[Th3Walrus]

And I gotta say, Clint is great to deal with. I literally just ordered the bushing (for my wife to put under the tree for me lol). I'm in Canada, and I wanted to make sure he didn't send via USPS because it gets handed over to Canada Post who is on strike. He worked with me for different courier options and just shipped the bushing.

[9kracing]

Originally Posted by joebie3

Important to note FJM stole that design, it's actually Clint's design. (Rennfix)

https://rennfix.com/bolt-saver-for-bmw-x3m.html

I believe you, I just want to verify they are more or less the same thing

[Max Well]

Originally Posted by 9kracing

So, am I correct... what most people are doing is just a cheaper version of the FJmotorwerks kit? But otherwise basically the same thing?

Originally Posted by 9kracing

I believe you, I just want to verify they are more or less the same thing

9kracing - wish I could answer but honestly, I don't know 'what most people are doing' to mitigate this issue. We all have different performance goals so cost-benefit-NVH all come into play.

BrockDM is St2 and IIRC he just frequently changes the bolt with the Belmetric M14. Others have gone full Einhorn. And some have opted for the CH/RM/FJM solutions possibly for NVH concerns c/w the Einhorn... Jnat arrived at a compromise I suspect for ease of installation (don't have to replace the center of the bushing) and even less NVH while still providing more confidence in withstanding stress than just M14 bolt replacement.

As one can tell if you read through the posts this is an evolving process we're all trying to work through to understand the best approach for our own individual performance (and risk tolerance) goals.

[Kevin_The_Clean1]

I have to say, the larger Belmetric bolt & corresponding hardware + the "Bolt Saver II" from Clint are a perfect combo. Now that the 12mm factory bolt is no longer sitting in the 14mm semi oval sleeve & the soft factory bushing isn't move / fussing all about on a daily basis, the positive upshifting feel & snappiness under all throttle conditions has been improved. It also not longer jumps around when the car is cold & you're just putting around in a parking lot in Sports +. This allows to you to feed in very subtle throttle inputs much more precisely translating to more overall driving pleasure & directness with the chassis. Regardless of what speed or gear you're in. Even revers feels better then it did before. No joke.

The ZF 8 speed in the X3 M seems to be shifting more crisply under all conditions &. the car is able to put the power to the ground even more efficiently now. No offense to the unicorn egg. But for me, it's simply not necessary. Not even in the slightest. There's a difference between something being super solid & stout. Or absolute concrete.

On a side note. Did observe on thing which I actually like. On a perfect smooth street when the car is simply coasting in low speeds in 4th gear I can here a very VERY subtle whine. Which is probably the tight straight cut gears in the LSD wiring about in the pumpkin back there. Once I put PowerFlex purple bushings in DD is does the same thing at higher speeds when on a super smooth highway & I like it. It's lets you know there's a very precise & precision built machine under your but doing exactly what it needs to. Getting to your destination quickly & with tons of enjoyment.

I highly recommend Clint's top notch donut busing + the corresponding Belmetric bolt with hardware. The X3 M continues to shine & this relatively simple solution is a must do in my book. As if I didn't like to drive this fine machine & AWD monster before. Now I like to drive this insane beast even more... !

[M4Lou]

Originally Posted by Kevin_The_Clean1

I have to say, the larger Belmetric bolt & corresponding hardware + the "Bolt Saver II" from Clint are a perfect combo. Now that the 12mm factory bolt is no longer sitting in the 14mm semi oval sleeve & the soft factory bushing isn't move / fussing all about on a daily basis, the positive upshifting feel & snappiness under all throttle conditions has been improved. It also not longer jumps around when the car is cold & you're just putting around in a parking lot in Sports +. This allows to you to feed in very subtle throttle inputs much more precisely translating to more overall driving pleasure & directness with the chassis. Regardless of what speed or gear you're in. Even revers feels better then it did before. No joke.

The ZF 8 speed in the X3 M seems to be shifting more crisply under all conditions &. the car is able to put the power to the ground even more efficiently now. No offense to the unicorn egg. But for me, it's simply not necessary. Not even in the slightest. There's a difference between something being super solid & stout. Or absolute concrete.

