Nokian Hakkapeliitta R2 Snow Tire Report

[Mayhemm]

Just had the Hakka R2s mounted today, at Discount Tire ($227 apiece plus usual charges). I put together a checklist of things to be mentioned to the dealer when not mounting the tires at a Tesla Service Center:

1) Show them the "Jacking" page in the manual
2) Put up a "how do you drive it" tutorial on the display and walk them thru it (I like VALET - TESLAMODS )
3) Warn them that leaving the fob in the car might get it locked in there while they're working
4) Ask them to mark the mounted location of the old tires so they can be put back in the same place come spring-time
5) Make sure they put the wheels back to the corner they came from so the TPS isn't confused
6) Confirm they get inflated to 45 PSI
7) Confirm no TPS warnings appear after they're done

Should we have a "checklists" thread? I need to put my "things to do when accepting delivery" checklist somewhere...

The only problem with that list is that most shops will just go "Yeah, okay buddy." and then proceed to do what they normally do.

That's why I always change/rotate them myself. Though, I understand this is not an option for everyone.

 

[jerry33]

6) Confirm they get inflated to 45 PSI
7) Confirm no TPS warnings appear after they're done

Set the pressures the next morning before driving using your own high quality pressure gauge regardless of what the tire shop thinks they have set it to. This includes Tesla Service Centres.

Don't rely on the TPMS to do anything other than warn you of a very low tire. It's 100% useless for day to day pressure maintenance.

Also don't forget to reset the TPMS from the display after a tire change.

 

[Cottonwood]

I can tell you that the Hakka R2's on my 16% driveway are amazing. I could do it most of the time in my P85 with Hakka 7's, but needed some care, good driving technique, and good momentum control. In the P85D with the Hakka R2's, the car just goes up the hill without question. I even came to a full stop on the steepest, snow covered (packed powder) sections then started again; there was no hesitation, the car just drove up the hill.

Here is a picture of the driveway up to my place from 600 feet vertical, above the house. The sun has already burned off some of the snow on the asphalt section up near the house, but there are still plenty of snowy sections below in the woods.

I love my P85D on Hakka R2's in the snow!

 

[Cottonwood]

Today was a good day in Boulder for winter tire testing. We had freezing rain last night followed by a dusting of powder, "dust on crust." There were many spots on the driveway where walking was difficult. The conditions were similar to walking on an ice rink in street shoes.

I had the P85D on Hakka R2's and the P85 in Hakka 7's both on Boulder. Another opportunity for some tire testing!!! An AWD P85D with Hakka R2 stud-less tires vs a 2WD P85 with Hakka 7 studded tires. The R2's have about 1,000 miles on them, and the 7's have about 12,000 miles and 2 years on them.

I used the same 0 to 20 to 0 test, with full accelerator then full brake, letting traction control and anti-lock breaking doing there thing. Here is a picture of the driveway showing a P85D launch in the powder covered ice.

I did two runs with each car, and picked the clearest of each. Below are plots of the acceleration data from these. I aligned the starts, and labeled the 0 MPH starts, the 20 MPH acceleration to braking points, and the 0 MPH end points.

Here are some observations from the acceleration plots:

1. In braking, the braking deceleration and time was approximately the same for both cars and tires. This makes sense because both are using all 4 tires to stop and similar anti-lock braking technology. What is significant is that the stud-less R2's seem to stop as well (or slightly better than) the studded 7's.
2. As expected, the AWD has about 2x acceleration in the start over the 2WD.
3. Interestingly, the acceleration after the initial start of the AWD was approximately equal to (and growing better) than the deceleration of both cars.
4. Both cars traction control has a brief moment of higher acceleration, followed by much lower acceleration, then settling into an increasing acceleration. This implies that "slip" mode to stay in the initial slipping mode may well help getting started in very slick conditions.
5. Both cars anti-lock braking had a larger deceleration before letting up, and settling in. The P85 seemed to let up at the end a little more than the P85D as the cars came to a stop.
6. Both traction control and anti-lock braking in both cars seem to have an oscillation or "hunting" cycle, with a period of 0.3 to 0.6 seconds.
7. Getting 0.3 to 0.4 g acceleration for the AWD P85D and the same deceleration for both cars is incredibly impressive on a driveway that was difficult for me to walk on!

