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Living in Minnesota, the inevitable winter snows are coming (insert Game of Thrones quip here)..
Couple of questions...
1. Recommendations for good winter tires
2. Can I drive with symmetrical tires instead of needing to get fronts and rears?
I have been doing some looking as well, and here's what I found. My owner's guide (I have a 2003 TT) shows 225/40-18 fronts and 265/35-18 rears for winter tires, 225/40-18 and 295/30-18 for summer tires, and I have used 245/40-18 fronts and 315/30-18 rears (GT2 sizes) for track tires.
Track tires are Nitto NT01's:
245/40-18 is 789 revs/mile
315/30-18 is 796 revs/mile
so the fronts are turning slower. Incidentally the digital speedo is exactly correct with these tires!
Summer tires are Sumi HTR3's:
225/40-18 is 823 revs/mile
295/30-18 is 837 revs/mile
so the fronts are turning slower here, too. Incidentally the speedo reads 4 mph slow at highway speeds. Indicated = 75, actual = 71.
Suggested winters, I looked up the Michelin Pilot Sport A/S on tire rack:
225/40-18 is 825 revs/mile
265/35-18 is 816 revs/mile
So now the fronts are turning faster. What's up with this, Porsche? I guess it's OK, as they recommend it. I've read many times of odd handling and performance issues with fronts turning faster though. Seems like the viscous coupling doesn't like that.
And I see CarloCarrera is suggesting smaller sizes for the Conti's, 215/45-18 and 275/35-18.
The Porsche recommended winter sizes raised my eyebrow a bit.
I run Bridgestone Blizzak LM-32s and like them very much as a performance oriented winter tire. They definitely lean more towards performance than deep snow traction, but I think that's probably what most people with a 911 are looking for.
I run 235/40 18 front, and 275/35 18 rear. One trick is that while it will stretch onto the rim, a 275 tire is not ideal on the stock 11 inch wide rears. Finding a 10 inch wide wheel with the right offset can be done, but isn't easy. I don't think you can find a 295 winter tire, and narrower is better anyway in snow. I bought Forgestar F14 wheels because they are reasonably priced and you can choose your offset. I went with 18x8.5 ET44 front and 18x10 ET25 rear. This fits nicely.
The winter size above runs a slightly smaller front tire. I did quite of bit of research into this, including talking to Porsche techs, my local indy shop, as well as the guy who wrote the book on the 996 (literally, it's called "Porsche 996: The Essential Companion.") The conclusion I am comfortable with is that the important thing for handling is that there is a slight difference in rotational speed front to rear. This difference in speed engages the viscous coupling, sending just a bit of power forward at all times (I have 5% in my head?). The OE summer wheels have a slightly bigger front (rears turning a bit faster), and that means that if the rears slip and move even faster still, the coupling is already engaged and power moves forward seamlessly, and more of it. If the fronts are slightly smaller but by the same ratio, then the power is still sent forward under normal driving, but if the rear wheels slip there would be a nano second where the wheels would match speeds (in theory no engagement) and then as the rears spin faster the viscous coupling engages again and power goes forward commensurate with the difference in speed (more difference, more power forward, up to a point).
I can tell you from many thousands of miles on winter tires that there is absolutely no perceptible feeling of engagement when the rear wheels slip with the above tire sizes. The transition is smooth, and the awd works as it should. Each of the sources I talked to said that the key for the health of the system is a slight difference in rotations front to rear (less than 1%), but it does no damage to the system to have the front slightly smaller. Porsche's engineers agreed, and the recommended Porsche winter tire sizes are the same orientation.
My advice is not to get hung up on bigger front or rear, but to concentrate on finding a setup that has about the same ratio front to rear as the stock Porsche recommended setups (about 0.5% difference), summer OR winter, and to find a tire that fits well on your wheels.
I run 235/40 18 front, and 275/35 18 rear. One trick is that while it will stretch onto the rim, a 275 tire is not ideal on the stock 11 inch wide rears. Finding a 10 inch wide wheel with the right offset can be done, but isn't easy. I don't think you can find a 295 winter tire, and narrower is better anyway in snow. I bought Forgestar F14 wheels because they are reasonably priced and you can choose your offset. I went with 18x8.5 ET44 front and 18x10 ET25 rear. This fits nicely.
Your car looks great on those wheels.
Porsche recommends a 10 inch ET47 wheel for the rear winter tires. I was able to find a Boxster wheel that's 18x10 ET65. I don't know how the ET's add up - would an 18mm spacer make an ET65 into an ET47? Of would it make an ET65 into an ET83?
The offsets quoted above are positive offset. In other words, the hub mounting surface of the wheel is farther outboard than the centerline, and the more offset, the farther "in" the edge of the wheel will be if overall width stays the same. Negative offset would move the hub farther inboard, and the greater negative number would poke the edge of the wheel out if wheel width stayed the same.
