Hi everyone,

I recently got a 2016 R with the stock PZeros. What's the consensus on optimal tire pressures for handling? The car understeers a bit, so I'm leaning toward running a little lower in the rear (maybe 35 rear, 37 front)

 

Oh damn, you asked for it.

 

Ha!

 

Suggest that you have an alignment done before you mess with pressures. That might cure your understeer.

Couldn't hurt tire wear results either.

I've driven our RWD V6 and an AWD V8 at Watkins Glen with no control issues.

 

Use exactly "ditch Pzeros and get MP4S" pressure, not more not less for optimal results.

 

I like how the car tells you the recommended pressures for "low speed" and "normal" which left me wondering, "what exactly is meant by low speed?" And then a quick glance in the booklet reveals that "low speed" is anything up to 155mph and "normal" is above 155mph.

"Do you know how fast you were going back there?"
"Yes officer, I was going at a low speed"

 

You mean "Yes Officer, my car TOLD ME I was going at a low speed"

Takes the human factor out of it.

OTOH, anybody been pulled over for speeding in a posted 50 MPH or less, and the knowledgeable cop said "I know you were going at least 62 MPH because I saw the spoiler extended"?

 

I have several posts explaining why I disabled the spoiler and that was one of the main reasons!

 

Only in a convertible, the coupe comes up at 70mph.

 

Mine (coupe) came up (back in the days before I disabled it) at 70 mph but it didn't go back down again until 50 mph so many is the time I had to slow right down to well under the posted speed limit to hide the tell-tale sign that at some point I was well over the limit! Another one of the annoying things that caused me to disable it.

 

mps4s... all I am gonna say

 

Yeah, that's how its designed. Convertible goes up at 60 and down at 40. I'm fortunate to have the fixed spoiler so no clues for the law!

 

I hope I have your question right...hard to tell from the answers.
i go 37# front and 35# rear. 2016 R awd
the track is a whole different topic

 

Haha, yes, that's exactly the answer I was hoping for AWD--thanks! Although the other answers were entertaining

 

Very interesting thread. I’m always asking people to try and lower the pressure and report what they think.
Many are severely overly inflated.

so, just for fun, lower the fronts as well. (But not too much!). Let me know what you think.

 

I chalk my tires and go for a spirited romp through the backroads twice a year. In the summer I'll pick a 90 degree-ish day. Drive hard, check the chalk. I add or remove pressure and rechalk until the chalk is scrubbed right to the tread ply arrow. Then if I feel like I want the car to rotate or push more I'll add or drop a little pressure front and rear. I'll do this to set up for winter on a 55-60 degree day. I run P4S all year so I don't generally take the car out when its under 50 degrees.

Currently on the summer setup and running 38 rear and 36 front on 305's in rear and 265's up front on a RWD v8. Play around w stuff. Its fun. There are a lot of variables at work so find what works for you.

Good luck, be safe.

 

Interesting way to setup - I'm going to try that once I locate the 'tread ply arrow' wherever that may be?

I run MP4S's front and back, 10mm wider on front and back (265/305 same as you) and find 37 p.s.i a reasonable number.
Once 'up to temp' they stay around the 41 p.s.i mark - I have a feeling they are a bit too hard I like the chalk idea.

What's your running pressures?

 

I like 38psi all around with MPS4S on 19” wheels.

 

See pic. Sadly this arrow is likely the first thing to rub off on an MP4S. I don't remember the running pressure, but I'll get out for a drive tomorrow and report back.

 

Learn something new every day - so I assume contact should be just showing witness marks just on the edge of the arrow - correct?
Thanks.