“Normal” Tire Wear

During the last two weeks I had quite an adventure with my Model S 21” tires. During this period I had two tire blowouts, four Model S tows, a 1 1/2 hour wait for my car to be delivered to my home from the Tesla service center, and a 2 hour wait for a tow truck driver on the side of the road on the same day.

This blog post will explain my Model S’s unusual rear tire wear pattern, the process of towing a Model S, and some significant improvements I feel are needed to the processes in the Tesla service department. Since I have some critical comments to make about Tesla, I have sent this post first to Tesla personnel to allow them to correct any factual errors and comment about my concerns. Noe Mejia, Director of North American Service, provided the comments from Tesla — written in red.

First and foremost, your feedback is greatly appreciated.  Over the last year,  we have identified areas for improvement in our Service organization, have made improvements,  and continue to improve our customer experience and Model S service every day.   I welcome your direct feedback at any time.     

During this process I did not take detailed notes on the exact amount of time I waited for my car or the tow truck or the number of phone calls I made, but I believe the general impressions I have represented here are accurate.

Three Prior Service Visits During First Year

With 12,500 miles on my Model S, I had planned to schedule an annual service visit in a few weeks. I was in no particular rush and my car had already been to the service center in August for a problem with the Tire Pressure System and three times for my Haunted Doors – a total of three (maybe four) service visits. Not once during any of those three visits during the year did anyone mention the wear on my rear tires, the fact that it is recommended to rotate the front and rear tires, and that Tesla service would offer this rotation for free. One of these visits was for a repair for the Tire Pressure System, so I assume the mechanics would have likely at least glanced at the tires during the repair.

Tesla does offer tire rotations free of charge.  Although it may have not been recommended on your previous visits,  we have made improvements to our standard service process.   Anytime your Tesla vehicle is brought into service,  we perform a courtesy inspection, free of charge.    As of recent,  a line item for rotating the vehicles tires, where applicable, has been added to our courtesy inspection document.

Tire Blow Out Number 1

Tire Pressure Very Low

I was on my way home one night and I got the warning message that my tire pressure was very low. I was less than 1/2 a mile away from home, so I figured I could pull over safely in my garage.

The next morning, I made a short unsuccessful attempt to fill the flat tire using a standup bicycle pump, then I quickly called AAA for the tow to Ron Raimes Automotive. When the tow truck driver arrived he quickly told me that he had just finished pulling a Model S with 19” wheels out of a ditch. He also said that he had seen just as many Tesla’s with 19” wheels with problems as 21” wheels.

The implication of the tow truck driver’s comments is inaccurate.  The 19” tires are more resilient to pot holes, impact damage, etc.  This is not unique to Tesla: all vehicle with low profile tires are more susceptible to this type of damage in comparison to identical vehicles equipped with higher profile tires. The OE tires on the 19” wheels have a higher side wall, making them more shock resistant than the 21” wheels.  The additional height of the sidewall acts as an additional damper to hazards encountered on the road.  

My tires were not worn out in the conventional way. I had been monitoring the tread wear on the back tires and had been happy that they still seemed okay at 12,500 miles.

The inside tread was shredded and steel was showing on both the back wheels. He concluded that my car was simply unsafe to drive and needed to be towed. He explained that I needed to run my hands back and forth on the inside of the tires to feel the wear. In hindsight, I probably should have perhaps driven the car straight to the garage when the flat occurred instead of driving home.

Towing the Tesla

The first driver was very comfortable towing my Tesla and I let him proceed as he wished. He set the tow mode himself but I do not think he raised the suspension. As you can see with a blown out tire at regular suspension, the first tow truck driver had to use wood blocks to get the car on the flat bed. He spent some time adjusting the wood blocks for the blown out tire. This first call I used my AAA card for the tow. The driver said AAA considers pieces of wood “special equipment” that is not included in a basic tow, but he ignores that rule.

 

 

Local Mechanic Impressions -Excessive Toe

After doing some research online and mostly on the Tesla Motors Club Forum, I decided the best set of tires were the Michelin Pilot Super Sport. These tires have a long durability and performance ratings than the earlier generation Michelins, which are on the Tesla approved list. Ron Raimes Automotive installed two new tires that I ordered from Tirerack. Since my car was due for the 12,000 mile service, I told my local mechanic not to align the wheels as this was included in the service at Tesla. My local mechanic was very dismayed at the alignment report and also the simple look of the tires. When my tire mechanic saw the numbers, he thought the car was simply seriously misaligned. He printed the alignment report and even saved the tires.