So when I went to 10 inch wheels, I wanted to account for the narrower wheel without them looking sunken in, so I looked for a little less positive offset (a lower "ET" number) than the stock ET45 on 11 inches. In fact, these Forgestars ET25 sit a bit more flush (the edge closer to the fender) than the stock 11 inch ET45 wheels. If you add a spacer, it has the effect of reducing the overall offset by the size of the spacer.
By the way, the Porsche recommended winter wheel size looks quite "sunken" into the fender in the rear. If you go 10 inches, I'd look for a bit less offset than that. Think of this this way, the recommended winter wheel is about the same offset as the summer, but it's 1 inch narrower, so each edge of the wheel is going to set about 0.5 inches closer to the center line. Visually, that's a lot.
We are having the same discussion over on 996outpost.com: https://996outpost.com/viewtopic.php?f=5&t=796
So, I thought I would post my main comment from that thread over here. Now, keep in mind I've decided to go with all season tires instead of winter tires for the reasons set forth below.
Time to revisit this topic. I've done quite a bit of research. Looked at expected usage. Called Discount Tire's national info line. I have come to the conclusion that an Ultra High Performance All Season tire is the best way for me to go for the winter. Here's why:
1. I'm never going to drive it on snow. If it is snowing, the 996TT will stay in the garage. We don't get that much snow here to begin with. I used to drive my '99 C4 when it snowed, but that was a $16,000 car with high mileage. The Turbro is a $50,000+ car. So, when it snows, it is going to stay inside. Therefore, the advantage that winter/snow tires offer regarding snow traction is meaningless. 2. Temperatures: on my way to Porsche breakfast on Saturdays, it could be as cold as 15 degrees Fahrenheit. That's as cold as I'll drive it. If it is single digits, I'll leave the 996TT in the garage. Even on the coldest of those days, by the time breakfast is over, it will probably be more like 20 to 25 degrees. And the rest of the day, temps will likely be above freezing. Yes, we do get some really frigid temps during the winter, but that is the exception, not the norm. It isn't unusual to have a 55 degree day in January or February. November & the first half of December aren't too bad. Those are the 4 months I'm concerned about. I'd probably switch back to summer rubber in early March. Winter tires offer a traction advantage over all-season tires beginning at 45 degrees Fahrenheit. At 35 degrees, it isn't that big of a difference. Below 20 degrees, yes, a marked difference. But, above 45 degrees, all-season tires offer a traction advantage. During November 1 through early March, I think I'd be doing at least as much, if not more, driving at 45 degrees than below. The entire point of a set of tires for the winter is damaging the summers by driving to breakfast when it's 15 or 20 degrees outside. I don't plan to drive like a madman on my way to breakfast when it's 15 degrees outside. Plus, the all-seasons should offer superior traction to the summer tires at those cold temps. 3. There are no winter tires that I found on either Tirerack.com or Discounttire.com that meet the load and speed ratings for the 996TT. For the record, the load rating is 92 on the fronts and 98 on the rears. Speed rating is Z or higher. I found 5 sets of tires in the 225/40-18 and 275/35-18 sizes that meet the load and speed ratings. There were no 265/35-18 tires that meet the load rating (98) for the 996TT rear tires.
I understand that there are many advocates of getting true winter/snow tires for the winter months. But, given the above factors, I'm going with ultra high performance all-season tires.
The options (all in 225/40-18 & 275/35-18, 92 or higher front and 99 rear load rating, all speed rated at Y): (all prices quoted are Discounttire.com, which was either the same or cheaper and is the final price after instant discount offers)
Milestar MS932XP+ $340 for the set. Notes: Man, I like me the discount option ('cause I'm cheap). Sports the damned-by-faint-praise "Good" rating on Discounttire.com
Nitto Motivo $572 for the set (after a $50 instant savings special) Notes: Rated as "Better" by Discounttire.com.
Toyo Proxes Sport A/S $640 for the set Notes: Nice looking tire. I have Toyo Proxes on my 928S4 and like them. Classified as "Better" rating by Discounttire.com
BF Goodrich G Force Comp2 A/S $676 for the set Notes: Also classified as "Better" rating on Discounttire.com
Michelin Pilot Sport All Season 4 $700 for the set (after a $100 instant savings special) Notes: Classified as "Best" rating by Discounttire.com
For me, I start by knocking out the Toyo and BF Goodrich. For the price differential ($60 or $24), the Michelins are a better call, based on reputation and the Discounttire.com rating of "Best" versus "Better."
That leaves the Michelins, the Nittos and the Milestars.
