Which swaybar for 135i?

[suprtran]

Which sway bars do you guys recommend? I've read H&R, E9X M3, Hotchkis. What else is there? Should I go a complete set (front/rear) or front only or rear only?

TIA

[Rodzilla]

It depends on what suspension you want to go with. Most go for the M3 bar and you don't need a rear bar unless you are putting an LSD.

I got the Eibach front sway, so I will probably get same for suspension when decide to switch.

[audimotion]

I just installed a 3M front sway a couple weeks ago. So far I like it a lot.

[KingOfJericho]

I did the M3 vert swaybar and like it. The most amazing thing is the quality of the parts used on the M3 vs the 135i. M3 pieces look like they're ready for war while ours look like flimsy Chinese-made imitations.

[mackeroni]

I have been wondering about this too. However, for me the desired result is flatter cornering without a harsher ride. Because the M3 sways are so heavy, would they create the much stiffer ride that I am trying to avoid?

All informed opinions welcome.

[KingOfJericho]

Swaybars do NOT change the ride quality of the car - they simply reduce the roll in corners. You would never be able to describe a car with stiff or heavy swaybars as having a harsher ride.

[Spoolin Montego]

Originally Posted by KingOfJericho

Swaybars do NOT change the ride quality of the car - they simply reduce the roll in corners. You would never be able to describe a car with stiff or heavy swaybars as having a harsher ride.

This is incorrect. By going with a thicker, bigger sway bar you will feel more of the road bumps as the suspension on each side is not permitted to flex as much independently.

[Vigilante375]

So you're saying sway bars limit the amount of flex/roll in the body when you're turning AND make your suspension not rebound as much? Huh, I'd like to see where you found this information at.

[JuuS]

I've installed the front H&R bar and love it. It's solid without the middle crimp. The stock bar was indeed a joke. I tossed it in a scrap metal recycling bin. lol

I did not notice any extra harshness in ride quality after the change, just the incredible flatness in the turns.

[1speedbike]

The only way I could ever see a sway bar affecting ride quality in the way explained above is MAYBE if you hit a bump with only the passenger side wheels and as a result of the stiffer swaybar linking between the driver and passenger side, the driver feels the bump more than normal. But I don't see this as really being an issue, even if it works that way (which I am honestly not sure about, I'm not that well-versed in this area). It reduces roll by reducing flex, but I don't think that flex reduction really influences the transmission of road shocks from one corner to the other. You hit a road imperfection with your passenger side tire, it extends/compresses then rebounds. It doesn't transmit to the other side... (at least I don't think so. It doesn't make sense to me that it would.. correct me if I'm wrong).

The weight difference between the M3 sway and the 135i sway is negligible because they are both hollow, and even though the M3 one is indeed thicker, since it's hollow you're not really adding much mass to the bar. But even if it wasn't, it really wouldn't matter. The H&R bar is indeed solid and not hollow, and even that one has no detrimental effects to handling.

The only negative effect I can even forsee is if the front is much more stiff than the rear, this can increase understeer. For fixing this, I really like this web page:

http://www.nyracer.com/overunder.htm

[MA128]

Originally Posted by 1speedbike

The only way I could ever see a sway bar affecting ride quality in the way explained above is MAYBE if you hit a bump with only the passenger side wheels and as a result of the stiffer swaybar linking between the driver and passenger side, the driver feels the bump more than normal. But I don't see this as really being an issue, even if it works that way (which I am honestly not sure about, I'm not that well-versed in this area). It reduces roll by reducing flex, but I don't think that flex reduction really influences the transmission of road shocks from one corner to the other. You hit a road imperfection with your passenger side tire, it extends/compresses then rebounds. It doesn't transmit to the other side... (at least I don't think so. It doesn't make sense to me that it would.. correct me if I'm wrong).

