09-04-2011, 05:34 PM | #23 |
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Thanks for that info. The quote I got from local dealer not to bad, 3200 plus tax for Pirelli Scorpions and alloy rims considering ordering from tire rack for tires and rims plus tpms sensors. If you have a flat with a run flat tire do you have to replace one or 2 tires. Believe in Ontario that both tires have to match, but I am a real novice re tires. Thanks again.
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09-04-2011, 07:45 PM | #24 | |
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If the difference is small (less then 1%) it's probably OK to mix brands (but not recommended). If it's more, you may have problems with the stability control system sensing an error. Also, it's never a good idea to have tires with different traction characteristics on the same axle. |
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09-04-2011, 09:48 PM | #25 |
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All of the tires are good options, but I think that the best option for a non-run flat is the Nokian Hakkapeliitta R, likely the best over all winter tire on the market.
We have been running them 2 years on our MDX and they are better than Blizzaks we have previously had - especially on ice. |
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09-05-2011, 11:26 AM | #27 |
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The dealer do have for the X3 the 225 60 17s. IF they have it on their website as winters for the X3 I take it they do fit and work. I am leaning toward 18".
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09-05-2011, 12:10 PM | #28 |
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We just bought a set of used aftermarket BMW rims with 245/50/R18 Yokahama W Drive tires on them. The rims and tires are like new! Unfortunately, we did our homework on tire size but not on rim compatibility. They are off of a 7 series. We will check with our tire guy this week to see if they will work. We are keeping our fingers and toes crossed!
Worst case scenario, we bought them for a good price so hopefully we can flip them if we need to. |
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09-05-2011, 12:15 PM | #29 | |
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09-05-2011, 06:16 PM | #30 | |
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wheel width = 8 inches Bolt circle = 5 X120 mm Hubcentric bore = 72.5 mm Offset = 45 mm (acceptable range 43 to 47) For the 7 Series (depending on year/chassis): wheel width = 8 or 8.5 inches (OK) Bolt circle = 5X120 mm (OK) Hubcentric bore = 72.5 mm or 74.1 mm (depending on model) (will fit if 72.5, but if 74.1 reducing rings can be installed) (qualified OK) Offset = 18 mm (acceptable range 15 to 20mm) (NOT OK) If the wheels are from a late model 7 Series, they might actually mount on the X3 because they have the correct center bore. However the centerline of the tires will be 25 mm further out on each side. That may cause the outer sidewall to rub on the fender, but more importantly the wheel bearing loading will be way off center leading to almost certain wheel bearing damage. Unfortunately, the lack of enough positive offset can’t be compensated. (spacers reduce the effective offset for positively offset wheels, so won’t help. The other issue is the that the TPMS transmitters in the 7 Series wheel won’t work with a F25 chassis X3, so would all have to be replaced if you want the TPMS system to function. Since they're aftermarket rims, you may be lucky and find the person who purchased them for the 7 didn't bother to get the correct offset for that chassis. It's easy to measure the offset (again it should be around 45 mm for the X3). Sorry for the bad news. |
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09-05-2011, 08:17 PM | #32 | |
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Just take a look at your valve stems. Alloy valve stems = TPMS transmitters, Rubber valve stems= no TPMS transmitters. You will find that all NA X3's use the same part number for the pickup antennas and the TPMS transmitter. Does anyone have a new X3 with rubber valve stems? Last edited by Lotus7; 09-05-2011 at 08:29 PM.. |
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09-05-2011, 09:12 PM | #33 | |
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__________________
2018 340i xDrive M Perf Edtn Sunset Orange
Previous BMWs - 19 others since 1971. |
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09-05-2011, 09:46 PM | #34 | |
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It's hard to believe that BMW would have to support (2) different tire pressure monitoring systems. Maybe the differing legally mandated system specs result in the need for differing ways to do it. At least you don't have to worry about adding the transmitters to aftermarket wheels, replacing batteries, and it also opens up the option of using tire sealers in leaking tires without destroying the TPMS transmitter. I'd be very interested in knowing how much pressure loss is needed in a wheel speed sensing system when running run-flat tires. Apparently the thick sidewalls don't deflect very much so the wheel speed does not change very much when the tire looses air. That should make it somewhat more difficult to detect a tire going down. The direct pressure measuring system (with TPMS transmitters) is apparently programmed to signal a low tire warning when the pressure drops 3 psi. |
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09-05-2011, 10:03 PM | #35 |
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So with the different monitoring system would it make a difference when one replace the RFT with regular tires? My old 2004 CTS-V actually had readings for each tire. Would be nice to know exactly if one is just a bit off.
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09-05-2011, 11:26 PM | #36 | |
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Either system will tell you if a tire is low, but how much of a loss it takes to trigger the warning is something that the design engineer determines. With wheels, which contain a TPMS transmitter that sends a radio signal carrying the pressure reading, the real pressure drop in PSI is measured and the trigger level can be calibrated in real units (PSI). With an "indirect system, the car's computer receives a reading of a slightly different average rotational speed of one of the tires and interprets that speed difference as a change in the effective rolling circumference which varies with the tire air pressure. Tires of different construction or tires of different aspect ratio or possible different brands/models, will have a different "air pressure vs. rotational speed factor". Since the rotational speed triggers the warnings, the tire pressure drop (in real air pressure) will vary. It probably will be more sensitive to small pressure drops using regular tires as compared to run-flats, but the only way to be sure is to test it. That's why I wondered in a previous post "I'd be very interested in knowing how much pressure loss is needed..." |
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09-06-2011, 10:43 AM | #37 | |
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Tiretrends, 1010tires, tirerack, should all be cheaper than buying anywhere locally in montreal. |
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09-06-2011, 03:56 PM | #38 | |
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Prices for RFT + rims are insane. |
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09-06-2011, 05:06 PM | #39 | |
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For the best (safest) possible situation if you have to drive on a completely flat tire, BMW recommends using "run-flat" wheels (these have an extra "hump" that helps keep the the bead completely seated on the rim under cornering loads). However, several tire manufacturers (but not all) now say that their "third-generation" run-flat tires can be used safely on any rim, as long as they are driven conservatively. I believe Bridgestone and Dunlop are in this camp, while Pirelli, GoodYear and Michelin are noncommittal, and don't say you shouldn’t use plain rims, but they also don't specify that a run-flat rim is absolutely necessary for their tires. Non run-flat tires can be mounted on RFT rims, it's just a little harder, usually more expensive, and requires a RFT mounting machine. Since all the BMW wheels have the extra "safety hump", and since it's obviously a theoretically better solution, that's all that BMW recommends. I have my Winter Dunlop SP Winter Sports ROF mounted on aftermarket wheels (no- rft hump), and if I get a flat will just drive carefully at speeds well below the 50 mph limit as well as corner very carefully. (Fingers crossed) ![]() |
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09-06-2011, 05:07 PM | #40 | |
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09-06-2011, 05:44 PM | #41 | |
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09-06-2011, 06:27 PM | #42 | |
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They will fit on all 5-Series except the M5 and E39 chassis (74.1 mm hubs). They will fit all 6-Series except the M6 (possible brake clearance problems) They will fit all Late model 7-Series including the E32/38, E63/64 They WON'T fit the 3-Series (except for the rears only of certain M3's) They WON'T fit any current or older model X-3, X-5, X-6 They WON'T fit any of the Z-Series cars (which use some very strange wheel specs.) Obviously, there may be special case exceptions as some models have body features or big brakes that require special wheels. Hope this is of some help. |
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09-07-2011, 12:47 PM | #44 | |
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