Welp, $340 for the set on those Milestars. Check reviews: Amazon users give them a 4.2 out of 5 rating. One reviewer says "I'm never buying Michelin again". Most negative comments are about them not lasting for the full 40,000 mile rating, whereas I would put about 6,000 miles on them before they aged out. Hmm, hmm, hmm. The Nittos at $572 mark the midpoint. Not el cheapo, but still a significant discount from the Michelins. They get very good reviews (4.6 out of 5 stars on Google).
The Michelins are the gold standard. I bought a set of Michelins for the 914 a couple of months ago. Normally I don't like to spend a lot on tires, but the Michelins for the 914 weren't that much more expensive than the rest. I'm pleased with that set. In this situation, they are more than twice the price of the el cheapos, but really not that much more than the others. $128 more than the Nittos - not a big deal on a set of 4 tires, frankly. Here's what Discounttire.com says about the Michelins in their review:
Get to know the newest member of the family, the Michelin Pilot Sport All Season 4, which brings all-season reliability to the top-notch performance of the Michelin Pilot Sport. Depending on where you live, you might feel certain seasons or weather would preclude you from taking your supercar out of the garage. A set of All Season 4 tires could change how you think.
Michelin track-tested this tire against several top competitors’ all-season performance models and their tread life came out on top by as much as 29%. And when it comes to weather, it is designed for traction and grip when the weather is wet or dry and the temperatures are at their extremes. These might not be as fun as the solely performance-oriented models we dig into below, but they are definitely the most versatile.
Under Michelin’s “Total Performance” ethos, they’ve truly balanced this tire for long-lasting, excited driving in all seasons. It’s no wonder Chevy has chosen it as the first all-season tire for the Corvette.
Bottom line, damn I'm tempted to buy the Milestars just to see how well they do. But, for the price differential, the Michelins just make the most sense. If it was over $1,000 for the set of Michelins, then I'd give the Milestars a try, or more consideration to the Nitto. But, if I can get a set of quality Michelins for $700 (due to the current $100 instant credit special), I think that makes it an easy call. Boring. Safe. But easy.
I run Bridgestone Blizzaks LMs on a 10" rear wheel. they work awesome and eat up the snow.
I bought these cheap wheels off tirerack as the winter setup. https://www.tirerack.com/wheels/Whee...ted&tab=wheels
Although I am not sure if they still sell these in an 18"
@GWIT996F I had no idea 996Outpost existed, great to know.
That sounds like a well reasoned decision to go with all seasons. If we didn't see snow covered roads for 4 months of the year (and a chance of snow covered roads for another 6), I'd go with all seasons in the winter too. But alas, I was already driving in some snow yesterday.
I had Michelin Pilot Sport A/S 3+ on my Fiesta ST, and they were absolutely awesome in the dry, and I had no issue with them in the wet (although some reviews say they are a let down in the wet). I almost always go with a dedicated summer tire when it's warm, but on that little Fiesta I wasn't even tempted to swap out the Pilot Sport All Seasons, they were really good.
The speed rating being lower on my winters doesn't bother me. I think mine are "V" rated, and that's plenty to open her up for a bit without trying to pierce the space time continuum on squishy rubber.
One thing that conflicts me is how much I like the ride quality on my snows, but then steering feel and turn-in definitely suffer. When I took my S0-2s off yesterday I noticed the rears are just about cooked. I'm looking forward to trying something different next summer.
@GWIT996F I had no idea 996Outpost existed, great to know.
That sounds like a well reasoned decision to go with all seasons. If we didn't see snow covered roads for 4 months of the year (and a chance of snow covered roads for another 6), I'd go with all seasons in the winter too. But alas, I was already driving in some snow yesterday.
I had Michelin Pilot Sport A/S 3+ on my Fiesta ST, and they were absolutely awesome in the dry, and I had no issue with them in the wet (although some reviews say they are a let down in the wet). I almost always go with a dedicated summer tire when it's warm, but on that little Fiesta I wasn't even tempted to swap out the Pilot Sport All Seasons, they were really good.
The speed rating being lower on my winters doesn't bother me. I think mine are "V" rated, and that's plenty to open her up for a bit without trying to pierce the space time continuum on squishy rubber.
One thing that conflicts me is how much I like the ride quality on my snows, but then steering feel and turn-in definitely suffer. When I took my S0-2s off yesterday I noticed the rears are just about cooked. I'm looking forward to trying something different next summer.
Living in Minnesota, the inevitable winter snows are coming (insert Game of Thrones quip here)..
Couple of questions...
1. Recommendations for good winter tires
2. Can I drive with symmetrical tires instead of needing to get fronts and rears?
Lemmeno, and let it snow!
Jim
I run 20" Pilot Alpin PA4's on my 991s in the winter and they are a great tire in light or packed snow, and damn sticky in the wet.
10-15-2020, 02:15 PM
Winter tires?
