New Tires...No Regen (Not Winter Tires)

[camalaio]

Here are the photos if it helps. I dont have a tire measuring tool.

Oh, so you have one type of tire up front and another in the rear? They have completely different behaviour to the car's systems.

Yeah. No traction control system tolerates that very well. Manufacturers very clearly recommend having the exact same model of tire at all 4 corners. Sorry, there's not much Tesla can do for you here.

EDIT: I'm surprised a tire shop in 2019 even agreed to do this. Did they make you sign a waiver?

 

[AlanSubie4Life]

I made an appt to get it checked out next week. Will report back what I find.

In the meantime, if you want, you could try boosting the front pressures to 46PSI and the rears reduced to 40PSI or something. In an attempt to get the diameters slightly closer.

Seems odd though - I have heard of this different diameter issue being a problem on cars before, but I would have thought on RWD Teslas a large front to rear diameter discrepancy would be so common we would have heard of this before. The tire type being different front to rear could do it too, especially if it only happens (triggers) under acceleration/deceleration (might be detecting excessive slip front relative to rear). But you said it always happens above 15mph regardless of how conservatively you are driving...

Still, while the simple explanation is certainly possible, I kind of wonder whether it's as someone else suggested - something happened to a wheel speed sensor.

All the TPMS read correctly and the pressures look good?

 

[gtg749m]

Yep, all the TPMS read correctly. When i left the shop the rears were at about 37 psi, and the fronts around 41. so i was thinking that was the issue. when i got home i filled them up so all show 41 psi. still no luck.

I've got traction control on my mazda, and i recently changed 1 rear tire to a completely different brand, and had no issues.

What about those that do an unsquare setup?

 

[AlanSubie4Life]

What about those that do an unsquare setup?

It's a good question. I would expect people who aren't running square to have something like 0.5-1% difference depending on exactly what they've chosen. Yet no reports of issues (that I've seen).

There's really no reason why this should be an issue for a properly designed traction control system - certainly not front to rear anyway - it should be able to measure the diameter of the wheels individually as a baseline, automatically, and then detect slippage from there. (I'm not saying it can't be a problem - diameter differences certainly can and do cause problems with some cars.) Anyway, the car has wheel speed sensors; it can figure out all the tire diameters very easily!

So I do wonder about your sensors.

 

[gtg749m]

Well, I'll report back as soon as i find out.

 

[camalaio]

Yep, all the TPMS read correctly. When i left the shop the rears were at about 37 psi, and the fronts around 41. so i was thinking that was the issue. when i got home i filled them up so all show 41 psi. still no luck.

I've got traction control on my mazda, and i recently changed 1 rear tire to a completely different brand, and had no issues.

What about those that do an unsquare setup?

You can get lucky and have a different type of tire behave similar enough that it doesn't cause problems in regular driving.

Non-square setups are of course expected to be non-square, but in precisely the manner that the manufacturer intended (especially side to side, but also the front/rear ratio). Look at the Smart fortwo for example. I knew the previous owners who put a different type of tire on, can't remember if it was front or rear. But the traction control system went nuts at odd times. Even with approximately correct but not exact original size tires I had it on it later, traction control liked to engage going over speed bumps. It was a bit funny.

 

[KenC]

I have a LR RWD. Just changed my rear tires to stock size Continental DWS. Now I have no Regen and traction control light turns on when accelerating in a curve and I cannot go faster. When I turn the car on as long as I'm below say 15 mph or so Regen will behave normal. Once I cross over a certain speed, Regen shuts off. Even if I try to go back down to slower speeds below 15 mph. But if I turn car off and turn it back on, it will again start Regen under 15 mph. Anyone ever experience this?

So you have worn OEM tires on the front and new Conti DWS on the back? Did you check the mfr spec to see if there are any rotational differences? Any slight mismatch can cause the car to think the tires are slipping because rotational speeds are different, due to the slightly different size rubber.

 

[SupraDude]

I'm more leaning towards something getting broken in the process. There are enough 3's out there with aftermarket wheels/tires and not OEM tire sizes that this should be a rampant problem we'd have heard of by now if simply replacing the rear tires was enough to make the car do this. Many people out there have staggered setups, some with dramatically different overall diameters front and rear and I've still not heard of this issue till now.

 

[David L]

This is off topic, but after you get the issues worked out, can you let us know what you think about the Continental DWS? I'm trying to decide between those, the Michelin A/S 3+, and the Pirelli P Zero All Season Plus.

 

[gtg749m]

So I drove the car to work today and on my way home everything started behaving normally again. My best guess is the car had to learn the new tires (if that is even a thing) or had to break it in and get all the manufacturing surface layer off of the tires which could have potentially triggered traction control and disabled regen???? Not sure.

 

[AlanSubie4Life]

So I drove the car to work today and on my way home everything started behaving normally again. My best guess is the car had to learn the new tires (if that is even a thing) or had to break it in and get all the manufacturing surface layer off of the tires which could have potentially triggered traction control and disabled regen???? Not sure.

Definitely could be either of those things. It is absolutely possible that it would try to learn the tire circumference (otherwise you would have this sort of issue with a staggered tire setup), and it may have been fearsome confused for a bit.