Legally, a vehicle manufacturer cannot void your warranty for installing an aftermarket automotive part unless they can prove that the aftermarket part caused or contributed to the damage directly or indirectly in the vehicle (per the Magnuson Moss Warranty Act (15 U.S.C. 2302(C)). Tesla’s warranty is governed by the Magnuson-Moss Warranty Act of 1975 in the United States and Canada.  Other countries have similar laws to prevent a manufacturer from voiding the consumers warranty.

Tesla must prove – not just say – that aftermarket equipment caused the need for repairs before they can deny warranty coverage on that basis.

YOUR RIGHTS:
Point out to Tesla that the provision of the Magnuson-Moss Act Require that they explain to you how the aftermarket equipment caused the problem. If they can’t – or their explanation sounds questionable – it is your legal right to demand they comply with the warranty.

Fact: If you are still being unfairly denied warranty coverage, there is recourse. The Federal Trade Commission, which administers the Magnuson-Moss Act, monitors compliance with warranty issues. Direct complaints to the FTC at (202) 326-3128.

This is the actual language of the act:

No warrantor of a consumer product may condition his written or implied warranty of such product on the consumer’s using, in connection with such product, any article or service (other than article or service provided without charge under the terms of the warranty) which is identified by brand, trade, or corporate name; except that the prohibition of this sub-section may be waived by the Commission if:

1. the warrantor satisfies the Commission that the warranted product will function properly only if the article or service so identified is used in connection with the warranted product, and

2. the Commission finds that such a waiver is in the public interest.

The district courts of the United States shall have jurisdiction of any action brought by the Attorney General (in his capacity as such), or by the Commission by any of its attorneys designated by it for such purpose, to restrain (A) any warrantor from making a deceptive warranty with respect to a consumer product, or (B) any person from failing to comply with any requirement imposed on such person or pursuant to this chapter or from violating any prohibition contained in this chapter.

— MAGNUSON MOSS WARRANTY ACT —

US Code – Title 15, Chapter 50, Sections 2301-2312

Now in regards to Tesla’s warranty specifically relating to half-shafts, which is the most common question/concern that we get; We have had many customers who have had half-shafts replaced under warranty after installing out kits without any hassle from Tesla. The half-shaft issue is probably the most well documented problem with the Model X. Tesla knows very well that this problem has absolutely nothing to do with anything other than their own engineering and I haven’t heard of a single owner being denied half-shaft replacement for any aftermarket parts. Tesla would need to prove that the aftermarket parts caused the problem. They can’t simply deny you because the components are a part of a particular system. This is not legal. This is difficult for a manufacturer to do in general but especially difficult for them to do being that the issue so well documented.

Here is more from the FTC’s website:

Will using ‘aftermarket’ or recycled parts void my warranty?

No. An ‘aftermarket’ part is a part made by a company other than the vehicle manufacturer or the original equipment manufacturer. A ‘recycled’ part is a part that was made for and installed in a new vehicle by the manufacturer or the original equipment manufacturer, and later removed from the vehicle and made available for resale or reuse. Simply using an aftermarket or recycled part does not void your warranty. The Magnuson-Moss Warranty Act makes it illegal for companies to void your warranty or deny coverage under the warranty simply because you used an aftermarket or recycled part. The manufacturer or dealer can, however, require consumers to use select parts if those parts are provided to consumers free of charge under the warranty.

Still, if it turns out that the aftermarket or recycled part was itself defective or wasn’t installed correctly, and it causes damage to another part that is covered under the warranty, the manufacturer or dealer has the right to deny coverage for that part and charge you for any repairs. The FTC says the manufacturer or dealer must show that the aftermarket or recycled part caused the need for repairs before denying warranty coverage.

For the Tesla Model S and X, we recommend setting the rear camber alignment to the outside of Tesla’s alignment specs.  Our exact recommendations can be found at n2itive.me/instructions at the top of the page. This is the optimal setting for even and improved tire wear and safety while at the same time maintaining Tesla’s recommended specifications. Tesla’s alignment spec is so broad that you can easily be “within spec” and still only get 4,000 miles out of a set of tires. This is not acceptable.

It is unlikely to get your alignment adjusted to our recommended settings with our adjustable camber arms by themselves. However every Tesla is slightly different so it’s not possible to say for certain. Installing the N2itive adjustable camber arms by themselves may reduce inner rear tire wear. However from our experience, since there is not much toe adjustment from factory, you’ll be left with too much positive toe which will wear out your tires faster than if your toe was within our recommended specs mentioned previously.  For this reason we recommend installing our adjustable toe arms to give you the flexibility to dial in the exact settings with no compromise.

If you use lowering links, drive in the low or very low positions, or if your Tesla is older or currently has extreme inner tire wear then you will definitely need both of our adjustable camber and toe control arms. If you drive a Model X then we recommend installing our Alignment Kit 1 to address acceleration shudder and inner tire wear together. That kit comes with both of our adjustable camber and toe arms as well as our RSX series ride height links to give you an ideal alignment and reduce the binding and potential damage of your front half-shafts, which is the cause of the acceleration shudder/vibration.

For a little more insight… Replacing your factory non-adjustable Tesla camber arms with N2itive adjustable camber arms will allow you to reduce the excessive negative camber of your rear wheels which is the common cause of inner tire wear on the Tesla Model S and X.  Especially if you’ve already had your car aligned but the inner tire wear persists.

However as you reduce the negative camber the geometry of the wheel changes which causes the wheels to begin to toe in.

With the Tesla S or X you can adjust the toe, but only slightly.  You have about 3.5mm of adjustment from the neutral position to try to push the toe back out slightly to the 0.10° – 0.20° setting. Generally this will not be enough to dial in the ideal setting which is why we recommend the combination of the adjustable camber and toe arms.  Alternately you can install our Alignment Kit which has both of these arms as well as our RSX series ride height links to help prevent the acceleration shudder issue as well as completely eliminate the inner tire wear issue. If you have any questions please reach out to us.

For the Tesla Model 3/Y, since they are not on air suspension you can probably just use camber arms to fix the rear inner tire wear.  If you have lowered your 3/Y then you would want to get both our adjustable 3/Y camber arms and toe arms since the geometry will change too much to be adjusted with the factory toe eccentric bolt.