On a side note. Did observe on thing which I actually like. On a perfect smooth street when the car is simply coasting in low speeds in 4th gear I can here a very VERY subtle whine. Which is probably the tight straight cut gears in the LSD wiring about in the pumpkin back there. Once I put PowerFlex purple bushings in DD is does the same thing at higher speeds when on a super smooth highway & I like it. It's lets you know there's a very precise & precision built machine under your but doing exactly what it needs to. Getting to your destination quickly & with tons of enjoyment.

I highly recommend Clint's top notch donut busing + the corresponding Belmetric bolt with hardware. The X3 M continues to shine & this relatively simple solution is a must do in my book. As if I didn't like to drive this fine machine & AWD monster before. Now I like to drive this insane beast even more... !

Good stuff Clean - my take (worthless, likely).

- installing the belmetric and Clint's bushing is pretty straightforward and seems to risk the dreaded "need for loctite repair" minimally.
- the quality "feel" of the bolt/bushing is great. My subjective side liked the installation - felt like an upgrade.
- I occasionally got a clunk w/ factory set up when putting in park and turning engine off in gear. Have not gotten that yet** w/ new set up.
- I also notice a tiny whine, but honestly never turned off radio and intently listened to my stock set up. So - that could be in my head.


Happy w/ install and waiting to see some removed bolts after 6++ months of heavy use to see any wear patterns.

[Jnat]

Originally Posted by Kevin_The_Clean1

I have to say, the larger Belmetric bolt & corresponding hardware + the "Bolt Saver II" from Clint are a perfect combo. Now that the 12mm factory bolt is no longer sitting in the 14mm semi oval sleeve & the soft factory bushing isn't move / fussing all about on a daily basis, the positive upshifting feel & snappiness under all throttle conditions has been improved. It also not longer jumps around when the car is cold & you're just putting around in a parking lot in Sports +. This allows to you to feed in very subtle throttle inputs much more precisely translating to more overall driving pleasure & directness with the chassis. Regardless of what speed or gear you're in. Even revers feels better then it did before. No joke.

The ZF 8 speed in the X3 M seems to be shifting more crisply under all conditions &. the car is able to put the power to the ground even more efficiently now. No offense to the unicorn egg. But for me, it's simply not necessary. Not even in the slightest. There's a difference between something being super solid & stout. Or absolute concrete.

On a side note. Did observe on thing which I actually like. On a perfect smooth street when the car is simply coasting in low speeds in 4th gear I can here a very VERY subtle whine. Which is probably the tight straight cut gears in the LSD wiring about in the pumpkin back there. Once I put PowerFlex purple bushings in DD is does the same thing at higher speeds when on a super smooth highway & I like it. It's lets you know there's a very precise & precision built machine under your but doing exactly what it needs to. Getting to your destination quickly & with tons of enjoyment.

I highly recommend Clint's top notch donut busing + the corresponding Belmetric bolt with hardware. The X3 M continues to shine & this relatively simple solution is a must do in my book. As if I didn't like to drive this fine machine & AWD monster before. Now I like to drive this insane beast even more... !

Kevin, that's a great review and each point is spot on, i would say ditto... I'm really hopeful that this combo approach stands up to the test... so far for me it has.

[Jnat]

Originally Posted by Max Well

9kracing - wish I could answer but honestly, I don't know 'what most people are doing' to mitigate this issue. We all have different performance goals so cost-benefit-NVH all come into play.

BrockDM is St2 and IIRC he just frequently changes the bolt with the Belmetric M14. Others have gone full Einhorn. And some have opted for the CH/RM/FJM solutions possibly for NVH concerns c/w the Einhorn... Jnat arrived at a compromise I suspect for ease of installation (don't have to replace the center of the bushing) and even less NVH while still providing more confidence in withstanding stress than just M14 bolt replacement.

As one can tell if you read through the posts this is an evolving process we're all trying to work through to understand the best approach for our own individual performance (and risk tolerance) goals.

