[embi]

Hi,

I'm still running into weird vibrations from the front axle. Upon putting new brake discs on the car, I feel like the culprit may be uneven surface of the hub, so I will try to do front bearings.

Can you please tell me, how hard is it to change them? Can they be unbolted from the rear without disassembling the suspension?

Thanks a lot!

[admranger]

I am sorry that I do not have a direct answer to your question. However, I have questions about your situation.

Do you have the stock wheels? Non-hub centric wheels can be the culprit here, even with centering rings.

I assume you have checked the wheels for balance, preferably having them road force balanced.

Good luck finding the issue as these can be hard to chase down.

[BMW012]

not sure if same issue, but there is a lot of good material in here

https://g30.bimmerpost.com/forums/sh...512720&page=16

[buddyboy]

If yours is xdrive, you need to remove the axle shaft from the hub , You need to remove the caliper and rotor and there should be 4 bolts accessible from the back of the hub carrier

[embi]

Originally Posted by admranger

Do you have the stock wheels? Non-hub centric wheels can be the culprit here, even with centering rings.

Interesting! I'm actually not running stock wheels. I'm running 18 inch Rial X12's (both ECE & ABE approvals for G30). The discs are brand new.

Originally Posted by admranger

I assume you have checked the wheels for balance, preferably having them road force balanced.

Rebalanced twice. My shop unfortunately doesn't have road force balance machine. I can try to search for one though. Or just try it out with winter tyres. Also geometry was done twice and the suspension linkages were checked for anything worn out or loose.

Originally Posted by admranger

Good luck finding the issue as these can be hard to chase down.

Thanks for the tips!! Next thing I'll do is try OEM BMW wheels (my winter setup) .
___________________

My car is not xDrive

[admranger]

Originally Posted by embi

Interesting! I'm actually not running stock wheels. I'm running 18 inch Rial X12's (both ECE & ABE approvals for G30). The discs are brand new.

Rebalanced twice. My shop unfortunately doesn't have road force balance machine. I can try to search for one though. Or just try it out with winter tyres. Also geometry was done twice and the suspension linkages were checked for anything worn out or loose.


Thanks for the tips!! Next thing I'll do is try OEM BMW wheels (my winter setup) .
___________________

My car is not xDrive

Have a fresh kolache for me. I miss my grandmother’s.

[embi]

Swapped the winter 17 inch wheels and the vibrations are 90% gone... wow.

Thanks I'll have some kolace :-)

[HighlandPete]

Originally Posted by embi

Swapped the winter 17 inch wheels and the vibrations are 90% gone... wow.

Thanks I'll have some kolace :-)

Definitely look at the thread linked in an earlier post. Wheel to hub tolerance is critical on all models, particularly showing up on the G30 models.

[TEF]

When spring arrives and you're installing summer wheels and tires, have you considered checking the hubs, rotors and wheels with a run-out gauge? It will likely indicate which component is causing the vibrations. Certainly, beats the cost and work of replacing front hubs. If your mechanic doesn't know what a run-out gauge is, look for a good machine shop as they work with these daily.

[embi]

I just replaced the front hubs. You need to remove one arm ball joint from the suspension knuckle to access one hub bolt from the back. The vibrations are not yet gone 100%, so now I'm having the front rotors resurfaced.

Impossible to check the rotors with run-out gauge on the car. As soon as you take the wheel off, the rotor isn't sitting 100% flush on the hub, as the small 6mm hex bolt isn't enough to reliably push it against the hub.

Wheels have just been balanced.

[admranger]

Originally Posted by embi

I just replaced the front hubs. You need to remove one arm ball joint from the suspension knuckle to access one hub bolt from the back. The vibrations are not yet gone 100%, so now I'm having the front rotors resurfaced.

Impossible to check the rotors with run-out gauge on the car. As soon as you take the wheel off, the rotor isn't sitting 100% flush on the hub, as the small 6mm hex bolt isn't enough to reliably push it against the hub.

Wheels have just been balanced.

Buy short bolts from McMaster Carr and snug the rotor to the hub. Now you can measure runout.

[Mike 540]

Came late to the threat. Embi, for the road force balancing go to E1 Cartronic in Běchovice. They have Hunter machines for that and the guys are good.

[embi]

Thanks for the tip, Mike. I found out that the vibrations are coming from the rear. I lifted the car in the rear and spun up the wheels to 140 km/h and the car started shaking like crazy. Just got the rear wheels rebalanced and tried to realign the brake rotor on the hub. Might need to get new brake disc if it doesn't help.

[andrease]

My bearing just broke and I’m planning on replacing it myself. What torques did you use on the bolts? It’s an xdrive so I need the axle bolt torque too.

[Mach550]

Originally Posted by andrease

My bearing just broke and I’m planning on replacing it myself. What torques did you use on the bolts? It’s an xdrive so I need the axle bolt torque too.

See attached

[andrease]

Originally Posted by Mach550

See attached

Thanks! Where did you find this?