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Faced with the unpleasant thought of locking my GT3 away for the long NY winter, I began looking for a winter tire for the stock GT3 wheels, but as many of you know the 12 inch rear wheels make finding a winter solution difficult because there don't seem to be 305 winter tires available (Sottozero 3s are available in 305 but somehow not available in 245 for the fronts). While some people here have successfully mounted 295 alpins or sottozeros to the 12 inch rears, these are technically "out of spec" for the 12 inch width, and was not recommended by tire rack and my local dealer would not install these. The only solution that I could find was to go with a high performance all season tire. As I didn't plan to drive in snow I thought these would be ok as all i needed was a more suitable cold weather rubber compound than the Sport Cup 2s. The only tire in that category that is available in 305 is the new Bridgestone 980AS. I purchased these from Tirerack (Damon was great help in securing them for me) and had them mounted on Friday at the dealer.
I was a bit surprised that the tires don't seem to provide anywhere near the coverage as the Sport Cup 2s in 305 did. As you can see in the pictures the rim of the wheel juts out slightly farther than the tire. For comparison are another member's 12 inch .2 GTS wheels with Michelin alpins in 295 which look a lot better than the Bridgestones in 305.
Anyhow just wanted to get your thoughts on whether this looked safe or not. Bridgestone 980 AS in 305 on 12 inch rear wheel Bridgestone 980 AS in 305 on 12 inch rear wheel Michelin Pilot Sport Alpin in 295 on 12 inch wheel Michelin Pilot Sport Alpin in 295 on 12 inch wheel
The RE980AS tires in the GT3's rear size (305/30/20) are not recommended for the 12" rear wheels and the maximum recommended wheel width is 11.5". Most 305/30/20 tires don't fit the GT3's wheels. The N-rated Cup and Dunlop Race Maxx 305/30/20 tires are unusual in that they are specially made to work on 12's (they resemble a 315mm or wider tire).
Check Bridgestone specs here (Have to expand to "See More Tire Details"):
Thanks for the input Grant. That makes sense. The RS winter wheel and tire set at suncoast does have 315s on the rear 12 inch. Anyhow tirerack is looking into my situation.
Thanks for the input Grant. That makes sense. The RS winter wheel and tire set at suncoast does have 315s on the rear 12 inch. Anyhow tirerack is looking into my situation.
Yep, and those 315's are 315/35/20 (instead of 30-series) which means they have taller sidewalls and will be even easier to use with a wide wheel. Unfortunately, you can't use those very well on a non-RS as they have significantly larger diameter (to replace the 21" stock wheels/tires on the RS) and width. Aside from fitment problems, it will also make your gearing too tall (and confuse the electronic systems like ABS and PSM).
Appreciate the tire wisdom Grant. So to the question of are there winter tires to fit the stock GT3 wheels, the real answer is no. You have to get the porsche set or buy some other aftermarket wheels.
Appreciate the tire wisdom Grant. So to the question of are there winter tires to fit the stock GT3 wheels, the real answer is no. You have to get the porsche set or buy some other aftermarket wheels.
That is my understanding, if you want to stay within the official size recommendations of the tire manufacturers.
It could be that a Winter tire will come out to officially fit the GT3 wheels (seems like there is a market), but I don't believe they currently exist on sale.
Thanks for the pictures Francis. Those are the first ones that we have seen.
The pictures show a perfect example of how tire sizing can vary by quite a bit between summer, all season, and N-SPEC summer.
OEM rear NSpec tires are sized as follows:
305/30R20 MI PILOT SPT CUP 2 N1:
Section Width........ 12.3
Tread Width.......... 11.6
Overall Diameter..... 27.2
305/30R20 DU SPT MAX RACE2 N1
Measure Rim Width.... 11.00
Section Width........ 12.3
Tread Width.......... 11.4
Overall Diameter..... 27.2
Now, take the tread width difference from a non-N spec summer tire. The Pilot Pilot Sport 4S is very popular. The tread with on that tire is 11.2".
The N Spec tires have a .2"-.4" average increase in width from a regular summer tire of the same size.
The OEM available rear snow tire is:
305/30R20 PI WIN SOTTOZERO3 :
Measure Rim Width.... 11.00
Section Width........ 12.4
Tread Width.......... 10.5
And all season - 305/30R20 BS POZ RE980AS
Measure Rim Width....
Section Width........
Tread Width.......... 10.4
Overall Diameter.....
