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BMW 3-Series Run Flat Tires

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Comments

  • We don't normally rotate tires here in the UK, even on same size wheels, as the roads are so bad and how they affect tire wear.

    As for repairs, the debate continues here as well. The UK's Tyre Industry Council (Tyresafe), don't recommend repairs unless specific criteria is met and qualified inspection takes place. Most tire shops won't take the risk, as the tire manufacturers also state a similar case. Liability is one of the main issues.

    One serious issue we have here is, we use the 'indirect' TPWS. ABS sensor based, so tires can slowly go down 'ahead' of a puncture alert. Some tires have shreaded within a few miles, suggesting users have already run many miles on low pressure, so any repairs are even more suspect. Inspections have shown the inside of the tires are in a right mess, even after just a few miles from the warning gong, completely over heated and turning to dust.

    As one tire shop stated to me, "you leave here with a new run-flat tire and get a puncture down the road, we won't repair it, it will be another new tyre". Then let forth on the way he really felt about the problems with run-flats. :mad:

    HighlandPete
  • So the width is different between the front and the rear in the sport package - 40s on the front, and 35s on the rear. If one rotated the tires, what would be the biggest drawback to even out wear? It would seem it would put the wider tire width on the rear, and the smaller patch on the front, but I would wonder if there were any other concerns, such as safety for this?
  • shiposhipo Posts: 9,152
    Given that the 35s are wider than the 40s, rotating the SP tires would involve putting wider tires on the front of the car, and as such, you would most likely have inner fender clearance issues when turning the steering wheel to near-lock. The other drawback of putting wider tires on the front is that when nearing the limit of adhesion (due to some combination of less than ideal conditions, emergency maneuvering, and / or spirited driving), the back end will break loose first and you could find yourself up against a guard rail (or worse).

    Best regards,
    Shipo
  • The wider tyres are on the back, they are 255 section and the narrow 225 on the front. The aspect ratio 35 & 40 is just that, an aspect ratio of the width.

    To think of changing front to back is a no, no. We are into the whole concept of handling, controlled understeer and handling balance. The 'staggered' wheels are a sport setup after all.

    HighlandPete
  • as everybody's been saying, the fronts are narrower than the rears.

    regarding the cost: you can go on tirerack or discount tire or probably others and get prices. I got a nice looking set of 17s that look exactly like some people's stock 328s for only 130 each. the tires are standard GFTs, only 130 each. tirerack also talked me out of getting high performance all seasons and into grand touring all seasons, which last up to 60,000 miles vs. 40,000 for the high performance (he asked me if I do any "high performance" related stuff. I said no). grand total, including shipping was 1160. or only about 300 bucks more than what I would;'ve spent on the rear RFTs alone!!

    so, if I kept the RFTs I would've had to replace them every 20,000 miles or so. with the grand touring tires, I won't ahve to change them for nearly 3 times as long. that defintely makes it worth while.

    performance: the 17s are lighter than the 18s. so, you'll have less unsprung weight=better handling in some situations (such as when encountering nyc potholes that literally swallow smart cars). also less weight to rotate=faster rotation. therefore, you might get a very slight improvement in acceleration. the down side is that I'll probably not be able to corner as fast anymore given the taller and softer sidewalls. not much loss for me.

    well, I still haven't received the new set of wheels and tires yet, but I'll let you know how they go. I just received my third replacement RFT for the fronts yesterday. so, for the first time in 5 days I was able to drive my car. which brings up another EXCELLENT point about the switch from RFT to GFs: I don't have to wait days for a replacemtn tire anymore. I just have to go to the nearest auto shop and they'll have my very ordinary touring tires for a very ordinary price.

    oh, and as for the spare: the front 18s fit on any corner of the car, so I'll just keep one of them in the trunk to use as a full size spare! it'll be a spare that you wouldn't even need to check the pressure on! I'll have the fastest buick, i mean , bimmer on the block!!
  • shiposhipo Posts: 9,152
    edited April 2010
    "the down side is that I'll probably not be able to corner as fast anymore given the taller and softer sidewalls. not much loss for me."

    That isn't entirely true. Why? Not only are the 18" wheels heavier, but the bulk of the weight is further from the axis of rotation, and if you've ever tried to turn a heavy gyroscope against its will, you'll realize that the further that weight is from the axis, the longer it takes to actually turn the wheel from its desired rotational plane.

    FWIW, there was a study done a few years ago that looked at the handling aspects of various wheel sizes, and said study found that the sweet spot for handling was in the 15"-17" range (many weekend racers have actually downsized the wheels on their E-36 3-Series cars to 15” and gotten better lap times). Move to smaller or larger wheels beyond the range and handling starts to fall off. The flip side of course is that larger wheels allow for larger brakes, so unless you're going to upgrade your BMW with a Big Brake Kit, then you're likely to get better handling with 17" wheels than 18" wheels. Counter intuitive I know, but there you have it. :)

    Best regards,
    Shipo
  • so, it's a win, win, win situation for me then? sounds good to me. i get cheaper tires and wheels, better ride, better pothole protection, easier replacement, etc, etc. can't wait to drive my bimmer with the grandpa tires!! :D
  • shiposhipo Posts: 9,152
    Win-win! Yup, unless you cannot live without the bling-bling 18s. ;)
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,779
    Nah, to be a real grandpa you'd have to switch to bias-ply tires with fat white walls!

    MODERATOR

  • larry175larry175 Posts: 68
    wait a second Grandpa. This grandpa has a 2009 335xi with all the trimming and a Porsch. And I don't have an white walls.
  • xeyexeye Posts: 162
    edited April 2010
    Hi all,

    I've ordered a new 2011 335i xDrive to replace my '07 335xi. I have ContiProContacts on the 335xi, but it's pot luck, sadly, what I get on the new version. I have 28,000 miles on the current set with not a single issue.

