[adamjs83]

I'm wondering if anybody would be able to help me identify the part number for this lug bolt for the X5. I did a number on the bolt and hole changing out my winter tires and I can't seem to find the exact replacement online.

Also, if anybody knows the thread pattern because a friend of mine is going to help retap the hub.

[Auricom]

Originally Posted by adamjs83

I'm wondering if anybody would be able to help me identify the part number for this lug bolt for the X5. I did a number on the bolt and hole changing out my winter tires and I can't seem to find the exact replacement online.

Also, if anybody knows the thread pattern because a friend of mine is going to help retap the hub.

Wheel bolt black - 36 13 6 795 153
M14 x 1.25

https://www.getbmwparts.com/oem-part...ck-36136795153

[LexxM3]

Originally Posted by Auricom

Wheel bolt black - 36 13 6 795 153
M14 x 1.25

https://www.getbmwparts.com/oem-part...ck-36136795153

That part number IS listed everywhere as the correct stock replacement. However, while it is difficult to tell after an hour of searching, I get a sense that that part is a one piece bolt rather than the shown two piece bolt that comes factory stock on G05s (two piece is the one that has a movable washer/sleeve that forms its cone seat). The world doesn't need that kind of chaos, but here we are.

Can we conclusively determine if that part number is in fact a two piece?

Regardless, two piece and one piece lug bolts should not be mixed on the same wheel and probably should not be mixed on the same car.

[nZtiZia]

I believe default thread length is 27mm?

[LexxM3]

Originally Posted by nZtiZia

I believe default thread length is 27mm?

Yap, stock bolt shank length is 27mm.

[adamjs83]

Originally Posted by LexxM3

That part number IS listed everywhere as the correct stock replacement. However, while it is difficult to tell after an hour of searching, I get a sense that that part is a one piece bolt rather than the shown two piece bolt that comes factory stock on G05s (two piece is the one that has a movable washer/sleeve that forms its cone seat). The world doesn't need that kind of chaos, but here we are.

Can we conclusively determine if that part number is in fact a two piece?

Regardless, two piece and one piece lug bolts should not be mixed on the same wheel and probably should not be mixed on the same car.

Wow, I really appreciate the hour of searching. Are you saying that I need to replace all of them now with that bolt since the existing has the sliding washer?

[LexxM3]

Originally Posted by adamjs83

Wow, I really appreciate the hour of searching. Are you saying that I need to replace all of them now with that bolt since the existing has the sliding washer?

The problem with mismatched one vs. two piece bolts is that you're unlikely to achieve the same consistent final seated torque between the types and they may not respond in quite the same way to mechanical load. Both issues run a greater risk of mechanical imbalance under, granted, extreme load conditions. Yes, it is best to not mix types.

But first things to figure out is a) if that part number is one or two piece, and b) if not two piece, what the two piece part number is so that you can just buy one.

For the record, I am not a fan of the two piece design and if you search carefully, you'll find a fair number of people (including myself) where the sleeve/washer got embedded in the rim. My tech lead agrees and my dealer replaced all my two piece bolts by the "old fashioned" one piece on my request (so, by the way, I still have 20 stock two piece bolts sitting around doing nothing). I have never found a good reason for the change to two piece design except that it theoretically doesn't scratch the inside of the rim lug hole since the bolt rotates in the sleeve rather than the hole; but that "benefit" is overwhelmed by the proven possibility of the sleeve embedding itself in the hole. Here are a couple of example issue threads: https://x3.xbimmers.com/forums/showthread.php?t=1711680, https://x3.xbimmers.com/forums/showthread.php?t=1739276

I am also wondering how you managed to strip yours like that? Whatever the root cause of that was, hopefully you've rectified it before putting the car back on the road.

[adamjs83]

Originally Posted by LexxM3

The problem with mismatched one vs. two piece bolts is that you're unlikely to achieve the same consistent final seated torque between the types and they may not respond in quite the same way to mechanical load. Both issues run a greater risk of mechanical imbalance under, granted, extreme load conditions. Yes, it is best to not mix types.

But first things to figure out is a) if that part number is one or two piece, and b) if not two piece, what the two piece part number is so that you can just buy one.

For the record, I am not a fan of the two piece design and if you search carefully, you'll find a fair number of people (including myself) where the sleeve/washer got embedded in the rim. My tech lead agrees and my dealer replaced all my two piece bolts by the "old fashioned" one piece on my request (so, by the way, I still have 20 stock two piece bolts sitting around doing nothing). I have never found a good reason for the change to two piece design except that it theoretically doesn't scratch the inside of the rim lug hole since the bolt rotates in the sleeve rather than the hole; but that "benefit" is overwhelmed by the proven possibility of the sleeve embedding itself in the hole. Here are a couple of example issue threads: https://x3.xbimmers.com/forums/showthread.php?t=1711680, https://x3.xbimmers.com/forums/showthread.php?t=1739276

I am also wondering how you managed to strip yours like that? Whatever the root cause of that was, hopefully you've rectified it before putting the car back on the road.

?[/QUOTE]


I have no idea, brute force and frustration with an overly powerful impact wrench? Lesson learned as I ended up having the entire hub replaced at a local service station. They ordered that part number for the lug bolts and it was in fact the two piece.

