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305/30/20 PS4's installed on Coupe + Dinan = bliss
Alright, well I got the new 305/30/20 PS4's installed on the rears today and man what a difference! On the way back home, I was still on stock programming and on ESP sport it barely intervened when I punched it hard in 2nd gear. Usually that would result in a lot a throttle cut and the traction control kicking in pretty hard. I turned traction control off and man, what a rocket! I think you could easily shave a few tenths off 0-60 and 1/4 mile with just these tires alone. It grips so well with the stock power.
I reinstalled the Dinan box when I got home and went out for another spirited drive for a back to back comparison and all I can say is I'm blown away. With traction control fully off, I can actually just nail it in 1st and it'll hook hard, bang into second gear (fully expecting the rear end to kick out like it used too) but I'm still just being shoved into the back of the seat going straight. Before you know it I'm in 3rd gear and it's pulling like a freight train. The last time I tried something like that with traction control off with the Dinan box, I was burning out for a few hundred feet with the stock 285's. Now with the 305's, it feels much more planted. It actually makes me feel more confident in the car now with the added power since before it felt like I was on ice skates even in decent weather.
Super happy with these tires, and they fit absolutely perfect on the Coupe (no rubbing with stock suspension). I was surprised that the tire doesn't seem to be bulging either. In fact, it fills the fenders in very nicely and seems to eliminate the need for spacers.
Here are some pics, the car is absolutely filthy right now so please excuse the dirt!
Did these new tires replace worn and/or old tires? Only reason I ask is that 20mm wider tires shouldn't make a night-and-day difference, especially if you are still running the same pressures as the stock tires. There will be a difference, there's no doubting that, but it shouldn't be so obviously apparent. I'm willing to bet that the majority of the difference you're feeling is either due to fresher (and therefore stickier) rubber or the warmer temperatures we've had here in TX recently.
Not trying to rain on anyone's parade here, but there are several other, more significant factors playing a role here. Width is just one of them.
Still running stock 255’s up front. Eventually I’ll go with 275’s to match the stock tire ratio. It handles great with the beefy tires in the back and takes more throttle to get the rear end out of shape around a corner... so I honestly don’t feel any rush to upgrade the fronts.
I do think 275’s up front would look great too in terms of filling in the fenders.
Did these new tires replace worn and/or old tires? Only reason I ask is that 20mm wider tires shouldn't make a night-and-day difference, especially if you are still running the same pressures as the stock tires. There will be a difference, there's no doubting that, but it shouldn't be so obviously apparent. I'm willing to bet that the majority of the difference you're feeling is either due to fresher (and therefore stickier) rubber or the warmer temperatures we've had here in TX recently.
Not trying to rain on anyone's parade here, but there are several other, more significant factors playing a role here. Width is just one of them.
That is true. When I first got my car in December, after break-in, I made a few runs and was just spinning tires in Sport+ mode in the colder temperatures. Also the street seemed to be textured differently, and slicker. When I had tried in warmer temperatures and when I tried punching it on newer paved roads my tires wouldn't spin as much.
I would still go as wide as I can on the rear, that's what she said.
Did these new tires replace worn and/or old tires? Only reason I ask is that 20mm wider tires shouldn't make a night-and-day difference, especially if you are still running the same pressures as the stock tires. There will be a difference, there's no doubting that, but it shouldn't be so obviously apparent. I'm willing to bet that the majority of the difference you're feeling is either due to fresher (and therefore stickier) rubber or the warmer temperatures we've had here in TX recently.
Not trying to rain on anyone's parade here, but there are several other, more significant factors playing a role here. Width is just one of them.
I replaced the stock 285 PSS’s, but they were far from worn (only had 6300 miles with plenty of tread, so I’m keeping them stored on my tire rack as backups). And the difference I felt was definitely not due to weather or other conditions because I did the testing back to back on the same day - all within an hour or so. Also, it was in the low 80’s here in Austin yesterday, so actually a very ideal temp for tire testing!