Detailed Independent Alignment Report

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Inside Tire Wear – Showing Steel

Tesla Response

I had an appointment for the service a week later, and I gave a copy of the alignment report and a full size photo of the tires to the valet. During the wait period between having the new tires installed and the alignment, I did not drive the Tesla. A valet picked up my car for service in the morning. Tesla did not have any loaners and since I have an ICE, I did not want an ICE rental vehicle. I told them it was fine if they kept the car for two days but I needed it back the next day by 3pm.

My service advisor did take the time to sell me the repair of my wheels due to curb rash. When I first got the car, I did scratch the front wheels significantly and the right rear wheel. I had not particularly planned to do this service. We spent probably fifteen minutes talking about the pricing and the potential pricing of upgrading to parking sensors later, which he said will probably range around $6,000 as a retrofit due to needing to rewire the car. Since I now felt comfortable avoiding any more curb rash, I went ahead and bought the repair for three of the wheels.

In all conversations with the Tesla Service Advisor I was told that my tire wear was “Normal” and the issue had to do with the excessive weight of the motor on the rear axle. He told me to go look at the model in the showroom to look at the axle and how that caused a problem with the camber.

Motor of the Model S along Rear Axle

I was also told that I should rotate my tires every 5K miles or so, and Tesla service would do that for free. If this was a free and recommended service, I had never been informed about this during my other service visits this last year.

But when you look at the alignment report, the real problem is both in the camber and in the toe alignment. Camber is when the tire is not vertical but leaning off of vertical. In the diagram from the perspective from the back of the car, the top and bottom of the tires are not vertical to the ground and the tire is leaning in slightly towards the car.

Illustration of Camber on a Tire

Toe occurs when the tires are not parallel to the vehicle as shown in the next diagram. The diagram illustrates a view from the sky looking down at the tire and the road. Both my rear wheels had excessive toe-out. With toe-out the fronts of the tires are further away from the car than the back of the tires. Toe-in is the reverse situation.

Illustration of Tires With Excessive Toe-Out

Both excessive camber and toe-out can cause wear issues on the inside of the tires. Interesting enough, another blogger on Edmunds.com had reported the exact same issue in September of 2013 at 10,000 miles.

He reported that there could be several causes for toe-out: nuts were not tight enough, the wheels had gotten whacked or the bolted joint is simply not robust enough. My left rear wheel had not been whacked by any curb rash as this wheel did not need curb rash repair. A number of other owners have reported similar alignment issues also. The problem could be misalignment at the factory or a weak physical part in the car that could require a recall. What to me is very disappointing is that Tesla at least replaced Dan Edmund’s tires on a “goodwill” basis. All I got was a repeated answer that my tire wear was “Normal” and that I needed to buy another pair of tires and rotate my tires more often.

Unacceptable Service Delivery and Towing Times

Around 2:40 or so, I talked with Tesla Service and told them to honk the horn when the car arrived as I would be in the back yard. A little while later I got another call that the car was still twenty minutes away. A number of minutes later I got another call that my car was going to be delivered by a tow-truck as they did not have any valets and the truck had just left Tesla. Yet another call later, I was told that the tow-truck driver was stuck in traffic and would still be another 20 minutes away. My home is less than ten miles away from the service center and before 4:30pm, there is not significant traffic on these roads.

These details may not be completely accurate, but the car did not arrive till after 4pm. I had kept several people waiting for me during this time with no opportunity to inform them I was going to be late as I had assumed the car would be there shortly. I told the service advisor that this was really unacceptable. The service manager did later call to apologize for the delay and offered to cover some of my curb rash expenses.

Second flat

A little after 7pm the same day, the brand new tire blew out with less than 25 miles on it. I got the same warning on the dash and could actually hear air leaking out of the tire right near the rim.

Sidewall crack

I called Tesla service because I believed it could have been related to my curb rash cleaning process. I was on the phone with them for probably 10 minutes before they began to call the tow truck driver. I did not write down all the details of what occurred during this period, but I was told over a two hour period three times that the driver would be there in 20 minutes. Needless to say, the tow truck driver did not arrive till two hours after the initial call.

A rare occurrence of a long wait is “okay”, but an hour and a half wait followed by a two hour wait can fray even the most patient person.

The tow truck driver said he was not trained on how to tow Teslas and handed me a sheet on how to set the car in tow-mode and raise the suspension to high. The second tow was not as difficult because I raised the suspension and the tire may also still have had a small amount of air in it.

