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which stopping mode is safest for rwd winter snowy day driving?
- Thread starter coolmanfever
- Start date
Candleflame
Active Member
they are all the same.
makensure you get winter tires.
Hold is terrible for icy conditions. It can essentially lock up the rear at low speeds easily.
I go with roll, creep seems to also work fine for my wife. Just not Hold.
I go with roll, creep seems to also work fine for my wife. Just not Hold.
RedModel3
Member
Well, if we are going to go with what was standard in the ICE age, anything that decreases sudden acceleration/deceleration is good. I'd never really thought about this because I live in Nashville and we rarely get snow, but I spent the first half of my life in Wisconsin, North Dakota, and Illinois. I might be inclined to NOT use Hold, because I always felt that I could feel the response of the car better if I had my foot on some pedal rather than letting the car do its own thing. So AP or EAP would be out, and Hold as well.
But on the other hand, with the traction tech in these cars, maybe all of this is out the window. Anybody have anything more scientific to add?
But on the other hand, with the traction tech in these cars, maybe all of this is out the window. Anybody have anything more scientific to add?
webbah
Active Member
To quickly adapt it's good to create a new Driver Profile called Winter (or something relevant) and set the settings up for that. I setup chill mode accel, roll, and disable mirror folding. I don't necessarily use this profile all winter but when it is snowing or icy. I also have one called Rain which only switches to low regen so I use the brakes more and keep the rotors and pads clean from rust.
I’m starting to reconsider my position on using Chill mode. In my experience in driving on ice and snow, the primary concern is to avoid locking the tires. The more you can keep the tires rolling, the more control you have over the car. On my previous vehicles, this meant cautious use of the brakes (pumping, antilock).
My understanding of the regenerative braking is that it does not lock the tires and allows them to roll while the motor slows down the car. The Model 3 behaved exactly how I expected with antilock braking when compared with previous cars. I didn’t feel that the regenerative braking had any negative impact on traction.
My understanding of the regenerative braking is that it does not lock the tires and allows them to roll while the motor slows down the car. The Model 3 behaved exactly how I expected with antilock braking when compared with previous cars. I didn’t feel that the regenerative braking had any negative impact on traction.
pan
Member
I'm a skier and live in Colorado. I travel the mountains regularly in the winter. I seek out bad weather just because skiing in fresh snow is best. I never, ever switch away from standard acceleration and regen. Once you learn to have a gentle touch with the accelerator, feathering the pedal is all that's required to keep your wheels rolling. A light touch on acceleration will get you going. I know many don't have the capability to use the pedals, brake, or accelerator lightly. So use whatever you like. Just understand those who can handle more precise motion can use the full set of tools Tesla offers.
ljbad4life
Member
As a RWD owner it's
Regen: Low
Creep, roll or hold: doesn't matter. Hold is only Holding the brake when at a stop nothing else. Regen braking is what slows the car down, set it to low.
Good set of snow tires in anything more than 4 inches (10cm) worth of snow.
Drive smoothly, resist flooring it from stops. 2 winters in without a problem.
Regen: Low
Creep, roll or hold: doesn't matter. Hold is only Holding the brake when at a stop nothing else. Regen braking is what slows the car down, set it to low.
Good set of snow tires in anything more than 4 inches (10cm) worth of snow.
Drive smoothly, resist flooring it from stops. 2 winters in without a problem.
When I had a manual transmission in my ICE car, I always downshifted to slow the car in order to avoid brake lockups.
Regen slowing, is almost like downshifting. Rather than apply the brakes, I prefer letting up gradually on the accelerator and letting the car's regen do the "braking" without brakes.
Regen slowing, is almost like downshifting. Rather than apply the brakes, I prefer letting up gradually on the accelerator and letting the car's regen do the "braking" without brakes.
Note regarding my last post: do note I'm talking about ice. With snow tires on relatively "grippy" snow, you can get away with a lot more. But I can't perfectly predict where ice is, so I play it safe.
Where I live, we constantly have ice on the roads at night in winter. Probably 50% of nights, and more often at certain high-traffic intersections if it recently snowed. I'm pretty familiar with how it behaves on ice.
