N55 Spun Crank Hub

Zbeck5 · 10-13-2019, 10:34 AM

[IMG][/IMG]

In my opinion one of the biggest design flaws on the n55. Not sure why a part with so much torque would only use a cheap friction washer to hold this assembly together. Should be keyed like some of the aftermarket options.

Orion4 · 10-13-2019, 04:35 PM

For some reason your images will not display. As for a "design flaw", this is the first I've heard of it. How frequent is this problem?

DreamerJoe · 10-13-2019, 05:33 PM

Quote:

Originally Posted by Orion4

For some reason your images will not display. As for a "design flaw", this is the first I've heard of it. How frequent is this problem?

doesnt look like an issue on the N55, more on the S55. even with all the people running fbo and/or pure stage 2 seem to be fine.. I think the problem here has more to do with the post I saw about the OP doing a good old money shift. you're lucky you didn't bend a rod.

ceedawg · 10-13-2019, 09:52 PM

Recently happened to me,money shifted and spun the crank hub

Motor replaced with low mileage motor.

harkes · 10-14-2019, 01:58 AM

Quote:

Originally Posted by ceedawg

Recently happened to me,money shifted and spun the crank hub

Motor replaced with low mileage motor.

Auch! Sorry to hear that

JaredG_F30 · 10-15-2019, 07:34 AM

This is my biggest fear on track days. Was it a 3rd to 2nd shift when you wanted 3rd to 4th? Rev matching on downshift will help prevent the spun crank hub as well as the crankshaft is up to speed with the transmission. A hard downshift is hell on the drivetrain and really upsets the balance of the car.

Quote:

Originally Posted by ceedawg

Recently happened to me,money shifted and spun the crank hub

Motor replaced with low mileage motor.

F32Fleet · 10-19-2019, 09:26 AM

It's not a design flaw on a stock vehicle. You can still float the valves regardless of how well the crank hub is designed.

ceedawg · 11-14-2019, 08:22 AM

Quote:

Originally Posted by JaredG_F30

This is my biggest fear on track days. Was it a 3rd to 2nd shift when you wanted 3rd to 4th? Rev matching on downshift will help prevent the spun crank hub as well as the crankshaft is up to speed with the transmission. A hard downshift is hell on the drive train and really upsets the balance of the car.

Went from 2nd to 1st when I wanted to go into 3rd. At well over 60 mph trying to speed shift.

BMW DIY Guy · 11-14-2019, 10:22 AM

Quote:

Originally Posted by ceedawg

Went from 2nd to 1st when I wanted to go into 3rd. At well over 60 mph trying to speed shift.

Oh damn dude.. I am so sorry to hear that!!! That just hurts!

TheShadow · 11-14-2019, 01:21 PM

So OP is mad he money shifted and ruined his engine but blames bmw design on his engine imploding? obviously it can be improved but the sole reason it happend is because well you know why.
Literally can happen on most if not all cars if you miss a gear like that.

10-13-2019, 10:34 AM	#1
Zbeck5 New Member 0 Rep 13 Posts Drives: BMW F30 Join Date: May 2019 Location: United States iTrader: (0)	N55 Spun Crank Hub [IMG][/IMG] In my opinion one of the biggest design flaws on the n55. Not sure why a part with so much torque would only use a cheap friction washer to hold this assembly together. Should be keyed like some of the aftermarket options.
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10-13-2019, 04:35 PM	#2
Orion4 Lieutenant Colonel 481 Rep 1,572 Posts Drives: 2013 335i Sport Line Sedan Join Date: Aug 2009 Location: Melbourne, FL iTrader: (0)	For some reason your images will not display. As for a "design flaw", this is the first I've heard of it. How frequent is this problem?
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10-13-2019, 09:52 PM	#4
ceedawg Major 468 Rep 1,348 Posts Drives: 2k15 335i xdrive MSport 6spd Join Date: Dec 2017 Location: Big City iTrader: (0)	Recently happened to me,money shifted and spun the crank hub Motor replaced with low mileage motor. __________________ 2k15 335i Msport xdrive 6spd Wagner Comp2 FMIC,FTP CP,stock exhaust. Fabspeed Sport catted DP, KW V2 coil overs,FBO BM3 Stg 2
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10-19-2019, 09:26 AM	#7
F32Fleet Lieutenant General 3570 Rep 10,351 Posts Drives: 2015 435i Join Date: May 2005 Location: Southeastern US iTrader: (0)	It's not a design flaw on a stock vehicle. You can still float the valves regardless of how well the crank hub is designed. __________________ "Drive more, worry less. " 435i, MPPK, MPE, M-Sport Line
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11-14-2019, 01:21 PM	#10
TheShadow Lieutenant 302 Rep 526 Posts Drives: 335i M sport Join Date: Aug 2018 Location: louisiana iTrader: (1)	So OP is mad he money shifted and ruined his engine but blames bmw design on his engine imploding? obviously it can be improved but the sole reason it happend is because well you know why. Literally can happen on most if not all cars if you miss a gear like that.
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