The weight difference between the M3 sway and the 135i sway is negligible because they are both hollow, and even though the M3 one is indeed thicker, since it's hollow you're not really adding much mass to the bar. But even if it wasn't, it really wouldn't matter. The H&R bar is indeed solid and not hollow, and even that one has no detrimental effects to handling.

The only negative effect I can even forsee is if the front is much more stiff than the rear, this can increase understeer. For fixing this, I really like this web page:

http://www.nyracer.com/overunder.htm

As stated above, standard theory holds that a stiffer FSB usually increases understeer (because the front end will slide sooner than before). However, as a reader of many posts over several years on this fine forum, it seems that - up to a point - a stiffer FSB reduces understeer in the 1 series. This is apparently due to the overall softness of our suspensions. If you read to the bottom of the linked page, you'll find: "Stiffer front sway bars will, in many cases, decrease understeer because of reduced body roll and better camber control."

[tracer bullet]

Fatter bars *will* change the ride in certain situations, as mentioned.

If you live in Florida and your roads are dead flat, you won't feel a difference. If you live in MN and the roads are full of holes, bumps from patches, and all kinds of other crap then you most definitely will notice.

You're right that you feel it only if you hit a bump with one side and not the other. The thing is, for some people, you just described what sometimes seems like every square inch of road surface! Obviously it's not that bad here, but it is noticeable.

I'd agree however it's more than worth the trade-off and not really worth worrying about.

Originally Posted by Vigilante375

So you're saying sway bars limit the amount of flex/roll in the body when you're turning AND make your suspension not rebound as much? Huh, I'd like to see where you found this information at.

Anti-roll bars don't affect body flex, not sure where you read that. He didn't say it. He said each side can't react as independently as it did before a thicker bar was installed and that is correct. The bar ties the sides together, a thicker one makes a stronger tie between the two. When one side wants to move up or down, it tries to take the other side with it. If you understand suspensions there's not much confusion here.

[christopherkriens]

Fatter bars *will* change the ride in certain situations, as mentioned.

This is true. Unless all of your road imperfections hit both front tires at the same time and with the same force, all other things being equal- you will have an increase in side roll response with a stronger bar.

[135i_lgnd]

has anyone put front and rear sway bars on there 135i ?

[tracer bullet]

Originally Posted by 135i_lgnd

has anyone put front and rear sway bars on there 135i ?

It may have happened once or twice. Check out the search function and you'll find lots of reviews from people that have done it.

[Bdh821]

I have the E93 FWB and debated on putting on the rear while doing my subframe bushings. I decided against it. I have HP Autowerks Koni coilover kit with swift springs, M3 front control arms and Dinan camber plates. And yes, I do have an LSD. Autox'ed the car this past weekend and it felt great!

[infinitekid2002]

Originally Posted by 135i_lgnd

has anyone put front and rear sway bars on there 135i ?

i have rear UUC bar set at medium and front m3 vert bar (just put in the front); going to the track on sunday so maybe ill write up my opinion

[cvc 22349a]

Originally Posted by Bdh821

I have the E93 FWB and debated on putting on the rear while doing my subframe bushings. I decided against it. I have HP Autowerks Koni coilover kit with swift springs, M3 front control arms and Dinan camber plates. And yes, I do have an LSD. Autox'ed the car this past weekend and it felt great!

Why did you decide against installing the rsb?

[mmilkov]

Originally Posted by suprtran

Which sway bars do you guys recommend? I've read H&R, E9X M3, Hotchkis. What else is there? Should I go a complete set (front/rear) or front only or rear only?

TIA

I installed an E93 M3 front swaybar on my 135i, which otherwise has a stock suspension. From my autocross experience I can say that there is noticeably less lean, but the car understeers more than before when pushed to the limit. If what you value is less body roll, then go for it, but the car won't be any faster in the corners or better balanced. See my thread about this topic:
http://www.1addicts.com/forums/showthread.php?t=677455

[avecta]

So M3 sway bars? or H&R?

[JWC]

Whiteline!