Conversations With Mechanics

Having had good experiences with Tesla in general, I went with their faulty explanations as I had not yet had time to look at the alignment report from the first garage. During these two weeks I talked to several people that were simply shocked that my tires were having these issues including someone who restores classic Porsches on the side and just happens to be a collector of Michelin men including this one from the 1920s, which he is interested in selling.

1920’s Michelin Man Costume

Someone even suggested that I could even strengthen the connections of my wheels with aftermarket parts, and I decided to call my first mechanic back to discuss this as I would prefer to have my tires last as long as possible.

I knew this problem was very serious when Ron Raimes himself then insisted on calling Tesla directly. I have owned several cars over the years including the Roadster and a Mercedes somewhat similar to the Model S, but I never experienced any irregular tread wear, so I appreciated someone with expert knowledge willing and wanting to call Tesla directly. I suggested to that he speak with the service manager not the service advisor because I did not feel I was making any progress with the first person, who I believe is a newer employee of Tesla.

Finding the Pothole

While my car was at Tesla, I stopped in to discuss my tires with the service advisor in person as I was in the area. On the way home, I actually found the pothole that most likely caused the second blowout. I think my second blow out was simple bad luck.

Pothole that Caused the Second Blowout

Lessons Learned For Me:

1. I need to very carefully run my hands over the inside of my rear wheels on a regular basis. I will also raise my car to very high suspension to look on the inside.   It is a good idea to monitor for tread wear on the center, outer, and inner tread areas.   The best is a visual inspection, by a professional, from a view point that will allow you to see the tread across the entire surface tread of the tire.  This will allow the viewer to take measurements using a tread depth gauge as well as identify nails or foreign objects in the tire.  Another addition we have made to our courtesy inspection is inspecting and documenting tread depth in the inner, outer, and center area of the tread.  Inspecting tread in this way will allow us to identify abnormal wear patterns if any occur.   I recommend staying away from “running your hands back and forth on the side of the tires to feel the wear” –  it’s best to avoid contact with your hand as there can be hazardous road debris lodged in the tread or in the case of worn tread, you would be exposing your hand to the steel cords. 
2. I bought a flat tire repair kit for my car that I will always carry. Another Tesla owner successfully drove a few hundred miles with a similar pothole blowout using this kit. I doubt I will drive that far, but it may enable me to drive the car to a garage instead of waiting for a tow.
3. I will carry a house key so I do not need to wait for a tow truck driver.
4. I will look at the surface of the road more to avoid any potholes.
5. I will keep in my trunk a warm jacket and some non-perishable food. I already carry water and a pair of shoes.

Hardware Improvements:

Clearly there is an issue with the alignment on some Model S’s. Enough people have reported very bad toe and camber issues. I do not know what is causing this problem, but Tesla needs to address this issue in an expedient manner. At a bare minimum pro-actively inform existing owners to watch for inside tread wear.

Software Improvements:

1. The tow mode should automatically raise the suspension on the car to very high if the car is equipped with air suspension.
2. The car should warn the user if the tires need to be rotated when they reach a certain mileage.
3. A readout should be available that lists the current tire pressure. Even the Roadsters very simple interface reported the tire pressure at all four tires.

Thank you for your feedback,  I have passed this information on to our team for consideration and implementation compatibility.     

Service Improvements:

In both experiences while I was waiting for my car from Tesla, I found the experience to be quite less than satisfactory.

I do appreciate on the first call that the service manager did call to apologize for the delay, and that I was given free curb rash repair on 2 of the 3 wheels, later on the second alignment and then an extended warranty. I also found all my interactions with the Tesla personnel mostly pleasant, although at times I simply did not believe the story of the driver stuck in traffic on Foothill Boulevard in Palo Alto. I also felt that the tow truck dispatcher was also giving me the run around.

Returning From Service in a Tow Truck?

In both cases, I would have much preferred to have been told the truth up front that the tow trucks would have arrived at 4pm and 9pm respectively. In the first case, I would have been able to notify the people that were waiting for me, so they could adjust their schedules. In the second case, I would have called someone with a house key to come and pick me up and simply left the Tesla parked there overnight as I was very hungry. But because I got the verbal run-around, I was not given the option. I think the service department needs to work on ways to get their cars to their customers. They clearly do not have sufficient Model S loaners as promised. They also clearly do not even have sufficient valet drivers to go to a location so close to their service center. Instead of using a tow truck driver, I would have preferred to at least been given the option to have a taxi pick me up, have someone drop me off at the service center or even just driven there myself in my ICE vehicle, and have the valet bring back my ICE at their convenience.

