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Discussion Starter #1 (Edited)
I figured I’d start an official thread on these new tires that I just had installed today, and provide my impressions over the next month or so.

For now some pictures of my dirty 4C and the new shoes. What you’re looking at:

225/40-18
255/35-19

10mm spacers on the front
25mm spacers on the rear

-2.1 camber front (Jamie’s race blocks)
-2.4 camber rear

Previously I’ve run PZero AR Racing for 42,000km (3 sets of rears, 2 fronts).

I chose these tire sizes because the fronts are the narrowest available in the new MPS4S.

Because of the larger diameter front and slightly larger rear, the speedometer is now almost dead-on accurate.







Very early impressions: cushy! Car rides great, no tramlining. Confidence is wayyyy up. The rear really sticks and hooks up now but I’ve only just played with it a bit. And this is in 4C(elsius) temps! Braking seems solid too. Again, I’ve only just explored slightly as I want to wear off the mold release and mounting lube first. Will post more over the coming days and weeks.
 

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I’m interested to see how you like the new tires and the new sizes once you’ve had some time with them. Would they fit without the spacers withiut rubbing? If I recall correctly these are a fair amount wider for the fronts, more than the 20mm the size would imply due to the relatively narrow width of the Pirellis compared to their spec. Any photos from the side?
 

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Those look great.

The PS4S is a great tire. I have the Pilot Super Sports on the 4C and the PS4S on the Giulia Quadrifoglio.

I love the Super Sports but the PS4S seems a little better at everything. The feel is mostly the same but they are just a tiny bit better at hooking up, and seem to gain a little more overall grip when they are really hot. Of course these cars are very different so it's not a direct comparison.
 

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Any side shots. Would love the see the stance of the whole car with the larger diameters. Do you feel any reduction in acceleration with the larger rear diameter on (+2)?
 

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I've got a full set in the garage ready to be fitted! Heard good reviews so see how they feel when they are on and i'm going in for the front geometry upgrade next couple of months.
 

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Discussion Starter #8
I’m interested to see how you like the new tires and the new sizes once you’ve had some time with them. Would they fit without the spacers withiut rubbing? If I recall correctly these are a fair amount wider for the fronts, more than the 20mm the size would imply due to the relatively narrow width of the Pirellis compared to their spec. Any photos from the side?
Forum member @Croc has the same front and rear sizes fitted in MPSS without issue. I have always had these spacers and just kept with them. I was actually worried it would be too much at the rear, but turns out they fit great.

Any side shots. Would love the see the stance of the whole car with the larger diameters. Do you feel any reduction in acceleration with the larger rear diameter on (+2)?
I did a lot of math before making this size choice, I'm quite OCD that way. I would have preferred 215 front and 245 rear, so this sizing was a stretch for me to come to terms with. My biggest concern is sidewall flex on the track, but it's simply too early to give feedback on that just yet.

All that said, the fronts are 2.5% larger and the rears 2%. I don't perceive a drop in acceleration, but if you do the math your 4.1s 0-60 would now be 4.19s. Not a really perceptible change. What I have observed though is that the grip in the rear is SIGNIFICANTLY greater than it was with the 235 ARRs, so whatever is lost in straight-line performance will be made up for on corner exit speed and confidence. Last night I hit 2C temps and wet snow--not sticking to the road, but cold and wet. I couldn't believe these tires. Unreal confidence and performance in the cold and wet compared to the ARRs, or compared to my Bridgestone RE71Rs. I was actually getting on it before the wheel was straight in the wet - something I'd never do before. Very surprised with these tires so far. I only hope the confidence and ability translates to hot track temps as well.

I will post side pics over the weekend. The tires definitely look beefier, not a look I've totally bought in to, but it's not that different. I think if I stick with this tire sizing I may investigate having .5" and 1" bands added to the stock 5-hole rims.
 

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Im actually getting mine installed next week, same concerns over the stretched sizing in the front and hopefully it will be fine on the track.

i know several members have ran these sizes on track and had no problems.

Will post pictures of mine as well when done but i think they look way better then the Pirellis.
 

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Discussion Starter #17 (Edited)
i also think to get tires soon

what tire would be better for some autocross sessions PS4S orBridgestone RE71Rs?

It’s too early for me to give you a fair opinion, but I can still share some thoughts.

I’ve had both MPSS and RE71Rs on my Mazdaspeed3. The Michelins were great, especially in the wet. They were grippy but not like the RE71Rs. The Bridgestones get up to temperature very quickly and really stick. This would be a more ideal tire for solo or time attack. Also, the Bridgestones are available in narrower sizing (215s), which would be better for tight autocross courses.

As far as MPS4S vs RE71R goes, my initial impressions are that the MPS4S grips very well out of the gate, so they may perform similarly to the RE71Rs in short events. Turn-in is not as sharp as the RE71Rs, or even the PZero ARRs, but this could be because of the 225 width (edit: or maybe because they are still so new and not scrubbed in?). How they will compare on overall grip I can’t say just yet, but I think if I was faced with the same decision as you, and my sport was autocross, I’d opt for the RE71Rs at this time. I think grip is close to the same level, initial warm up is very short, but more importantly they are available in a 215/245 which I think would make for a more agile autocrosser.
 

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it’s too early for me to give you a fair opinion, but i can still share some thoughts.

I’ve had both mpss and re71rs on my mazdaspeed3. The michelins were great, especially in the wet. They were grippy but not like the re71rs. The bridgestones get up to temperature very quickly and really stick. This would be a more ideal tire for solo or time attack. Also, the bridgestones are available in narrower sizing (215s), which would be better for tight autocross courses.

As far as mps4s vs re71r goes, my initial impressions are that the mps4s grips very well out of the gate, so they may perform similarly to the re71rs in short events. Turn-in is not as sharp as the re71rs, or even the pzero arrs, but this could be because of the 225 width (edit: Or maybe because they are still so new and not scrubbed in?). How they will compare on overall grip i can’t say just yet, but i think if i was faced with the same decision as you, and my sport was autocross, i’d opt for the re71rs at this time. I think grip is close to the same level, initial warm up is very short, but more importantly they are available in a 215/245 which i think would make for a more agile autocrosser.
thanks
 
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