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Negative Camber in the Rear and Expensive Tires
- Thread starter lolachampcar
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- Driving Dynamics Model S
+1 -- TPMS is not a substitute for regular tire care (looking at the tread for wear and damages, checking inflation). Modern high quality tires are good enough that many folks don't do this and get by, but the more regularly you check the tires, the better results you will get. You'll also get a feel for when they are not right.
Two observations-
First, I too was concerned when swapping tires across the rear that wet traction would be reduced. I took a good long look at the difference in tread pattern across the rear of the pilot. It is true that new tires will pump more water from the inside shoulder. However, I would be willing to bet that 100% tread depth on the outside of the tire would do a better job of pumping water than 30% tread depth on the inside. If I am correct, swapping the tires across the rear of the car at 30% remaining inside depth would INCREASE wet performance.
Second, MS has attracted a high percentage of people with less practical car maintenance experience when compared with the normal high performance car buying community. Tire wear issues are a hot topic in the AMG, M, S Line community where there is an awareness of how high negative camber can affect wear. The MS community attracts a good number of customers with a completely different (Normal) experience base. They expect 40K miles from their tires and have the shop check for wear where I take one look at the back of the car and know I need to watch those puppies real close.
The big question for me is how do we forum members help other owners (and Tesla) deal with this very real issue without doing unintended harm? How do we make people aware of the issue without scaring potential buyers or providing fodder for shorts or faux media? There is a lot more depth to this question for me but perhaps a full public posting is not the way to have that conversation.
First, I too was concerned when swapping tires across the rear that wet traction would be reduced. I took a good long look at the difference in tread pattern across the rear of the pilot. It is true that new tires will pump more water from the inside shoulder. However, I would be willing to bet that 100% tread depth on the outside of the tire would do a better job of pumping water than 30% tread depth on the inside. If I am correct, swapping the tires across the rear of the car at 30% remaining inside depth would INCREASE wet performance.
Second, MS has attracted a high percentage of people with less practical car maintenance experience when compared with the normal high performance car buying community. Tire wear issues are a hot topic in the AMG, M, S Line community where there is an awareness of how high negative camber can affect wear. The MS community attracts a good number of customers with a completely different (Normal) experience base. They expect 40K miles from their tires and have the shop check for wear where I take one look at the back of the car and know I need to watch those puppies real close.
The big question for me is how do we forum members help other owners (and Tesla) deal with this very real issue without doing unintended harm? How do we make people aware of the issue without scaring potential buyers or providing fodder for shorts or faux media? There is a lot more depth to this question for me but perhaps a full public posting is not the way to have that conversation.
cfOH
Member
Lola: How long did it take (man-hours) to swap out the control arms on your P+? Maybe the solution is for Tesla to provide, on request, new UCAs with more adjustment so that those of us comfortable with less neg. camber can dial that back. But, there should also be a pretty massive campaign to educate Performance model buyers that they need to get their cars' alignment checked for proper toe. That is one downside to some people (like me) relying on Ranger service for nearly everything...Rangers can't do alignments.
They don't have the mobile equipment to do an alignment, but they will go with your car to your local shop and train or monitor the local mechanic to do the job properly. This is what they have done for local cars many hours drive from the service center.
Curious to know more about what you see here and what that potential problem may be. Thanks
cfOH
Member
Good to know that's an option. We have an excellent alignment shop here in town, but I suspect they don't have any first-hand experience with Model Ses.
Models S?
These cars.
strider
Active Member
Well, I think this was Tesla's thinking with their all-you-can-eat service plans. That customers would bring their cars in to have the tires rotated for free and Tesla could take a look at them and notify the customer if they are toast. Now whether the SC's are set up to do quick in-and-out tire rotations is a different story.
Also I believe they were expecting 12,500 miles out of the tires with a rotation and assumed that they would catch worn tires at the annual, even if someone did the rotation themselves or had another shop do it. I rotated my wife's tires at 3,500 and again at 8,500 and they are doing just fine. She'll easily make 12,500.
But for us on the forum I think we just need to stress to people to get their tires rotated every 5-6k religiously. Any problems will be spotted then.
They are most definitely not. I had to get a regular appointment three weeks out for a rotation.
Today, the ranger came out to perform some maintenance on my vehicle. When performing a TSB for the rear hub nut, he had to pull the tires... and that's when I noticed (yikes!)
What you see here is the former left rear tire of my car (which from about 5,500 miles to 10,100 miles was on the left rear, swapped earlier today to the front when the hub nut was replaced per TSB). The right looks just as bad, symmetrically. These tires were originally on the front at delivery and were swapped to the back at 5,500 miles with no visible wear on the inside edges. I'm just now over 10,100. This incredible wear on the inner surface was the result of only 4,600 miles on the rear!
