08-29-2019, 04:38 PM | #1 |
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OEM Size RE71 vs Wider PS4S
My 255/275 Cup 2's are at the end of there life and I have been brainstorming on my next tire setup for a few weeks.
I did run RE71 on my M235i and I am well aware that they are terrible street tires. I never ran PS4S but from friends and forums they seem to be capable of track duty if you take care of them. No doubt Cup 2's will be faster but you still have to be gentle or you can destroy them in no time.. So I'm wondering, PS4S on wider wheels (19inch) lets say 275/30F-295/30R or even 305/30R. Would they offer close to Cup 2's or RE71 grip in 255/35F-275*285/35 format ? I don't really want to invest on another wheel set but If I can get good performance and smoother road manners at the same time maybe I could live with the compromise of concentrating on my driving, taking care of my tires and relying less on grippy tires. Cup 2 price is just a little too high to live with the delicatess they require, yes they are livable on the street but don't be fooled they are stiff and no PS4S. I think they make much more sense on the GT3/4 and these kind of ''track ready'' cars. Another option would be to slap 255/275 PS4S or my oem wheels and buy another cheap set of 437M's to put 255/285 RE71 on for more serious track days. Good idea or waste or $ and time ? please share your thaughts
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08-29-2019, 05:34 PM | #2 | |
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08-29-2019, 05:38 PM | #3 | |
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I am about to swap out my Dinan HAS for Ohlins.
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08-29-2019, 08:22 PM | #4 |
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I’ve run similar times on track with 265/35/18 square RE-71R and 265/285/35/19 PS4S, but they drive completely differently.
The 71R setup was better under braking and to apex, but the staggered PS4S is better balanced on corner exit and allows nice throttle control & four wheel drift to maximize speed onto the straight making time back up. PS4S gets greasy after 15-20min but you can’t kill them if you have proper camber. 71R will last if you keep hot PSI below 35 and don’t slide them. 255/285/35/19 71R on OEM wheels is the fastest tire combo you can put on an M2 bc you get the grip and staggered benefit. Only slicks or 265/35 305/30/19 71R on wider wheels are quicker. Last edited by ZM2; 08-29-2019 at 08:38 PM.. |
08-29-2019, 09:46 PM | #5 |
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Isn't 285 on a barely 200tw tire like the RE71R too wide for 10" wide wheels? Doesn't seem like they'll offer any benefit over 275s.
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08-29-2019, 10:15 PM | #6 |
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More lateral and corner exit grip with the 285, fits the 10” fine. Altho, if you’re dropped more than 20mm you’ll rub the height of the tire under heavy compression.
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08-30-2019, 01:30 AM | #7 | |
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OP, I'd suggest OEM size RE71s. This is also my plan next year when the factory MPSS are done.
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08-30-2019, 05:50 AM | #8 |
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The question remains..
street: PS4S even in larger size 275/305-30 should be confortable, maybe little more tramlining ? Anyone can confirm ? Track: RE71 for sure but oem wheel size 255/285-35 still that big of a gap vs above ? Keep in mind all track sessions I run are 20min max and I often have to drive 3 hours just to get to the track.
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08-30-2019, 06:19 AM | #9 | |
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I’m guessing your experience will be similar to what I mentioned, and the times will be similar, too. Regardless of sizes, the 71R will be better under braking and to midcorner bc of it’s softer compound and it can consistently hold 1.0-1.1g. The 4S is 0.9-0.95g. But the much larger contact patch of the wider 4S setup will be as good or better coming off the corners, which is the most important point on the track to make up time. As I mentioned, the setups drive completely differently. You’ll have to be very patient in the corners with the 4S and will get frustrated as the guys around you on stickier rubber will pull away. But if you drive to the tire’s capabilities you’ll figure out how to best exploit it. I will say big fat rubber like you’re thinking is no fun on the street. It makes the car feel heavy and less responsive. You probably know a lot of this, so you’ll have to run the experiment and let us know the outcome. The best thing about tires is you can resell them or burn them up and try others. |
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08-30-2019, 06:40 AM | #10 | |
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much worse turn in that 255 ? Any rubbing at the front ?
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08-30-2019, 06:47 AM | #11 | |
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The 265 does have more ultimate grip on track, but the 255 is much more responsive and hydroplanes less. And, the 265 does rub under compression until you wear some of the tire or fender liner down. |
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08-30-2019, 06:55 AM | #12 | ||
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Any chance this would affect the DSC in MSM mode ?
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08-30-2019, 07:06 AM | #13 | |
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The only time I’ve had weird DSC intervention was after a day of running 265/35 295/30/19 R7’s at the track and then driving home on my 265/285/35/19 4S’s. A few times going home the DSC would cut power around corners even when going slow. After driving for a day the car adapted and everything was fine. This year I ran 265/35 305/30/19 71R’s and then switched to 255/285/35/19 4S the next day. No DSC interventions at all. That 295/30 R7 is slightly shorter than the 265/35 R7, so that’s what made the car unhappy for a bit after switching. Was fine on track with DSC off, tho. |
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08-30-2019, 12:16 PM | #14 |
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OEM Size RE71 vs Wider PS4S
Is it easy to overdrive the 265 fronts with all the grip of the 305 re-71 in the rear on track?
Was planning on 265/285 re-71 on 9.5/10.5 wheels but not all that experienced so looking for feedback (FBO m2c). 255/275 best for stock wheels (street tires)to retain playfulness at low speeds, thinkong about trying some Firehawks for next set of street tires |
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08-30-2019, 01:15 PM | #15 |
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It definitely shifts the balance to a setup more prone to understeer, and you have to make sure not to overdrive the fronts. But, there’s a ton a grip in the rear and you can use more throttle to help rotate the car. Both are good skills to have.
I’ve only done one open track day on this setup and will do another soon to decide if I’ll stick with these sizes or drop to 285. I’m guessing the balance with the 255/265 and the 285 will feel better, but the reality is the more tire you have the more available grip there is and if you drive the 265 fronts and 305 rears to their limits, they will be quicker than 255/265 and 285. Worth it to sacrifice some handling balance? Not sure, yet. |
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08-30-2019, 01:24 PM | #16 | |
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thought thought of doing 275 295/305 30 ad08r Ya think I'd rather have oversteer but also only handful not track days in car so |
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08-30-2019, 02:43 PM | #17 |
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275/295 will be a nice balanced setup.
275/305 will be quicker if you’re comfortable at the limit using the throttle to help rotate the car in the corner. |
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08-30-2019, 08:35 PM | #18 |
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AD08R has an extremely blocky shoulder design for a 200tw tire. If we're still talking about the stock 9"/10" wide wheels front and back, 275 and 295/305 is way oversized. I feel like that's pushing it even for a 9.5"/10.5" setup, too (especially for the fronts).
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08-31-2019, 10:35 AM | #19 |
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It’s not as impt to have the rear tire on a 19x11, 10.5 is good enough. Plus, the clearances would be super tight with a 19x11 and you would need the wheel offset to be millimeter perfect to run a 305 in the rear.
But, a front 275/30 will drive better on a 19x10. Likely would need at least ET22-24 depending on setup, which means it’ll be sticking out from the fender some and will throw more stuff up on the side of the car. |
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08-31-2019, 01:58 PM | #20 | ||
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so your suggestion would be a 265/295 30r19 for ad08r for proper fit. getting camber plates also |
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08-31-2019, 02:35 PM | #21 | |||
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09-01-2019, 08:56 AM | #22 | |
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Also to the OP - why do you think the 71R is a horrible street tire? I love it on the street, gonna use em on my OEM’s next summer. |
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