[J-Blizz]

So I have a 2011 335xi w/ "M Sport" suspension ~70k miles and everything is fine for the most part. My only problem is that when I hit bumps sometimes, especially if it's mid turn, it will feel like the back end is sliding out a bit. The car recently had the drivers side front tire replaced not too long ago and I wonder if they did the alignment correctly. I heard another variable is my rear tire pressure which I'm going to check tomorrow. Possibly rear shocks too?

One thing to add would be that sometimes when I'm going about 70+ the steering wheel and car a little will start to shake a tiny bit. Some say im being extra picky but I think something is up and I want it to go away. Tires have even wear btw.

Took it to one shop and they told me to do the rear subframe bushings but another shop went in there with a pry bar and had no clue what the original shop was talking about. Needless to say, a little torn! Any advice would be appreciated

[juld0zer]

If the rear subframe bushes are moving that much, they will leave marks on the chassis. However, it is well known that the rear subframe bushes are really soft. I noticed a huge change after swapping them out for M3 bushes. Worth the effort. The result is more noticeable than replacing the rear shocks with a new set of OE type shocks. In fact, many say that you will never truly feel shocks work properly until the subframe is more firmly secured.

That is if your tyres are in good nick and are good quality, and alignment is all good.

[J-Blizz]

Originally Posted by juld0zer

If the rear subframe bushes are moving that much, they will leave marks on the chassis. However, it is well known that the rear subframe bushes are really soft. I noticed a huge change after swapping them out for M3 bushes. Worth the effort. The result is more noticeable than replacing the rear shocks with a new set of OE type shocks. In fact, many say that you will never truly feel shocks work properly until the subframe is more firmly secured.

That is if your tyres are in good nick and are good quality, and alignment is all good.

Originally Posted by juld0zer

If the rear subframe bushes are moving that much, they will leave marks on the chassis. However, it is well known that the rear subframe bushes are really soft. I noticed a huge change after swapping them out for M3 bushes. Worth the effort. The result is more noticeable than replacing the rear shocks with a new set of OE type shocks. In fact, many say that you will never truly feel shocks work properly until the subframe is more firmly secured.

That is if your tyres are in good nick and are good quality, and alignment is all good.

So you're saying this feeling would be noticeable even if the tires/alignment was solid? The feeling can be pretty dramatic at times.

In terms of the subframe leaving marks, would that be blatantly obvious?

[avocet]

Sub frame bushings are a must, in my opinion, if you want a decent handling e90. I did m3 bushings, but I have heard good things about inserts. They are much cheaper, easier to install, and will give you a good idea of how it can change the way your chassis handles. I kinda wish I went solid bushings...

And getting a good wheel balance is where you want to start with an at speed vibe issue(unless it is obviously not coming from the wheels/tires)

[Torgus]

If you are going to mess with the subframe bushing upgrade to solid, m3 subframe bushings are not a large enough upgrade to justify the cost and labor. All of the newer BMWs come with solid subframe bushings from the factory. They add no NVH.

[gjm120]

Originally Posted by avocet

Sub frame bushings are a must, in my opinion, if you want a decent handling e90. I did m3 bushings, but I have heard good things about inserts. They are much cheaper, easier to install, and will give you a good idea of how it can change the way your chassis handles. I kinda wish I went solid bushings...

And getting a good wheel balance is where you want to start with an at speed vibe issue(unless it is obviously not coming from the wheels/tires)

Inserts are easy and inexpensive and give some improvement. Never had M3 or solid bushings, but, from what others have said maybe about 1/3 to 1/2 the way to a full bushing replacement.

[Tambohamilton]

M3 rear subframe bushings made a huge difference to the handling of my 330d e91. Almost entirely cured a tramlining issue too. I did notice an increase in noise, but no extra vibration or harshness...though the latter at least is hard to say for sure.

Sounds like you also need your wheels to be balanced...maybe road force balanced if a regular balancing procedure doesn't find anything.

[SlimE92]

Originally Posted by Torgus

If you are going to mess with the subframe bushing upgrade to solid, m3 subframe bushings are not a large enough upgrade to justify the cost and labor. All of the newer BMWs come with solid subframe bushings from the factory. They add no NVH.

Hey torgus which would you recommend? I'm currently shopping for some.

[Torgus]

Originally Posted by SlimE92

Hey torgus which would you recommend? I'm currently shopping for some.

This is what I have installed: https://www.turnermotorsport.com/p-1...minum-e82-e9x/

Honestly all the others look about the same and probably knocked off the turner design. There is nothing special about any of them. Any solid aluminum bushing should be exactly the same. You might be able to find another brand slightly less expensive.

I went with turner because they were in stock and I knew they would fit. Didn't seem worth the hassle to save say $50 bucks on another brand.

What is interesting is Turner has two different models of them for m cars and none m cars which makes sense as the rear subframe is different on an m3. Where other companies just have 1 for all the models.

[SlimE92]

Originally Posted by Torgus

This is what I have installed: https://www.turnermotorsport.com/p-1...minum-e82-e9x/

Honestly all the others look about the same and probably knocked off the turner design. There is nothing special about any of them. Any solid aluminum bushing should be exactly the same. You might be able to find another brand slightly less expensive.

I went with turner because they were in stock and I knew they would fit. Didn't seem worth the hassle to save say $50 bucks on another brand.

What is interesting is Turner has two different models of them for m cars and none m cars which makes sense as the rear subframe is different on an m3. Where other companies just have 1 for all the models.

Ahh interesting.

Thanks for the tip I'll probably grab the turner ones as-well to avoid any issues.

[Torgus]

Originally Posted by SlimE92

Ahh interesting.

Thanks for the tip I'll probably grab the turner ones as-well to avoid any issues.