It's confusing, but I'm talking about the "Hold" stop mode, not the "Hold" brake-holding feature. The stop mode continues regen even at low speeds (whereas "Roll" greatly reduces it), all the way to a stop. It can even apply reverse power to try to stop the car that way. Once stopped in "Hold" stop mode, it will engage the "Hold" brake-holding feature.
The Hold stop mode, on slippery ice, without exception, always locks up on me at very low speeds (<5km/h or so). Sometimes this is without much consequence, but at one set of lights it will always swing me 45 degrees out for example. Unlike an anti-lock braking system, it doesn't "release" it at these very low speeds.
So yeah, it's a thing. It can be completely avoided by using Roll. The owners manual also has some statements regarding regen in icy conditions, because it's not great in such conditions.
Chill plays an important roll in very icy conditions (or for unexpected ice). When starting from a stop, Model 3 is not gentle without Chill for that first few degrees of forward acceleration. It will almost always break loose first on ice even with the most carefully controlled input. Putting it in Chill seems to prevent this, and is something I could test reliably last Winter. This breaking loose matters because it can send your back end sideways at an intersection, for example (as most aren't perfectly flat).
But do note I'm talking about ice. On relatively "grippy" non-compacted snow, your pedal input plus traction control is probably sufficient as you expect.
The regenerative braking absolutely can result in lost traction as well, and when it does so it performs much worse than an ABS system. If it catches it, it removes regen all at once (jarring) and then generally re-engages it all at once some seconds later (jarring yet again). If you previously drove an ICE vehicle, the panic response to lost traction (i.e. remove foot from accelerator) is probably detrimental in this case and very hard to fight. But regardless, the behaviour is counter-productive.
Friction brakes are better for control, especially as ABS systems are much more mature. The regen bang on/bang off approach to regain traction is counter-productive.
Further,
See above in this post re: stop mode vs. brake hold mode, both of which are labeled "Hold". It's confusing. The Hold stop mode does more than holding the brake at a stop, it uses regen and input power to slow you down to a stop, then applies the brake hold.
Where I live, we constantly have ice on the roads at night in winter. Probably 50% of nights, and more often at certain high-traffic intersections if it recently snowed. I'm pretty familiar with how it behaves on ice.
It's confusing, but I'm talking about the "Hold" stop mode, not the "Hold" brake-holding feature. The stop mode continues regen even at low speeds (whereas "Roll" greatly reduces it), all the way to a stop. It can even apply reverse power to try to stop the car that way. Once stopped in "Hold" stop mode, it will engage the "Hold" brake-holding feature.
The Hold stop mode, on slippery ice, without exception, always locks up on me at very low speeds (<5km/h or so). Sometimes this is without much consequence, but at one set of lights it will always swing me 45 degrees out for example. Unlike an anti-lock braking system, it doesn't "release" it at these very low speeds.
So yeah, it's a thing. It can be completely avoided by using Roll. The owners manual also has some statements regarding regen in icy conditions, because it's not great in such conditions.
Chill plays an important roll in very icy conditions (or for unexpected ice). When starting from a stop, Model 3 is not gentle without Chill for that first few degrees of forward acceleration. It will almost always break loose first on ice even with the most carefully controlled input. Putting it in Chill seems to prevent this, and is something I could test reliably last Winter. This breaking loose matters because it can send your back end sideways at an intersection, for example (as most aren't perfectly flat).
But do note I'm talking about ice. On relatively "grippy" non-compacted snow, your pedal input plus traction control is probably sufficient as you expect.
The regenerative braking absolutely can result in lost traction as well, and when it does so it performs much worse than an ABS system. If it catches it, it removes regen all at once (jarring) and then generally re-engages it all at once some seconds later (jarring yet again). If you previously drove an ICE vehicle, the panic response to lost traction (i.e. remove foot from accelerator) is probably detrimental in this case and very hard to fight. But regardless, the behaviour is counter-productive.
Friction brakes are better for control, especially as ABS systems are much more mature. The regen bang on/bang off approach to regain traction is counter-productive.
Further,
- Friction brakes apply to all 4 wheels, and you thus get the stopping power and available traction of four different spots at all times.
