Road Car Steering Wheel on Fanatec Universal Hub?

LeonS · Jan 31, 2019

Hey guys,

I'm wondering if any of you are using large-diameter road car steering wheels on their rig?

Proper DD wheels should have enough power to reasonably simulate the forces and turning speeds that one experiences in road cars, so it wouldn't be so far fetched to put a road car wheel on a DD wheel base. Since I'm waiting for the shipment of my DD1 wheel base, and I still have that 350€ voucher for the delay, I was thinking about getting a Universal Hub and a large diameter road car steering wheel, in the 36-39cm range. However, this seems to be more difficult than I had originally assumed.

- the largest Fanatec wheel is only 35cm and looks nothing like a road car wheel
- it's hard to find good-looking, regular road car wheels without airbags at a reasonable price, I wouldn't know how to connect them to the hub, and the hub's buttons would likely be out of reach
- the largest tuning wheel I can find is 36cm. it might do the job okay, but ideally I'd like something a little larger and a little more road-car looking.

Am I the only one who finds the idea of having a large diameter road car wheel on a sim rig intriguing? The purpose would obviously be immersion / real feel for road car racing, and it would give me a chance to better compare the in-sim feeling to real road cars.

If any of you have a large diameter wheel in use for that purpose, what are your impressions?
Oh and is the Fanatec Universal Hub even a good idea in the first place? I'd want that solution to be as solid as any of the regular Clubsport Wheels.

Thanks!
Leon
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edit: Out of curiosity I'll just collect some wheel diameter sizes of road cars here in the top post, measured from outer edge to edge. Feel free to measure you car's steering wheel and post the diameter, then I'll add it to the list

2008 Volvo S40/V50/C30 - 38cm
1991 BMW 5 series - 40cm
2009 Land Rover Defender - 42cm
2006 Renault Clio - 38cm
1953 Ford Anglia - 41cm
2012 Suzuki SX4 - 37cm
2015 Mercedes Vito - 36.5cm
2017 Audi A3 S-Line - 36cm
2012 Mercedes E-Class - 37cm to 37.5cm

AJ McDaddy · Feb 1, 2019

Not sure how responsive such a large rim would be, but you might want to check with Fanatec about button placement suitability (unless you have extremely long fingers).

Turk · Feb 1, 2019

A lot of modern cars use a fairly small wheel, I'm always surprised by how small the steering wheel is on the transit van for instance. Most sports cars also go with a small wheel as far as I know. I think they've been shrinking since power steering came along.

I'm subscribed to a guy on youtube (I can't find his channel now, I'll have a look again later) but he did a full BMW interior for his sim rig, he's a German guy. So it can be done.

LeonS · Feb 1, 2019

AJ McDaddy said:
Not sure how responsive such a large rim would be, but you might want to check with Fanatec about button placement suitability (unless you have extremely long fingers).

On a DD wheelbase I wouldn't expect it to be an issue. After all, road car steering wheels aren't that responsive in the real world. How far out the buttons can go is a valid question though. Thanks!

LeonS · Feb 1, 2019

Turk said:
A lot of modern cars use a fairly small wheel, I'm always surprised by how small the steering wheel is on the transit van for instance. Most sports cars also go with a small wheel as far as I know. I think they've been shrinking since power steering came along.

I drive a 2008 Volvo S40 and measured the rim to be 38cm in diameter. I'd say that's still a pretty normal size today, and no road car I've driven was anywhere near 32cm, I'm sure.

edit: first post updated.

LeonS · Feb 2, 2019

Small update:
1) Just drove a current-gen A3 S-Line and it had a 36cm wheel. It did feel quite small for a road car, but I think for the sim rig, 36cm is "close enough" (though I'd prefer 38cm). First post updated.
2) I asked Thomas Jackermeier of Fanatec if they had anything planned in terms of road car wheels and he suggested to use the Universal Hub to mount a road car wheel. I take this as "nothing planned at this moment".

knucleon · Feb 19, 2019

My brother sent me a link to this thread as I am building some custom Fanatec-compatible Audi steering wheels for him. We have talked about possibly offering to make some for other sim racers too.