[gqgambler]

Originally Posted by adamjs83

I have no idea, brute force and frustration with an overly powerful impact wrench? Lesson learned as I ended up having the entire hub replaced at a local service station. They ordered that part number for the lug bolts and it was in fact the two piece.

Glad you were able to get in fixed and taken care of. Switch to hand tools and avoid the impact wrench. I learned in my early car days when I didn't change the wheels myself what damage an impact wrench can do watching fools at NTW (now NTB) doing tire changes.

[GREENPUS]

Originally Posted by adamjs83

?

I have no idea, brute force and frustration with an overly powerful impact wrench? Lesson learned as I ended up having the entire hub replaced at a local service station. They ordered that part number for the lug bolts and it was in fact the two piece.[/QUOTE]

I ordered bolt hangers to help mount wheels to avoid the stripping of bolts. Hopefully this will help me prevent the stripped bolts

[jad03060]

While an impact wrench is fine for removing bolts, I always use a manual wrench and torque wrench to install them...it's too easy to mess things up when installing the bolts with an impact wrench. I don't really trust the torque limiting sockets...they may work just fine, but I think some of that is the pressure used, and skill level...a torque wrench is easier to use IMHO.

[zhangyi17]

Originally Posted by LexxM3

I get a sense that that part is a one piece bolt rather than the shown two piece bolt that comes factory stock on G05s (two piece is the one that has a movable washer/sleeve that forms its cone seat). The world doesn't need that kind of chaos, but here we are.

What comes from BMW originally is two piece design? Why I was under the impression mine was a single piece?

[LexxM3]

Originally Posted by zhangyi17

What comes from BMW originally is two piece design? Why I was under the impression mine was a single piece?

Stock G-platform bolts are two-piece, except for possibly the lock bolts which, in my case, were one piece — definitely a bad idea to mix. It was confirmed by the OP that that part number is a two-piece bolt matching stock.

[zhangyi17]

Originally Posted by LexxM3

Stock G-platform bolts are two-piece, except for possibly the lock bolts which, in my case, were one piece — definitely a bad idea to mix.

I will check mine.... what's the point of these overly complicated design for a simple mechanical bot? Just make it solid piece and give the owners peace of mind.....

[LexxM3]

Originally Posted by zhangyi17

I will check mine.... what's the point of these overly complicated design for a simple mechanical bot? Just make it solid peace and give the owners piece of mind.....

I agree and I don't really know what the purpose of the bolt design change was. Best (and not good enough even if true) I've heard is that the sleeve prevents rim bolt hole wear as the bolt turns inside sleeve rather than the lug hole directly — but that seems like a serious complicated "solution" in search of a trivial non-existent problem.

[Havy]

Hey,
from a technical point of view is the spherical collar, which is now mandatory for most manufacturers, a torque relief for the rim.
While the wheel stud rotates, the ball collar stops and presses on the rim without any frictional forces. Without a spherical collar, the high torque would cause the wheel studs to rotate / grind into the material of the rim.

[LexxM3]

Originally Posted by Havy

Hey,
from a technical point of view is the spherical collar, which is now mandatory for most manufacturers, a torque relief for the rim.
While the wheel stud rotates, the ball collar stops and presses on the rim without any frictional forces. Without a spherical collar, the high torque would cause the wheel studs to rotate / grind into the material of the rim.

Can you link to some formal engineering documentation on this? It deserves a read. Off the cuff, the two piece design has caused documented problems and one wonders how we survived 100+ years without it.

Also, how does this concept work for hub studs rather than our bolts? Are lug nuts now to also to be double piece?

[jad03060]

Probably since the invention of nuts and bolts, having a washer under the nut is standard practice. Sometimes, they also call for one underneath the head as well, but normally, when a nut is involved, you hold the head stationary, and turn the nut. In the case of the wheels, you are turning the head, so you will be damaging the finish on the wheel as you tighten it up unless there's something to prevent that.

[LexxM3]

Originally Posted by jad03060

Probably since the invention of nuts and bolts, having a washer under the nut is standard practice. Sometimes, they also call for one underneath the head as well, but normally, when a nut is involved, you hold the head stationary, and turn the nut. In the case of the wheels, you are turning the head, so you will be damaging the finish on the wheel as you tighten it up unless there's something to prevent that.

Usually those washers are straight, unrestricted by nut or bolt mechanics, and can't get stuck. None of this is true of the two-piece lug bolts being discussed, apples and oranges.

[zhangyi17]

I took the picture today. The OEM part is a 2 piece design, but I don't see any movable washer you all mentioning. Am I missing something here? Is the grey cone shape part the washer? In my mind, washer is a flat piece (flat washer, lock washer)

[LexxM3]

Originally Posted by zhangyi17

I took the picture today. The OEM part is a 2 piece design, but I don't see any movable washer you all mentioning. Am I missing something here? Is the grey cone shape part the washer? In my mind, washer is a flat piece (flat washer, lock washer)

The silver-coloured part is the "washer". Twist it, it will freely spin but is restricted from moving up and down the bolt. For some reason I always want to call it a "sleeve", but others call it a "collar" which is probably the most correct name out of those 3.