02-02-2022, 07:48 AM | #1 |
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xDrive in the snow
Last year I purchased a 2018 440i xDrive GC. This is my first winter with it. Previously I have watched lots of youtube vids about xDrive in the snow. I was very excited to see how well it seemed to handle in this weather.
Although it has been brutally cold here in upstate NY, we have only had 2 small snow storms where I live. First one was just a bit more than a dusting of snow on the roads. And my 440i was all over the place. Even slow turns the rear would slip out. Second storm: just about 1.5" on the ground. Roads semi-plowed and slushy but not icy. Again - my 440i was awful on the roads. Really had a hard time keeping control, even slow driving. Now, I have to put things in perspective. I drove a huge Escalade for many years. Obviously there is a big big difference in snow handling. But I didn't expect it to be this awful for AWD car. Second - I have the runflats. and YES - this is probably the issue at hand. Better tires will improve things. But, the RF's were brand new and lots of tread. I don't love the RF's, for sure. But I want to get my money out of them before I upgrade my tires. So, I will push through this winter and replace them before next winter. Hopefully that helps - but I still feel a bit lackluster over xDrive AWD. |
02-02-2022, 08:02 AM | #2 | |
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02-02-2022, 01:18 PM | #3 | |
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02-02-2022, 02:57 PM | #4 |
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xDrive is great with a good set of winter tires, it's also more fun with a proper LSD in the back.
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Operator Mo64.50 silenced313.00 |
02-02-2022, 04:27 PM | #5 |
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With the stock Conti run flat all seasons my xDrive was better in snow than any 2wd car I ever owned, be it FWD or RWD, even with winter tires. I've got to figure you have summer tires or the world's worst all seasons. Last fall I put on Michelin Cross Climate 2 all seasons and it's even better.
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Operator Mo64.50 |
02-02-2022, 04:42 PM | #6 |
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xDrive/AWD only makes a difference when accelerating. Steering & braking, it's all the tires. I would never run all seasons where I am in the winter, and I would also never run all seasons on a performance car in the summer.
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Operator Mo64.50 celsdogg329.00 |
02-02-2022, 05:06 PM | #7 | |
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I have Michelins and they drive on Black Ice like it's dry pavement. You will see a tremendous difference with winter tires. Why wait? It's a safety issue. You can order from TireRack and have them installed in a few days. Hope this helps! |
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02-03-2022, 03:53 AM | #8 |
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Sounds like you have an issue with your tires... (as others pointed out).
You didn't specify what they are? Run-flat or go-flat, that's not the issue - Most BMWs come with Run-flats. Put proper winter tires on. I'm surprised all-seasons tires are still popular in the states - no one uses those in Europe any longer, as they are compromised both in the summer and in the winter, with very little economical benefit for a car which is driven regularly. I have been driving in the snowy mountains, no problems whatsoever. The only thing I noticed is that when I intentionally provoke it (hard acceleration in the snow), the rear does go out to the side for a second or two (since it is rear-biased vehicle... I guess), but then xDrive puts me back on track. Very happy with it.
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Last edited by Skyhigh; 02-03-2022 at 04:56 AM.. |
02-13-2022, 04:04 PM | #9 | |
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02-13-2022, 04:33 PM | #11 | |
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Comments such as the following... in G30 data, "The torque distribution towards the front wheels can be completely cut-off in driving situations where all-wheel drive is not needed". Another example is M-Performance models, also set up with more rear wheel bias. Doesn't take much to imagine the thresholds for torque transfer are therefore different. |
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02-13-2022, 04:39 PM | #12 |
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02-13-2022, 04:43 PM | #13 | |
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xDelete documentation does however also mention different default torque distribution depending on the model and even on the engine within the same model. The technology behind it is the same though. No reason to think SUVs are more "effective" even assuming a different bias.
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02-13-2022, 04:54 PM | #14 | |
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02-13-2022, 05:49 PM | #15 |
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Yes in that regard there probably are differences....the thing that drives me nuts in when after driving in wet packed snow for a bit the amount of snow that sticks in clumps in wheel well. It’s gets so bad that I worry about the snow pushing into and jamming wheels as I’m driving. I’ve pulled over many times just to break apart the snow and ice that collects in wheel well.
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02-13-2022, 07:48 PM | #16 |
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The ATC 35L transfer box was used in 1 through 6 series cars. The ATC 45L was used in the X3 through X6. Physically they're different, which is logical considering the differences in the chassis they go into. According to BMW how they operate is the same, both with a normal 40:60 front/rear axle bias, able to allocate up to 100% of its power to one axle. There could be programming differences, but I wouldn't expect them to be significant. It's not like an X3-6 is intended as an off-road vehicle. They're still soccer mom machines.
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02-14-2022, 01:39 AM | #17 | |
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So anything from 50:50 to 0:100 with default at 40:60. (According to xDelete guys however, the default bias varies from model to model end even within the same model.)
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02-14-2022, 03:39 AM | #18 | |
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BMW do state for some models the default bias is 50:50, not the 40:60 that used to be the normal default. |
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02-14-2022, 04:19 AM | #19 |
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No, it cannot! Mechanically, with the xDrive system in our cars, the maximum torque which can be distributed to the front axle is 50% and max to the rear - 100%. When the TCU clutch is open - 100% goes to the rear, when it is fully closed - 50% front and 50% rear. Anything inbetween is also possible. but the rear cannot be less than 50% and the front cannot be more than 50%.
http://www.awdwiki.com/en/xdrive/ : "Proactive automatic all wheel drive system. The rear wheels are powered at all times. Torque can be transferred to the front wheels via electronically controlled multi plate clutch that is located in the transfer case. XDrive does not have a center differential. Most of the time, the clutch is partially locked and power is transferred to both axles in proportion 40/60 front to rear. The power distribution can be altered to continuously variable levels (from 50/50 to 0/100). For example, when driving at high speed, or when parking, the clutch is disengaged and all power goes to the rear wheels. XDrive is linked to DSC (Dynamic Stability Control) - when the vehicle understeers, the clutch is disengaged thus transferring more torque to the rear wheels (10/90 torque split). When oversteering is detected, the clutch locks fully transferring more power to the front wheels (50/50 torque split)." Newer BMW models like the 1-Series and some X models have a completely different AWD system (more like in Audi) which allows full-FWD by default. For F-series, the default claimed by BMW is 40:60.
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Last edited by Skyhigh; 02-14-2022 at 04:32 AM.. |
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02-14-2022, 06:22 AM | #20 |
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Yeah what tires do you have?
If you don’t want a dedicated setup then get some of the new all weather tire like the CrossClimate2s. But i would personally do a dedicated winter and summer setups. |
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02-14-2022, 10:48 AM | #21 | |||
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BMW state: Quote:
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02-14-2022, 11:07 AM | #22 | |
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