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OEM vs 3rd Party Wheels/Tires

Discussion in 'Wheels & Tires' started by Mekerek, Nov 9, 2014.

    • Member

    Mekerek

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    Hello, First time post, and I had a question. I have recently gotten a 2006 M3 Convertable. Loving it, the tires are pretty thin in tread, and since I don't have a record of the last time the tires were changed, I am looking at the cost of new tires. Is it suggested to use BMW wheels with BMW provided tires. I guess, do I goto my dealer and have them do the work, or is it better in ways to get Tires/Wheels myself (tirerack) and have them mounted/etc by a 3rd party (discount tire or the like)? I am also looking at getting some different wheels, they are currently the silver style and I believe I would like black.

    Two parts, the current tires are front/back pairs.
    Front: 235/35 zr19 91w Proxes4 Toyo
    Back: 255/35 zr19 96w Porxes4 Toyo

    Thanks for input.
    Brent
    • Member

    MGarrison

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    I would trust any wheels that the Tire Rack sells; Unless you want a specific BMW O.E. wheel that can only be sourced through a dealer, then you'll likely find the Tire Rack offers much better pricing for wheel/tire packages. If Tire Rack has wheels you like and you're getting tires, it's obviously easier to let them mount & balance them. Then all you have to do is swap 'em onto your car. There's no particular reason to source your wheels or tires through your dealer unless they're really competitively priced with what you can get online. I look for the lightest-weight wheels that are within my price range that fit my aesthetic preferences (ie, easy to clean as possible, like 5-spoke designs).
    • Member

    Mekerek

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    Anything special to get them on the car? (Yes this is the most high perf car I have had)
    • Member

    MGarrison

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    If any additional hardware is required, such as wheel spacers, longer/shorter lug bolts, or hub-centering rings, the Rack folks should know exactly what's needed for anything they sell. As far as swapping them on and off the car, any competent tire shop can do that (Tire Rack has a list of recommended installers) or obviously the dealer. Unfortunately, the days of BMW's coming equipped with tire-changing equipment appear to be over for do-it-yourselfers. If you want to do it yourself, you'll need a jack stand or two, a floor jack (easily had from Harbor Freight Tools), a 1/2" torque-wrench and 1/2" breaker bar, wheel-chock or two, 1/2" socket of the right size (likely 17mm) and a 5 inch-long 1/2" extension... and knowing where to jack on the underside of the car that doesn't damage anything. You wouldn't have to haul the wheels anywhere, but, for what you'd spend on that collection of tools, having someplace swap the new ones on would likely cost less, possibly a lot.
    • Member

    Mekerek

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    Thanks for the input, I decided I like the Style 67 that are on it, I have found some nicely refinished ones on Ebay and they will be here soon. (Warranty/Good rating/Good price etc). Now my focus is on Tire size.

    As the original Post says.. I have 235/35ZR19 front, 255/35ZR19 rear on my Style 67 19" wheels. I am going to get new tires, according to this these are the two sizes:
    19x847225/40R1919x9.527 255/35R19BMW (tirerack recommends this setup)
    or
    19x847235/40R1919x9.527 265/30R19BMW (this sounds more aggressive)

    (http://www.alloywheelsdirect.net/inf...ting_chart/bmw)

    So do i keep same size I have and just replace like for like or do I change the size to one of the ones recommended for these? My biggest question is that I have 35s front and back, and it wants a 40/35 set. I know it will look different, but I am more concerned about how it affects driving and performance.

    I am looking at Michelin Pilot Super Sport or Pilot Sport A/S 3 (W- or Y-Speed Rated). I am in the PNW and we do get lots of dry time, but lots of wet roads too, I think I don't need A/S as we don't get snow but just considering them.
    • Member

    MGarrison

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    This includes an explanation of the aspect ratio number in tire sizes:

    http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=7

    Changing aspect ratios means changing the sidewall height of the tire (& thus overall diameter), depending on whatever the width is -

    235mm width w/ 35 aspect ratio = 3.1 inches sidewall height (approximately)

    225mm width w/ 40 aspect ratio = 3.5 inches sidewall height

    235mm width w/ 40 aspect ratio = 3.7 inches sidewall height

    The differences here are relatively small from the options you post, .6 inches, a tad over 1/2 inch.

    Tire sizing recommendations typically are meant to keep the overall diameter of the tires within the acceptable, safe range for any particular vehicle, so it's no surprise there's not much difference.

    If you increase the difference in width between front & rear (keeping the rears wider than the front) would tend to make for an increase in the understeer handling characteristic. Realistically, you'd likely only notice this if you were pushing the car really hard, which if you're keeping things sane for street driving, presumably you're not exploring that extreme of the car's handling capabilities too much or too often. A square or squarer setup (ie, tire widths the same or closer to the same) reduces understeer & tends to move the car's handling towards more neutral. BMW tends to outfit it's cars with a staggered setup of narrower front tires to help reduce oversteer, as the average driver may not be very practiced with oversteer skid recovery or have much of a skillset in that regard. If one is driving quickly and senses the car is starting to slide and the slide is understeer (ie, the nose of the car is pushing, generally speaking), the typical driver's reaction of lifting off the gas to slow down unloads the rear end & transfers weight to the front tires, increasing the front's grip (hopefully), &, hopefully allows for the slide to be minimized & have the driver getting the car back under control - &, hopefully, without having the rear end losing enough grip to get into an oversteer skid.

    So, as for changing width difference front to rear, you have to decide if you like how your car handles now, or if you might prefer what a change might bring. Increasing overall width both front & rear should up your lateral grip levels.

    More sidewall height means more rim protection & less risk of blowout or pothole, etc. damage, the tradeoff being a potential loss of immediacy of steering response (more sidewall height = more sidewall flex). That's probably less noticeable within the range of high performance summer tires, which are going to tend to have stiffer sidewalls compared to, say, all-seasons. And, again, if the range variance is something like a 1/2 inch, you might not notice that in most driving scenarios, unless you're particularly sensitized to such differences in tire performance, and, again, feeling any difference might mean being at speeds in turns way beyond what's sane for street driving.

    Within the "plus-sizing" concept (see: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=25), a 235/40 makes for a larger overall diameter (+.3") compared to a o.e. size of 225/40, whereas your current 235/35 is -.6" o.d.. compared to o.e.

    If you read through info @ those Tire Rack links, you should have enough info to settle on your performance priorities to make a tire size choice. The stock wheel setup is also typically staggered, with the fronts being narrower - that can be a constraint (besides the usual clearances) for maximum tire-width fitment, although if you're not going beyond what you have now, none of that is probably much of a concern.
    • Member

    Ken.S.330

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    Just a quick comment on the floor jack. I have an old Harbor Freight floor jack that will not fit under the front of my car. I am waiting on delivery of a low profile jack from Amazon (free shipping with Prime). I also hacked up blocks to put in the jack points. I had an old wooden hockey stick that I cut small sections from that fit in the jack points so they do not get crushed when I lower the car onto the jack stands.

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