[FaRKle!]

So I had a G20 on loan to me for a bit and was really curious to see what BMW did for the next generation 3/4 series' suspension.

Originally Posted by Index

0:00 Intro
0:15 Static ride height measurements
0:44 Under the hood/shock tower comparison
1:45 Jack points and lifting the car (QuickJack users take note!)
2:27 Wheel bolts and pattern
2:50 Damper travel before bump stops
4:11 Front strut assembly and components
7:15 Front control arms and sway bar
8:54 Rear suspension layout
9:34 Rear sway bar
10:35 Rear springs
10:52 Rear damper and components
11:44 Rear rotors and variants
12:09 Front rotors and variants

Overall, the suspension layout is near identical to that of the F2x/F3x! It has all of the same functional components, which are just slightly different in shape. The process to replace the springs and shocks is the same as the F2x/F3x, and if you're interested in that you can see my video on that here.

Some key differences I noticed are that the shock towers on the G20 look a lot beefier, and BMW went to mostly directional brake rotors on the G20. That means the vanes should be optimized for pumping air through them for better cooling.

One thing I'm pretty annoyed with is how far apart BMW made the side jack points on the G2x. They've made it so if you're a QuickJack user (like myself) you can't put your skids along the sides unless you have the most expensive XLT model. If you have the EXT you can go side to side, however that limits a lot of types of work you can do.

I wish I had some more time with this car to take a look at some other items. One thing in particular I forgot to measure was the rear motion ratio. On the F2x/F3x the spring motion ratio is about 0.59. It'd be interesting to see if this was maintained. It'd also be interesting to see if F2x/F3x dampers and springs fit G2x vehicles. At least from the 330i I looked at, the spring ends/mount patterns are the same as F2x/F3x, however the springs on this car weren't from the series of springs that BMW used for the F2x/F3x.

While driving the car around, I actually thought BMW did a pretty good job with the base suspension. It felt pretty decently damped and wasn't harsh at all. I actually liked it more than the Adaptive-M Suspension on the M340i at the UDE autocross last year. I'm looking forward to the next G2x I get to inspect.

[Bee Pee]

Originally Posted by FaRKle!

So I had a G20 on loan to me for a bit and was really curious to see what BMW did for the next generation 3/4 series' suspension.

Overall, the suspension layout is near identical to that of the F2x/F3x! It has all of the same functional components, which are just slightly different in shape. The process to replace the springs and shocks is the same as the F2x/F3x, and if you're interested in that you can see my video on that here.

Some key differences I noticed are that the shock towers on the G20 look a lot beefier, and BMW went to mostly directional brake rotors on the G20. That means the vanes should be optimized for pumping air through them for better cooling.

One thing I'm pretty annoyed with is how far apart BMW made the side jack points on the G2x. They've made it so if you're a QuickJack user (like myself) you can't put your skids along the sides unless you have the most expensive XLT model. If you have the EXT you can go side to side, however that limits a lot of types of work you can do.

I wish I had some more time with this car to take a look at some other items. One thing in particular I forgot to measure was the rear motion ratio. On the F2x/F3x the spring motion ratio is about 0.59. It'd be interesting to see if this was maintained. It'd also be interesting to see if F2x/F3x dampers and springs fit G2x vehicles. At least from the 330i I looked at, the spring ends/mount patterns are the same as F2x/F3x, however the springs on this car weren't from the series of springs that BMW used for the F2x/F3x.

While driving the car around, I actually thought BMW did a pretty good job with the base suspension. It felt pretty decently damped and wasn't harsh at all. I actually liked it more than the Adaptive-M Suspension on the M340i at the UDE autocross last year. I'm looking forward to the next G2x I get to inspect.

Insightful video - well done.

Curious about the car had no strut brace yet Realoem quotes part no 51617423989 which has 2 fixings per strut top and 2 more fixings to the firewall.

BMW appear to have more options as far as front camber correction hubs for G20 offering upto +/- 1deg of correction whereas F3x only has +/- 0.5deg.

Be curious to know if G series hub carrier/uprights are interchangeable between G and F series as it would give f series owners an OEM retrofit if the wanted to add more front camber.

I would imagine the owner of the G20 in yr video would see a benefit in retrofitting the oem brace and even more if the retrofitted these BMS braces too

https://burgertuning.com/products/bm...40i-and-m340ix

[FaRKle!]

Originally Posted by Bee Pee

Insightful video - well done.

Curious about the car had no strut brace yet Realoem quotes part no 51617423989 which has 2 fixings per strut top and 2 more fixings to the firewall.

BMW appear to have more options as far as front camber correction hubs for G20 offering upto +/- 1deg of correction whereas F3x only has +/- 0.5deg.

Be curious to know if G series hub carrier/uprights are interchangeable between G and F series as it would give f series owners an OEM retrofit if the wanted to add more front camber.

I would imagine the owner of the G20 in yr video would see a benefit in retrofitting the oem brace and even more if the retrofitted these BMS braces too

https://burgertuning.com/products/bm...40i-and-m340ix

It looks like only vehicles with the M-Sports suspension or Adaptive-M suspension get the strut brace. The vehicle in this video was a base suspension model.

That'd be really interesting if the knuckles were the same, but I highly doubt that. There's probably slight geometry differences so the arms won't mount exactly the same.

Hrm, those BMS braces look pretty good. I wonder how much difference using steel there instead would make.

[Bee Pee]

Originally Posted by FaRKle!

Hrm, those BMS braces look pretty good. I wonder how much difference using steel there instead would make.

Hub cross compatibility from G to F series - might work given that F8x front hubs are a common oem upgrade for e9x m3 owners wanting to oem upgrade by retrofitting f8x blue brembos and 380mm rotors.

Ref steel bracing - if you know someone with g29 z4 - they have oem steel braces from factory - might be worthwhile seeing if these are x compatible & retrofitable to g20 cars ???