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BMW 328i/328xi

24

Comments

  • fedlawmanfedlawman Posts: 3,118
    I basically agree spirit, but we're talking about a BMW, not a Buick. BMW's non-sport suspension is still quite sporting and capable - it hardly qualifies as "bad/soft."

    A 328i with non-sport suspension is not soft or wallowy, and will still benefit greatly from an improvement in grip. The upgrade from an "all-season" compound to a "max performance summer" compound is dramatic, and no upgrade in suspension is required to reap the benefits.
  • fedlawmanfedlawman Posts: 3,118
    Sorry absolutic, I didn't know they were 205/45-16 (BMW's website says they're 205/55-16).

    Here, use this calculator to find a comparable size in 225mm width:

    http://www.miata.net/garage/tirecalc.html

    Remember, you can even stick with the stock size if you want. The upgrade to a summer high performance compound is much more significant to improved handling than adding a mere 20mm of width.
  • shiposhipo Posts: 9,152
    Okay, as best as I can answer, and all in one swell foop too:

    Base tires on a 328i are 205/55 R16, the optional tires that have been discussed here are 225/50 R16, 225/45 R16 and 225/45 R17. Consider the following specs (Key: OD=Outer Diameter, SH=Sidewall Height, RWR=Rim Width Range, ORW=Optimal Rim Width:

    205/55 R16 - OD: 24.9" SH: 4.45" RWR: 5.5"-7.5" ORW=6.5"
    225/50 R16 - OD: 24.9" SH: 4.45" RWR: 6.0"-8.0" ORW=7.0"
    225/45 R16 - OD: 24.0" SH: 4.00" RWR: 7.0"-8.5" ORW=7.5"
    225/45 R17 - OD: 25.0" SH: 4.00" RWR: 7.0"-8.5" ORW=7.5"

    I know that many of y'all have all of this memorized, however, it's new to others so bare with me.

    The basic tire size formula is: OuterDiameter = RimDiameter + (SectionWidth * ((AspectRatio / 100) * 2))

    We're working with four primary measurements here, Outer Diameter, Rim Diameter, Section Width (tread width) and Aspect Ratio (sidewall height as expressed as a percentage of Section Width). Widening the Section Width but keeping the Wheel Diameter and the Outer Diameter the same means that the only other measurement that can "give" to keep the equation in balance is the Aspect Ratio, and as such, by increasing the Section Width from 205 to 225 on our 16" rim, the Aspect Ratio MUST decrease from 55 to 50. As you can also see in the case of the 225/45 R16s, decrease the Aspect Ratio too far and the tire gets too small.

    Since the goal of this exercise is to keep the outer diameter as close to 24.9" as possible AND to increase the section width from 205 to 225, we have two real options here, move to 225/50 R16 tires (thanks FedLawman I'd forgotten this size even existed), or change wheels and move to 225/45 R17.

    Other general truths regarding tire sizes:
    - As the section width increases, so too does grip at the limit.
    - As the wheel size increases, then the sidewall must shrink and so too does the aspect ratio.
    - As the aspect ratio decreases, the tires become more responsive to steering inputs.

    Then there is the rim width measurements. As it turns out, the OEM rims on the 328i will accomodate the 225/50 R16 tires perfectly. And that my friends is the last criteria, and as such I think we have a winner. absolutic, contrary to what your friend has told you, you can safely mount wider tires in the form of the aforementioned 225/50 R16 size and your car will be quite happy. It won't handle as well as a true SP equipped 328i, but it should be noticeably better than the relatively skinny 205s that your car currently has. Want to increase responsiveness a bit more? Fine, buy new wheels and go with the 225/45 R17s.

    As for things like brake clearance, that isn't an issue with 17x8" wheels I've recommended as those wheels are the same size as BMW offers as front wheels on SP equipped cars.

    Clear as mud? Sorry, it's late and I'm tired. ;-)

    Best Regards,
    Shipo
  • shiposhipo Posts: 9,152
    "I didn't know they were 205/45-16 (BMW's website says they're 205/55-16)."

    You didn't know it because that's not what absolutic's car has. Like the BMW-USA web site says, his car has 205/55 R16 RFTs.

    Best Regards,
    Shipo
  • absoluticabsolutic Posts: 29
    Shipo, so according to your formula either 225/50 R16 or 225/45 R16 should fit ok on my wheels, correct?
  • kyfdxkyfdx Posts: 29,863
    Nope..

    225/50-16

    205/55-16

    Either of those will fit... Like fedlawman says.. I'd go with the 225/50-16.

    I think 225/45-16 is a typo..

    On another note.. in '05, at least.. the coupes had the sport suspension standard, but the convertibles didn't..

    MO still stands... To get the best/cheapest handling upgrade to your non-sport 3-series.. put summer performance tires on it (you don't even have to upgrade the size).

    Better yet, order the sport package the next time.. ;)

    regards,
    kyfdx
    still not the host of this forum

    MODERATOR
    Prices Paid, Lease Questions, SUVs

  • shiposhipo Posts: 9,152
    Yes, but...

