A search did not reveal anything on this. Has anyone created a device to measure front and/or rear strut tower movement? Seems that all you would need is something like a stress bar but with concentric pieces of tube steel--one connected to each tower--with, say, a pencil led inserted tightly into a whole near the very end of the outer tube. This should leave a line on the inner piece of tube steel (a flat white surface could be painted or stuck on) indicating how much movement has occurred between the strut towers, if any. A similar kind of thing could be done with a sliding tongue-and-groove kind of setup.

 

That would be interesting - you should do it!!

 

Thanks for posting your idea.

For interesting reading try this old thread-
https://www.northamericanmotoring.co...mp;topic=12467

Yfoiler did a static flex test-check out that post.

Interestingly RandyBMC mentioned that with the strut brace installed, the lap times on the track were minimally changed.

 

a simpler and more accurate way is to bolt a tube solidly onto one side, provide sliding support across the car so it doesn't bend under its own weight, and mount a tell tale dial indicator on the opposite side of the car.

flyboy2160

 

Awhile back I was talking with Randy about the benefits of the Strut Tower Brace. He told me that he did some very basic testing be measuring with a pole with dial caliper attached to one end. Jacked the Mini up so that one side was over 1 foot in the air.He said there was no deflection between the strut towers.

 

>>Thanks for posting your idea.
>>
>>For interesting reading try this old thread-
>>https://www.northamericanmotoring.co...mp;topic=12467
>>
>>Yfoiler did a static flex test-check out that post.
>>
>>Interestingly RandyBMC mentioned that with the strut brace installed, the lap times on the track were minimally changed.

Yeah. I remember reading that topic. It just seems to me that before one buys a strut bar, that person would want to see performance results that could demonstrate the usefulness of the product. A simple table would do:
Rear Strut Tower Flex Measurement Table
OPERATION---------FLEX AMOUNT (mm)
<someoperation>----<n mm>

The competition people here would know that the actual operations should be--skidpad, slalom, right hand power slide around 90 degree turn, left hand power slide around 90 degree turn, whatever.

But it seems like the companies selling these bars would have already provided this info in their marketing literature.

 

>>Yeah. I remember reading that topic. It just seems to me that before one buys a strut bar, that person would want to see performance results that could demonstrate the usefulness of the product. A simple table would do:
>>Rear Strut Tower Flex Measurement Table
>>OPERATION---------FLEX AMOUNT (mm)
>><someoperation>----<n mm>
>>
>>The competition people here would know that the actual operations should be--skidpad, slalom, right hand power slide around 90 degree turn, left hand power slide around 90 degree turn, whatever.

Yes, that would be another set of tests to run- some subjective results- how does it feel and some objective tests- how much measurable flex can be detected.

>>But it seems like the companies selling these bars would have already provided this info in their marketing literature.
Several points here- it is not in the interest of manufacturers of strut bars to do the testing to "prove" that their products are more than cosmetic. Since they can sell for $230 each or more and since it is known that in cars with front end flex the addition of a front stress bar is quite helpful then by not providing any test results they leave it open to the buyer to decide. No promises-buyer beware.

If indeed some of the strut bars are not helpful then one would need to sort out which were helpful. I would not assume that all designs are equally beneficial. Also the weights of each bar is different with the titanium bar being the lightest followed by the BMP alumimun bar and then the steel bars. Both materials and design will affect the usefulness of the strut bar-and ultimately the price.

Finally lets assume that the front end of the MINI is quite ridgid. With use over time I would expect some metal fatigue and less rigidity with hard cornering. By adding a strut bar early when the frame is solid might help to slow down noticable fatigue over time and keep things working that much better a year from now. Some MCS owners have already reported quite a bit more rattles and creaks and more body flex with 20,000 miles on their cars.

 

So people are spending real money for devices that have never been proven to benefit the MINI.

What we do know appears to be the following:
-strut bars are conceptually sound and are known to benefit cars that are known to exhibit strut tower flex
-no one, including people who have purchased strut bars, has ever bothered to measure that flex on a MINI
-not many people are interested in finding out if the MINI's strut towers flex and fewer still want results posted on this site
-people who bolt them on say that they're great

 

>>So people are spending real money for devices that have never been proven to benefit the MINI.

 

>>Awhile back I was talking with Randy about the benefits of the Strut Tower Brace. He told me that he did some very basic testing be measuring with a pole with dial caliper attached to one end. Jacked the Mini up so that one side was over 1 foot in the air.He said there was no deflection between the strut towers.

Randy seems to be an honest guy, and he's right. Strut bars on most newer cars are not needed. And cars that truly need them are probably already bent so they won't fit anyway.They are merely eye candy, or an engine theft deturrent. Think of it as the "engine club"

 

Heh.

