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      03-08-2019, 11:26 AM   #133
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Old Geezer, I'm curious what psi you are running with your RE's. I'm finally next on the list for a 2020. Been a long wait...

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Originally Posted by Old Geezer View Post
What's the intended usage - track or autocross? I found running my '17 M2 on square 265/35-18 RE-71s with 18x9F/18x10R EC-7s using stock offsets, I had to run a few PSI more in the rear to get the car to rotate.

With my M2C running 255/35-19F & 275/35-19R RE-71s on stock rims, it rotates nicely with equal pressures front and rear.

My 2 cents is that people get a bit preoccupied with running a square tire setup. I'm not convinced its necessary. It's something of a moot point if one has to run 19's anyway. The height of the front tires effectively limits how wide you can go.
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      03-08-2019, 12:34 PM   #134
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Quote:
Originally Posted by Karazy View Post
Old Geezer, I'm curious what psi you are running with your RE's. I'm finally next on the list for a 2020. Been a long wait...
My experience on my Ď17 M2 was that due to the relatively stiff sidewalls, the RE-71R is tolerant of a wide range of pressures. With the square 265/35-18ís, I started at 32f/32r on the recommendation of a fellow M2 driver. Another friend of mine in a Ď18 M2 said he ran 36f/36r. I tried that and liked it, although I ended up at 36f/38r to get better rotation.

With the M2C, I started at 32/32 with the 255/35-19, 275/35-19 setup. On a low-grip surface, running 30 in back makes the rotation easier to manage. Most of my events take place at a venue with grippy but abrasive concrete. I donít know how much more abuse the fronts will take, so Iím going to try 36/34 for my next event. I may roll the dice and try 265/285 next.

Run some events with the OEM tires. The M2C is way more throttle-steery than the base car. You need to learn how to cope with it.

More than you wanted to know?
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      03-09-2019, 10:36 PM   #135
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Thank you for the info! I've been running 30 psi all ends the last few years in my C7. Planning on putting RE-71 on immediately when I get the car, and just saving the stock tires for another time. I'm on the fence about also jumping to 265/285 over the 255/275. Do you think there will be rubbing / clearance issues?




Quote:
Originally Posted by Old Geezer View Post
My experience on my Ď17 M2 was that due to the relatively stiff sidewalls, the RE-71R is tolerant of a wide range of pressures. With the square 265/35-18ís, I started at 32f/32r on the recommendation of a fellow M2 driver. Another friend of mine in a Ď18 M2 said he ran 36f/36r. I tried that and liked it, although I ended up at 36f/38r to get better rotation.

With the M2C, I started at 32/32 with the 255/35-19, 275/35-19 setup. On a low-grip surface, running 30 in back makes the rotation easier to manage. Most of my events take place at a venue with grippy but abrasive concrete. I donít know how much more abuse the fronts will take, so Iím going to try 36/34 for my next event. I may roll the dice and try 265/285 next.

Run some events with the OEM tires. The M2C is way more throttle-steery than the base car. You need to learn how to cope with it.

More than you wanted to know?
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      03-10-2019, 06:14 AM   #136
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Quote:
Originally Posted by Karazy View Post
Thank you for the info! I've been running 30 psi all ends the last few years in my C7. Planning on putting RE-71 on immediately when I get the car, and just saving the stock tires for another time. I'm on the fence about also jumping to 265/285 over the 255/275. Do you think there will be rubbing / clearance issues?




Quote:
Originally Posted by Old Geezer View Post
My experience on my ‘17 M2 was that due to the relatively stiff sidewalls, the RE-71R is tolerant of a wide range of pressures. With the square 265/35-18’s, I started at 32f/32r on the recommendation of a fellow M2 driver. Another friend of mine in a ‘18 M2 said he ran 36f/36r. I tried that and liked it, although I ended up at 36f/38r to get better rotation.

With the M2C, I started at 32/32 with the 255/35-19, 275/35-19 setup. On a low-grip surface, running 30 in back makes the rotation easier to manage. Most of my events take place at a venue with grippy but abrasive concrete. I don’t know how much more abuse the fronts will take, so I’m going to try 36/34 for my next event. I may roll the dice and try 265/285 next.

Run some events with the OEM tires. The M2C is way more throttle-steery than the base car. You need to learn how to cope with it.

