Hey gang,
Shopping for a set of very inexpensive set of staggered winter tires for my 987.2 locally.
Found an inexpensive set of used and staggered 235/40/R18 front and 255/35/R18 rear from a tire reseller (2018 date code, hardly any wear), who says that the different heights wouldn't make that much of a difference and he says they should fit.
Again, stock front is 235/40/R18 (
UNCHANGED
), which is great.
However, stock rear is 265/40/R18, which means that the 255/35/R18 is off by 5.27% (speedometer difference).
If anyone has any idea if these will fit, let alone if the change in speedo per the rear would be an issue (how the car responds per the electronics), please let me know. Cheers and thanks.
Assuming your offsets are standard (or can be adjusted with spacers if needed) I can't see clearance being any problem. My rear autocross tires are even smaller (285/30R18, fronts are standard diameter) and I've had no issues at all from long distance driving. Mine is a 2006 Cayman S.
Thanks,
@arthurc604
!!! - My wheels themselves are ET54 all around; the wheels were from a square set that I used to use on my former 987.1. I'll just have to get a set of spacers for the rear again for the 987.2, which I doubt is a big deal. Just wish I knew what size spacers were on there.
1) Will the speedo stay the same because the fronts are stock size?
2) Any concern about the P-car's electronics (no-slip) getting confused with different diameters with front and rear?
3) Finally, zero concerns at all about running a different size rear but as stock front? I'm guessing I'd be going in the opposite direction here than you...where you're running a wider (but shorter sidewall)...which is different for winter needs.
Porsche used to specifiy 255/35 18 for rear winters, presumably because there were no N-rated winters available in the 265 width. I ran 255's as winters for many years on previous 987's with no apparent issues.
That's really great news,
@Caymancouver
- Thanks for pointing that out! Figured the old spec was for 255/40/R18 for rears (not 35). So if that's the case, this would be very viable.
Meanwhile, to complicate things further, going in the other direction -- I found a square of 235/45/r18 -- which is even more affordable. Clearly a narrower tire in the rear (which is fine...I used to run 235/40/18 square) but a taller tire. I think it should clear as I don't have PASM, but curious if it would also be an option.
I may have spoken too soon about the 35 aspect ratio. I'm not at home so I can't check if the 255 winters were 35 or 40 series. Internet seems to have conflicting information.
I’d go with the 235/255… or 225/255.. remember the narrower the winter tire the better they work
Okay - Here's an update. I've held off on everything so far to see what my options might be.
Anyhow, I found a very inexpensive square set of 245/40 R18 that I'm now seriously considering. This means:
As compared to the FRONT, we're talking the following difference per tiresize.com:
245/40R18
+1.2%.
25.7"
9.6"
18 x 8-9.5"
As compared to the REAR, we're talking the following difference per tiresize.com:
245/40R18
-2.3%.
25.7"
9.6"
18 x 8-9.5"
So the diameter size obviously increases slightly with the front, and then decreases slightly with the rear. So, that's I think a total 3.5% difference as opposed to staggered stock? Would this mess up ABS or stability controls? (I think one is supposed to keep the fronts under 3% of each other to prevent this from happening...but I'm unclear on this.)
Regardless I'm assuming a slightly larger front would be slightly less nimble but not a big deal. The rears would be narrower than stock, but again -- narrow is good for winter and my previous 235s were great in the snow in the rears. More for just ski trips and getting around town; these would be standard snow tires (not performance snow) and I wouldn't be tracking or doing DE days.in the winter anyhow.
Again, keep in mind that I used to run
235
/40 R18 square the winters just fine on the 987.1 and these would be
245
/40 R18 square on a 987.2.
Would love everyone's advice on this as I'd like to jump on this set if it's a close-enough fit. Thanks!
You mentioned that your rims are ET54 but what is the width? I
would think
that running same circumference front and rear would be fine on our cars - it needs to have a some tolerance to accommodate different rim/tire combinations from factory.
Good question,
@arthurc604
- I don't know. However, they were narrow enough to mount the 235/40 R18 -- so I'm guessing around 8" wide or a bit wider? I'll have to double check.
Anyone else want to weigh in?
