Regenerative Braking, Vibration, and Cold Weather

[ncridgerunner]

It was about 14 degrees when I started out this morning. I drove about 100 yards down the road with nothing unusual but when I let off the accelerator to go down a steep hill it there was a vibration that almost felt like driving over a rumble strip. The regen braking was not working which I understand is not uncommon in cold weather. The vibration however was a little disconcerting. At first I thought I ran over something but upon checking the road behind there was nothing in the road. Did not happen again on the 50 mile trip for the day.
Any ideas about what this could be or has anyone else experienced this?

 

[nate704]

What Causes Flat Spots on Tires? | Firestone Complete Auto Care

Notice vibrations and a thumping sound while driving? You may have flat spots on your tires. Learn what causes tire flat-spotting and how to prevent it.

www.firestonecompleteautocare.com

 

[ncridgerunner]

What Causes Flat Spots on Tires? | Firestone Complete Auto Care

Notice vibrations and a thumping sound while driving? You may have flat spots on your tires. Learn what causes tire flat-spotting and how to prevent it.

www.firestonecompleteautocare.com

Thanks for the reply. My tires are rotated every 5k. Pressures are good. This only happened one time. Flat spots on the tires would cause an ongoing issue.

 

[Waltjo]

It is just possible that the vibrations were a result of antilock brakes. The software is likely set to add braking when regen is limited, and very cold temperatures cause regen to be very limited. As you, " let off the accelerator to go down a steep hill", the brakes would applied by the software and it might be enough to trigger the antilock function, if the roads were slick that would make the antilock kick in more dramatically. Just a guess but it might be the cause.

 

[ncridgerunner]

It is just possible that the vibrations were a result of antilock brakes. The software is likely set to add braking when regen is limited, and very cold temperatures cause regen to be very limited. As you, " let off the accelerator to go down a steep hill", the brakes would applied by the software and it might be enough to trigger the antilock function, if the roads were slick that would make the antilock kick in more dramatically. Just a guess but it might be the cause.

I bet that is exactly what happened. It felt like a brake shudder the more I think about it. I was not aware that the software added braking when regen is not fully working. The regen braking was not working as I had to ride the brakes down the steep hill this morning which I have not done before.

Thanks for the heads up.

 

[ewoodrick]

And where was your car parked? Inside or outside? If you are like we are here in Atlanta, the temps were 17F this morning, cold enough to freeze some tires.

The car doesn't add braking when no regen unless you have that option turned on.

 

[jkdman123]

I bet that is exactly what happened. It felt like a brake shudder the more I think about it. I was not aware that the software added braking when regen is not fully working.

Edit: What ewoodrick said.

 

[ncridgerunner]

And where was your car parked? Inside or outside? If you are like we are here in Atlanta, the temps were 17F this morning, cold enough to freeze some tires.

The car doesn't add braking when no regen unless you have that option turned on.

The car was parked under our carport. Here in the mountains of NC wintertime low temps are not uncommon. Never heard of a tire freezing though they do ride a little rougher when temps are getting near zero. The temp was 11 degrees when I started out this morning and the vibration occurred once at about the same place on our road as yesterday. It felt exactly like an anti-lock brake pulse so I believe it is some setting in the software. I do not recall turning on an option to add braking when there is no regen but I will check the menu for this when I have a chance.

 

[ewoodrick]

The car was parked under our carport. Here in the mountains of NC wintertime low temps are not uncommon. Never heard of a tire freezing though they do ride a little rougher when temps are getting near zero. The temp was 11 degrees when I started out this morning and the vibration occurred once at about the same place on our road as yesterday. It felt exactly like an anti-lock brake pulse so I believe it is some setting in the software. I do not recall turning on an option to add braking when there is no regen but I will check the menu for this when I have a chance.

I was out in Breckinridge CA years ago. They often make fun of tourists that have problems starting cars when the temperatures get around 0F.

Well, this week, they were at -30F. The radio was telling everyone to just stay home, even the tow truck's tires were frozen. If you couldn't get the car going, the tow trucks weren't going to be able to help.