More than you wanted to know?
No rubbing issues on my '18 with this setup (255/35 & 275/35) with stock suspension and PS4s.
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      03-10-2019, 06:37 AM   #137
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Quote:
Originally Posted by Karazy View Post
Thank you for the info! I've been running 30 psi all ends the last few years in my C7. Planning on putting RE-71 on immediately when I get the car, and just saving the stock tires for another time. I'm on the fence about also jumping to 265/285 over the 255/275. Do you think there will be rubbing / clearance issues?
From what I can gather from other forum posts, the 265/35-19 up front will rub due to its diameter increase. There are various posts discussing where and how severe the rubbing can be.

If we could just get 275/30-19 and 295/30-19 in RE-71R or Rival S 1.5....BFG did just release the S1.5 in 275/35-19 however.
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      03-10-2019, 05:58 PM   #138
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Quote:
Originally Posted by Karazy View Post
Thank you for the info! I've been running 30 psi all ends the last few years in my C7. Planning on putting RE-71 on immediately when I get the car, and just saving the stock tires for another time. I'm on the fence about also jumping to 265/285 over the 255/275. Do you think there will be rubbing / clearance issues?
Really donít know if 265/35-19 in front is doable or not. The forum posts on the subject go both ways. Although the M2C might benefit from more tire in front, it desperately needs more tire in back.

FWIW, I think your Corvette can run less pressure due to the amount of camber you can get with the factory suspension. I have a friend with a gen6 ZL1 1LE Camaro, and he runs pressures similar to yours.
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      03-10-2019, 06:36 PM   #139
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Thanks for all the feedback guys!


Quote:
Originally Posted by Old Geezer View Post
Really donít know if 265/35-19 in front is doable or not. The forum posts on the subject go both ways. Although the M2C might benefit from more tire in front, it desperately needs more tire in back.

FWIW, I think your Corvette can run less pressure due to the amount of camber you can get with the factory suspension. I have a friend with a gen6 ZL1 1LE Camaro, and he runs pressures similar to yours.
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      03-22-2019, 06:20 AM   #140
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Just an FYI: the 2019 M2C has been classified as A-Stock, up from the OG M2's B-Stock classification. Somewhat annoying, but I think they lump all M Competition models in A-Stock.
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      03-22-2019, 06:51 AM   #141
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Quote:
Originally Posted by Blue2 View Post
Just an FYI: the 2019 M2C has been classified as A-Stock, up from the OG M2's B-Stock classification. Somewhat annoying, but I think they lump all M Competition models in A-Stock.
Yeah, I saw that a few weeks ago. It has no chance in A-street (unless Rich is driving it like his A-stock days of lore with the roller skate) I would guess. At least it is small (short) albeit wide though. Mid-range torque is insane in this car, so fitting up 305/30-19 RE71Rs in the rear would be helpful.
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      04-05-2019, 09:59 PM   #142
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I’m interested to see what happens. I’ve got a Dinan front bar on full soft, and 285 x 18 in front, 275x18 in back. The last event of last year I tried 265x18 in front and 275x18 in back and it was a pushy pig that was somewhat frustrating to get to do what I wanted. Now, the tires were virtually dead, but I felt the car needed a lot more front grips not just rear grip.

If this turns out to be too over-steer-e I should be able to dial it out with the front sway. If that doesn’t work I can always go to wider 19’s in back. The car should be able to get plenty of tire to be a freakin’ riot. Last event last year it was freakin’ frustrating.
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      04-05-2019, 10:21 PM   #143
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Quote:
Originally Posted by CSBM5 View Post
Mid-range torque is insane in this car, so fitting up 305/30-19 RE71Rs in the rear would be helpful.
Just out of curiosity, what M Engine Dynamics setting are you using?
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      04-06-2019, 06:17 AM   #144
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Quote:
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Just out of curiosity, what M Engine Dynamics setting are you using?
Sport or Sport+ (M2C).
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      04-06-2019, 07:43 AM   #145
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Quote:
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Sport or Sport+ (M2C).
Finally tried Sport at my last event, and found the car much easier to control than with Sport+.
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      05-01-2019, 09:18 PM   #146
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At Sunday's autox the nanny's kicked in on me on the last run of the day. I was in Sport with the DSC completely off. The car told me my pressures were too low about 2 minutes before pulling off to the start line, . I pulled them up and the car had them all at either 32 or 33 lbs. I had been bleeding down to 35 lbs all day with a borrowed gauge - it was likely showing a lb or two lower than actual. A timing issue delay must have given them enough time to drop temps and pressure. The car was cutting power within the first 10 seconds of the run and continued to cut power throughout whenever I began to load up a corner. Miserable...