The wider rubber (11.2” vs 12.0”) in conjunction with the overall improved grip of the PS4 vs the PSS is definitely noticeable. There is a certain section of road on an incline where I’ve done dozens of low RPM 3rd gear pulls, and on the stock tires I would always end up spinning tires and kicking the rear out when the torque peaks. With these 305’s on that section, I can hear the tires squirming a bit and digging for traction hard, but I’m pointed straight and it’s pulling harder than it ever has.
I will honestly say that if you are tuned and running stock tires, you are probably slower than stock at any speed below 60 because you’re either spinning (and need to lift before things get hairy) or traction control, even in Sport setting, is holding you back because of the wheel spin from all that torque.
I replaced the stock 285 PSS’s, but they were far from worn (only had 6300 miles with plenty of tread, so I’m keeping them stored on my tire rack as backups). And the difference I felt was definitely not due to weather or other conditions because I did the testing back to back on the same day - all within an hour or so. Also, it was in the low 80’s here in Austin yesterday, so actually a very ideal temp for tire testing!
The wider rubber (11.2” vs 12.0”) in conjunction with the overall improved grip of the PS4 vs the PSS is definitely noticeable. There is a certain section of road on an incline where I’ve done dozens of low RPM 3rd gear pulls, and on the stock tires I would always end up spinning tires and kicking the rear out when the torque peaks. With these 305’s on that section, I can hear the tires squirming a bit and digging for traction hard, but I’m pointed straight and it’s pulling harder than it ever has.
I will honestly say that if you are tuned and running stock tires, you are probably slower than stock at any speed below 60 because you’re either spinning (and need to lift before things get hairy) or traction control, even in Sport setting, is holding you back because of the wheel spin from all that torque.
How was the Dinan box install? I'm looking at bench flash tunes, but might go the piggy back route till a OB2 solution is out. I'm not a fan of having the ECU rerouted and zip tied to the firewall like some ricers. Glad you like the 305s, I'm most likely doing 265/305 PS4s combo this summer.
How was the Dinan box install? I'm looking at bench flash tunes, but might go the piggy back route till a OB2 solution is out. I'm not a fan of having the ECU rerouted and zip tied to the firewall like some ricers. Glad you like the 305s, I'm most likely doing 265/305 PS4s combo this summer.
Not too bad, a few basic tools and a set of angled picks to unplug and disconnect the sensors helps a lot. It’s about 2-3 hours the first time around. I can have the whole air box assembly and all bolts removed for the front harness in 20 minutes or less. The part that takes a while is actually unplugging the sensors and plugging the Dinan harness in because some of them are placed in an extremely tight area.
It’s not something I’d want to do everyday, but still beats whatever is involved with removing the ECU, shipping and unlocking it (which is irreversible once it’s done), and then reinstalling or relocating. Personally, I would never relocate the ECU from the stock location. These modern ECU’s are literally computers that produce major heat and need to have airflow to keep it them cool. MB didn’t put the ECU where it is to make it annoying for us to get to. They put it there so that there is sufficient airflow to keep it from overheating in any circumstance.
I replaced the stock 285 PSS’s, but they were far from worn (only had 6300 miles with plenty of tread, so I’m keeping them stored on my tire rack as backups). And the difference I felt was definitely not due to weather or other conditions because I did the testing back to back on the same day - all within an hour or so. Also, it was in the low 80’s here in Austin yesterday, so actually a very ideal temp for tire testing!
The wider rubber (11.2” vs 12.0”) in conjunction with the overall improved grip of the PS4 vs the PSS is definitely noticeable. There is a certain section of road on an incline where I’ve done dozens of low RPM 3rd gear pulls, and on the stock tires I would always end up spinning tires and kicking the rear out when the torque peaks. With these 305’s on that section, I can hear the tires squirming a bit and digging for traction hard, but I’m pointed straight and it’s pulling harder than it ever has.
I will honestly say that if you are tuned and running stock tires, you are probably slower than stock at any speed below 60 because you’re either spinning (and need to lift before things get hairy) or traction control, even in Sport setting, is holding you back because of the wheel spin from all that torque.
What kills the grip of a tire is the number of heat cycles it goes through, not necessarily the mileage on it. The stickiness of the rubber on a worn tire that's been driven a ton of short trips (especially if driven in cold temps) will degrade differently/quicker than a worn tire that has a ton of long distance highway miles on it. You only have so many heat cycles you can go through before the tires noticeably loose grip.
