RWD & Hydroplaning

[tech_nerd]

Just curious, from other RWD owners, how well do you think the M3 in RWD configs handles the rain? I'm completely shocked how scary it has been a couple times I've been in heavy rain situations. I continuously felt the rear end start to move out on me, and that's while going 45-50mph, it felt completely unstable. And even though it was heavy rain, I was by far the slowest person on the road, so I don't think it was purely the conditions. I've had a mustang before, I figured nothing could be worse than that in the rain, but I legitimately got off the highway and took back roads because of how unstable it felt.

Brand new M3, 3k on it, tires inflated to 45 all around. Have others experienced this? Just curious for answers, as I rented a M3 RWD on Turo before i bought mine, and he had just put new tires on it, and I was shocked at how well it handled the rain, so I don't know if there is something up with mine, or if the stock tires are just that bad?

 

[jjrandorin]

Rain performance is going to be due to tires, not vehicle, if you have had other RWD vehicles and are used to that platform in general.

 

[Vines]

There are a few cases of M3 coming out with bad alignments, and this sounds like that may be the case, I would especially check toe settings.

Also, I wouldn't go beyond 42 psi myself, though I understand higher pressures are supposed to prevent hydroplaning.

 

[GtiMart]

Some people complain about the RWD in slippery conditions, under acceleration, as they feel the back end get sideways a bit. I don't have first hand experience as I have a dual motor. I think the stability control is more than capable of handling it and you will not do a 180, but it's possible that the couple inches of sideways play before stability control kicks in scares a lot of people. Better tires are always useful. In this case, tires that are better in the rain.

EDIT: I should add that you should not accelerate hard on a slippery surface. With an EV it's hard with all that instant torque. Be gentle on the pedal, or use chill mode if it's easier for you.

 

[SteveISU]

A lot depends on your right foot and what tires you have on the car. I had a Subaru Legacy GT that I could break loose pretty easily and rip donuts like no ones business, car had full time AWD.

 

[SFLM3P19]

what tires are actually on the car? my m3p with dual motors is one of the best wet handling vehicles ive owned, even with race tires.
Your experience isnt totally out of line, but heavy rains and standing water is going to do this. Could there have been excessive standing water on that highway?

better wet rated tires keep you straighter even with hydroplaning...my Hankook RS4 tires have a huge center band tread that acts like a rudder when driving aggressive through puddles.

 

[CarlThompson]

I live in NorCal and here it rains a lot every winter. I drove a RWD Model 3 here for 4 years (just sold it) and it handled better in the rain than most cars I've had (a lot).

But regardless of the car you must know how to handle hydroplaning safely. Rule #1 for everything is always travel at the appropriate safe speed for the conditions. Lots of people in CA don't seem to get this rule, unfortunately. If there is standing water in the roadway you should be able to see it in time day or night to react properly if you are driving at the speed you need to be. You want to put yourself in a position where you don't need to turn the wheels while you're in the puddle. You also want the car to be coasting... not accelerating or decelerating. Finally, you want to make sure you are running on tires with a reasonable amount of tread remaining that can handle lots of water if you can. If you follow those rules you can handle any car safely in the rain.

I'll add that if the conditions are wet and you suspect there may be standing water on your route then you may want to select the lowest amount of regen your car allows. This will make it easier to coast if you hit a patch of water. Tesla has removed the option to select regen level on newer cars and I think they should reconsider that decision because there are some conditions like this where lower regen may be safer.

One more thing... You probably already know this but if it has been dry for a very long time before the rain then the first few days of rain the roads are MUCH slicker than after it's been raining for a while. This is because all the oils that have seeped into the road during the dry time float to the surface during those first rains making the road slippery. After it's been raining for a while the oils get washed away and the roads aren't as treacherous. In CA it can be completely dry for months at a time so this is common when the rains start.

 

[Vines]

I live in NorCal and here it rains a lot every winter. I drove a RWD Model 3 here for 4 years (just sold it) and it handled better in the rain than most cars I've had (a lot).

But regardless of the car you must know how to handle hydroplaning safely. Rule #1 for everything is always travel at the appropriate safe speed for the conditions. Lots of people in CA don't seem to get this rule, unfortunately. If there is standing water in the roadway you should be able to see it in time day or night to react properly if you are driving at the speed you need to be. You want to put yourself in a position where you don't need to turn the wheels while you're in the puddle. You also want the car to be coasting... not accelerating or decelerating. Finally, you want to make sure you are running on tires with a reasonable amount of tread remaining that can handle lots of water if you can. If you follow those rules you can handle any car safely in the rain.

I'll add that if the conditions are wet and you suspect there may be standing water on your route then you may want to select the lowest amount of regen your car allows. This will make it easier to coast if you hit a patch of water. Tesla has removed the option to select regen level on newer cars and I think they should reconsider that decision because there are some conditions like this where lower regen may be safer.

One more thing... You probably already know this but if it has been dry for a very long time before the rain then the first few days of rain the roads are MUCH slicker than after it's been raining for a while. This is because all the oils that have seeped into the road during the dry time float to the surface during those first rains making the road slippery. After it's been raining for a while the oils get washed away and the roads aren't as treacherous. In CA it can be completely dry for months at a time so this is common when the rains start.

All great tips!

One more tip is to drive just out of the tire grooves, usually with one set of tires near the line. The roads get deeper puddles where the cars tend to travel most often.