This is both hilarious and sad at the same time.

I disagree that it looks cool in the engine bay. I think it just looks like a PITA--something I would want only if it actually improved performance. In the boot it's even worse--bisecting the storage area when the seats are folded down. Ridiculous.

 

I was recently reading an article in SCC mag, where someone built a jig and tester to measure chassis flex for a custom car - and, his findings were somewhat interesting on the Ultima GTR, a car purpose built to provide McLaren F1 performance at a fraction of the price.

Initially, he found 3500 ft/lb per degree of chassis twist, which is about as stiff as a stock Miata. They braced some strategic locations up, adding some 38 pounds of metal, and got up to 9500 ft/lbs per degree. That seems like a HUGE difference, and it is. Of course, this is on a tube chassis car...

I posted a link to a study that someone had done using a CAD model and some other modeling software on a generic unibody car, and he found that the front strut brace did make a considerable difference in rigidity. Actually, a VERY considerable difference...

Personally, for me the verdict is still out. When I look at the unibody construction of my MC, it looks quite rigid to me - however, I am NOT a chassis engineer. I have no idea what BMW was shooting for on rigidity, chassis twist, or the like. I haven't seen the drawings, nor the measurements they originally did - has anyone else? Does anyone really know if strut braces help or not?

I have still seen no convincing proof for either side... while I trust Randy's evaluation of parts, I don't think his test is quite robust enough to provide any significant conclusions. ALL unibody cars have some chassis twist, period. Consider the massive loads the car is being subjected to during hard cornering, and there's simply no way that there isn't 'any' movement. There would be some - the question is, 'How much'? Jacking the car up on one corner doesn't subject it to the loads that hard cornering would...

If a vendor actually went the extra mile to do a study, possibly using engineering students from a local university, and the proof was conclusive, I'd think their products would fly out the door...

 

I wasn't much for the jacking test either. I'd like to see some real tests conducted--escpecially before I go and bolt some PITA strut bars into my car.

In the mean time, I'm about three quarters of the way through the fabrication of a rudimentary gauge for the rear.

 

Good morning.....

As an avid road racer a strut tower brace is a no brainer, all my race cars I ever had or road raced had a STB.
Here in SoCal my favourite race track is Willow Springs Raceway, a very fast track with some incredibly fast
sweepers wich I can reach 120mph easy,without the STB, I will wash out the front end of the car (understeer)
making it feel some what sloppy and not very precise, with the STB the car feels more precise allowing me to place the car excactly where I want to on the track with less understeer. I realise that some one who does not race on track either road racing or Auto-x will propably never reach the limit where the STB is needed and for you it's more of a decoration of the engine compartment then a necessity.

I would propose that we make a poll asking people who road race their Mini if they have an STB in their vehicle.
My take on this is.......if you roadrace, you use a bar....... period.

I use the H-sport bar.....road race tested to perfection:D

peter horvath
562-712-3270

 

>>I posted a link to a study that someone had done using a CAD model and some other modeling software on a generic unibody car, and he found that the front strut brace did make a considerable difference in rigidity. Actually, a VERY considerable difference...
>>

that study looked like a student class paper. unless you know all the details of the model, i don't think it should be used as evidence. my comments about the pilo rear strut bar still apply: before anybody claims it will work on a mini, let's see some free body diagrams, some measured deflections, or a fea model of the car.

a generic model or an analysis of a different chassis, such as a flexy flier miata, don't count. and to repeat what someone else said: why doesn't nuzzo motorsports use them?

flyboy2160

 

I know I'm going to catch flack for this, but did anyone
else notice that the consumers are proposing some
fairly easy to setup testing to see if a strut-tower makes
ANY difference, and a vendor, instead of saying "Yeah, we'll
do that for you consumers" says let's take a POLL and
ask how many people use one????????

To put my money where my mouth is, I will build a jig to measure
the deflection between the strut towers before and after
installation of a strut-tower brace if someone else volunteers
to buy or get a loaner brace, and run their MINI on a track
somewhere in Minnesota.

Maybe someone can ask several vendors for loaner braces.

 

See this thread:

http://groups.google.com/groups?q=st...com&rnum=1

 

Ohh Trippy we shall meet again

If you read my posting I said roadracing not street driving. Theres a huge difference in chassis stress between a street driven car and and a car that sees road racing use. If you ever road raced you realized that a competiton tires addehsive
properties are much higher putting more stress on the chassis then even the stickiest street tire on the market.
As I wrote somewhere else I have roadraced for over 20 years and every car I had used had an STB unless it was
a tube chassis then bracing was allready welded in.

