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      09-16-2020, 09:55 AM   #31

Drives: 2015 BMW 335i x-Drive Auto
Join Date: Oct 2017
Location: New Jersey

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Originally Posted by gippy View Post
Originally Posted by johnung View Post
If I was only permitted one suspension mod it would be upgraded sway bars. Body roll is the top issue in F3x. Rear bushings are at the bottom of my list.

When my rear sway bar, shocks and springs were being replaced I was looking at rear bushings and discussed it with the BMW tech who was doing the work for me. He strongly cautioned me not to replace my rear bushings with solid or stiffer bushings because it would introduce Noise Vibration Harshness. From what I know now, I would only consider sealed monoball street bushings.
well you've convinced me.

i just spoke to my trusted local indy, to replace front+rear ARB's.
3 hours labour, £75/hr = £235. Which i'm super happy with.

A decision has been made then - time to shop around for some serious arb's front and rear. i think i'll just start calling them 'sway bars' now for this forum!

Any recommendations? or just go with what you've got! why did you choose H&R over others in the end?

seems to be some reservations about bushes then from your side compared to others....... i guess if i'm replacing the sways then seems like the right time to do the bushes too - but i duno which ones to go for. Some disagreement here about just how much of an impact they make.... i can see both sides.
You got an awesome price quote on sway bar labor. Do it quick before he revises the quote!

Technically they are anti-sway bars, but easier to say just sway. What does ARB stand for? I was beginning to think it's something to order in a corner pub.

I've been using German H&R sways for decades. Their engineering and manufacturing are the best. They use solid bars. Some manufacturers play up their high tech hollow tubular bars (Dinan is one) but there are photos on forums of them suddenly breaking. Not likely to happen with a solid H&R bar.

Often not understood is the relationship of the ratio between the front and rear bars. If you put too heavy or too light of a bar on the front or the rear, you can significantly change the dynamics of the suspension. Suddenly the car is oversteering or understeering which can cause very bad consequences on the roadway.

H&R has always understood this and matched their front and rear bars to remove unwanted body roll without changing the dynamics of the suspension.

That's why I cringe when I read guys recommend only upgrading the rear sway bar on an F3x. They are doing so because of cost, because it's more expensive labor to do the front bar. Sways should always be upgraded in matched pairs unless you're on a race team or something and really understand the engineering of what's being removed and what's replacing it. It's scary to think of someone pushing a daily driver hard after a single bar swap, the car acting unexpectedly and ending up wrapped around a tree.

My installer/BMW Tech was doing my H&R bars on the side so he upgraded one bar and I had to wait several nights until he had time to do the opposite bar. The dynamics around turns was very different. I didn't dare push it. Once the second bar was on the chassis dynamics were back to normal and the body roll was gone!

He hadn't done H&R sways on an F3x before. The roads where he lives are a beautiful undulating curvy test track. He came back with a huge smile and said it was the best handling F3x that he's ever test driven. He had installed sways on many cars before and was expecting an improvement, but he still expressed amazement at the results of the H&R's on my F3x chassis.

Compared to other aftermarket sway bars on the market for the F3x, the H&R may be the strongest. But that's what I wanted. Sways are not like springs where if you go too stiff it really effects ride comfort.

If you are cruising down a country road or a super highway you can't tell what sway bars are installed. They aren't doing much when the car is going in a straight line and there's no body roll. But when you hit a turn or a high speed curve you want a strong set of sway bars to keep the body from rolling and keep the car planted and powering through the turn. H&R sway bars were designed to do that perfectly.

If you read my stuff I think it's apparent that I research pretty thoroughly. I don't just read but I talk to tech's, service managers, shop owners who have much hands-on experience. Sometimes I know automotive engineers and racing engineers who are helpful. Believe me that I researched the bushings thoroughly. I know some guys who can ship them to the UK. Just PM me.

Are you RWD or xDrive? Front control arms appear the same but are different part numbers? Critical to order the correct parts when you do.

I personally wouldn't do sway bars and bushings at the same time. Do the sways first and drive the car to really get to know the suspension with the body roll removed. It's not like springs and shocks where the labor completely overlaps.

Every time that I've done multiple changes at once, I've eventually regretted it because I can't tell what change was responsible for what I'm feeling when I drive. Then if I want to make an adjustment or an addition, what do I do because it's all mixed together by the overlapping installations?