[jhbodle]

I popped the hood (bonnet) of my E90 325i today to show my mate the engine and he immediately pointed out the strut brace that connected the two suspension turrets. I'd never noticed that before! Sorry if everyone already knew this, but none of my previous 3 Series cars had a strut brace, and I thought it was pretty cool that an item that many people put on as an aftermarket mod was now present and correct as standard

[YYdoodle]

Best handling 3 ever out of the box

[E90Fleet]

All new BMW's have them standard, it started with the Z4 then the 5 Series

[CC 330i]

I did notice it, and was very pleased myself. The brace is somewhat hidden from view, but you can see it if you are looking for it.

I'll bet the aftermarket will be somewhat disappointed that they won't be able to sell those to e90 owners!

[HRC]

The aftermarket will still make these products, i.e. strut tower brace. They will point out that OE is fine but x-brand is better, just like all other aftermarket products...and people(not all of course) will buy them.

Danny

[romeo26]

hay can you take pictures of this plz

[CC 330i]

Originally Posted by HRC

The aftermarket will still make these products, i.e. strut tower brace. They will point out that OE is fine but x-brand is better, just like all other aftermarket products...and people(not all of course) will buy them.

Danny

True, and the stock pieces aren't very pretty, so if the aftermarket came out with fancy polished strut braces, I am sure that some people would definitely buy them. (maybe even me!).

[nexus66]

Sorry it's not a great picture, but I've highlighted where the strut brace sits! It only mounts to one bolt on the suspension tower, and kinda disappears in the middle!

[E90Fleet]

Its actually 2 pieces, with each piece mounting to a shock tower and then to the centre of the firewall

[EVO_S4]

Originally Posted by CC 330i

True, and the stock pieces aren't very pretty, so if the aftermarket came out with fancy polished strut braces, I am sure that some people would definitely buy them. (maybe even me!).

same here,even thou its standard I will most likely get one so that it can make my engine bay looks better

[RichReg]

Originally Posted by jhbodle

I popped the hood (bonnet) of my E90 325i today to show my mate the engine and he immediately pointed out the strut brace that connected the two suspension turrets. I'd never noticed that before! Sorry if everyone already knew this, but none of my previous 3 Series cars had a strut brace, and I thought it was pretty cool that an item that many people put on as an aftermarket mod was now present and correct as standard

It isn't just the "polish" that drives the aftermarket in this regard. Although it is a nice feature and does help tighten up the front, it should be noted that BMW's braces (5 Series & now 3 Series) are hollow, while other aftermarket manufacturer's are solid. They will still sell those with no problem.

Yes, BMW's is a cheapie but, it's better than nothing.

[ward]

Originally Posted by RichReg

it should be noted that BMW's braces (5 Series & now 3 Series) are hollow, while other aftermarket manufacturer's are solid. They will still sell those with no problem.

Yes, BMW's is a cheapie but, it's better than nothing.

I'd just like to point out that a hollow tube is better in terms of strength/stiffness to weight than a solid tube. The BMW design is better than a solid tube, which would just be heavier (although solid tubing would allow a slightly smaller diameter)

[Tierfreund]

Originally Posted by ward

I'd just like to point out that a hollow tube is better in terms of strength/stiffness to weight than a solid tube. The BMW design is better than a solid tube, which would just be heavier (although solid tubing would allow a slightly smaller diameter)

As so often, aftermarket cares more about looks than function

[RichReg]

Originally Posted by ward

I'd just like to point out that a hollow tube is better in terms of strength/stiffness to weight than a solid tube. The BMW design is better than a solid tube, which would just be heavier (although solid tubing would allow a slightly smaller diameter)

Pardon my ignorance but, isn't the whole idea behind a strut brace to reduce flex in the chassis, and thereby improve things like high-speed maneuverability, etc.? If the brace is hollow, wouldn't it tend to flex more than would a solid brace?

[ward]

Originally Posted by RichReg

If the brace is hollow, wouldn't it tend to flex more than would a solid brace?

this is only true if the diameter is the same. A larger diameter, but hollow tube will be stronger than a smaller solid tube.

if you roll a sheet of paper into a tube, you can support a book. If you rolled it so tight that there was no airspace inthe center it couldn't support anything.

it all has to do with moment of inertia, and the farther away you can get mass from the neutral axis the better.

[quackman]

Originally Posted by ward

this is only true if the diameter is the same. A larger diameter, but hollow tube will be stronger than a smaller solid tube.

Well, there's nothing stopping the aftermarket from making a solid tube that has the same or even a larger diameter than the OE bar, thus making it much stiffer. is there?

[ward]

The point is weight, sure you could make a solid tube that was stronger than a hollow one. but it would be HEAVIER, smaller in diameter but much heavier.

a solid tube is NOT the most efficient shape for making a stiff structure, why do you think bicycle frames are hollow?????? Why are roll cages in racecars hollow???

[ward]

on that note, i'm done arguing with high school kids about engineering

[coco]

hey relax man nobody was arguing with you. what you're saying makes sense and it sounds like you know engineering/physics so thanks for explaining.

[xcalibr]

Originally Posted by ward

on that note, i'm done arguing with high school kids about engineering

hahahhahaha... well here's some evidence for everyone.... http://www.pirate4x4.com/tech/billav...terials/21.jpg

you're all/both right. solid is ultimately stronger than hollow (same diameter), but hollow is very advantageous because it weighs significantly less without sacrificing very much strength. You can remove a lot of the middle of a solid rod and still maintain almost all of the same strength... the differernce is almost insignificant --so choosing hollow over solid is a no-brainer.

[RichReg]

Well, I would like to thank both ward & xcalibr for this extraordinary piece of engineering trivia!

And also for saving me the trouble of ever listening to any aftermarket tuners that are trying to sell me a small-diameter, solid strut brace.

[johnfkitchen]

If the objective of the brace is keep the end points from moving away from each other, a solid brace is efficient. It consumes the smallest space while providing good tensile strength. It is not so efficient in bending, twisting or compression (resisting the tendency of the end points to move towards each other). For these, hollow is good.

Now, what problem are we trying to solve with such braces?