Got new tires and now regenerative braking does not work.

[FishMann]

Got 3 new tires from Mavis yesterday (they lost the 4th one) and everything was fine. Went back today for the other one and now the regenerative braking does not work. Any ideas?

 

[RayK]

Some things to thing about that directly affect the feel of regen...

• Is the car charged to near 100%?
• Is it also particularly colder than before?
• Have you checked the regen setting to see if it's been moved to Low?

I seriously doubt that a new tire would cause regen to not work at all.

 

[FishMann]

Yeah its none of that. 80 degrees with a charge of 55%.

At best regen will activate for a few seconds then stop. I scheduled an appointment with the service center a week from now....

 

[RayK]

That sounds like the best course of action. Good luck.

 

[FishMann]

Page 69 in the manual.

However, your vehicle is designed to continuously recalibrate itself, and after changing tires it will increasingly restore regenerative braking power after some moderate-torque straight-line accelerations. For most drivers this occurs after a short period of normal driving, but drivers who normally accelerate lightly may need to use slightly harder accelerations while the recalibration is in progress.

Don't have time to test this out right now. Will report back later

 

[RayK]

Hmmm.... don't recall ever reading that but it's been some time since I put my nose into the .PDF. I changed out two rear tires about a year ago but don't remember ever feeling regen change at all. Could be that I don't accelerate gently.

 

[Zoomit]

I seriously doubt that a new tire would cause regen to not work at all.

Unfortunately, it’s not uncommon. Just google it for YT videos and forum posts on the subject.

 

[RayK]

I must have missed seeing posts/threads on the subject. I don't change over to winter tires (which it seems to be the cause of many of the occurrences), nor have I rotated the tires (they're fairly evenly worn after 18K miles, despite having newish rubber in the back). I'll keep this in mind when I do have to change tires next time. Thanks for teaching me something new!

 

[Hblick48]

I just put 4 new tires on my MS. Regen works same as before.

 

[Dangerous Fish]

Regen not working at all is a very different thing to reduced regen.
Reduced regen can happen for a number of reasons but no regen is very unusual.
I'm guessing this is a case of reduced regen.
Also, I swap between winter tyres, track tyres with not much tread and road tyres with a lot of tread quite regularly and have never had anything like this happen.

 

[FishMann]

I can confirm that after a short drive the regen is back to normal

 

[Daniel in SD]

Regen not working at all is a very different thing to reduced regen.
Reduced regen can happen for a number of reasons but no regen is very unusual.
I'm guessing this is a case of reduced regen.
Also, I swap between winter tyres, track tyres with not much tread and road tyres with a lot of tread quite regularly and have never had anything like this happen.

Have you tried swapping only 3 tires at a time? It sounds like that's what happened here.
Regen on bald rear tires is super dangerous, my theory is that the car tries to detect that state by measuring the difference in diameter between front and rear.

 

[zhu-]

Hmmm.... don't recall ever reading that but it's been some time since I put my nose into the .PDF. I changed out two rear tires about a year ago but don't remember ever feeling regen change at all. Could be that I don't accelerate gently.

I also won't have this problem

 

[TomB985]

Regen on bald rear tires is super dangerous, my theory is that the car tries to detect that state by measuring the difference in diameter between front and rear.

I don’t think that’s quite accurate. Bald tires will actually provide MORE traction on dry roads, which is why racecars don’t have treaded tires.

I’m guessing the computer uses the acceleration runs to determine available traction from the rear wheels to ensure commanded regen doesn’t exceed what’s available for that particular tire. I’ll be very surprised if diameter had anything to do with it.

 

[RayK]

I don’t think that’s quite accurate. Bald tires will actually provide MORE traction on dry roads, which is why racecars don’t have treaded tires.

Said race cars also use a different rubber compound which is inherently more "stickier" than a normal tire.

 

[Daniel in SD]

I don’t think that’s quite accurate. Bald tires will actually provide MORE traction on dry roads, which is why racecars don’t have treaded tires.

I’m guessing the computer uses the acceleration runs to determine available traction from the rear wheels to ensure commanded regen doesn’t exceed what’s available for that particular tire. I’ll be very surprised if diameter had anything to do with it.

I'm talking about wet roads, regen is nowhere near strong enough to break any tire loose on a dry road. This is the situation I think they're trying to protect people from: Hydroplane and lifting off the accelerator
Admittedly I have no idea how they're doing it.

 

[Sam1]

Page 69 in the manual.

"However, your vehicle is designed to continuously recalibrate itself, and after changing tires it will increasingly restore regenerative braking power after some moderate-torque straight-line accelerations. For most drivers this occurs after a short period of normal driving, but drivers who normally accelerate lightly may need to use slightly harder accelerations while the recalibration is in progress."

Don't have time to test this out right now. Will report back later

Guess that means I would only need 11 seconds after putting new tires on to get everything recalibrated completely.

 

[Wennfred]

Next time try a reset, didn’t see anyone mention it here.

Fred

 

[Dangerous Fish]

Have you tried swapping only 3 tires at a time? It sounds like that's what happened here.
Regen on bald rear tires is super dangerous, my theory is that the car tries to detect that state by measuring the difference in diameter between front and rear.

Funnily enough I haven't swapped just 3 tyres and then driven any distance.
If the OP had a problem due to the rolling circumferences being different I would at least have expected the car to throw an error or warning before reducing regen, much like it does it you disconnect a wheel speed sensor.
I think without any more hard evidence or data to go on, at this stage it's difficult to draw any conclusions but I've driven my P3D on various tyres in all sorts of conditions including several times on skid pans and I've never experienced anything like the OP is reporting.

 

[Mattopotamus]

I can confirm that after a short drive the regen is back to normal

good to know and glad you made a post. I probably would have freaked when I do a tire change and experience this.