I'm on my 4th set of rear tires on my '15 C63S sedan. First the stock set of Dunlop 265s, then Michelin PSS 265s, then Continental 275s, and now in the last month an identical set of Continental 275s. I felt the same increase in rear grip with each set of new rear tires. With lower pressures the 275s felt like they held a bit better (and my lower I mean 31-32ish psi), but again nothing earth shattering or night-and-day different. And tuned or not, our cars have enough low-end and mid-range power the break loose any street tire, so that shouldn't even be a determining factor. You'd have to pedal the car either way.
And just so we're all on the same page, this isn't aimed at you or said as a rebuttal toward you or anything like that. It's for anyone else coming on here that isn't familiar with all the technical details and just wants to know what makes their car go faster.
What kills the grip of a tire is the number of heat cycles it goes through, not necessarily the mileage on it. The stickiness of the rubber on a worn tire that's been driven a ton of short trips (especially if driven in cold temps) will degrade differently/quicker than a worn tire that has a ton of long distance highway miles on it. You only have so many heat cycles you can go through before the tires noticeably loose grip.
I'm on my 4th set of rear tires on my '15 C63S sedan. First the stock set of Dunlop 265s, then Michelin PSS 265s, then Continental 275s, and now in the last month an identical set of Continental 275s. I felt the same increase in rear grip with each set of new rear tires. With lower pressures the 275s felt like they held a bit better (and my lower I mean 31-32ish psi), but again nothing earth shattering or night-and-day different. And tuned or not, our cars have enough low-end and mid-range power the break loose any street tire, so that shouldn't even be a determining factor. You'd have to pedal the car either way.
And just so we're all on the same page, this isn't aimed at you or said as a rebuttal toward you or anything like that. It's for anyone else coming on here that isn't familiar with all the technical details and just wants to know what makes their car go faster.
I do agree that fresh tires (even same size) will grip better initially, but I don’t think you’re going to feel a huge difference going up only 10mm especially if you’re trying to improve 60 ft times. 275’s are too small even for stock power. I shouldn’t have to pedal the car rolling into 3rd gear at 60-70 mph on the highway, that’s just wasted/unusable power from the Dinan box. With these 305’s, I can stomp on it at highway speed and it’ll just squat and go with traction fully off!
Also, take into consideration the differences between the Sedan and Coupe. Two completely different rear ends (Coupe sharing the rear end of the new E63S), so the Coupe hooks up better out of the box, and arguable, tuned since the rear fenders have more clearance for wider tires.
Don’t get me wrong, I can still spin 305’s if I try to with deliberate throttle in 2nd if conditions aren’t optimal. But instead of kicking the rear out, they regain traction after a little squeal and keep me straight. On the stock tires and stock power, even when they were fresh with only 2000 miles on them, I’d be banging off redline and correcting a slide instead of accelerating 😅
Last edited by AlexZTuned; 02-28-2018 at 11:33 AM.
I do agree that fresh tires (even same size) will grip better initially, but I don’t think you’re going to feel a huge difference going up only 10mm especially if you’re trying to improve 60 ft times. 275’s are too small even for stock power. I shouldn’t have to pedal the car rolling into 3rd gear at 60-70 mph on the highway, that’s just wasted/unusable power from the Dinan box. With these 305’s, I can stomp on it at highway speed and it’ll just squat and go with traction fully off!
Also, take into consideration the differences between the Sedan and Coupe. Two completely different rear ends (Coupe sharing the rear end of the new E63S), so the Coupe hooks up better out of the box, and arguable, tuned since the rear fenders have more clearance for wider tires.