Tesla is improving the time it takes to repair vehicle by use of a team system which allows multiple Technicians to work on one vehicle in a team setup,  thus reducing the need for loaner or rental cars.   Simultaneously,  we are building our fleet of loaner vehicles to adequate levels. In cases of unexpected demand for loaner cars,  we will always have a rental car program in place as a backup.  We are also boosting the number of valets available to deliver or valet your vehicle in metro areas,  picking up your vehicle with a ride to the service center is always an options in metro areas as well.  

When talking to the truck driver, I was quite surprised to learn some people did not want a valet person to drive their car, and that Tesla has their own tow truck. I think using an ICE tow truck to pull an electric car seems environmentally incorrect, and requires a fair amount of time to load and unload. The tow truck driver is required to drive the car off and on the flatbed. Also a toe truck gives the impression to the public that the Model S has serious issues and cannot be driven. Perhaps a tow truck is a reasonable solution for long distance service calls. Last year they also added two new service centers in my area.

Elon did tweet about improving service on May 11, 2013 and unfortunately almost a year later this still is a big challenge.

Elon Musk’s service tweet

Regarding negative towing experience

I apologize your towing experiences have been less than ideal.  I would recommend always using our Tesla Roadside assistance and Technical Support hotline.  In recent months, we have completely internalized the management of our Roadside Assistance providers and implemented measures for quality improvement,  performance feedback,  and training for our tow providers.  Having experienced instances of tow providers not providing the level of service expected and deserved by our customers,  we decided to take this approach in order to enable us to work towards an excellent Model S ownership experience in all scenarios.  We have already experienced an improvement in customer feedback.  Additionally,  scenarios where the tow truck driver does not know how to engage tow mode should no longer occur.   With our new feedback loop and customer surveys,  tow providers that do not provide excellent service will not continue to be part of our network.

Regarding tire wear       

Abnormal Tire Wear: The points you bring up regarding camber and toe are correct.  As per our conversation,  your Model S was out of alignment, which caused abnormal tire wear.  Unfortunately,  your vehicle was  likely delivered with misalignment, thus causing accelerated inner tire wear. For this, we again apologize. As we did with Edmunds,  when any customer comes to us with abnormal and excessively uneven tire wear, we proceed to cover the cost of replacing the tires as it is Tesla’s responsibility the vehicle was misaligned causing abnormal wear to the inside edges of the tires. 

The Tesla representative with whom you spoke should not have assumed your tires had worn out quickly and evenly.  Faster tire wear is normal on the rear tires, but it should be a more even tire wear than illustrated in your photos.  Like other performance vehicles, Model S has pronounced negative camber, per design. Therefore, even under ideal conditions, accelerated wear on the inner edge of the tire is normal,  but less pronounced than your vehicle experienced. 

Rapid Tire Wear

With 21” wheels,   the “Treadwear Rating” is lower, indicating the tires will wear out faster.    For comparison,  here is the tread wear or our OE tires:  

• Ø 220 Tread Wear – 21” OE Michelin
• Ø 340 Tread Wear – 21”  OE Continental
• Ø 440 Tread Wear – 19” OE Goodyear
• Ø 500 Tread Wear – 19” OE Michelin

Higher Treadwear Rating does not mean it is a better tire.  Tires with higher Treadwear Ratings last longer but do not offer the same performance.  A lower tread wear rating indicates a higher friction coefficient, meaning the tire is a softer, more sticky tire and wears off its material faster to provide better performance.  

Wikipedia is a good reference regarding tread wear rating: http://en.wikipedia.org/wiki/Treadwear_rating  

Safecar.gov has a good link with illustration on where these ratings can be found: http://www.safercar.gov/Vehicle+Shoppers/Tires/Tires+Rating/Treadwear  

As the Model S is a powerful, rear-wheel drive vehicle,  the wear on the rear tires is amplified.   Through the course of acceleration and pure regenerative breaking,  the torque is added and removed strictly through the rear tires, thus amplifying the wear on the rear tires.  Rotating your tires are the recommended intervals will help you in maintaining a more even wear profile amongst front and rear wheels.  It’s important to note,  during harder applications,  a more conventional braking profile is used in regards to stopping power applied through the front and rear wheels.    

As mentioned earlier,  I always welcome feedback from our customers.