Maxwell, my logic on the combo was when i watched Cliff's video which was fantastic btw, i noticed that after he did the insert and installed the factory bolt there was still some play in there, not a lot, just a little. The thought popped into my head that if the thicker M14 bolt would leave about the same or less amount of play then the insert/stock bolt left, that would be a win. i think that's what we have here, a thicker bolt with about the same amount of play or less that the insert/stock bolt allows... So with Cliff's bushing and a thicker bolt maybe we're onto something here.

[Jnat]

Originally Posted by M4Lou

Good stuff Clean - my take (worthless, likely).

- installing the belmetric and Clint's bushing is pretty straightforward and seems to risk the dreaded "need for loctite repair" minimally.
- the quality "feel" of the bolt/bushing is great. My subjective side liked the installation - felt like an upgrade.
- I occasionally got a clunk w/ factory set up when putting in park and turning engine off in gear. Have not gotten that yet** w/ new set up.
- I also notice a tiny whine, but honestly never turned off radio and intently listened to my stock set up. So - that could be in my head.


Happy w/ install and waiting to see some removed bolts after 6++ months of heavy use to see any wear patterns.

Agreed, hoping for positive results as we all are.

[Max Well]

Originally Posted by joebie3

Important to note ... it's actually Clint's design. (Rennfix) https://rennfix.com/bolt-saver-for-bmw-x3m.html

Originally Posted by Th3Walrus

And I gotta say, Clint is great to deal with. ... He worked with me for different courier options and just shipped the bushing.

Wonder if Clint could have the OEM rear hex bolt and washer and combination nut (part nos. 33-32-6-775-040 and 33-32-6-760-380) cloned as a true M14x1.5x148 hex bolt (not socket) only at 12.9 rather than 10.9 and not in black oxide as Th3Walrus cautioned against?

Suspect those would sell well and would probably surpass Belmetric's M14 version since its only 10.9 and 140mm length.

[Kevin_The_Clean1]

Originally Posted by Max Well

Wonder if Clint could have the OEM rear hex bolt and washer and combination nut (part nos. 33-32-6-775-040 and 33-32-6-760-380) cloned as a true M14x1.5x148 hex bolt (not socket) only at 12.9 rather than 10.9 and not in black oxide as Th3Walrus cautioned against?

Suspect those would sell well and would probably surpass Belmetric's M14 version since its only 10.9 and 140mm length.

I had no idea the factory bolt (12.9) was about 20-25% stronger then the Beltmetric unit (10.9) until I read what you wrote. I think with Clint's donut installed there's far less play involved, so the increase in tensile strength will never be explored or pushed that far. But it does make complete sense, that we can make it even more bullet proof than it already is now.

[Jnat]

Originally Posted by Kevin_The_Clean1

I had no idea the factory bolt (12.9) was about 20-25% stronger then the Beltmetric unit (10.9) until I read what you wrote. I think with Clint's donut installed there's far less play involved, so the increase in tensile strength will never be explored or pushed that far. But it does make complete sense, that we can make it even more bullet proof than it already is now.

My theory is the movement/play in the factory bolt/bushing set up is the killer, not so much the bolt strength... although important. With the amount of torque these things make even stock, giving the bolt a head start with movement and slamming it is bad. The Clint doughnut snugs up the end of the factory bushing incredibly well and the Bellmetric bolt takes up most of the play in the factory insert.
The idea by Maxwell for an upgraded bolt would be fantastic if possible.

[sp33djunkeem3]

When dropping the diff to install the bolt saver bushing, do you have to do the loctite fix as well? I'm trying to avoid this as much as possible.

[Kevin_The_Clean1]

Originally Posted by sp33djunkeem3

When dropping the diff to install the bolt saver bushing, do you have to do the loctite fix as well? I'm trying to avoid this as much as possible.

That's definitely not necessary by all means. Unless you have the dreaded drivetrain clunk, there's no reason the loctite is needed.

[Th3Walrus]

Originally Posted by Kevin_The_Clean1

I had no idea the factory bolt (12.9) was about 20-25% stronger then the Beltmetric unit (10.9) until I read what you wrote. I think with Clint's donut installed there's far less play involved, so the increase in tensile strength will never be explored or pushed that far. But it does make complete sense, that we can make it even more bullet proof than it already is now.