The difference is noticeable and I highly recommend them.

You have to drop the rear subframe to install. You probably want to change out your rear sway bar at the same time(if you are ever going to). Also, you can get to the two short small brake lines which are a PITA to get to with the subframe in. Just replacing the lines at the wheels with SS still leaves you with the 2 stock rear lines, most people never change these. You will obviously want to flush the brakes after. Finally you might want to do rear diff bushings while you are in there having so much fun. Solid rear diff bushings will give you diff whine as a word of warning. Doesn't bother me, might bother some. You only hear it at highway speeds.

Just a thought.

[J-Blizz]

Originally Posted by Torgus

The difference is noticeable and I highly recommend them.

You have to drop the rear subframe to install. You probably want to change out your rear sway bar at the same time(if you are ever going to). Also, you can get to the two short small brake lines which are a PITA to get to with the subframe in. Just replacing the lines at the wheels with SS still leaves you with the 2 stock rear lines, most people never change these. You will obviously want to flush the brakes after. Finally you might want to do rear diff bushings while you are in there having so much fun. Solid rear diff bushings will give you diff whine as a word of warning. Doesn't bother me, might bother some. You only hear it at highway speeds.

Just a thought.

The rear sway bar would be a cool mod! Definitely down to do that at the same time. I'm not tracking the car or anything but Im not satisfied with the way it currently handles.

Thank you everyone for all this feedback! It seems fairly clear to me that it is probably the rear subframe bushings. Sounds like the solid ones are the way to go.

[SlimE92]

Originally Posted by Torgus

The difference is noticeable and I highly recommend them.

You have to drop the rear subframe to install. You probably want to change out your rear sway bar at the same time(if you are ever going to). Also, you can get to the two short small brake lines which are a PITA to get to with the subframe in. Just replacing the lines at the wheels with SS still leaves you with the 2 stock rear lines, most people never change these. You will obviously want to flush the brakes after. Finally you might want to do rear diff bushings while you are in there having so much fun. Solid rear diff bushings will give you diff whine as a word of warning. Doesn't bother me, might bother some. You only hear it at highway speeds.

Just a thought.

Good to know. The sound won't bother me one bit.. thanks again for the info.

[cvc 22349a]

The solid ones are definitely the way to go if you're going to replace mounts. Wish I'd had installed those instead of M3 rsm as I still have noticeable rear lateral movement as you've described. But I have a tune and upgraded suspension. If your car is otherwise stock I'd suggest trying the rsm inserts first, way less labor and should be sufficient for a DD.

[avocet]

Originally Posted by Torgus

If you are going to mess with the subframe bushing upgrade to solid, m3 subframe bushings are not a large enough upgrade to justify the cost and labor. All of the newer BMWs come with solid subframe bushings from the factory. They add no NVH.

M3 bushing are definitely a worthwhile upgrade, IMHO. It is just that my car has changed missions... as an hpde/ occasional track day with r compound tires it demands more from the chassis.

[hellokitty]

Do solid aluminum subframe bushings. This is caused by the soft subframe bushing moving independently of the chassis.

I went to solid aluminum with no downsides (NVH) and do not regret it one bit.

[hellokitty]

Here is a spreadsheet of my existing suspension mods. The cherry on top was a corner balance and alignment done by West End Alignment. They managed to get my corner weights exactly identical to the pound (perfect 50%). All I can say is my E93 now handles just as well as my F80 M3 if not slightly better.

https://docs.google.com/spreadsheets...it?usp=sharing

[Ttkforeign335]

Originally Posted by J-Blizz

The rear sway bar would be a cool mod! Definitely down to do that at the same time. I'm not tracking the car or anything but Im not satisfied with the way it currently handles.

Thank you everyone for all this feedback! It seems fairly clear to me that it is probably the rear subframe bushings. Sounds like the solid ones are the way to go.

Mines does the same after much research gonna go with m3 bushings

[gjm120]

Originally Posted by hellokitty

Here is a spreadsheet of my existing suspension mods. The cherry on top was a corner balance and alignment done by West End Alignment. They managed to get my corner weights exactly identical to the pound (perfect 50%). All I can say is my E93 now handles just as well as my F80 M3 if not slightly better.

https://docs.google.com/spreadsheets...it?usp=sharing

Noticed the AKG rear adjustable endlinks. How have those held out? I've Whiteline fronts and am looking for something for the back.

[cvc 22349a]

Originally Posted by Ttkforeign335

Mines does the same after much research gonna go with m3 bushings

There's a few ppl here including me, and Many others not on this thread, reporting M3 subframe bushings still do not eliminate rear subframe movement under hard acceleration and cornering. They're better than oe but if one has a high torque 335i and is going through the trouble of dropping the subframe to replace bushings Solid is the way to go, no downside according to Many ppl. If I ever have to drop my rear subframe I'll be replacing the M3 bushings with solid. Lots of info on this and the M3 forum going back to 2007,08

[IllSic_Design]

I have to say the M3 rear subframe bushings are a big improvement over stock, but if I were to do it again I would probably do solid mounts. If you don't plan to track at all then M3 are fine though.

[hellokitty]

Originally Posted by IllSic_Design

I have to say the M3 rear subframe bushings are a big improvement over stock, but if I were to do it again I would probably do solid mounts. If you don't plan to track at all then M3 are fine though.

I would do solid mounts simply because you will never have to worry about them again (i.e., no more broken bushings).

If the installer needs to drop the subframe to install, you might as well do aluminum or poly differential bushings at the same time so you don't have to double down on labor down the line.

Also, ECS rear trailing arm and upgraded whiteline bushings while at it too.

All 3 of those things require the rear subframe to be dropped.