A few questions for you BMW experts out there: I just bought my first BMW (2008 335xi) about 6 months ago and have been really happy with the car except for a few things. The biggest concern I have with the car is the rough ride and abuse the car seems to take on broken up road. I got the stock 18" tires from the dealer and am driving in Chicago area on all sorts of paved roads. The roads in Chicago really stink because the pot holes are HUGE. I have damaged my 2nd wheel/tire in 6 months ! I have never heard/felt impact when hitting a bump or pothole like I feel in my BMW. - Are bimmers more prone to impact issues because of the suspension on low profile tires ? - Can you cause serious damage to the car besides wheel when you hit a pot hole with low profile tires ? The impact can be jarring. - Has anyone abandoned run flats in favor of regular tires ? Run flats seem very hard and wondering if they make the impact worse because there is no give in the tire. - What are the best rims to go with that will give you a good look + durability ? Thanks, Mike
There's a number of discussions here on the forums in various places about pluses/minuses & various experiences/thoughts about run-flats. Search the forums for 'run flats' or some such. BMW engineers it's suspensions to work together w/ the wheels & tires. I'm not sure how likely the current models are to suffer any damage from pothole impacts, but I think it's almost a given that the less tire sidewall height you have, the more likely you may be to suffer a bent rim. I think some folks have opted-out of the runflats. Consider if you want to tote a spare on a rim in your trunk along w/ a lug wrench and jack of some sort (I don't know if the run-flat equipped bimmers provide a jack anymore). Any well-designed-and-engineered wheel should be fine for durability. One nice thing about the Tire Rack is they take a lot of that research upon themselves in order to make sure they're offering quality wheels. Being in Chicago, you might find it fun just to trek over to South Bend to check them out, if you have the time. If I was trying to drive a late-model bimmer w/ run-flats all year 'round in Chicago, I'd want minus-sized rims (assuming that's possible) w/ dedicated snow tires, (and a limited slip diff.), in addition to all the traction goodies, but I'd presume the awd might mostly make up for lack of a lsd. Having bent two rims in a brief time period, I'd probably go for some minus-sized rims and all-season or summer tires for the non-winter months, and opt to haul around a spare and accessories. I would also write an irate letter to BMW pointing out that your experience is showing that their only oem-option (assuming it's your only purchase choice) of low-profile run flats is obviously inappropriate for some of today's urban environments, and has costed you 2 wheels & rims in short order. Then, save the run-flats for a country drive on a sunny day, and use something else that may take the abuse of Chicago-area roads for your daily driving. That's likely the route I'd choose, but you might very well not want or find it convenient to do any of that. Good luck, whatever course you do decide upon.
Pot Holes in Chicago II Thanks, Right now I have 18" OEM BMW wheels w/factory Bridgestone tires that came on the car. Bent 1 of those going approx. 30 in Oakbrook IL. Last night on the highway going about 65-70 hit a sunk grate (yes, roads are all torn up here) and bent my 17" Rial Salenro RFT snow tire. I had no idea these tires would be so touchy ? For such a nice ride, it does me no good if I cant put it on the highway. If you do go to standard non-runflat, does the tire repair fix it cans work if you get a flat ? Or do those mess up the rims ? I use my trunk and dont want to have to hide a tire in there. What are other people doing out there ? Mike
I've never used fix-a-flat, but I don't think it hurts the rims (I could be wrong!), just makes a mucky mess in the tire/rim air-chamber. Might not be good for tire pressure monitoring systems. Whether it works I'd have to guess would depend on the nature of the flat. I don't know if it would affect anything as far as your car's electronics go, but I usually dispense w/ exact speedometer accuracy in favor of taller sidewalls, for snow tires. You can _probably_ do that without a problem, perhaps a 225/55-17 snow tire, as long as it's all 4 tires. Various places warn of brake failure if you go to a dia. over 3% from oem, though I think it's more of a problem if you have a smaller rolling dia. vs oem, or don't have all 4 the same, which could confuse the abs system. A 225/55-17 would give about 1" more sidewall height vs. the recommended 225/45-17, according to http://www.1010tires.com/TireSizeCalculator.asp - I hope some others will kick in a response here -
Like MGarrison said, the runflats have a really bad reputation for being incredibly harsh on pot holes. It makes sense though, the runflats, by their very nature, have much stiffer sidewalls. I have them on the 135 and I hate them! I am trying to wear them out as quickly as I can (now THAT process is fun!!) because once they are gone, I am going with non-runflats and an M-Mobility kit in the trunk. The tire slime will definitely mess up the new in-wheel TPMS sensors but even if that happened, replacements are available from Tire Rack for a reasonable amount. Going with 1"diameter smaller wheels and then compensating with a slightly taller and narrower (non-runflat) tire is definitely the way to go for a winter set-up (that's exactly what I did when I lived there and it worked great). It smooths out the ride and removes 90% of your concern about pothole/wheel damage. The trade off is that you give up some of the really sharp steering response and handling that the car is famous for but in the winter...not too much of a concern.
Who needs it? One thing my old pal Marshall overlooks in his zeal to get you to haul around a spare & jack is the real need for it. A decade ago, you might not have had a cell phone, but today, who doesn't? It is a simple matter to call for a road service provider (again, who doesn't? I have AAA because, even though I am capable of fixing everything on my car, I am not always motivated to do so.) and/or a taxi and/or a friend to deal with the rare flat tire. The remake of "Adventures in Babysitting" could never be believable in Chicago today. Now, I know damage is more common with really crappy roads like those in Chicago, but I've driven there, too. It isn't all that hard to keep your wheels intact if you pay attention to where you're going. I do not remember the last time I had to change a road-damaged wheel. I do remember laughing at folks who hit the holes I knew were coming because I could see three cars ahead dodging them. His other suggestions for a separate set of higher profile winter wheels and tires is a good one, though.