My design is based off of the Fanatec universal hub, though completely disassembled and using a custom CNC milled adapter bracket to attach the wheel to the Fanatec quick-release component; the Fanatec main board will be relocated to a milled plate inside the wheel, and the "button bar" on top relocated using ribbon cables and a small custom enclosure.

I am also building a circuit board which will interface the original Audi buttons and knobs to the Fanatec board. This will run off of an ARM Cortex MCU with USB-upgradable firmware. The Audi buttons took a little reverse engineering but can be accessed with some simple code and a <$1 interface chip.

At his request I am not attaching the individual "game" button clusters that come with the Fanatec but doing so probably wouldn't be terribly difficult using some milled aluminum "extension arms" to bring the buttons closer to the wheel itself.

It's going to be a while before it's complete but all aspects of the design have been validated and the mechanical interface part is essentially finished at this point. The one I'm currently building is using a 2016 Audi S6 steering wheel. The electronics are all removed so I can work on them without having to have the wheel rolling around on my desk.

LeonS · Feb 19, 2019

knucleon said:
My brother sent me a link to this thread as I am building some custom Fanatec-compatible Audi steering wheels for him. We have talked about possibly offering to make some for other sim racers too.

My design is based off of the Fanatec universal hub, though completely disassembled and using a custom CNC milled adapter bracket to attach the wheel to the Fanatec quick-release component; the Fanatec main board will be relocated to a milled plate inside the wheel, and the "button bar" on top relocated using ribbon cables and a small custom enclosure.

I am also building a circuit board which will interface the original Audi buttons and knobs to the Fanatec board. This will run off of an ARM Cortex MCU with USB-upgradable firmware. The Audi buttons took a little reverse engineering but can be accessed with some simple code and a <$1 interface chip.

At his request I am not attaching the individual "game" button clusters that come with the Fanatec but doing so probably wouldn't be terribly difficult using some milled aluminum "extension arms" to bring the buttons closer to the wheel itself.

It's going to be a while before it's complete but all aspects of the design have been validated and the mechanical interface part is essentially finished at this point. The one I'm currently building is using a 2016 Audi S6 steering wheel. The electronics are all removed so I can work on them without having to have the wheel rolling around on my desk.

Very nice project, feel free to post regular updates in this thread. For me personally, that solution is certainly way outside my price range (say 500€ total), and I'm currently looking at the universal hub + raid 36cm steering wheel (430€ total), if I decide to go with a large diameter wheel (will decide in April / May once I have the DD base).

Back to your project though, can you show a bit more of what you're doing mechanically with the universal hub and the wheel?

knucleon · Feb 21, 2019

@LeonS sure thing -- and sorry for the delay. I didn't want to overload it with details if nobody was interested.
As mentioned in my previous post, I have disassembled the Universal Hub and am relocating the circuit boards (main board and button board) to hardware mounted directly to the Audi wheel and/or my wheel adapter bracket. The full mechanical / structure wheel "sandwich" is essentially the following (from bottom up):

1. Fanatec universal hub quick detach mechanism w/ internal connector and cable

2. Custom milled Fanatec-to-Audi mechanical adapter with pressed-in wheel spline (allows Fanatec cable to pass through)

3. Audi wheel itself; radial position is maintained by the wheel spline component while axial fastening is performed by 2x M6 bolts

4. Circuit Mounting Plate (not built yet) - Mounts to M6 bolts and has mounting holes / standoffs for Fanatec and custom circuit boards

5. Circuit Boards - Fanatec universal hub main circuit board and custom interface circuit board (Audi buttons to Fanatec I2C / discrete logic) The latter is currently in breadboard phase but I will probably start on the actual PCB design soon once I have some time.

6. Air bag "filler" and cover -- Since a real air bag is expensive and dangerous, my brother purchased a salvaged cover (like-new condition) and I will use probably a 3d printed internal frame with springs and a switch with electrical connection to my custom board to make the "horn" work. (not designed / built yet)

The spline piece I am using is a standard VW / Audi part which was about $30 USD at the local VW dealer -- the spline shaft has very fine teeth and I wouldn't be able to make it with the equipment I have. As far as I can tell all recent-model Audi (and probably VW) cars all use this 26mm 84(?) tooth spline shaft. I cut off the excess length on a lathe and gave it a rust-resistant exterior plating. It was a moderately tight press-fit into the aluminum bracket body (with arbor press) and I added some high-strength retaining compound just in case.

