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03-15-2010, 07:27 PM | #23 |
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03-16-2010, 12:19 PM | #24 |
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Bridgestone Potenza RE050A RFT.....2009 Sport Package Tire
Front: 215/40R18 BMW RunFlat Sidewall Style: Blackwall Serv. Desc: 85Y Load Index 85 = 1135lbs (515kg) per tire Speed Rating “Y” = 186mph (300kph) UTQG: Treadwear: 140 Traction: A Temperature: A140 A A Dunlop SP Sport 01 DSST RunOnFlat.....2009 M Sport Package Tire Front: 215/40R18 RunFlat Sidewall Style: Blackwall Serv. Desc: 85Y Load Index 85 = 1135lbs (515kg) per tire Speed Rating “Y” = 186mph (300kph) UTQG: Treadwear: 280 Traction: A Temperature: A280 A A Treadwear rating on the Bridgestone is 140.. significantly softer compound.. In my opinion this is the most important difference between the Sport package and the M Sport Package....on the 2009 model. Don't know if 2010, and 2011 are the same. Shane |
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03-19-2010, 02:15 AM | #25 | |
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If so, STOP now and reverse those numbers. This car tends to understeer as is, so a softer pressure up front can only help give more bite to the front, which is what understeer needs. With non RFT's I can run those pressures with a nice ride to handling compromise, and those numbers keep the sidewalls nice and firm giving better steering feel. If you lower tire pressure too much you can gain a softer ride, and some traction, which can be beneficial when driving in snow. But, too low on pressure and the sidewalls are too soft and you lose handling feel and get slower transitional steering. Also, depending on sustained speeds driven, a low tire pressure can result in overheating the tires, which is NOT a good thing. The door sill recommended pressures work pretty good, but they work even better with NON RFT's ime (in my experience). |
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03-19-2010, 07:24 AM | #26 | |
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03-19-2010, 07:30 AM | #27 |
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Drives: M-Sport 128i, 328xi, 3.0CS
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My 2009 M Sport came with Pirelli P Zeros.
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03-19-2010, 10:07 AM | #28 | |
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http://www.tirerack.com/tires/tirete....jsp?techid=58 Or are you saying that more understeer is desirable? Tom |
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03-25-2010, 01:10 PM | #29 |
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I wish i had the black headliner..... i have every single possible option, but that wasnt available as an option when i ordered ....... seems like way to much work to change it...
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03-25-2010, 01:22 PM | #30 |
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Drives: '08 135i, '88 325is
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I wish I had it too. It can be done, but is rather expensive.
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03-25-2010, 09:31 PM | #31 | |
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So, I base my comment on my experience with how most auto makers tend to setup general consumer automobiles. Auto makers tend toward safety rather then performance, thus some under-steer is dialed in and preferred for safety. Tire pressure adjustments can have an affect on overall car handling, though more so on race or track prepped cars, where air pressure is considered in relation to overall suspension tuning. So, you set your pressures based on what it is you are trying to do/tune. The better answer to which pressure to use, is; it depends. Yes, my comment is a bit generalized, but it is what I have experienced more so. The comments made by the Tire Rack also do not give the whole answer, because the answer is, it depends. It depends on a number of things, including tire type, what you are trying to accomplish, and it can depend on what affect lowering or raising the pressure has on the car. Here is some information, not written by me, that is already written in a better way than I can put it, and with more information that I can give. If you are inclined, please read it. It offers some very good and insightful information, that will also help understand Tire Racks comments too. Well... Tire pressure towards car balance, what a vast topic! I'd start simply by trying to identify what is really happening. Tire pressure variation on static change dynamic tire pressure, so tire stiffness and all that. But as far as tire are concerned they do work basically as a combination of friction law and rubber imprecation in the surface. Theoretically, with this simple model the more vertical load on the tire the better. As in real life everything has its limits, that is not the case all the time. Cross weight variation in dynamic and tire deflection speed are also preponderant factors. From all that and from my experience I'd say that tire pressure change in one way or the other can reduce understeer. The real question in fact is to identify the couple vertical load on the tire Vs Grip. The main point being to identify what is the reason of the understeer. Generally you can use this as guide lines: (all here is just treated towards tire pressure and no driver steering characteristics or suspensions set up) (This is for a rear wheel drive car) Entry understeer: (This is where my thinking is, when I wrote, as this is the scenario that comes to my mind when someone says, "under-steer") Main point is to get the tires loaded enough to make them react accordingly and give grip but not overloaded causing them to skip. If when you trail brake on the entry the understeer is reduced then it means the relation load to tire pressure is wrong. The tire doesn't deflect enough and adding "artificially" vertical load on the tire by trail brake induces more of the deflection so better grip. If that is the case, lower the front tire pressure will reduce entry understeer. If trail braking makes things worse it is just the opposite, the tire is overloaded. For the driver it often results in an initial bite (even very short) of the tire then a sudden lose of grip. In that case increase front tire pressures Middle corner understeer: A bit more difficult to understand