Will TACC usage cause greater brake-pad wear?

Will TACC usage cause greater brake-pad wear?

Took delivery of my P85D a couple of weeks ago. Flawless process for me from confirming the order to picking up the car. A special shout-out to my DS Nikki M. who was very responsive during the wait period. Delivery was great too; armed with the checklist from these forums, we went over the car with a fine-toothed comb and couldn't find a single thing wrong. Fit and finish was excellent, great job by Tesla QA! I may also be one of the last ones to get next-gen seats both front and back, so perhaps I have a classic too :)

I've been using the TACC for the last two weeks and very frequently find that it allows the car to get too close to the car in front (I have the 6.2 update) and doesn't really use regen as effectively as I would do myself. I find myself frequently canceling the TACC to allow regen to slow the car down instead of braking hard at the end. I'm wondering, will regular TACC usage cause greater brake-pad wear? What do people think? | April 11, 2015

Sounds likely you'll have more wear, but not enough to really matter. I suspect brakes will last 100K miles or more (and maybe a lot more). Tesla used significantly oversized brakes, partly since they have to work even if there is no regen.

tezzla.SoCal | April 11, 2015

Unlike most cars, Tesla brakes are warrantied for wear.

Tstolz | April 11, 2015

Sounds like you need to set your following distance to a higher number. Twist the end of the cruise stock to set distance. There is no need to use your brakes in normal driving other than to come to a full stop or emergency braking.

KL | April 11, 2015


I've had the exact same experience. The 6.2 TACC is worlds better than before, but it is not as good as manual control (when a driver is fully attentive). Overall, I like the TACC a lot because it doesn't get tired, it doesn't get stressed out, it doesn't get distracted, etc. But it could still be smoother and use less brake pad vs. recouping watts. :) I find that in stop-and-go traffic situations, be it highway or city, it uses the brakes a lot more than it should.

- K

jeffjo | April 11, 2015

Maybe I'm a bad driver (nevermind 20+ years of no accidents), but I feel I'm safer on TACC supervising the car than driving myself. Just me...

Uncoiled | April 12, 2015

@sandpiper @KL
What following distance do you normally use?

Have you tried a higher number to see if it brakes less?

garygid | April 12, 2015

I use max following setting 7, which seems to work fairly well.

However, merging into an adjacent lane of closely-spaced,
different-speed traffic generally requires disabling the TACC.

Is there an easy way to see that the car is using mechanical
instead of (or, more usually, in addition to) regen braking?

KL | April 12, 2015

I always use the max setting of 7 for following distance, which is bout 3.5 seconds of time.

I wish it were 4-6 seconds which is what I prefer so I can use that buffer to smooth out deceleration events (an avoid hitting potholes in the 21"s!). My reflexes are still fast and safety is a very important value in my life so I tend to drive very attentively. 21 years of driving experience, zero accidents at fault (I was hit while parked once ...). Still, TACC improves safety because it relieves stress and frees up my attention to do more complex tasks, like scan the road, mirrors, and instruments. I just wish it would be smoother and I'm sure it will in 6.3

- K

sandpiper | April 12, 2015

I'm using 5 as the car-length distance setting. The problem is that while TACC tries to maintain this distance at cruising speeds, it needs to close it when stopping. This is understandable, stopping 5 car lengths behind in stop-n-go traffic wouldn't be good. What I find is that in traffic that frequently picks up speed but then abruptly stops, the TACC will happily want to rush headlong into the car in front and then brake quite abruptly at the end. It's a thrill no doubt but one I'd rather live without :)

I haven't tried settings greater than 5 extensively, smaller ones make me too uncomfortable. I don't know if the latest update (.153) makes a difference, I'll find out next week.

Overall I think I'll use the TACC more when I'm tired or distracted instead of all the time. In stop and go I'll keep it engaged but cancel it to allow the car to coast to a stop on regen and re-engage it again.

sandpiper | April 12, 2015


Yes I was wondering the same too, I don't think there is. You can see the regen activating but sensing whether the brake also is, isn't easy. I've tried keeping a light foot on the brake pedal but can't always tell. A brake light on the dash would be nice.

BTW, entirely different topic, how does one quickly flash one's headlights in Model S? Sorry if this is obvious and I missed it.

Son of a Gunn | April 12, 2015

Sandpiper, have you cleaned your radar's aperture window? Imagine dirty eyeglasses.

sandpiper | April 12, 2015

SoaG: How do I clean the radar's aperture window? Is there more to it than keeping that section of the windshield clean? Thanks.

freemarket | April 12, 2015

I've thought the same thing in traffic regarding break wear. The system is no where near nor likely will ever be as good as a human to make the slightest decisions on breaking and when and when it's not necessary. The TACC clearly uses the regen, but you also know when it's breaking. I would say distance settings accounts for 10% of actual brake usage, the rest is just coming down from cruising speed where most drivers probably allow way more regen. I rarely hit my brakes. The TACC to me seems to have a near 5-10x usage of the brakes than me controlling it myself.

I'm not worried at all however. I would assume over time too that Tesla will continue to improve the TACC in this area under future updates.

Haggy | April 12, 2015

In theory, it should come down largely to how much regen the car can use. If the car is slowing down and the regen isn't at maximum, then more could be done with regen. If it is at maximum, it doesn't necessarily imply that the brake pads are needed, especially if it's slowing down but not expecting to stop. That may be a bit simplistic, but when there isn't a lot of regen, it may be that there isn't a lot of need, and not necessarily that the brake pads are being used instead.

Brian H | April 13, 2015

No flash.