12-09-2017, 01:09 PM | #67 | |
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I reccomened them to my buddy who runs mpss on his c7 stingray. He says the same thing I'm fbo with meth too. |
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12-09-2017, 01:23 PM | #68 |
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I agree, on dry roads the 225 wide Sottozero tyres at sub zero temperatures have grip levels as good as the 245 wide MPSSs until the ambient temperature climbs above 20°C.
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12-11-2017, 05:52 PM | #69 |
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I read somewhere that thinner tires provide more grip for launching a car, but less grip in the turns. Apparently, the contact patch on a thinner tire is longer than the contact patch on a wider tire. So perhaps the 225 rear Sottozeros that you run in the winter provide the same grip as the 245 MPSS do in the summer: the long contact patch on the 225 Sottozeros offsets the stickier rubber of the 245 MPSSs (in warmer temperatures).
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12-11-2017, 07:11 PM | #71 | |
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Let's say you put 2 tires of the same size together, side by side, the tire would be twice as wide but the contact patch will not get any longer, it will be exactly the same cause it's the same tire..... To increase the length of the contact patch you need to increase the diameter of the wheel... that's why dragsters use huge wheels on the rear The only condition I know where you want thinner tires for traction is on snow...cause you want the tire to claw in... so the less surface, the more it sinks on it... |
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12-11-2017, 07:59 PM | #72 | |
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I'm homing in on the part where it says "Installing fatter tires widens the patch, but it also shortens it front-to-back. Because of this, cornering gains can be offset by diminished straight-line traction, including braking and hydroplaning resistance." |
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12-11-2017, 08:23 PM | #73 | |
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"Merely increasing the width of a tire doesn't increase the area touching the pavement" If I double the width, then the area will double.. "Installing fatter tires widens the patch, but it also shortens it front-to-back." How on earth does the patch shortens with a wider tire ? |
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12-11-2017, 08:35 PM | #74 | |
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The only way to have a wider tire with a longer contact patch than a skinnier tire is either to increase the weight of the vehicle or to reduce the air pressure in the tire. The reason that BMW uses staggered wheels and tires on RWD cars is to reduce oversteer because the contact patch on the wider rear tires will resist lateral movement more so than a square tire set up would. At the track, where you want rotation, a square set up will improve handling, but it will also create the risk of unintended oversteer. I actually use the 225 Sottozeros in a square set up for my winter tires. They handle pretty well, but I have to remind myself that they are more prone to oversteer because the rear tires are skinnier than stock and the rubber compound is not as sticky as the MPSSs. |
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12-11-2017, 09:13 PM | #75 | |
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Don't get me wrong... I'm not saying your are right or wrong... I just can't understand the logic.... |
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12-11-2017, 10:29 PM | #76 | |
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Pressure = tire pressure Force = Mass of the car (times gravity) Area = Tire contact patch As long as tire pressure and mass of the car stays the same, contact patch area will stay the same. |
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12-12-2017, 06:41 AM | #77 | |
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What this doesn't take into account is the tread block squish and the additional force from weight transfer accelerating, and the fact that the contact patch gained by dropping psi or adding weight is not linear. You can keep adding weight to a car or taking psi out of the tire, but at a certain point the car would be resting on the rim. If that were the case, then doubling the tire width would be doubling the contact patch. That's an extreme example though. So I guess the article is right in saying that wider is not always better, but I do think they over simplify the topic. I'm just half talking out my ass though, so who knows |
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12-12-2017, 07:18 AM | #78 |
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You're thinking of the tire as a solid object, but remember that it's squishy with the air. So if you make it wider, it's not going to deform as much in the forward-backward direction.
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12-12-2017, 11:24 AM | #79 |
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If you think winter performance tires are providing the same level of lateral and transitional grip as the MPSS tires, then you're not driving the car hard enough in the cold LOL
I can attest to the fact that narrower winter performance tires do indeed improve straight line acceleration grip. I have far more acceleration traction in 1st and 2nd with my 75% worn 225/40R18 Michelin Alpin PA4 compared my half worn MPSS 245/35R18s. I attribute the grip increase to the PA4's soft winter rubber compound, soft sidewalls, and the tall, siped tread blocking that brushes and displaces itself against the pavement under hard load compared to the stiff, unsiped tread block and sidewalls of the MPSS which can't bit downwards nearly has hard. With that said, in the dry and at their ideal operating temps and ambient conditions, the PA4s DO NOT have the same threshold braking abilities. I can get my PA4s to lock up much quicker than my MPSS tires. I'd venture to say that from 60mph, the PA4s take 20+ more feet to stop. It's a trade off with winter tires. |
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12-12-2017, 01:55 PM | #80 | |
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Personally I was saying that I was impressed with straight line acceleration. I do not ever push my winter tires, I do drive them quickly though. I just always think of burning marshmallows in my head anytime I think of driving the winters hard. One those things get about 50 F they feel pretty squirmy. Also on a side note I did an hpde event in NH at Cannan speedway at the end of October. I ended up running a 1:11:xx for my best lap with a maximum of 1.24 g on mpss. It was dry and about 38F. It took about 8 laps to get tires up to temps the first session. |
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12-12-2017, 02:22 PM | #81 |
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So true. I think about it every time I throw my car into a corner or hammer it in a straight line. My rears are certainly more worn than the fronts
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12-12-2017, 02:52 PM | #82 | |
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Me - (holding breath, one eye open) "really!?....great!" Car in background fbo, catless, meth, gold intake, hre wheels, carbon everything, tint. Jb4 tuckup up away from obd2 port hahahahah. Also apologies for aiding in this thread derailment. I did learn something new about tire width and lateral grip though so that's good. |
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02-21-2019, 04:55 PM | #83 | |
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Test run came in at 4.25 0-60 Stage 1 Dinan plus Dinan cold air induction. Problem 4,970 altitude The app on my phone recorded 0-60 in 3.0 So I spent $100 and got a Matrix Kat so it could tell me I am slow. Had my doubts about the 3.0 in the first place, but I really felt good while it lasted |
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02-21-2019, 05:35 PM | #84 |
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Well, at least it was in the ballpark, though, right?
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02-21-2019, 09:38 PM | #85 |
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You guys need to pick up a Dragy if you're hell bent on recording accurate times. I have real world track time slips and the Dragy is very, very close.
http://www.burgertuning.com/dragy_gp...nce_meter.html
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02-22-2019, 07:39 AM | #86 | |
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02-22-2019, 10:59 AM | #87 | |
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Makes me hesitant to spend $150 on it. |
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02-22-2019, 04:05 PM | #88 | ||
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I think I'm going to be ordering the Dragy this weekend. |
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