Alstoy

I can only find one standard of 19" wheels on the 991. Am I missing something or is there only one choice? Cheers.

991Dreamer

Looks to be just the one.

william_b_noble

have you (anyone) experience with the 19 versus 20 inch wheels? on a road that is less than perfect how does the ride compare?

991Dreamer

In my test drives, I drove the 19 & 20 back to back and couldn't tell any difference. Not pushing the car real hard but just around town driving.

chuckbdc

I have driven 991s with both on the street and on the track. On the street (at street speeds) I found them equally supple over all the roads I was on.

That surprised me as I expected the 20s to ride noticeably harder. I guess that was because of the difference that used to be so noticeable between 18s and 19, when 19s were PS2s. That may have been as much due to the 19s in the 2008- 11 era being Michelin PS2s. I changed my PS2s for SuperSports when they needed to be replaced and they were far more supple and comfortable especially on poor surfaces. So it could be the new suspension or the Pirellis that are standard on the 20. The 19 in Goodyears were fine.

In my very limited track run (one stint in each at a Porsche World event) there was a noticeable difference in handling- which could have been due to many things- brands, sizes, one car being an S with Sport PASM, the other not, or even tire pressures.

rnl

Have 20 inch classic wheels with pzero tires and 19 inch wheels with sottozero ii tires. The 20 inch wheels and tires yield a harsher ride.

william_b_noble

so, if I wanted to soften the ride around town a bit, I could change the tires on the 20 inch to something else? I certainly didn't expect that answer - Historically, I've gravitated towards Michelin tires because they are reliable and last a long time, but those are a harsher ride? I don't intend to drive on the track, so I can give up some handling at the extreme end to have a little more smoothness going over normal cracks and bumps in the street

simsgw

Yes, because different model tires have distinctly different ride properties, William. The Michelin Pilot Super Sport will be less harsh than the Pirellis.

I know of no reason the 20's with the same model tire would be less comfortable than the 19's and a couple of technical reasons to think that would not be the case. They should be about the same, with any noticeable advantage going to the 20's. You weren't around as I remember when I was placing my order, but this was a big deal to me because spine problems were what motivated me to look at a 991 in the first place. I examined the question after someone called me on a false assumption that 19's 'naturally' would be more comfortable.

Gary

rpilot

My rather simplistic take on this is that the 19" Goodyear F1 AS2 that are the only summer tires available for the 19" wheels are the most comfortable tires of them all for DD. Of course these may not be the best tires on the track where I believe that the MPSS have an advantage. And I do think that both are better from a comfort perspective over a Pirelli PZ. I am not sure where sottozerro's fit in either in 19in or 20 in since they are winter tires. Of course all of this assumes driving a 991 without PASM. What a PASM equipped 991 or a 991S does to make a ride more pliable at any given time is a very huge variable and it really does make even a subjective comparison quite a challenge.

chuckbdc

Also consider tire pressure. All tires offer a range, but with the 991 the owner's manual gives the 20 in Pirellis as large a range as I have ever encountered. The the normal load, speed under 165 mph specs if I recall correctly are something like 32- 36 cold whereas the autobahn specification is for 4 more lbs in each tire. The ride will be notable softer than at the lower pressures. I so rarely drive over 165 that I have opted for comfort.

rnl

My exlerience is that the Comfort pressure yields lower mpg while not really increasing comfort.

chuckbdc

For sure more pressure should lower rolling resistance and that is good for mileage. I did a 150 mi run each way to visit family yesterday. For relaxation, I watched tire pressures move up from 32-36 to 35-39 (~40 F temps), and the tach "sailing to idle" some of the time.

I relieved more than boredom at rest stops, and just to be extra safe, did sport+ run ups (and slow downs) to merge into traffic. Ahh. Early am, one empty stretch of road, I tried the top of a few of the middle three the PDK gears and got to "OMG I can't believe it", once and then back down. The guilt!

Up and back despite the playing, I managed 28 MPG indicated. That kind of mileage is just fine with me, given that traffic averaged about 75 MPH (10 over) and so did I for the whole trip, according to the CAR screen on the PCS.

rnl

My experience with the comfort setting was with the first 1000 miles. I now use standard partially full car setting and average 25 mpg in mixed urban surburban driving and 31+ highway usually 75-80 mph steady driving no wot except on on-ramps