These data present graphically and quantitatively why the AWD P85D does so much better than the 2WD P85 on my 16% winter driveway in Pagosa. Subtract 0.16 off of both of those plots and the P85 does not have much left beyond just maintaining forward speed.

 

[MrClown]

Wow, nice comparison. I'm also surprised by the studless stopping better than the studded on the ice but maybe it's due to better ABS on the D or maybe the extra weight over the front wheels? Either way, it's good to see that the R2 are very competent on ice. I'd be interested to see that graph with both runs aligned at the 20 MPH point so we could better compare both the acceleration and braking profiles.

I may have to trade my studded tires for a set of the R2 on my other car now.

 

[stevezzzz]

Thanks for the data, Cottonwood. Makes me happy that I was able to find a set of R2's for my D: they get installed on Monday.

 

[wycolo]

Did you wind a coil around an oatmeal box and suspend a steel ball from pano roof into the box which was filled with styo peanuts or . . . ??

Enquiring minds *need* to know!!
--

 

[Cottonwood]

Did you wind a coil around an oatmeal box and suspend a steel ball from pano roof into the box which was filled with styo peanuts or . . . ??

Enquiring minds *need* to know!!
--

From Nokian Hakkapeliitta R2 Snow Tire Report - Page 6:

... I use the "Motion Data Logger" app from JadeMind on the iPhone to log the accelerometer data at 100 Hz and then post processed it in a spreadsheet. I averaged and subtracted out the gravity vector and then calculated the magnitude of the remainder acceleration vector. This makes both acceleration and braking (deceleration) positive. ...​

 

[wycolo]

> to log the accelerometer data [Cottonwood]

But what accelerometer (transducer) might you be employing to measure g-forces? Or should I have already known that all iPhones have one built in?
--

 

[Cottonwood]

> to log the accelerometer data [Cottonwood]

But what accelerometer (transducer) might you be employing to measure g-forces? Or should I have already known that all iPhones have one built in?
--

iPhones have had 3D accelerometers, 3-axis gyroscopes, and a magnetometer for a long time. "Motion Data Logger" just logs the raw hardware samples and saves them as a csv file that you can load into a spreadsheet and analyze.

 

[tga]

I had the P85D on Hakka R2's and the P85 in Hakka 7's both on Boulder. Another opportunity for some tire testing!!! An AWD P85D with Hakka R2 stud-less tires vs a 2WD P85 with Hakka 7 studded tires. The R2's have about 1,000 miles on them, and the 7's have about 12,000 miles and 2 years on them.

Have you given any thought to running a similar test, swapping wheels, and re-running the test? That way you could eliminate the tire variable and get a true AWD/RWD comparison. Or you could find someone to take your Hakka 7's and get a set of R2's for the P85.

Does anyone have any experience with a RWD S on R2's, on steep roads, with hardpack snow/ice? My driveway has some steep sections (not sure how it compares to Cottonwood's 16%), and I don't have a good sense of how well a RWD car on winter tires would handle it. The last steep section is at the intersection with the road, so taking a running start isn't really an option (although a bucket of sand is a good idea). Plus the surrounding roads have some steep sections (and aren't plowed very well).

I'm trying to decide between ordering a new S85D or getting a used P85 for a bit less. While there's a lot of discussion/videos about the P85 in bad winter, very little that I can find talks specifically about hill climbing capability (beyond Cottonwood's trip up his driveway and Bjorn's very first video).

 

[Cottonwood]

Have you given any thought to running a similar test, swapping wheels, and re-running the test? That way you could eliminate the tire variable and get a true AWD/RWD comparison. Or you could find someone to take your Hakka 7's and get a set of R2's for the P85.

