Designing The Right Wheel For The Rivian R1T Pickup Truck And R1S SUV
Having the utility and off-road capabilities of a pickup truck or SUV has long been a gas or diesel affair. As technology has been getting better and better, however, the EV or Electric Vehicle market is bringing its own power. With the ever-pushed-back Tesla Cyber Truck and Rivian R1T leading the charge, for some it does beg the question…will I be able to modify these vehicles? Will technology restrict and limit what can be done with these vehicles?
Not everyone likes to take their vehicles to the limit as not everyone likes to modify their vehicle. A vast majority of truck and SUV owners very much like to keep their ride in its stock configuration. While there’s nothing wrong with that, it's nice to have options and technology can get in the way, sometimes.
With an idea and newly acquired Rivian R1T pickup truck, in typical Thuren Fabrication Fashion, Don immediately started the wheels turning (pun intended) on how he could make the R1T better. But where to start?
Modifying Electric Vehicles (EV) And Why Customizing Them Can Be Difficult
Companies like EV Sportline and Unplugged Performance are just a couple of forward thinkers that have dove head-first into the Electric Vehicle market when it comes to modifications. Most EVs are pretty locked down from the factory providing much difficulty when it comes to performance. So where does that leave someone that wants to make their car personal and give it their own flare or better looks?
As bolt-on upgrades go, wheels are where most people go first. At Thuren Fabrication, we are no different with one huge exception, it has to perform. Anyone can add a little paint and polish to the worst of vehicles and find (or make) a diamond in the rough. This is not the case with the Thuren Fabrication DECA/HD. Don’s wheel design would outperform the stock wheel configuration and have a sleek but speed-driven aesthetic to it.
Inception Of A Better Wheel Design
Once receiving the R1T you could see the excitement on Don’s face, that of a kid getting to open Christmas presents first thing in the morning! However short-lived that feeling of excitement was, it was quickly replaced with an analytical energy and engineering-based focus.
Every aspect of the vehicle had a question mark hovering over it as if it wasn’t complete…yet. While the clean design and attention to detail were immeasurable and received kudos from everyone in the shop, you could see in his eyes that this journey was far from over.
Here at Thuren Fabrication, we can’t leave well enough alone and that driving force stems from Don himself, while factory engineers have their parameters, we like to take trucks to their full potential by manufacturing parts and components that are not only more robust but will perform under the harshest demands for years to come.
Why Design Wheels For The Rivian First?
With limited wheel options on the market and only a handful of designs offered from OEM, it was time to put the Doosan SMX through its paces. After some in-depth discussions and plans of attack for taking on this challenge, the design process had officially begun.
Don started by taking exactly what he wanted from a wheel design and putting it in the equation. Taking into consideration every facet of what he liked and didn’t like from the options currently on the market, it became clear that while wheels are an easy upgrade, they are far more challenging to design properly.
Skilled and ready for the task at hand, it all began by taking the OEM wheel off the R1T and seeing what he had to work with. Backspacing, and brake design, how big could the tire be and clear the R1T’s 8 driving modes, should it be a 20” wheel, 18” wheel, or 22-inch wheel. All of these questions and much more came into play.
Why Design A Hub Centric Wheel?
Most manufacturers design wheels specific to their vehicle for a perfect match mounting surface. This allows for the wheel to be perfectly centered on the wheel hub and that is why we went with this design.
It’s a safer option and better resists impact loads from being used on typical roads as well as off-road applications. With the anticipation that you will be taking your R1T off-road, this added feature to the DECA/HD was a no-brainer. We wanted to ensure the safest and most robust wheel design for the consumer possible.
Rivian Original Equipment Manufacturer Wheel Specifications
Insight From Don Thuren
Don - If you don't know what Hub-Centric is, here are a few points that make Hub-Centric so important on certain vehicles. The most important detail, in my opinion, is that a Hub-Centric wheel takes any Shear-Forces from impacts off the lug studs. This means that the only loads the studs see are fastening clamping forces or rotational Shear Forces from braking/accelerating.
