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Brushed Motors and Warranty

7K views 11 replies 8 participants last post by  Karl 
#1 · (Edited)
Hello all,

My husband and I just ordered my M60 in Storm Bay Metallic after being blown away by a test drive. I have a couple of questions and concerns I'm hoping the community can address.

I read a Motor Trend article recently that BMW uses brushed motors in the iX M60, not brushless like everyone else. These brushes, while of a much different design than the brushed motors of the past, are still a wear item. When asked by Motor Trend how long the brushes are expected to last, BMW answered that they did not know. Does that seem like a red flag to anyone?

BMW's answer concerned me enough to check into the drivetrain warranty which is only 4 years/50,000 miles. Tesla's drivetrain warranty is 8 years and 120,000 miles (P model). Rivian's drivetrain warranty is 8 years/170,000 miles. Porsche Taycan's drivetrain warranty is 8 years/100,000 miles. Hyundai's Ioniq 5 drivetrain warranty is 10 years/100,000 miles.

I am concerned that BMW's drivetrain warranty is half or less than that of Tesla's, Rivian's, and Porsche's combined with the wear item that BMW is unsure how long will last. Replacement motors for Tesla are north of $10,000 each. I imagine BMW motors may be more expensive, still.

BMW's warranty does not show much confidence in the design. Is an extended drivetrain warranty available? How is everyone else dealing with this? In the 8 years I owned my Tesla the rear motor was replaced four times, twice after the 4 year/50k mile warranty expired.
 
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#2 ·
I'm hoping to be in the shop less with the iX than we were with the two Teslas so hopefully it won't be an issue. But that's a great question. I've reached out to our salesguy and asked for info about extended warranties. Levels offered, costs, etc. As soon as he responds, I'll post the info here. I'm also interested to hear if others on this site have explored the extended warranty offerings from BMW. There's some wizardry with this car that will be expensive to fix down the road and we plan on keeping this car for quite a while.
 
#6 ·
Unfortunately, owning a Tesla has been death by a thousand cuts. I'm coming from a Model S that was in the shop more in its first year than all of my previous ICE vehicles combined over the entire ownership period. The motors lasted an average of 25,000-30,000 miles before developing problems. My last motor replacement was actually last year and just before the warranty expired.

I am hopeful that BMW has better engineering, testing, and QC to provide a better ownership experience. I looked into extended warranty, but based on what I'm seeing online it could cost over $7,000 for an additional 3 years and total of 100,000 miles. Not sure if that would be worth it.
 
#3 · (Edited)
From my understanding, the xdrive40 and xdrive50 use magnet motors, while they use the brushed motor in the M60. I have an M60 going into production in mid-May and this post makes me a bit nervous. I also do plan to keep this vehicle for quite a while-- I've had my last BMW for almost 10 years without any issues whatsoever. If anyone finds anything out, please keep this post updated. I will not hesitate to order an xdrive50 instead-- I will even wait longer if it means the motor will last longer.
 
#4 ·
Good Morning from Austria!

I ordered my M60 in February 2022 - no production date yet

Starting with the iX3, BMW uses their 5th generation e-motors. They now have current-energized synchronous motors in all new models. iX3, i4, ix 40/50/M60 and the upcoming i7.

For sure, a current-energized synchronous motor needs brushes (except some new designs with inductive transmission) but they don't use a commutator ring like a DC-motor which will wear of the brushes very heavy.
Brushes are still a wearing part but BMW says that they will have a lifetime of 8000hrs!! Additionally they build the motor for a service friendly replacement of the brushes.

current-energized synchronous motor do have a lot of advantages over permanent magnet SMs.

Alex
 
#5 · (Edited)
Good Morning from Austria!

I ordered my M60 in February 2022 - no production date yet

Starting with the iX3, BMW uses their 5th generation e-motors. They now have current-energized synchronous motors in all new models. iX3, i4, ix 40/50/M60 and the upcoming i7.

For sure, a current-energized synchronous motor needs brushes (except some new designs with inductive transmission) but they don't use a commutator ring like a DC-motor which will wear of the brushes very heavy.
Brushes are still a wearing part but BMW says that they will have a lifetime of 8000hrs!! Additionally they build the motor for a service friendly replacement of the brushes.

current-energized synchronous motor do have a lot of advantages over permanent magnet SMs.

Alex
Greetings from Arizona where it will be 35ºC today!

Thank you for the reassuring information. I'm trying to figure out how to reconcile that 8,000 hour figure, would you mind sharing where you read that so I can read it in context? Here's my thinking... assuming 20,000 miles per year driven... that's an average of 55 miles per day. What is that equivalent to, about 90 minutes of mixed city/freeway driving? Based on my simplistic calculation the brushes should last 10 years.

I have confirmed with BMW's promotional materials that the xDrive 40/50 variants contain permanent magnet motors. I assume those are brushless?

UPDATE - BMW's materials state the xDrive 40 has PMM, but the reviews I've read about the xDrive 50 say current energized motors. So I don't know at this point! lol
 
#7 ·
I have only some sources in german.


Maybe there is a difference in the models depending where the are build. The iX 40/50/M60 coming from Germany/Dingolfing will all have current-energized SMs
 
#8 ·
Just 10 hrs ago motortrend posted this article

Stating that these brushes should last at least 186,000 miles and can accessed and replaced if worn out. However the cost is the major concern.

I also have a m60 in production and a 50 in quality check coming to NJ, but I believe they both use the same brushed motors, so models don’t have any difference in types of motor being used.
Please keep an update on the cost and availability of extended warranty on the drivetrain, the less than average coverage worries me now.
Also I want know if anyone know how to properly lift the iX? I’m ordering another set of wheels and looking to swapping them in summer and winter.
 
#11 ·
Motor trend did a write up on the BMW electric motors. All of the versions, 40, 50 and 60 use the same motors and technology. It is a bit technical in the explanation, but the jist of it is that brushless motors use magnets/rare earth elements, and that goes against the attempt to build the iX as planet neutral as they can. Both brushless and brushes have their pros and cons. With the motor being sealed, the ideal of eliminating dust(think brake dust type dust) should allow the motor to function cleanly for a long time. Agree that it is slightly unknown how long it will work, but seems from multiple folks in here, the Tesla seems to also have issues.

 
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