- Model 3, RWD or AWD, will only really use the rear motor for regenerative braking. And that one motor serves two wheels - the one with the least traction is your limit! (because of the open differential)
- Because of that, it will be easier to lose traction momentarily with regen-only braking.
- Anti-lock brake systems + traction/stability systems generally have independent control of each individual brake (4 total) when traction is lost.
- When traction is lost during regen for the Model 3, all it can do is modulate the "brake" on that motor's axle, which again results in one tire being the limit of your available traction.
See above in this post re: stop mode vs. brake hold mode, both of which are labeled "Hold". It's confusing. The Hold stop mode does more than holding the brake at a stop, it uses regen and input power to slow you down to a stop, then applies the brake hold.
webbah
Active Member
See the post above this. As I mentioned previously, I use this profile when it is heavily snowing and I expect ice. The above post is very clear and informative. In Switzerland we have many steep and tight roads in the alps, with no side barriers, single lanes almost and in some cases rarely plowed. Using heavy regen CAN break the wheels lose in a decent when the car suddenly shifts from snow to ice no matter how much you are feathering the go pedal. I've found low regen to be the best option. The second reason is I like to use my brake pads in these conditions to remove the salt and grime that accumulates and keep my brakes in clean working order.
I've driven a full winter in Quebec (read multiple feet of snow fall, ice etc) on normal regen, normal acceleration, hold. The car's stability system is the best I've ever seen. The regen will lower if the car senses the wheels locking, just like abs would. It's almost magical. Other cars cut regen when it slips and that gives a very bad feeling, not so with the 3.
Don't lower your regen in fear as most seem to do. Don't cut yourself from potential power in chill mode. DO however drive carefully when it's slippery and get good winter tires.
Don't lower your regen in fear as most seem to do. Don't cut yourself from potential power in chill mode. DO however drive carefully when it's slippery and get good winter tires.
With an AWD car, I prefer Hold for the ability to carefully regulate the braking force through regen.
For an RWD car, it might be problematic - there's no way to stop the rear wheels from slipping while getting any brake force from the front wheels unless you switch to low regen. I haven't driven a RWD EV in slippery conditions.
For an RWD car, it might be problematic - there's no way to stop the rear wheels from slipping while getting any brake force from the front wheels unless you switch to low regen. I haven't driven a RWD EV in slippery conditions.
Thanks for the detail scientific explanation
I do have winter tires. In conclusion I guess HOLD stopping mode will be safest for winter driving on snow and ice
In general, I am in total agreement with what you wrote; however, when it's a Snow Day (that's my driver setting name) I have my settings on low regen, and chill accel, seat's a little higher and further back. The reason being that if it's a real snow day, I've got heavy winter boots on, and my foot sensitivity is not as good as with non-boots, so I change my settings to give me a little more margin of error, since I don't think I modulate the pedals quite so precisely.
For two winters on the original all season tires (not all weather but maybe next set), I haven’t changed any settings. I certainly drive carefully but feel that it is extremely easy to do so without engaging any system limitations.
I will say that, for the most part, these past two winters have been relatively mild but there was enough snow to rut my alley which caused an ice patch under my drive wheels just as I was slowly backing into garage. After trying all different settings and methods, the trick was to pour out an entire salt bag so I now carry one for weight and extraction in the winter. However, starting and stopping on actual roads has never been a problem even when they haven’t been properly cleared.
Ultimately, modulating your accelerator is probably the best thing over changing any settings but everybody is different so see how you feel.
(chill mode is a gimmick unless you have a lead foot with a mind of its own)
I will say that, for the most part, these past two winters have been relatively mild but there was enough snow to rut my alley which caused an ice patch under my drive wheels just as I was slowly backing into garage. After trying all different settings and methods, the trick was to pour out an entire salt bag so I now carry one for weight and extraction in the winter. However, starting and stopping on actual roads has never been a problem even when they haven’t been properly cleared.
Ultimately, modulating your accelerator is probably the best thing over changing any settings but everybody is different so see how you feel.
(chill mode is a gimmick unless you have a lead foot with a mind of its own)
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