10-18-2019, 05:58 AM | #89 |
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Drives: 2017 M3 MG/SO ZCP DCT
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What is impressive is a classic 25 year old timeless design, naturally aspirated, Manual coupe, with a mere 240HP did it in 3:11.
+ Fun factor https://www.bmwblog.com/2019/10/15/c...lightning-lap/ |
10-18-2019, 07:47 AM | #90 | |
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hope bmw goes back to lighter cars instead of pigs |
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10-18-2019, 11:10 AM | #91 | |
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10-18-2019, 12:51 PM | #92 | |
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1) Keeping the factory stagger will help preserve that balanced feeling you enjoy, but as you guessed there is more to this 2) Rubber compound. Staying with Michelin will likely be the easiest way to maintain similar feel at the limits, because of the blend of the chemicals. Each tire makes use a more or less proprietary blend of rubber which behaves better/worse in different temperatures and in presence of H20. But if you like a feel of a particular blend chances are you will also enjoy the feel of their next level of aggressiveness. 3) Wider tires genrally provide more grip. But there is a whole lot more toconsider here too. Even if you go from 255 MPSS to a 275 MPSS the breakaway behavior of the 275 will be more abrupt than 255. Because Physics. Very very (overly) simply put because as you increase grip you also increase cornering forces. If you increase Force without changing anything else you also increase acceleration. Meaning gripper tire lets go more abruptly! 4) And perhaps more important. TEMPERATURE of tire! Most people have very little understanding of how important this factor is. Take a racing slick at 90F and compare it to MPSS of fame dimensions at 170F, and very likely MPSS will have more grip in this scenario. This is VERY important. A lot of people want more grip, but don't realize that even during spirited runs they never enter the envelope of optimal tire grip temperature off track. 130F is well below max grip of even a street tire. So pay attention to your pressures AND temperatures. You could have the best tire but if you don't operate in it's sweet spot of pressure and temperature it will perform poorly. Most people would be surprised at how grippy MPSS can be at proper temperature. 5) Pressures. Some tires like having no more than 33psi. Some are happy at 40psi. There are trends to tire type, and +/- 3PSI for different manufactures. So research and pay attention. So if you like Canyon carving but not track days, and you live in some elevation my recommendation would be keep stock size but get MPS4 or one size up (255/275 MAX) but be ready for more abrupt breakaway. Again, not huge difference but still. Little things add up. 6) then there is suspension geometry, camber, caster, toe ... but no. We keep this simple. Loaded topic but I hope this helps you consider most important variables.
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10-18-2019, 01:27 PM | #93 |
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Thanks! I have experimented with tire pressure. I generally achieve 115 degrees F in the twisties depending on outside temperature. I have pretty much decided to go with MPS4S. It will be interesting to see if they come out with * ratings for that tire. They've already come out with Mercedes rated tires. I wonder if those ratings even matter.
Thanks again for your well thought out informative posts. I guess I'll stop hijacking the thread now 😂. |
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10-18-2019, 02:06 PM | #94 | |
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Also, do you find the tire temp gauge BMW offers through I-drive reliable? I usually get my tires into the 120-125F range...surprised to hear they can go up to 170F.
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10-18-2019, 02:44 PM | #95 |
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MPSS start loosing grip around 190F. And this is what most people miss. Track temps are WAY above street temps. But this is exactly my point! MPSS doesn't start gripping at the max till about 140-150F. 170F is the sweet spot at the track, along with ~34-36PSI in my opinion. The problem when you're pushing on track is keeping them in the temp and pressure window.
And MPSS are almost identical for M2 and GT350. The star spec comes down to homologoation testing, and manufacturers like to make a big deal about the 0.1% compound or pattern change to meet some very specific requirements they have. But don’t be fooled. MPSS is still MPSS regardless on MBO or BMW star rating. The iDrive temps come directly from tire pressure sensors. Those are probably +/- 5F but still. Close enough. And to keep things consistent, you’re right. Keeping stock spec tires will result in most repeatable experience. Since Apls was asking for a bit more grip I gave the recommendation I did. Last edited by 5.M0NSTER; 10-18-2019 at 03:18 PM.. |
10-19-2019, 01:09 PM | #96 | |
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10-19-2019, 09:31 PM | #97 |
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[QUOTE=5.M0NSTER;25362823
And MPSS are almost identical for M2 and GT350. [/QUOTE] Some great info Just wanted to mention a couple of things in the case of the GT350 The MPSS for the GT350 start with a bit less tread depth than in most other sizes 7.5/32" F and 8/32" R for the GT350 versus 10/32" F and R for the M2C Also worth mentioning is that beginning with the 2019 model year, GT350s come with MPSC2s from the factory |
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10-20-2019, 04:48 AM | #98 | |
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This effect also provides better feedback to the driver ... if the electric power steering unit has the ability to provide it to the wheel.
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10-20-2019, 10:00 AM | #99 | |
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What would be your advice for better wet grip, in stock F80 ZCP sizes (265/285)? MPSS * or MPS4S? I'll be due to replace my original set in the spring, and these act as my wet setup for the track as well.
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10-20-2019, 01:13 PM | #101 | |
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So are you trying to maximize wet traction on the street while keeping the same tire for dry track days? If so one thing is clear, semi-slick or extreme performance summer tires with 180-200 thread wear rating is not for you. Those are better for dry track, but are atrocious in the rain. I think for this use case it's best stick to Max Performance Summers. I don't have first hand experience in the wet with MPS4, but i think you can trust Tire Rack and car magazine reviews. They typically run instrumented tests in addition to subjective feel reviews. I have very good experince with MPSS in the wet and the dry as well as some other times. I would say Bridgestone Potenza S04 Pole Position is a little better in the Wet. But not as good in the dry. MPSS is just very good all around, and MPS4 is the next step in the evolution.
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10-20-2019, 10:19 PM | #102 | |
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But still I gather from your post that the MPS4S will be better still in the wet. I just love driving on the stock Michelins on the track in the wet, blowing by GT3's and other serious exotica running Cups, slicks or similar, which are atrocious in the rain.
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