My car was checked for alignment in January by the Chicago service center after hearing & feeling a bit of a jolt up front (as if something shifted in the suspension) and having the car pull to the right a bit, although it may have only been a front alignment.
I may drive with a bit more zip but I can assure you that I don't do burn-outs or anything of the sort.
What you see here is the former left rear tire of my car (which from about 5,500 miles to 10,100 miles was on the left rear, swapped earlier today to the front when the hub nut was replaced per TSB). The right looks just as bad, symmetrically. These tires were originally on the front at delivery and were swapped to the back at 5,500 miles with no visible wear on the inside edges. I'm just now over 10,100. This incredible wear on the inner surface was the result of only 4,600 miles on the rear!
My car was checked for alignment in January by the Chicago service center after hearing & feeling a bit of a jolt up front (as if something shifted in the suspension) and having the car pull to the right a bit, although it may have only been a front alignment.
I may drive with a bit more zip but I can assure you that I don't do burn-outs or anything of the sort.
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I've tried not to make absolute statements but it really needs to be said. Negative camber tilts the tire onto the inside edge. The stiffer the tire and the shorter the sidewall (adds to stiffness) the less the tire has a chance to comply with the pavement. In short, moving the rear toe around within the allowable range set by Tesla will dramatically effect inside shoulder wear and, even with near zero toe, there will be inside shoulder wear. This result is more pronounced in MS given that it is a 4700lb car where all the acceleration and most of the braking loads are handled by just the rears.
You either remove the camber or you swap tires across the back while you still have an acceptable amount of inside shoulder tread depth. I hate to be so absolute in these statements but it is simply how negative camber works.......
It is also worth repeating that the negative camber on MS is designed in and is not a design flaw. It is there to help prevent oversteer (back passing front) in an emergency maneuver. Removing negative camber from MS must be done with a complete understanding of this and an acceptance of the reduced oversteer protection.
You either remove the camber or you swap tires across the back while you still have an acceptable amount of inside shoulder tread depth. I hate to be so absolute in these statements but it is simply how negative camber works.......
It is also worth repeating that the negative camber on MS is designed in and is not a design flaw. It is there to help prevent oversteer (back passing front) in an emergency maneuver. Removing negative camber from MS must be done with a complete understanding of this and an acceptance of the reduced oversteer protection.
I suggest:
1) Promote the 19" wheels and all-season tires as the best option for the 99% of buyers that are not serious high performance people. Stress that 21" is set up for "Summer-only max performance short tire life," with expensive replacement tires and a need for winter tires in many climates.
2) Strider's suggestion to stress rotations every 5000 miles is a great idea.
GSP
PS. I really appreciate your knowledgeable posts on suspension set ups
Judging by the wear bars and the lighter area shown in the picture, I tend to agree with Heems that something is rubbing against the shoulder of the tire. The part that is worn doesn't look as if it contacts the ground.
With the tire off the car see if you can tell where the rubbing takes place--and does the tire on the other side match?
With the tire off the car see if you can tell where the rubbing takes place--and does the tire on the other side match?
GSP, I think your summary that 19'' will be best for most MS owners seems spot on. I hope to add an MS to join my Roadster sometime next year. I hope by that time, Tesla will have a handling upgrade option for MS Standard that firms and improves its handling significantly, but with 19" wheels that have good life and retain much of the ride comfort.
teslasguy
MSP P#1117
I now have around 8000 miles on my P85. The most recent 4000 miles are on my 21" tires and I now see the same kind of wear oh the inner edges of both err tires. I'm going to take it to the sc soon and ask if they will rotate these to the front.
Rotating the tires front to rear only tears up four tires at a time so I'm not sure it is better than swapping the rears.
By chance was the outside shoulder wear directly above driven by slight under inflation? That would account for wear on the sidewall to tire patch junction.
By chance was the outside shoulder wear directly above driven by slight under inflation? That would account for wear on the sidewall to tire patch junction.
It is in that you should always try to replace tires in sets of four (assuming all four are the same size). The reason is that tire manufacturers will silently change the tires over time.
I didn't see the stress marks that would happen with underinflation. Of course, stress marks might not have shown up in the picture, but it looks like rubbing on something to me. In addition, those are usually on the outside shoulder even with poor toe and a lot of negative camber.
Here are the results after loosening the sub-frame and allowing toe to equalize right to left. The sub-frame was under tension to the right which prevented us from getting the left wheel below 0.25 degrees of toe in.
Ignore any data for the front of the car as one of the reflectors had a bent pin from being dropped.
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