Running Re71R's. 275/35/18's and 305/30/19's.

Has anyone tried to run with pressures in the lowish 30's range with success? I was surprised, frustrated and disappointed at the intrusiveness.
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      05-01-2019, 09:41 PM   #147
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Quote:
Originally Posted by boony1968 View Post
At Sunday's autox the nanny's kicked in on me on the last run of the day. I was in Sport with the DSC completely off. The car told me my pressures were too low about 2 minutes before pulling off to the start line, . I pulled them up and the car had them all at either 32 or 33 lbs. I had been bleeding down to 35 lbs all day with a borrowed gauge - it was likely showing a lb or two lower than actual. A timing issue delay must have given them enough time to drop temps and pressure. The car was cutting power within the first 10 seconds of the run and continued to cut power throughout whenever I began to load up a corner. Miserable...

Running Re71R's. 275/35/18's and 305/30/19's.

Has anyone tried to run with pressures in the lowish 30's range with success? I was surprised, frustrated and disappointed at the intrusiveness.
I had that happen a few times with my Ď17 M2. What I found helped was to reset the TPM before the first run, but after setting my initial tire pressures. This was running 32/32, w/square 265/35-18 RE-71Rs.
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      05-01-2019, 09:41 PM   #148
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I don't see the Comfort Mode forcing until I'm under 29psi.

Your issue may be due to pressures dropping while the car's running. I think you might be able to get around this with a TPMS reset at the lower pressures.

Good luck. Coding folks, please weigh in with a real solution.
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      05-01-2019, 09:44 PM   #149
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Quote:
Originally Posted by rwalker View Post
I don't see the Comfort Mode forcing until I'm under 29psi.

Your issue may be due to pressures dropping while the car's running. I think you might be able to get around this with a TPMS reset at the lower pressures.

Good luck. Coding folks, please weigh in with a real solution.
Just a hunch, but I donít think itís related to a specific value as much as how much the pressure has changed relative to what it was when the TOMS was last reset.
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      05-01-2019, 09:44 PM   #150
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Has anyone tackled the camber correction knuckles that are available? The claim is an additional -.5 degrees of camber. From what I can see the job looks straightforward enough. What I can't see is what concerns me as I'd prefer to do the install myself. $700 is steep but -1.7 or so negative camber would be helpful and might pay for itself in tires alone over two to three seasons.
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      05-01-2019, 09:49 PM   #151
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Quote:
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Just a hunch, but I donít think itís related to a specific value as much as how much the pressure has changed relative to what it was when the TOMS was last reset.
I wish. There's no way to reset past a sub-27psi pressure in my car, and I've screwed around with the DSC pressure settings a bunch to no avail.
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      05-01-2019, 09:51 PM   #152
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Quote:
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Just a hunch, but I donít think itís related to a specific value as much as how much the pressure has changed relative to what it was when the TOMS was last reset.
Thanks, this potentially makes sense. The warning caught me of guard and didn't think much about it at the time. I piddle with a lower reset value and see what happens.
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      05-01-2019, 09:59 PM   #153
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Quote:
Originally Posted by rwalker View Post
I wish. There's no way to reset past a sub-27psi pressure in my car, and I've screwed around with the DSC pressure settings a bunch to no avail.
27 is a pretty low target, much lower than I'd need with my tire sizes. 27 was borderline too low on my Corvette GS with correct tire to wheel sizes running BFG Rivals. I normally run 35 to 36 lbs but this particular lot was sealed asphalt, lower pressures should have been somewhere in the okay to optimal range.
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      05-01-2019, 10:04 PM   #154
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Quote:
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I wish. There's no way to reset past a sub-27psi pressure in my car, and I've screwed around with the DSC pressure settings a bunch to no avail.
You could be right. Iíve never gone that low. In my experience, the RE-71Rs tolerate a fairly broad range of presures. Iíve found I prefer the way the car drives towards the high end of the range; the shoulders on the front tires last longer as well.
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