[Tuner1]

Originally Posted by Matt@Evolve

CS has the same rear ARB as the other models, and front is the same as a G81.

Does anyone know the stiffness increase from the G8x Comp xDrive to the CS/G81 front bar?

[Hit_Apex]

Originally Posted by Tuner1

Does anyone know the stiffness increase from the G8x Comp xDrive to the CS/G81 front bar?

Are you looking for the roll stiffness delta in nm/radian? Curious as to what calcs you're looking to do.

[Tuner1]

Originally Posted by Hit_Apex

Are you looking for the roll stiffness delta in nm/radian? Curious as to what calcs you're looking to do.

Roll stiffness delta in nm/radian would be useful or even just a basic bar-only calculation based on diameter, wall thickness (if hollow) and lenght/lever arm. Example from Dinan (F8x):

Add a 32mm Lightweight Tubular Adjustable Front Anti-Roll Bar ... This anti-roll bar is adjustable from 57% to 103% stiffer than the stock bar.

[blorraine]

Just installed the 30mm H&R sway bar on my xdrive M3. I measured the stock one and it’s about 22-23mm in the middle, and increases in diameter as you move outward.

Just sharing here since I did not find a reference for the diameter of the stock bar on xdrive cars when researching before. Hopefully that’s useful! Excited to see how the new one performs.

[lukahtx]

How dose the handling change on the car? Is it a worthy upgrade over stock?

Originally Posted by blorraine

Just installed the 30mm H&R sway bar on my xdrive M3. I measured the stock one and it’s about 22-23mm in the middle, and increases in diameter as you move outward.

Just sharing here since I did not find a reference for the diameter of the stock bar on xdrive cars when researching before. Hopefully that’s useful! Excited to see how the new one performs.

[blorraine]

Originally Posted by lukahtx

How dose the handling change on the car? Is it a worthy upgrade over stock?

I took it to the track this weekend, and it's hard to say for sure since obviously you cannot do a side by side comparison, but IMO it felt more planted w/less body roll through the corners, and I felt like I had more front end grip with less tendency to push the tires.

It's worth noting though that I added camber plates at the same time, so obviously those played a role in these changes as well.

[TselaG80]

Originally Posted by blorraine

I took it to the track this weekend, and it's hard to say for sure since obviously you cannot do a side by side comparison, but IMO it felt more planted w/less body roll through the corners, and I felt like I had more front end grip with less tendency to push the tires.

It's worth noting though that I added camber plates at the same time, so obviously those played a role in these changes as well.

did you just do front? when looking under the car it looks like the entire subframe needs to be dropped in order to install the rear, or i could be wrong?

[shwayne5]

You’re correct, subframe needs to be dropped to do the rear. Just put H&R on mine and can confirm. Have not driven since install so can’t comment on differences. But can say that the weight of the H&R is significant over the stock bars. Guessing they’re solid.

[PabstBleuRibbon]

Originally Posted by shwayne5

You’re correct, subframe needs to be dropped to do the rear. Just put H&R on mine and can confirm. Have not driven since install so can’t comment on differences. But can say that the weight of the H&R is significant over the stock bars. Guessing they’re solid.

I've looked and thought that was the case for the rear sway bar. How hard is it to drop the rear subframe? Support on the rear 2 jackstand points, then a center support/transmission jack under the rear diff jack point was what I was thinking might work.

Also, chime in with your H&R experience!

[shwayne5]

First trackday back (since the one last week got cancelled) is the 24th. Hoping that one doesn’t get cancelled but I’ll report back for sure.

Full disclosure, I did not install the bars. I paid the Motorsports shop here in Austin to do it. They’ve done almost everything on my car. But dropping the subframe for first time is probably a big job. Not to mention the alignment needing to be done after. The front should be relatively easy though. I’m guessing that if you paid a shop around you with experience doing it they’d probably charge for 6 hours of labor and I’m not even sure that would cover the alignment after. So if you do it, consider doing anything else to the rear that you’d ever considered.

[all_my_rides]

Here is what I was able to find for the rear. Says it fits:

This product fits 20 vehicle variants.
BMW: 8 models, 20 variants between 2021 and 2023.

M3 Comp. M xDrive Sedan
M3 Comp. M xDrive Wagon
M3 Competition Sedan
M3 CS Sedan
M3 Sedan
M4 Comp. M xDrive Coupe
M4 Competition Convertible
M4 Competition Coupe
M4 Coupe

https://parts.bmwnorthwest.com/p/BMW...relatedProduct


Here is the H&R front and rear set. There is a guy in the BMW G87 M2 2023+ FB group that is putting these on his 2024 G87. I would imagine they would fit the G8X M3/M4 etc.

https://www.h-r-shop.com/h-r-set-of-...-p-606169.html

[sinkung]

Originally Posted by all_my_rides

Here is what I was able to find for the rear. Says it fits:

This product fits 20 vehicle variants.
BMW: 8 models, 20 variants between 2021 and 2023.

M3 Comp. M xDrive Sedan
M3 Comp. M xDrive Wagon
M3 Competition Sedan
M3 CS Sedan
M3 Sedan
M4 Comp. M xDrive Coupe
M4 Competition Convertible
M4 Competition Coupe
M4 Coupe

https://parts.bmwnorthwest.com/p/BMW...relatedProduct


Here is the H&R front and rear set. There is a guy in the BMW G87 M2 2023+ FB group that is putting these on his 2024 G87. I would imagine they would fit the G8X M3/M4 etc.

https://www.h-r-shop.com/h-r-set-of-...-p-606169.html

So if I get this right, you are saying that G80 xdrive comp has different front sway bar compare to g80 cs

While in the rear share the same part number ?

Am I right?

[all_my_rides]

Originally Posted by sinkung

So if I get this right, you are saying that G80 xdrive comp has different front sway bar compare to g80 cs

While in the rear share the same part number ?

Am I right?

That's what I got out of it also. 🤷🏽‍♂️