Don’t get me wrong, I can still spin 305’s if I try to with deliberate throttle in 2nd if conditions aren’t optimal. But instead of kicking the rear out, they regain traction after a little squeal and keep me straight. On the stock tires and stock power, even when they were fresh with only 2000 miles on them, I’d be banging off redline and correcting a slide instead of accelerating 😅
All I'm saying is that there are dozens of factors at play, and because of that you can't isolate one factor and claim it's responsible for the difference experienced. Tire width, tire pressure, tire compound, tire tread pattern in conjunction with alignment settings, tire internal (air) temperature, tire surface (rubber) temperature, tire condition (old vs new), road surface material/temperature/condition, air temperature and humidity (engine power), and the list goes on and on. Hell, even the type of shoes you're wearing can make a difference (perceived throttle response). All these things play a roll, and all work in conjunction to produce the difference in performance feel that you'll get when testing out a new set of tires.
Take tire pressures for example. If someone is running the same pressures with 285s as they are with 305s, they'll have (basically) the same tire contact patch area with each set. The weight of the car is the same as is the distribution, so the tire is carrying the same load. With the same pressure, it'll create the same sized contact patch. The 305s will just have a wider but shorter contact patch. You'll only get more rubber on the road if you drop the pressure.
Funny thing is I was just talking to a buddy of mine the other day about scuffed tires and how/why they're used by race teams. They purposely run a few hard laps on a new "sticker" set of tires to wear off any remaining residue from the mold as well as any old/oxidized rubber that's formed before installation. That isn't even taken into account here either.
And with that I'll let the inner engineer voice in my head shut up. Once you let him out, he's hard to put back.
Not too bad, a few basic tools and a set of angled picks to unplug and disconnect the sensors helps a lot. It’s about 2-3 hours the first time around. I can have the whole air box assembly and all bolts removed for the front harness in 20 minutes or less. The part that takes a while is actually unplugging the sensors and plugging the Dinan harness in because some of them are placed in an extremely tight area.
It’s not something I’d want to do everyday, but still beats whatever is involved with removing the ECU, shipping and unlocking it (which is irreversible once it’s done), and then reinstalling or relocating. Personally, I would never relocate the ECU from the stock location. These modern ECU’s are literally computers that produce major heat and need to have airflow to keep it them cool. MB didn’t put the ECU where it is to make it annoying for us to get to. They put it there so that there is sufficient airflow to keep it from overheating in any circumstance.
That's why I'm leaning towards a piggy back till OB2 port flashing is available. Will these piggy backs support catless donwpipes?
All I'm saying is that there are dozens of factors at play, and because of that you can't isolate one factor and claim it's responsible for the difference experienced. Tire width, tire pressure, tire compound, tire tread pattern in conjunction with alignment settings, tire internal (air) temperature, tire surface (rubber) temperature, tire condition (old vs new), road surface material/temperature/condition, air temperature and humidity (engine power), and the list goes on and on. Hell, even the type of shoes you're wearing can make a difference (perceived throttle response). All these things play a roll, and all work in conjunction to produce the difference in performance feel that you'll get when testing out a new set of tires.
Take tire pressures for example. If someone is running the same pressures with 285s as they are with 305s, they'll have (basically) the same tire contact patch area with each set. The weight of the car is the same as is the distribution, so the tire is carrying the same load. With the same pressure, it'll create the same sized contact patch. The 305s will just have a wider but shorter contact patch. You'll only get more rubber on the road if you drop the pressure.
Funny thing is I was just talking to a buddy of mine the other day about scuffed tires and how/why they're used by race teams. They purposely run a few hard laps on a new "sticker" set of tires to wear off any remaining residue from the mold as well as any old/oxidized rubber that's formed before installation. That isn't even taken into account here either.
And with that I'll let the inner engineer voice in my head shut up. Once you let him out, he's hard to put back.
I'm not going to argue that all those factors can affect performance in one way or another, though you can eliminate density altitude as a factor since I tested the same day, same location/section of road, all within an hour or so. And I'm running the same tire pressure (always 32 psi rear, 34 psi front). Oh, and I was wearing the same shoes too, although I won't say there was any perceivable difference in throttle response 😉
At the end of the day, traction is greatly improved (as is my confidence)... and that's all I was looking for with these 305's 👍
That's why I'm leaning towards a piggy back till OB2 port flashing is available. Will these piggy backs support catless donwpipes?