Hold on. Do we know the factory bolt is 12.9?

Also, stronger doesn't always equal better. More strength = more brittle, which means instead of bending, it'll shear/snap. Also, IF the factory bolt is 12.9, it's still only 12mm on the non-threaded part.

The shear strength of a 12mm 12.9 is ~18000lbs vs 14mm 10.9 ~21500lbs.

But, it's likely the slop/play that causes the issue. It gives it a running start. What hurts more, pushing your head against a wall, or banging it?

[Max Well]

Originally Posted by Max Well

Wonder if Clint could have the OEM rear hex bolt and washer and combination nut (part nos. 33-32-6-775-040 and 33-32-6-760-380) cloned as a true M14x1.5x148 hex bolt (not socket) only at 12.9 rather than 10.9 and not in black oxide as Th3Walrus cautioned against?

Suspect those would sell well and would probably surpass Belmetric's M14 version since its only 10.9 and 140mm length.

Originally Posted by Kevin_The_Clean1

I had no idea the factory bolt (12.9) was about 20-25% stronger then the Beltmetric unit (10.9) until I read what you wrote...

Originally Posted by Th3Walrus

Hold on. Do we know the factory bolt is 12.9?...

Apologies if my original quote was confusing re 10.9 vs 12.9.

Both the front and rear diff bolts are 10.9 (I'll edit this post with images showing the stamps on the heads when I get a chance).

My main point - if we had access to not only a larger diameter true M14 like the Belmetric (as opposed to the OEM which we've measured as ~M13) as well as increased strength like 12.9 c/w the OEM's and Belmetric's @ 10.9, then intuitively it would seem to be a more robust simple changeout when c/w what even the Belmetric offers.

But again, I have zero engineering background so will defer to those with more knowledge as to whether this makes sense.

[Jnat]

Originally Posted by Th3Walrus

Hold on. Do we know the factory bolt is 12.9?

Also, stronger doesn't always equal better. More strength = more brittle, which means instead of bending, it'll shear/snap. Also, IF the factory bolt is 12.9, it's still only 12mm on the non-threaded part.

The shear strength of a 12mm 12.9 is ~18000lbs vs 14mm 10.9 ~21500lbs.

But, it's likely the slop/play that causes the issue. It gives it a running start. What hurts more, pushing your head against a wall, or banging it?

Very correct sir! Good analogy...

[9kracing]

I thought they changed the diff bolt on LCI models?

I see the same part number above

[Kevin_The_Clean1]

Originally Posted by 9kracing

I thought they changed the diff bolt on LCI models?

I see the same part number above

BMW simply revised that original part number with a new bolt + nut. Not sure if it (the proceeded hardware / parts) ever made its way into the production line though. MaxWell would probably know more details on this.

[Max Well]

Originally Posted by 9kracing

I thought they changed the diff bolt on LCI models? I see the same part number above

Originally Posted by Kevin_The_Clean1

BMW simply revised that original part... MaxWell would probably know more details on this.

They modified it minimally from what I've observed - just the combination nut/washer design. The bolt and bolt class appear the same (still 10.9). This was discussed in post #206 [https://x3.xbimmers.com/forums/showp...&postcount=206].

Changing the part numbers would confuse as they discontinued the old design and this version now directly supersedes (IMO ).

[3beeps]

Originally Posted by sp33djunkeem3

When dropping the diff to install the bolt saver bushing, do you have to do the loctite fix as well? I'm trying to avoid this as much as possible.

Yes. The second we dropped the diff to install the Ryan kit, it created the clunking problem. We brought it back up on the lift, did the loctite fix, and it was all good the next day after it dried.

[VerySlowM235i]

I'll be installing the vtt rear bushing hopefully in a few weeks on my 2020 x3m with pano roof. I'll report back on nvh after install

[Kevin_The_Clean1]

Originally Posted by VerySlowM235i

I'll be installing the vtt rear bushing hopefully in a few weeks on my 2020 x3m with pano roof. I'll report back on nvh after install

That's a pretty cool setup. So does this VTT kit also stiffen up the two side differential mount bushings as well... ?