to double-check the tightness of each one.

4. Mount the QR Hub to the Hub Adapter

I should save it for the review but the ease of fitting these wheels by comparison to some other brands I’ve worked with is significant. And you get a red anodized aluminium hub for your trouble! I wish there was a red anodized SQR hub:

Note that my SQR hub is pre-assembled – for instructions on how to assemble the SQR hub itself, scroll down to “SQR Hub installation” on this Simucube 2 review.

Assuming you have the QR hub ready to install, we’ll move to the next step:

5. Arrange the Bolts around Your QR Hub Base and Place onto the Wheel

If you go back to the previous image of the QR hub side of the Cube Controls hub adapter you’ll notice that there is a 50.8mm PCD diameter mounting option on the inner ring and the outer ring is 70mm.

I use a wheel hub extension with a 70mm *unthreaded* BG Racing Extension adapter. Extensions are optional, by the way! This makes the Universal hub all the more useful as all of the holes are drilled. To have the choice of both PCD fitments is nice, too:

SQR hubs are a little quirky in that they never quite line up vertically. There’s always a bit of offset, for which you simply recalibrate the centre position once the wheel is fitted.

Work your way round placing the bolts in each of the threaded holes.

Work your way around the hub, tightening each bolt. Then do a second round to check the tightness. Don’t be afraid to use as much torque as your hands can muster.

Once you’ve completed the task, you’ll be able to mount the wheel:

Simucube

The Simucube wheelbases come with a wheelbase side SQR hub supplied. The SQR hub kit will accommodate any 50.8mm or 70mm PCD wheel (the wheel side mount is tapped with M5 threads.

You’ve seen in my “how to install a QR hub” section, a “wheel side” SQR being fitted – here’s the wheelbase side:

There are, of course, other compatible QR options for the Simucube 2 series:

Simucube Quick Release (SQR): This is a direct fit for the Simucube 2 Pro as I’ve demonstrated above. It’s my preference as it’s the manufacturer supplied hub.
Buchfink Q1R: This is another option that is compatible with the Simucube 2 Pro (view here).
Sim-Lab Xero-Play V3 Quick Release: Featured in the images at the start of the article, it’s SC compatible and has a lovely anodised finish (view here).
QRX Simucube Adapter by Cube Controls: The QRX adds some USB throughput functionality to minimise cable issues (view here).

Mounting any other QR hub to the wheelbase side of a Simucube is the tricky bit, as they have a unique 3 bolt pattern. If you want to use an alternative (non-Simucube) QR mount, you can mount it to the existing SQR components or (better) take the wheelbase side SQR system off entirely, and mount an Ascher Racing 70mm SQR adapter in its place.

The Ascher adapter will allow a 70mm or 50mm bolt pattern item to mount directly onto the Simucube shaft from which you can attach any QR hub or spacer directly to the wheelbase.

Fanatec: QR1 and QR2

Fanatec very recently updated their somewhat maligned QR1 hub with the revised QR2:

Fanatec is a closed “ecosystem”, meaning that only a Fanatec wheel is intended for a Fanatec DD wheelbase (like my CSL DD). You can mess around making non-Fanatec wheels compatible with the Fanatec Podium QR hub, but in my experience most sim racers are eitehr in the Fanatec ecosystem, or they’re not.

Chances are if you have a wheelbase fitted with the QR2 variant, you already have the correct QR2 wheelside hub attached to your Fanatec sim racing wheel.

The problems start for owners of “legacy” Fanatec wheels, that have the QR1 mount fitted to them. My best advice is buy the QR2 wheel side mounts hub for your Fanatec wheels (sorry!).

Mounting non-Fanatec wheels with the Podium Hub

If you own a QR1 variant of a Fanatec direct drive wheelbase, you may want to experiment with wjheels outside of teh Fanatec ecosystem. This is where the Podium Hub becomes useful:

As I wrote in the review, this is a quick-fix solution to build up a wheel rim and button plate (like this rather nice Turn Racing BP2 and R305 rim) ready to mount on your Fanatec wheelbase.

You can mount paddle shifters on the side and mount a simple rim directly on the Podium hub to build a really simple replacement wheel.

Asetek

If you own an Asetek wheelbase, you’ll have their standard QR hub mount attached to the wheelbase side. You probably own a Forte, La Prima Formula Steering wheel, too – which is supplied with the compatible QR hub attached.

If, however, you want to add a new wheel, it might be wise to check out the options. I have this Asetek QR for Artura Series hub, for my Artura wheel:

Note how it has a USB connection inside the hub, so that the wheel can piggyback the USB connection through the wheelbase, alleviating the need for a cable.

Cube Controls also make an aftermarket hub for the Astek series of wheelbases. Check out this Cube Controls Asetek Invicta Quick Release Adapter:

The key thing to know about these Asetek compatible hubs is that the wheel side PCD fitment is 70mm PCD. Thus, the wheel compatibility is universal.

SIMAGIC

Having recently reviewed the GT NEO, I can show you the standard hub that comes fitted with all SIMAGIC wheels, the QR50:

The SIMAGIC QR hubs are a ball bearing type hub adapter – they click into place when you pull back the lip. It’s a very secure fitting and mates perfectly with the wheelbase side QR system.

Depending on the wheel fitment you’re using, SIMAGIC makes an adapter in either 50.8mm PCD (QR50) or 70mm PCD (QR70):

Additionally, there are aftermarket solutions available too. For example, there’s a QR adapter designed for the Alpha Mini available on Thingiverse. This adapter allows you to mount a wheel or aftermarket quick-release directly to a Simagic wheelbase. 

If you’d like to mount your favourite rim on a Simagic wheelbase, something like this GT Pro Hub and QR button box would work:

In my GT NEO review, I fitted a SIMAGIC wheel to my Simucube 2 Pro wheelbase with the MAGLINK adapter place and an SQR hub:

The QR hub adapter plate mounts snugly on the back of a SIMAGIC wheel:

MOZA

Moza wheels and wheelbases tend to be part of an ecosystem which means it’s pretty unlikely that you’ll need a QR hub. If however, you have a non-Moza wheel that you’d like to mount to your wheelbase, try this:

This NRG style adapter is compatible with the R5/R9/R16/R21 wheelbases, featuring a standard 70mm PCD wheel side fitment.

My closing advice on buying a QR hub for your sim racing setup: When you’re choosing a QR hub don’t forget to check the PCD sizes at each end of the hub. Make sure you know the sizes of the adapters you’ll need. That way, there shouldn’t be any delays or headaches when you’re keen to get into your simulator. Enjoy!

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Topic: Direct Drive Wheels