    The 225/45 R16s will introduce a 3.8% speedometer error, the 225/50 R16s will keep your speedometer and odometer accurate. Consider the following:

    205/55 R16: 16+((205*((55/100)*2))/25.4) = OD of 24.87795"
    225/50 R16: 16+((225*((50/100)*2))/25.4) = OD of 24.85827"
    225/45 R16: 16+((225*((45/100)*2))/25.4) = OD of 23.97244"
    225/45 R17: 17+((225*((45/100)*2))/25.4) = OD of 24.97244"

    What those outer diameters mean is that the factory tires will go around fewer times per mile than the other two, however, the 225/50s are so close that they are well within the margin of error. Consider the following:

    Inches in a mile = 63,360
    205/55 R16 Revs per mile: 810.6822
    225/50 R16 Revs per mile: 811.3242
    225/45 R16 Revs per mile: 841.3042
    225/45 R17 Revs per mile: 807.6149

    The more times per mile your wheels rotate, the faster your car thinks it's going and the further it thinks it's gone.

    Said another way, DO NOT put the 225/45 R16s on your car. If you want the "45" aspect ratio then you need to buy new 17" wheels.

    I hope this helps.

    Best Regards,
    Shipo
  • absoluticabsolutic Posts: 29
    in addition to 225 it appears that certain 245/50/16 would also fit! For example these
    link title
    seems to fit 7-inch rim!
  • circlewcirclew Posts: 8,388
    Be Careful! If the rim is too narrow, the tire will not track correctly. Just my 2 cents.

    Regards,
    OW
  • shiposhipo Posts: 9,152
    Will 245/50 R16s be able to be mounted on your rims? Yes. Is it recommended? Not a chance. Why? In addition to the fact that optimal rim width for those tires is wider than what you have, there are also separate reasons for the front and rear axles of your car.

    For the front end, the 245s most likely will destroy your inner fender liners in short order, possibly shredding the inner sidewall of the tire in the process. They're just plain too wide. In addition, as circlew pointed out, as the bead will effectively be tucked well in from the outer edge of tread, your car may not track properly, especially if you are driving on older road surfaces that are rutted.

    For the rear end, you are introducing speedometer and odometer error, 3% in the other direction this time (i.e. your car will be traveling 3% faster than indicated and your odometer will be indicating 3% fewer miles).

    Short of buying new wheels, your single option is to buy a set of 225/50 R16 tires. If you buy new wheels, then the criteria that you must stay within is an outer tire diameter of 24.9" plus or minus 0.2", and tread no wider than 225 in the front and 245 in the rear. Also, please keep in mind that if you do decide to go with a staggered setup (i.e. 225s in front and 245s in the rear), you will lose your ability to rotate your tires.

    A final thought. IMHO, tires that have been mounted on wheels that are marginally too narrow or too wide for the intended tires, look stupid.

    Best Regards,
    Shipo
  • kyfdxkyfdx Posts: 29,863
    245s are too wide for a 7" wheel.. I'd concentrate on the best rubber I could get, that stays within stock parameters..

    As shipo states... 225/50-16 is your best bet.. If you put some ultra-sticky tires in that size on your vehicle, then you'll see massive improvements in grip and turn-in.

    Now, all that said... Maybe we should continue any further tire discussions here: BMW 3-Series Tires and Wheels

    Because... the actual title of this discussion is 2007 BMW 328i Performance

    Thanks!
    kyfdx
    (not the host here)

    MODERATOR
    Prices Paid, Lease Questions, SUVs

  • circlewcirclew Posts: 8,388
    Tires ARE performance! But you set the direction.

    Regards,
    OW
  • patpat Posts: 10,421
  • abfischabfisch Posts: 591
    You are soooo right. And then some are talking about tracking the car. This original thread was a person who was leasing a car, in a city environment.

    Some people just have to have the bigger tires for the look. But it is quite the opposite for driving sport.

    abfisch
  • absoluticabsolutic Posts: 29
    I'm the original person who started the thread. And after driving the car for about 230 miles in the last 6 days, I decided to keep the original 205s. The car drives very good as it is. I also discovered the DS position. At the beginning, I thought it was either D for fully automatic or I had to shift M1 through M6. Yesterday after reading this site I discovered that the intermediate position of DS means more fun. I tried it and I am loving it. I am never going back to MB.
  • Recently got the 07 328XI coupe, I notice the oil temp running past the middle. Is this normal? Mines runs around 2-3 clicks past the middle.
  • shiposhipo Posts: 9,152
    Did you install your oil temperature gauge from an after market supplier of did you somehow manage to get BMW to supply you one from their parts bin?