I'm more of an opportunistic tester; when the conditions are right in front of me, I will collect data.

If you look at my data, the stopping performance for the R2's on the P85D and the 7's on the P85 were about the same. This makes sense because both cars have 4 brakes and good anti-lock brake controllers. It also tells me that for the conditions of the test the studless R2's and the studded 7's had about the same traction. Most people agree that studs only have a significant advantage on wet or melting ice. For snow or cold, hard ice, studs offer little advantage over good, studless snow tires. My test was on cold ice covered with a dusting of dry snow.

Given the performance that I have seen so far with the Hakka R2's, I doubt that I will buy a studded tire again. I highly recommend them as a great winter tire.

As to AWD vs 2WD, with the even weight split of the MS, it's very simple. Can you get along with 50-60% of forward force in slippery conditions in the 2WD, or do you want (need) 100% of forward force using all 4 wheels (AWD)? I could make it up my 16% driveway in the 2WD P85, but I had to be careful and skillful. The AWD P85D just goes up the driveway without question.

Percent grade is just rise over run. Grade (slope) - Wikipedia, the free encyclopedia 16 feet of elevation gain in 100 feet of driveway is a 16% grade. For the techies, that is the tangent of the pitch angle; tan(9˚)=16%, so a 16% pitch is a 9˚ rise. Digital level will measure it directly, you can use yard sticks, levels, etc to do a direct measurement, or you can use other ad hoc methods with a level to measure rise over run.

 

[tga]

If you look at my data, the stopping performance for the R2's on the P85D and the 7's on the P85 were about the same. This makes sense because both cars have 4 brakes and good anti-lock brake controllers. It also tells me that for the conditions of the test the studless R2's and the studded 7's had about the same traction.

I hadn't paid attention to the breaking data, but that's a good point and makes sense.

Digital level will measure it directly, you can use yard sticks, levels, etc to do a direct measurement, or you can use other ad hoc methods with a level to measure rise over run.

Now that you mention it, I'll just grab some 2x4's from the garage and lay them on the hill (to average out the measurement over a longer area) and use a digital level. Thanks.

 

[hingisfan]

How much tire life can one expect from these R2's?

 

[widodh]

I'm currently in Sweden and heading to Norway with my Model S and driving the Hakka R2s. Great tires! It's currently -12C here (Krokum SuperCharger in Sweden) and snowing heavily, but with my RWD Model S I have perfect control.

I'd really recommend these in winter conditions with snow.

 

[jerry33]

How much tire life can one expect from these R2's?

Winter tires don't get UTQG ratings because the wear can vary dramatically depending upon temperature and road conditions. Anecdotal numbers also don't mean a lot because by the time enough winters have passed to get a good handle on tire life, the tires have changed. You basically purchase winter tires for safety, not for longevity.

 

[Denarius]

How much tire life can one expect from these R2's?

I've never had a set of winter tires last less then 2 winters, usually more and I'm hard on tires. Do make sure you rotate!

 

[MrClown]

How much tire life can one expect from these R2's?

Winter tires generally don't come with an expected life. Michelin's XIce XI3 have a 40,000 mile warranty though. I'll believe it if/when mine last that long.

 

[jerry33]

Winter tires generally don't come with an expected life. Michelin's XIce XI3 have a 40,000 mile warranty though. I'll believe it if/when mine last that long.

A tread life warranty is basically a sales tool. If you really get far less than the warrantied miles, it's an alignment or foot problem which have a good chance of being disallowed, so the normal payout is for something like 80% of the warranty life. This means you'll get 20% off of your next set of tires. However, that 20% is based on the MSRP--not on what you actually paid. Mostly tires are sold for 20% to 25% off of MSRP (with some exceptions). MSRP on 245/45ZR19 PS 3 is $449 vs 365 at Tirerack 81%.