I wouldn't wait for OBDII flashing, that's probably years away if it ever does come to fruition. Piggybacks don't support catless DP's, only an ECU tune because it codes out the CEL. I have no intention of running catless DP's since I think it makes the M177 sound kinda gross and raspy. If you want more sound, you could delete secondary cats (no CEL), go the aftermarket cat-back route, or get an exhaust valve flap controller that will keep the valves open 100% (I'm currently looking into this option).
Still running stock 255’s up front. Eventually I’ll go with 275’s to match the stock tire ratio. It handles great with the beefy tires in the back and takes more throttle to get the rear end out of shape around a corner... so I honestly don’t feel any rush to upgrade the fronts.
I do think 275’s up front would look great too in terms of filling in the fenders.
Will the 275's fit up front without rubbing or spacers?
I replaced the stock 285 PSS’s, but they were far from worn (only had 6300 miles with plenty of tread, so I’m keeping them stored on my tire rack as backups). And the difference I felt was definitely not due to weather or other conditions because I did the testing back to back on the same day - all within an hour or so. Also, it was in the low 80’s here in Austin yesterday, so actually a very ideal temp for tire testing!
The wider rubber (11.2” vs 12.0”) in conjunction with the overall improved grip of the PS4 vs the PSS is definitely noticeable. There is a certain section of road on an incline where I’ve done dozens of low RPM 3rd gear pulls, and on the stock tires I would always end up spinning tires and kicking the rear out when the torque peaks. With these 305’s on that section, I can hear the tires squirming a bit and digging for traction hard, but I’m pointed straight and it’s pulling harder than it ever has.
I will honestly say that if you are tuned and running stock tires, you are probably slower than stock at any speed below 60 because you’re either spinning (and need to lift before things get hairy) or traction control, even in Sport setting, is holding you back because of the wheel spin from all that torque.
I would be curious to know if there was a traction difference between 285, 295, or 305 in PS4. I'll bet the improved traction is mainly from the tire compound, vs. the PSS. I like hearing the great results you are seeing with the new shoes. I might prefer the 295's if results are similar.
I would be curious to know if there was a traction difference between 285, 295, or 305 in PS4. I'll bet the improved traction is mainly from the tire compound, vs. the PSS. I like hearing the great results you are seeing with the new shoes. I might prefer the 295's if results are similar.
I'm running 275/30/20 front and 295/30/20 rear PS4 , originally I had PSS 18s. I have a lot more grip with the PS4s. The PSS had about 1500 easy miles on them and the PS4 have more than twice that (with a lot fun miles on them). I had to remove the PS4s due to damage to one of my wheels. I'm now using 19s on Continentals until I get my wheel back. The Continentals break loose all the time no matter the mode I'm in, the only difference is how soon. At first I was worried that a tune may make the car faster but harder to control and use that added power. Then I thought maybe these tunes aren't as good as they are made out to be, but now I'm thinking these PS4s are some really good tires.
I'm running 275/30/20 front and 295/30/20 rear PS4 , originally I had PSS 18s. I have a lot more grip with the PS4s. The PSS had about 1500 easy miles on them and the PS4 have more than twice that (with a lot fun miles on them). I had to remove the PS4s due to damage to one of my wheels. I'm now using 19s on Continentals until I get my wheel back. The Continentals break loose all the time no matter the mode I'm in, the only difference is how soon. At first I was worried that a tune may make the car faster but harder to control and use that added power. Then I thought maybe these tunes aren't as good as they are made out to be, but now I'm thinking these PS4s are some really good tires.
I've used many different tires over the years, I can confidently say PS4S are the best all round tires EVER!
If you are looking for performance only - R888 are good but will fail you with over all results like wet or longevity.
The compounds used in the tires are far more advanced and superior than any of its competitors.
I've used many different tires over the years, I can confidently say PS4S are the best all round tires EVER!
If you are looking for performance only - R888 are good but will fail you with over all results like wet or longevity.
The compounds used in the tires are far more advanced and superior than any of its competitors.
Thanks for your input. I'll give the R888R's a try. I know they may be a little noisier and not suitable in rainy cond. I just want to break into the 10's and I think these tires will get me there. I have a GTS and currently running 11.1's @130 tune only
02-27-2018, 08:03 PM