Overall Diameter..... 27.3
The lesson here is that even though most 305 rears look best on 11 or 11.5" wheels, Porsche OK's a 305 NSPEC for the GT3 because THEIR 305 tires in the N ratings are made to be fatter than an industry standard. That's why an N spec 305 summer looks fine on a 12" Porsche wheel - they're wider. We routinely see tires that are 35 series or less that look very pulled on to the wheels that are at the end of their rim range
In this specific situation, we're OK being outside of the likely rim width range. Since the OEM homologated a 305/30R20 tire for use on the 12" wide wheels, they are indicating that is an acceptable combination. For this exact platform only (911 GT3 specifically) we can sell a tire and wheel package featuring 305/30R20 tires on 12" wide wheels, because Porsche confirmed it is acceptable.
Concerning the appearance, while the sidewall of the tire doesn't sit flush with the lip of the wheel, this is actually a pretty common fit. We see wheel/tire combinations that are within the specified rim width range that look "worse" than this. The tire mounts and seals much further down, at the bead seat near the barrel of the wheel, so it does not present any safety concerns, it is purely aesthetic.
If this appearance isn't going to be acceptable to you, don't put them on the car. If your car has an 11 wheel there will be no problem. 11.5" would be slightly more stretched, but still OK. Personally, I would not install this tire on a 12" wheel moving forward, but that does not mean we have another all season option if you don't......
The bottom line is that all winter and all season tires within the same size will be skinnier tires that have dimensions that fall withing Industry standards, but not Porsche's idea of the correct size because their tires are almost always wider than average.
Am I afraid to sell it to another GT3 owner with a 12" wheel? No, not from a safety standpoint. Would I personally buy them for a 12" wheel?
Nope.
The RE980 has a mild raised rim protector style, which accentuates the appearance of the gap versus the 295 Alpin winter that has a recessed rim protector style that minimizes the appearance somewhat.
Frank, if you want the tires off please reach out to me. I may be able to get you credited for these, but that doesn't mean I'm going to have an alternative A/S for you if you keep using a 12" wheel. Your best bet is keep all tires, front wheels, and try and find a set of matching 11" rear wheels.
Last edited by brad@tirerack.com; 11-14-2018 at 02:08 PM.
The Suncoast Winter option (https://www.suncoastparts.com/produc...1G2GT3WWS.html) for the GT3 is actually the Turbo S Rim whereas the GT3 RS Option on Suncoast (https://www.suncoastparts.com/product/SKU991GT2WWS.html) is the GT3 Rim. Interesting to note that the GT3 rims with winter tires and TPMS is cheaper than just buying the GT3 rims without tires and TPMS. I went with the RS winter set through local Porsche dealer to save even more $$. Don't plan on driving the RS in the muck but when it is sunny and 10 degrees Fahrenheit, the RS should make pretty good power and the winter wheel set should provide the grip.
Interesting to note that the GT3 rims with winter tires and TPMS is cheaper than just buying the GT3 rims without tires and TPMS
That is interesting (but Platinum GT3 wheels still $300 cheaper than these sets)! Too bad these tires won't work with the GT3 (rear tire sizes problematic on that chassis), but should be great on the RS
You may find some extra Winter tires for cheap when GT3 owners buy these RS winter sets just in order to keep the GT3 wheels and TPMS...
Damon, thanks for the detailed explanation. It's pretty confusing because the 295 Alpins actually look a lot better mounted on the 12 inch wheel than the 305 bridgestones. Also adding to the confusion is that porsche dealers regularly install the 295 alpins on the GT3 wheels. I've even heard them say that the 295 alpins are the ONLY winter tire porsche authorizes for the GT3.
Anyhow, if it wasn't such a pain to take off the Bridgestones that I have and go with something like the alpins, I would probably do it, but the prospect of going back and forth to the dealer multiple times and hauling the old tires back and shipping them off, doesn't sound that great. I think I'll stick with the bridgestones for this winter season. As long as they are safe and won't damage the wheel I'll live with them for the next few months. Then switch back to the Sport Cup 2s. Hope Pirelli or Michelin can make a winter tire in the right size for us.
Damon thanks. I wish you guys had the rears in stock as I had to go elsewhere but my dealer did get the fronts from tirerack.
Stretch it is for me. Maybe I will swap wheels, but I sold my OZ. On my lotus I ran mismatched wheels front and rear and thought it was a good look (like minilites on the back and Fuchs front on old racing 911) so maybe I do that if I can find some 11in rear centerlocks.
I should add, on tirerack’s website, the rim width for sport maxx is only up to 11.5 and on cup2 is blank.
Also adding to the confusion is that porsche dealers regularly install the 295 alpins on the GT3 wheels. I've even heard them say that the 295 alpins are the ONLY winter tire porsche authorizes for the GT3.
I think the Porsche approval probably is valid only on the approved Winter wheels (11” rear).
11-13-2018, 03:18 PM
Do these tires look unsafe on my .2 GT3?