And again, for street use you will not see much use for STB but at the track it will help. For that rear brace that
Pilo is selling I do not know as I HAVE NOT HAD A CHANCE TO TEST IT!!!!!!


Peter horvath
562-712-3270

 

>>that study looked like a student class paper. unless you know all the details of the model, i don't think it should be used as evidence. my comments about the pilo rear strut bar still apply: before anybody claims it will work on a mini, let's see some free body diagrams, some measured deflections, or a fea model of the car.
>>
>>a generic model or an analysis of a different chassis, such as a flexy flier miata, don't count. and to repeat what someone else said: why doesn't nuzzo motorsports use them?
>>

Yes, it was a student paper - the details of the model were in that paper and plainly visible in the renderings. Even so, it was interesting...

Like I said, someone needs to do all this for the MINI - on that we agree.

I also still say regardless of the design, ANY unibody vehicle will flex.

 

I'm a long-time lurker, infrequent poster. I doubt that there will ever be enough proof to satisfy the majority of posters here.

Let a vendor say that they have proof that the stb helps and watch folks jump on him like a pack of hyenas on a waterbuffalo carcass.

The stb makes sense to me, racers like them and they're relatively inexpensive.

I'm in.

 

>>If you read my posting I said roadracing not street driving. Theres a huge difference in chassis stress between a street driven car and and a car that sees road racing use. If you ever road raced you realized that a competiton tires addehsive
>>properties are much higher putting more stress on the chassis then even the stickiest street tire on the market.
>>As I wrote somewhere else I have roadraced for over 20 years and every car I had used had an STB unless it was
>>a tube chassis then bracing was allready welded in.

Peter,
Thanks for your posts on this. It makes sense to me about the tower brace making a difference at high speeds on a track. Our local track doesn't really allow for that sort of speed, just a bit on the straightaway. In street driving and some track my BMP strut brace isn't really detectable to me. Others can tell the difference. I think it all depends how hard you push your MINI.

If you install a front tower strut brace in a new MINI before all that stress from driving fatigues the chassis, don't you think the chassis will hold up to hard driving a bit longer than without the added brace? Same for the rear stut brace? Just a thought. I know metal will fatigue over time.

 

Minihune you are absolutely correct there's always metal fatigue from hard driving, either on track or on a rally
course. annything you can do to stabilize the chassis is helpfull.
If you would look at a sophisticated chassis builder, he will start with a bare shell, weld each seam in the chassis
to make it stronger then the roll cage goes in with a triagulated design, allowing almost 0% chassis flex.
Part of the cage structure is the strut tower, tying them toghether for superior stability.

Peace And happy New Year..... :smile:

peter horvath
562-712-3270

 

As you know, the suspension consists aof a lot of links whick have to flex for compression and steering movements.
for the front:
-upper strut bearing mount: this is a rubber biscuit held in a fender mounted frame and can flex with strut movement under steering articulation. they can also mover towrd each other durring hard loading, affecting the camber. the strut brace might stiffen the fender, but it does nothing for the biscuit.
-control arm rubber bush: a flexible mount designed to accomodate roation of the control arm under compression loads, but because it is compilant, it also allows lateral movement which will affect the toe setting under braking and acceleration and can lead to wheel hop, steering and tracking cjhanges, etc
-steering rack rubber bush: one end is held by a compliant bush (passenger side). under hard loads, this can compress and affect the toe. For example, you jam on the brakes, your sticky tires biting hard, gripping the steering wheel, and find the PS tire wants to turn right a bit; you let off the brakes, gas it and just the opposite occurs, since you are loading the bush the other way.

the point is there are several elements to consider in tightening up the front suspension that have considerably more influence than the tower brace. I have changed out my upper biscuits for adjustable camber plates with spherical ball joints and just this holiday, dropped the subframe and am replacing the soft rubber with mre compilant polyurethane for the control arms and steering rack. I am also doing the same for the rear control arm bushings. This is not a job for the faint of heart, but no doubt every race car that M7 has driven, for example, has these mods.

 

jlm, what are your thoughts on how these changes affect day to day driving? Harsher? Crisper? Or totally unnoticeable until you really get on it?

 

>>As you know, the suspension consists aof a lot of links whick have to flex for compression and steering movements.
>>

jlm,
thanks for an excellent analysis and writeup. i agree 1000% and made the same, albeit generalized, remark about the bushing movement with regard to pilo's rear strut bar.

and i'm still waiting for somebody's free body diagram to show how the lateral cornering loads get to a lateral load at the top of the shock towers...

flyboy2160