The weight of the vehicle, how hard you drive Off-Road, big potholes, etc, are a non-issue as the center hub is taking the impact forces, instead of the lug studs. Much safer! When lug nuts come loose on Lug-Centric wheels, it's generally going to be from hard impacts allowing the wheel face to slightly shift a tiny amount on the hub, but that small amount can grow quickly into a loose wheel, as the wheels spin down the road.
Hub-Centric also makes the wheel run more true down the road if there are issues with machining or lug-stud or lug-nut symmetry, with the hub forcing the wheel dead-center and true.
In the future, we do plan to make a lighter-weight version wheel, for people mostly concerned with range or racing around a paved track, but really, 5lbs off of a wheel on a 7000-pound vehicle is not going to change a lot in the range department. For the best range, a lightweight tire with a smooth, low rolling resistance tread like the Rivian original, is the biggest player. Reducing the weight far out near the tread of the tire is what will give you the biggest effect in the rotating mass reduction effect.
Hub Centric Wheel Mounting
Lug Centric Wheel Mounting
Will The Doosan SMX Live Up To The Task?
Without question, our Doosan SMX can handle the task of machining whatever wheel design that Don could come up with but the more pressing question was, “How to design the mounting fixture?” While there are companies that will assist with the creation of such a fixture, it isn’t the Thuren Fabrication way to buy a product if we can make it ourselves and that is exactly what we did.
With proprietary design and purposeful calculations we did exactly that and created our wheel mounting fixture to meet every requirement we could ask for.
Trial And Error
In implementing those ideas the process remains, measure twice cut once right? In this case, it was time to measure and design as much as possible within Fusion360 and Siemens NX programs. Determining load variabilities while making a cool but different design and staying within the machine space capabilities is what lay in store for Don and Anthony.
Technology being what it is in our case it most certainly was a blessing because we can run simulations for many variables and get the program dialed in well before we mill 1mm of material.
How Well Does Fusion 360 Communicate With Siemens NX?
While it is possible to export a file from Fusion 360 and import the solid model into NX, you are then greatly limited when adjusting or modifying the model once the file is retrieved. The most seamless way to incorporate a design like this from Fusion into NX is to redraw the part.
Don drew his initial design in Fusion360 and Anthony recreated this model in NX to make adjusting the CAM process a seamless transition. NX is similar to Fusion in how the CAD and CAM communicate. A user can adjust a feature on the model and the CAM side will recognize the change so long as it is not too drastic.
Fusion is capable of programming the SMX but NX is the only software currently that can simulate Numerical Control code in the software and accurately depict the equipment in a digital environment. We have some 5-axis tool paths that put the machine extremely close to crunching itself together and it is less nerve-wracking when you’re aware of the situation going into it. These are just a few reasons why we chose NX to run the SMX.
CAM (Computer Aided Manufacturing) Processing
Most CNC programmers will tell you there is no “right way” to process a part regardless of the machine. As the saying goes you can only have it 2 ways: cheap, fast, or good. But you can’t have all three. Anthony’s main concern when manufacturing parts is excellent quality and as fast (and safe) as possible.
In doing so it all comes down to the semantics within the process. Attention to detail and a firm understanding of the limitations of the machine, the available parameters of the programming, and the durability of the tooling and fixtures once machining begins.
Fortunately, we are not very limited by anything in this shop in terms of available technology. Thuren Fabrication truly is a top-of-the-line manufacturing facility with equally capable equipment and we are constantly investing in the most relevant technology.
This project really allowed us to put this machine through its paces. We are taking a 0.750” (¾ for the carpenters out there) milling tool and sinking it three inches deep into aluminum and just tearing it away from the forging. It’s truly a joy to watch the 30 HP milling spindle sit at 100% load. Once the aggressive roughing is finished, we then come back and take off just a little bit of the remaining material from the surfaces, and voila! You’ve got a wheel.
Watch The Video Below To See The Final Product