I have also added some more pictures which may make it a little clearer. Keep in mind there are no electronics other than the Fanatec connector / cable right now as they are all wired up to a breadboard setup for development.

LeonS · Feb 21, 2019

looks like pretty awesome work. how much will all the parts be in total, and how many hours of work are you estimating to put into it in total?

knucleon · Feb 22, 2019

LeonS said:
looks like pretty awesome work. how much will all the parts be in total, and how many hours of work are you estimating to put into it in total?

I didn't purchase the wheel but I believe it was around $800 USD including the wheel and center cap (air bag cover). The Fanatec Universal Hub, being a retail part, was I believe $300 USD. The spline shaft adapter was about another $30. Raw material for the adapter bracket is about $5 (2" x 3" x 3" block of 6061 aluminum). I used 2 sets of soft jaws in the CNC mill at about $3 per set. Figure an extra $5 or so for fasteners and other miscellaneous hardware -- it's hard to quantify because a lot of them are things that I have on-hand and/or things that have to be bought in large packs (25-100 units) even if I only need a few for this project. The cost of electronic components and custom PCBs will probably come in at about $50 or so, though I will have enough components to make probably 5-10 of the custom board. The center cap inner frame (for horn / airbag cover) will probably use under $5 worth of 3d printer filament. There are a bunch of little things that I have on hand that would otherwise require purchase (paint / powder coat supplies, various electronic components, cable supplies, etc.)

In all the material & parts cost is probably around $1300 USD. I am estimating my total design time including CAD/CAM, 3d printed parts, machine operation time on CNC, circuit design and assembly, and firmware development and testing at around 25-35 hours. The trickiest part is that none of the components have any sort of readily available engineering docs or design specifications so everything must be found by measuring or reverse engineering. Of course once I have the first one perfected, making subsequent units will be much faster, so the investment in engineering cost (most of the time investment) can be spread out more. I believe I am going to be making at least 3 wheels for my brother's use in the long run, all from Audi cars and so virtually all of the design components should be re-usable.

I may get in touch with Fanatec and see what they might be willing to do as a sort of OEM partnership -- the Universal Hub device contains a ton of parts that are not strictly necessary for building these wheels so if I could get them to sell me just the parts I need (circuit boards and quick release) it could potentially cut a good chunk of the cost. I am also going to explore other brands too -- for instance I personally like Cadillac and I can get a brand new Cadillac ATS steering wheel for in the $200 or less range, compared to $700+ for used Audi S-series wheels. I measured the wheel on my ATS and it's approximately 14.75" or about 37.5cm.

LeonS · Feb 22, 2019

Very informative, thanks a lot! I'm keeping my fingers crossed for the Fanatec partnership, sounds like you could make Cadillac wheels for around 700-800$ total if it all works out? Still outside my price range, but possibly very interesting to some other readers here. I'm definitely curious to hear how it all feels in the sim once the wheel is done. Please keep us updated on that!

knucleon · Mar 4, 2019

Just figured I'd drop a few more screenshots here -- I have done a lot of work on the electronics, to the point that I just sent the board design off to get some prototypes made

I also put the Audi wheel back together and did some testing with it and my prototype circuits on the Fanatec CSL base I am using for testing. Once I have the actual custom boards I can finish the code and testing easier since I won't have to deal with wires flopping all over the place and coming loose

Vojvoda · Mar 7, 2019

Hi @knucleon ! Is this PCB a matrix button or a fanatec hub emulator?

Regards!

Leonardo Ratafiá · Mar 7, 2019

Wow nice project and thread. I talked to Thomas as well and he mentioned there will be a new podium universal hub later this year costing less than the current one, which is too expensive (though is brings the Xbox one compatibility)
You have to take in consideration the weight of the wheel also but for a DD it wouldn't be an issue. But that fanatec elite wheel would suffer a bit maybe. I'm looking forward to any new and cheaper universal wheel hub since I'd love to attach a Momo 35mm road car wheel I used to have. Certainly aftermarket wheels come around 35mm usually, like Momo, sparco, Mardi and maybe some a little bigger but the main concern for less torque wheels would be its weight.