    I have heard 'not-bad' things about the 3G version of the Bridgestone RFTs. I like the idea of the RFT and I've not had any bad experiences. Some of you will insist staying away from RFTs but I have to rely on my own experience.

    My question is: Does anyone have specific driving experience, hopefully with BMW AWD, with the Bridgestone 3G RFTs in 225/45R17 All Season?

    By the way, the '07 Sparkling Graphite Metallic version has only ~28,000 miles after not quite three years. I am due to receive better than KBB and Edmunds.com trade-in value for the car. The new one will be Tasman Green Metallic, Oyster w/black interior, ZSP, ZPP, ZCW, H/K stereo, satellite radio, PDC front & rear. It's being built as I write this. Oh, and the heated steering wheel and HD Radio at no extra cost.

    Here is a quote from Bridgestone's own web site:

    Bridgestone's first run-flat tire was introduced in the early 1980s with an aim to keep disabled drivers' vehicle mobile, even after complete air loss. The Porsche 959 was the first mass-produced vehicle equipped with run-flat tires, making them standard equipment in 1987. In this early application, these tires could not offer the smooth, comfortable ride as compared to conventional tires.
    Striving to solve this problem, Bridgestone developed a second-generation run-flat tire in 2005 which offered improved riding comfort. And, in 2009, Bridgestone introduced new technology in the third generation run-flat tires, which offers almost the same riding comfort as conventional tires.
  • Have you got Bridgestone 3G's in the States? There is nothing over here yet, the word is, they have not been signed off as approved tyres.

    Bridgestone certainly are not saying when they are due in the UK either.

    HighlandPete
  • Mr_ShiftrightMr_Shiftright CaliforniaPosts: 44,779
    Geezer Power! Today's Grandpa is yesterday's Uncle :P I have a SC MINI (no longer with the dreaded RFT on top of sport suspension---ouch!) and a Norton with which to challenge mortality.

    MODERATOR

  • johnsamjohnsam Posts: 55
    INTERESTING !

    Wonder what the wear rating is on these "new" RFTs?

    Current tires are rated "1" which is the lowest possible. Even WalMart does not sell tires rated this low.

    GIMMICK or not a GIMMICK. Only time will tell.

    Regards to all.
  • taxesquiretaxesquire Posts: 681
    So...if I wanted to change my rears to 17s when my rears are rundown, is it just a matter of getting a wheel made for a 17" tire, or are there suspension, brake, or other modifications that'd be needed?
  • shiposhipo Posts: 9,152
    If/when you decide to change to 17" wheels, you should change all four wheels, not just the rears. Assuming you buy wheels that fit your car, then no, other than different size tires so that you keep your overall diameter the same, you will not need to make any modifications.

    Best regards,
    Shipo
  • Thanks for your thoughts everyone. It just seems so anti-intuitive to be unable to rotate the tires to get the most wear out of them possible....
  • shiposhipo Posts: 9,152
    edited April 2010
    If you change your tires to be the same size all around, then there will be no issues vis-a-vis tire rotation.
  • slr123slr123 Posts: 2
    Tired of the red exclamation point, tired of the run flats not lasting and the rough ride, tired of being blamed by BMW for my "poor driving habits" which apparently was the cause of my recent cracked rim ($457). I see an Infiniti or an Audi in my future.
  • larry175larry175 Posts: 68
    infinity, see. audi, no.
  • slr123slr123 Posts: 2
    Ok, G37 it is. Anything else I should consider?
  • johnsamjohnsam Posts: 55
    "POOR DRIVING HABITS" Where have I heard that before?
    The way it was put to me was, "Perhaps it is your driving habits!">>>>A nicer way of laying fault. At 67 years of age, do I speed? / take corners faster than a speeding bullet? DAMN RIGHT I DO.................That's why I bought 4 BMWs one after the other. Otherwise a Ford Fiesta would do just fine.

    Anyway.........well expressed sir123.
  • Can you replace ONE tire with a non-runflat?
    I have one tire on the back that's worn out but I don't want to buy 2 new non-RFT.
    What would happen if I just replaced one?
    Would the car run like crap?
  • shiposhipo Posts: 9,152
    One tire? No, don't even think about it.

    One axle? Ummm, maybe.

    All four corners? Yes, absolutely YES!
  • finally got around to putting on my new 17" rims with kumho all seasons. I gotta say that the ride is improve noticeably. a lot less noise. i don't feel all the little bumps anymore. kept one of the front oem 18 inch RFTs in the trunk as spare. what to do with the other 3? don't know. but, i don't want to sell all four and be left with no spare.

    come to think of it...that's the best thing to do with RFTs, use them as spares. people often forget to check the pressure on the spare anyway. so, even if you never refill the RFT spare with any air, it would still be good to be used to get you home in case of a flat. loving my car again.
  • johnsamjohnsam Posts: 55
    As with all types of tires, unless you replace 1 tire with the exact same tread etc etc. you ask for trouble. This is not what it sounds like you are contemplating.

    Stay clear of that idea......NO QUESTION.

    John
  • jtlajtla Posts: 375
    It will be hard to sell 3 tires/rims. If I were you, I will sell all 4 sets of identical 18" OEMs and buy a lesser set for spare. Bimmerfest is probably your best venue to sell.
  • thanks,
    went on bimmerfest, but could not find button to click on for selling stuff.
  • jtlajtla Posts: 375
    edited April 2010
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