Today’s cars are safer than ever, and we put our cars to the test in ways that they would’ve never dreamed of 50 years ago. Traditional cars are doing pretty well these days, but with the way that electric cars so dramatically change the architecture of how cars are built, they still have some catching up to do in order to test as safe as their gasoline-powered counterparts.


The Tesla Model S’ IIHS (Insurance Institute of Highway Safety) crash tests were released today, along with those of the BMW i3 and Toyota Prius. While it’s not surprising the Model S and i3 didn’t do spectacular, they did get a passing grade for their passengers, but something that stood out to us during the small overlap crash test is how the Model S’ 19in Slipstream style wheels seen in the test just shatter like glass during a collision.

Tesla Slipstream 19×8 – 29lbs!! Might as well be made of lead…

What is really interesting here is that this failure was not present in the case of the i3 or Prius – for the purposes of electric-only vehicles, we’ll just talk about the i3. The i3’s wheels, on the other hand, remain intact even as they are torn away with the suspension – likely because of the fact the optional wheels used for the i3’s IIHS testing are forged wheels, as opposed to gravity cast, to shave as much weight off that car as possible.


OUCH. Look at the things just explode like throwing a wineglass against a brick wall. Brutal.

Why is this happening? The obvious answer is the quality of the wheels. While both BMW and Tesla do use gravity-cast wheels as factory equipment, it’s clear that gravity cast wheels are simply not up to the task. The Model S, unlike the i3, is a rather heavy vehicle, exceeding the load rating of most wheels – so it’s only natural that they wheels would fail spectacularly when they’re already such a highly stressed component. There is a definite hierarchy to the quality of a wheel based on how it was manufactured. The order from weakest to strongest is Gravity Cast, then Low Pressure Cast, then Rotary Forged or Flow Form, then at the top tier, you have outright Forged Wheels.

Gravity cast wheels are the most common because it’s the least expensive method for producing wheels, but it’s also the weakest and requires more material to make a wheel of sufficient strength. When you consider the fact the Model S tips the scales at between 4,469 to 4,941 lbs, a set of aftermarket wheels with a beefier load rating sufficient for the heavyweight Tesla Model S is a great idea. Not to mention, reducing the car’s ‘unsprung weight’ by replacing the super heavy (29lb!!) factory wheels with lighter weight alternatives will also enhance performance, handling – and RANGE.

As an alternative to the weak factory gravity cast wheels, here are some options that are rated for the extreme load of the beefy Model S and its absurd torque output. These are set of Forgestar Wheels for Tesla, and they’re one of the first wheels to hit the market that’s actually rated for the model S.

Forgestar F14s use a split 7-spoke design, 7 spokes being the strongest configuration for any wheel (as discovered by Mazda when they were developing the original Miata), and their rotary forged construction means that they offer an outstanding strength-to-weight ratio, and in a collision, are less likely to shatter but rather deform and deflect the energy, as you see happen with other wheels.

Forgestar is by no means the only option, either. Several major aftermarket wheel suppliers have stepped up recently with offerings rated for the unique demands of the Model S, Model X and Model 3.

HRE Performance Wheels offers both Forged and Flow Form wheel options for both Tesla Model X and Model S, making them another ideal choice to replace the factory wheels.

Not to mention, the HRE Styling really adds a lot to the appearance of the car.

You can find out more about HRE Flow Form Wheels in this video.


Avant Garde Wheels also has some great options – for those who like the directional look of the factory Turbine wheels, the Avant Garde M621 is offers the strength of flow form production with the flair of a different style. Avant Garde’s M621 is a true directional wheel as well, meaning the turbine blades face the right direction regardless of which side of the car you’re looking at.

An aftermarket set of wheels both replaces the weak Slipstream style wheels currently used on the Model S as standard with a stronger set and enhances the appearance of your Model S, making your Model S safer in a crash because your wheels are more likely to remain intact after the collision, rather than shattering like glass.

Here at ModBargains, we’re well equipped to sort your Model S out with a set of high strength, high performance, great-looking aftermarket wheels – we’ve got a huge selection of wheels in stock in your fitment. Talk our team of Mod Experts like Sean, give us a call at 714-582-3330 (x8009 for Sean), chat live at or just stop by the ModAuto showroom (which is also our install facility) in La Habra, CA on Lambert Rd at Harbor Blvd Monday thru Saturday, 8am – 5pm PST.

Thanks for reading, and we’ll see you next time!

Story by Nick Gregson