LeonS · Mar 7, 2019

Leonardo Ratafiá said:
Wow nice project and thread. I talked to Thomas as well and he mentioned there will be a new podium universal hub later this year costing less than the current one, which is too expensive (though is brings the Xbox one compatibility)
You have to take in consideration the weight of the wheel also but for a DD it wouldn't be an issue. But that fanatec elite wheel would suffer a bit maybe. I'm looking forward to any new and cheaper universal wheel hub since I'd love to attach a Momo 35mm road car wheel I used to have. Certainly aftermarket wheels come around 35mm usually, like Momo, sparco, Mardi and maybe some a little bigger but the main concern for less torque wheels would be its weight.

That's some very interesting information. Would you mind posting the bit of your conversation about the new universal hub and its price here? Or do you have a guess as to how much it will cost? I'm gonna have to decide between getting one of the new formula rims and a universal adapter + the raid wheel shown in the first post, and I'm currently leaning towards the latter option. I wouldn't wanna wait several months to save another 50€, but if the new universal hub is priced around 200€, I think I'd rather wait and go with the formula rim for now.

Leonardo Ratafiá · Mar 7, 2019

LeonS said:
That's some very interesting information. Would you mind posting the bit of your conversation about the new universal hub and its price here? Or do you have a guess as to how much it will cost? I'm gonna have to decide between getting one of the new formula rims and a universal adapter + the raid wheel shown in the first post, and I'm currently leaning towards the latter option. I wouldn't wanna wait several months to save another 50€, but if the new universal hub is priced around 200€, I think I'd rather wait and go with the formula rim for now.

didn't talk about price he just told me: "The Podium Wheel Adapter will be announced later this year. All the best"

OfirZ · Mar 7, 2019

Of my experience with Accuforce V2 which have 13nm of tourqe there is no problem fitting a real 350mm momo mod78 steering wheel.
The Accuforce motor is powerfull i would even say it was build for that, as i got the V2 Yourway ver. of the accuforce - this ver. is without wheel rim, only a motor.
I was using a 350mm deep dish steering wheel on my old T500RS which you could feel a bit of difficulty on the thrustmaster motor.
But generraly i belive any DD motor will handle a real car wheel of Momo, Sparco etc.
By the way real nice project with the Audi steering wheel - have no experience with this kind of wheels, as it must be heavier so i don't sure how it beahive.

Neil Farren · Mar 7, 2019

I fitted a 35cm OMP wheel to my universal hub and use it with my CSW v2 with no issue.

knucleon · Mar 8, 2019

Vojvoda said:
Hi @knucleon ! Is this PCB a matrix button or a fanatec hub emulator?

Regards!

The main interface is the actual circuit board from the Universal Hub. It is the actual original Fanatec part so it should not have any compatibility issues and should work with any of their firmware updates etc.

The adapter board I made reads the steering wheel button information from the Audi wheel (a serial protocol using 4-bit addresses per button, hold-down time counter, etc.) and translates them into outputs that the Fanatec board is expecting. I originally thought the Fanatec button clusters were I2C (another serial protocol) but upon taking one apart I found they are simple switches with polling logic -- the controller drives one pin high and then reads the voltage of the other 3 pins to see which ones are pressed.

As far as if it were possible to build an emulator type board, i'm not sure about that. I also took apart my CSL Steering Wheel and the common component seemed to be a small unidentifiable controller chip -- I am guessing this provides communication to the base and very well may implement some form of lock-out to prevent unauthorized 3rd party parts. I didn't try interfacing directly to the base so I can't provide any details about that.

Regarding the adequacy of torque, I don't have any experience with DD bases; once I have the wheel finished to the point where it can be tested with actual gaming I will definitely try it out on the base I have on hand (CSL Elite belt-drive base).

I should be getting the custom boards in on Monday or Tuesday and plan to design the remaining structural features (airbag / horn switch assembly and top button bar enclosure) so that may be fairly soon