    Best Regards,
    Shipo
  • The coupe comes with it instead of the MPG gauge.
  • kyfdxkyfdx Posts: 29,863
    Hey! We learn something new every day.. :)

    MODERATOR
    Prices Paid, Lease Questions, SUVs

  • habitat1habitat1 Posts: 4,282
    The oil temp and water temp guages in my 911 run at the middle of the guage under normal conditions. The oil pressure guage runs near 5 on a scale of 1 to 5 when the car is driving along at normal speeds (drops lower at idle).

    If your oil temp guage is running to the high side by a noticable margin, I'd check with your service manager, but also test drive/check some other vehicles on the lot. That does not sound right to me, but I'm not sure how BMW aligns their guages.
  • circlewcirclew Posts: 8,388
    Does the 911 have numbers on the gauges for temp/volts? The '06 330 has no gauges! Ridiculous!

    I prefer knowing what's going on in the engine room. You'd think that with on-board computers, it would be a cinch to see operating metrics at a glance!?

    Regards,
    OW
  • I plan to replace the style 156 wheels that come from the factory on a new 328i. I have found a beautiful set of 16 inch chromed M3 style wheels at a decent price. Can anyone tell me where to find the offset spec of the original wheels so I can be sure I am putting something compatible on the car? I dont have the car yet so I cant physically measure them..
  • pearlpearl Posts: 336
    finally replaced my beloved 97 528, which was hitting some serious maintenance plateaus and I did not want to put a ton of money into it at this stage (163K miles). Quite a change for me since I am getting an automatic - first time in 27 years. I drove the 335 - absolutely awesome power - but much more than I can imagine ever needing. The 328 goes very well and handles incredibly well too. I'll see if I can get more than 160K out of this one! :)
  • circlewcirclew Posts: 8,388
    Best of luck and enjoy! I love the handling as well on my 330.

    Regards,
    OW
  • cdnpinheadcdnpinhead Forest Lakes, AZPosts: 3,291
    I hope to be right (more-or-less -- my present car needs to exhibit more symptoms first) behind you. I generally keep cars well beyond 100K miles & enjoy handling more than power.

    Good to hear stories like yours. Keep us posted on your new ride.
  • error438error438 Posts: 17
    I have a simple question- is there a a differance between summer tires and all season tires in the snow with RWD? Some people say there isn't.
  • shiposhipo Posts: 9,152
    Yes, and it's HUGE.

    My first BMW had All-Season rubber, and it served me fairly well for the four winters that I had it. Not GREAT mind you, but I was able to get from point A to point B, with only a certain amount of white knuckling the steering wheel. My second BMW came with Summer rubber, and with only a quarter of an inch of snow on my drive way I was unable to make it up to the street. That thing was downright scary to drive with even so much as a dusting on the streets. That said, I ordered a set of winter tires for it and was astounded at the difference those tires made in the car. It went from the worst winter driver I've ever had (and I've driven through thirty some winters) to the very best. If I had to rate the tires on a scale of one to ten for winter capabilities (ten being the best), I'd put the Summer rubber at a 1 (maybe not even that high), the All-Season rubber at a 4 and the Winter rubber at a 10.

    Best Regards,
    Shipo
  • habitat1habitat1 Posts: 4,282
    I disagree slightly with Shipo. It's not HUGE. It's ENORMOUSLY HUGE. ;)

    I have a FWD TL 6-speed with summer tires and it performs far worse in 2-3 inches of snow than a RWD 5-series would with all seasons. The summer tires get hard as nails in sub 30 degree temperatures and the traction sucks.

    We were up in my hometown in Erie over Easter and got snow every day. Fortunately we drove our MDX. But I took out my 1995 Nissan Maxima from our second home and was shocked at how much better it handled in the snow than my TL would have. Absolutely no unintended excitement. All because it has 15" 215/60 all seasons (with 40,000 miles on them, no less) instead of 17" 245/45 summer tires. My knuckles would still be white if we had driven the TL.
  • hugo5hugo5 Posts: 68
    Hi there,
    my lease on a 325i is coming to an end on may 26. Needless to say, the dealer I leased from has been calling me for the last 2 month, but although he says he will get me into another BMW, he doesn't seem to come up with numbers I can afford. I have done the math, looked at residuals posted here, took 5 % off MSRP, tried as low as .0014 money factor, and I don't see how I can get to a comfortable number either. So, question: is there any possible way, to get into a base 328i, for a 36 month lease, with 10k miles/Year, with putting down $2000, including tax, bank fee, first month (don't need security, since I am returning a BMW) and paying under/up to $400.00 a month. I am sure, something out of the normal upfront fees has to be rolled over into the monthly.
    The only dealer that is willing to apparently work with me, is about 90 min away from where I live, and I have been begging him, not to make me come out there, if he can't get to what I can afford, but he won't obviously commit to any numbers until I am there. Again, he asked me to come in next Saturday, saying he will give me a deal that I "will be completly satisfied with", I just don't see how he could. What do you think? Is he just trying to get me out there and sell me a car I can't afford, or is there a way to getting to what I am able to pay?
    Sorry for the long assey. This buying another car thing is about to drive me crazy...
    Thanks,
    Hugo
This discussion has been closed.