clearly. Best being data acquisition (G loads, steering angle and suspensions pots) but as I don't know if you have I'll explain as if you don't. So question is: under or over loaded front? Generally speaking with a rear engine car middle corner understeer is under load of front tires. so reduce tire pressure will work. (on race car with proper suspension setting and I know it is a lot simplified) If the tire is overloaded in this phase, it means it is already unable to handle more vertical load when you turn in with trail brake as the vertical load is greater so overload of tire in mid corner is generaly associated with the incapacity of the car to handle trail brake at the entry (use trail brake until the apex and not just the entry to validate that on your car) in this case increased tire pressure is the way but this case is rarely seen as the driver will first complain of entry understeer. Exit understeer: Well, at that point you are supposed to be on the throttle. So unless you are completely off in tire pressure it is underloaded tire. So reduce pressure. All this is valid as general figures. Driver actions have a primary impact on that. Steering speed at the entry is critical with low profile tires. So here are the differences between high and low profile tire: Low profile have a total deflection being lateral or vertical smaller in terms of distance but not in angles. Meaning that they do work but the window is smaller as it is for specific angles ranges that you will get the best part of the grip curve. That explains the sudden skip characterisitc of very low profiles. They also are difficult in dynamic and sensitive to the way you transfer the load. Steering speed too high will make the tire unable to deflect accordingly to requested steered angle. Reduced tire pressure will help as the initial deflection will be easier to get. If that helps but then creates mid corners understeer bigger and bigger the more you reduce the pressure that means that the main problem was steering speed which needs to be reduced. High tire profiles (formula tires typically) are basically the opposite. As now to know which tire to work on, front or rear, that will depend on the tire itself and the minimum requested tire pressure from the manufacturer. keep in mind that as well as the suspensions' stiffness, the softer it is the better. But don't get too low start pressure on cold tires or you might end up damaging the structure of the inner wall on the outlap with the pressure too low. Conclusion of all that is that increase or decrease the tire pressure will mainly depend on the amount of deflection you have when the tire start to lose grip. Too much deflection: increase tire pressure Not enough tire deflection: reduce tire pressure note: suspension geometry, suspension stiffness etc all are preponderant in all that too but here the question was about tire pressure Last edited by RPM90; 03-25-2010 at 09:38 PM.. |
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09-07-2014, 04:23 PM | #32 |
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a bump for an old interesting thread...
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06-03-2015, 04:33 PM | #33 |
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Seems to me that people are missing some of the most important Msport package features.
* The 18" wheels are "staggered" widths. The rears are 1/2" wider. * The ride height is lowered 10mm from standard * The RF fascia air intake feeds an engine oil cooler, which vents into the RF wheel well. You won't find the oil cooler info anywhere, except as an aftermarket "accessory". It may no longer be a component of any Msport package. I've tried to determine whether the oil cooler is or not because I'm considering a new 535i with the Msport option; but if the cooler isn't there, I may not want the Msport option at all. I want to run a hotter engine map and the cooling is key. |
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06-03-2015, 07:51 PM | #35 | |
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06-04-2015, 01:03 AM | #36 |
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06-04-2015, 01:55 AM | #37 | |
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The difference between the two packages are cosmetic, as established earlier in the thread (wheel style, anthracite headliner, body kit on the 128i, and numerous M trim pieces).
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06-04-2015, 02:47 AM | #38 |
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Non sport 128i's had square 17X7 style 262 wheels. That's what my 128i had.
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06-04-2015, 09:53 AM | #39 |
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mine came on 256 wheels 17x7; 262's are staggered 17 x 7(f)/7.5(r)
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10-09-2016, 05:34 PM | #40 |
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I believe the M-Sport Pkg has a slightly lower suspension, or a 10 mm drop with the valving changed on the shocks so the bound & rebound are stiffer!
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10-10-2016, 10:02 AM | #41 |
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A very minor point, but the '08 135i was available with 17" wheels. I do not know about later model years, but my E88 came with the same M-sport suspension as any other 135i and 17" wheels (style 256). It had the 17" wheels when i bought it and the VIN report lists them as coming with the car. I have converted to 313s which i love, but still have the 17" wheels.
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10-10-2016, 12:07 PM | #42 | |
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My 1st 135i ('08) had the sport package and came stock with the 18" 264 wheels. My 2nd (and current) 135i has the M Sport package and came stock with the 18" 261 wheels, which I switched to the 18" 313s. I love the 313s as well. |
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10-10-2016, 12:28 PM | #43 | ||
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Another possibility is that the original owner spec'ed 17" wheels. I believe that was a no-cost option on all 135i's, mostly chosen by those in northern climates. If you know the Style number, we can dig around and figure it out.
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10-10-2016, 01:42 PM | #44 | |
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