I would have to strongly disagree there. Granted, I don't work in the chassis area for an OE, but I do for engine components. Quite simply, the aftermarket just doesn't have any idea how to properly validate a component (or the resources to do so) before putting it out in the marketplace. An OE would run over a hundred vehicles through durability testing you can't replicate with your car (on track or the road) as well as put the part through FEA and NVH testing the aftermarket just can't afford. The result is an aftermarket designer almost always will have to rely on benchmarking of other components he's built before or try to perform his own "durability test" which will usually include a couple of friends' cars that race and maybe his own race car.

In the end you're relying on an aftermarket company's experience in building similar components for other cars (and learning from those experiences) when you select them for use on your car. I have good faith in companies like Suspension Techniques, LG, etc but when they come out with a new component for a new car don't ever think it's been durability tested and validated like the component you're taking off your car to begin with.

In the case of a k-member where the only real selling point is maybe some additional header clearance and a weight reduction, I just don't think it's worth it. I'm using Global West upper arms because they gave me more favorable suspension geometry, have been on the market for years with great reviews, and coincidentally are built beefy enough they actually weigh more than my stock uppers. I'm still using my stock lowers because I have no reason to change. Until I see a k-member on the market with a good track record, and a good performance advantage (other than just weight) I have no plans to put one on my car. I do have hopes for LG's unit, but have stopped trying to ask him when it will be ready.

 

Having looked at a BMR K-member and the stocker
up close, today, there's one big difference - the
stocker is a continuous sheet of steel, stamped,
while the BMR is tubes and smaller stampings,
welded. A weld -could- be as strong as virgin
material it connects, but that's not the way to
bet. No freakin' way that stamping is going to
decide to separate from itself.

I'm pretty sure there's some poor bastard down
in the bowels of GM who did in fact engineer the
hell out of that stamping, and made it so heavy
just to obtain the 99.99% confidence that nobody
would ever sue them over it (successfully).

Maybe taking a hole saw to it would be a better
lightening approach than substituting a new piece.
You could lose a lot of that stamping before you
started to concentrate stress like is in the tube
constructed pieces.

I know for sure that these aftermarket weldments
could be better designed. Use of saddle fittings
(like they do on bicycles) or running the tube
through both sides of the arm "channel" and
double-ring-welding would greatly improve the
stress limits. I think the mechanical analysis
tools the Big 3 apply are out of reach for some
welding shop making a hundred pieces a year
for hot rodders. So are hotshot engineer salaries.
At $379 a pop, retail, better not be more than an
hour's worth of certified welder labor in there
either.

Strong and beefy in the tubing and the sheet
stock is not the question, though it's what draws
the attention. It's totally down to the weld quality
which is hidden behind the shiny powdercoat and
you'll never get a chance to know, until that
chuck-hole provides you your impact toughness
test.

 

I don't see why everyone is jumping on BMR's ***. I don't see how any LIGHTWEIGHT k-member could be stronger than the OEM piece. It's just not physically possible unless it's a cast piece of titanium or something. It's been said before, lightweight k-members are not to be daily driven. So when a weld breaks after a year and a half of daily abuse, I don't think there should be this many flames. Yes it could have caused a serious accident, but so could driving on ET Streets, or using N2O.

When we mod our cars in any way we're raising that risk factor a bit. If you want parts that don't break, don't mod your car. Like said above, it going to be hard for a mom & pop shop to have the resources to design and produce a piece that's not only lighter and smaller, but stronger than an OEM peice.

I applaud BMR for replacing it at no cost. How many other businesses of any type would replace something for free after a year and a half of use?

 

Racehead:
No, me saying its been on the car for a year and a half wasn't an example of quality at all. It was showing that, yes there have been problems but when I was thinking about and finally ordered the K-member, I couldn't find one problem with BMR's. Plus, almost every post I read shunned the PA and suggested the BMR. Sorry about the "wise ***" comment, I did think you were attacking me.

Mitch:
That's the exact weld that broke on my K-member, except it was the driver side (that looks like the pass. side). Supposedly that's the part the re-designed.

Angst911:
"This additional weight reduction allows us to use larger diameter tubing and thicker mounting plates for additional strength over the competition. This means that you can use the k-member for street use, road race, autocross, or drag strip use without worrying about long term fatique." and "without compromising strength or driveability!" Taken directly from the BMR site. Not knocking BMR and saying they are lying, but your saying that after a year and a half I shouldn't be surprised?!

LS1blackZ28:
I didn't post this to flame BMR. I've been more than happy with thier parts and service up until now, zero problems. I posted this to get feedback on what I should do and how I should take care of this. But like copied and pasted above in bold red, they say it can be used for street without worrying about long term fatigue and without compromising strength or driveability. Now if you think a year and a half is "long term", then I see what your saying. But I don't think it's long term at all.

 

Excellent, excellent post, Mike. Spot on target. There are just too many enthusiasts out there who are really good welders thinking they can get a piece of the pie.

The points you raise about testing and validating is the EXACT reason why I am sold on LGMs components. Lou designed, built and tested the components in his catalogue during his years running a 4th gen Camaro to 3 World Challenge championships.

While it might not be DOT type certification and validation, it's certainly a tested design.

For those who are happy with your particular brand of suspension components, whatever it may be, that's great. I'm glad for you and hope you have many miles and years of uneventful service from them. All we can do is share the results from our own experiences.

 

94bird,
Your points are well taken. As an engineer in the aerospace industry I know exactly what you describe about testing and validation. I experience it ad nauseum. I think racehead's point, though, was that with an OEM piece there is a compromise. OEM's rarely put factory headers on a car (for example) due to noise and cost issues. Of course, that's one of the most commonly replaced aftermarket components. Same can be said for exhaust systems, intakes, etc - they are compromises. Hell, most of my factory exhausts used tubing likely on par in wall thickness with BMR's K-member Yet, I still chose to replace them. Now if my proclaimed stainless steel catback or my coated headers fell apart in a year I'd be pissed and rightly so. IMO, there is a HUGE responsibility on the part of the aftermarket to properly engineer parts - especially major suspension pieces such as a K-members - before ever offering them for sale to the well-intentioned, but often naive public. Track use, street use, or whatever, not doing so is simply unethical.

 

Sniper, I wasn't directing this to you. I have no problems with what you said, I completely agree. I was talking to the people that are jumping on BMR's *** because a weld broke.

 

Though, this is not the first thing we've seen break that came from the BMR shop. That is part of the issue. I've never seen a Hotchkiss LCA or PHB break (though I don't like poly/poly parts), I've never seen a Lakewood LCA fail (even though they seem to be cheaply made), I've never seen an LG Motorsports part break, etc. This trail of broken parts seems to lead to BMR's doorstep. Now, maybe it's because they sell 12 times as many parts, I don't know. I know my BMR stuff was cheaply made and was pulled from my car after a year (with rod ends that were "toast"). I'm not slamming BMR (though I am "done" with their parts myself), I'm just stating that they seem to have most of the aftermarket suspension parts failures attributed to their parts. I know of at least 1 and maybe 2 PHB's, 2 K members, 1 poly/poly LCA that just "split", and that is just off the top of my head. I can't think of another company that I can produce a single failure for (ok, I think there were some PA K-members that had issues, but I'm not sure).

I don't hate BMR, I just wish they would make some changes to their designs in the interest of safety. I fear that one of these failures will cost someone dearly and it is not worth it. I understand that there is a demand for inexpensive parts, but if one fails and someone is seriously injured or killed, was it really worth saving $50?

I just have safety concerns and don't want to see anyone injured.

By the way, I used to work in general avaition. A weld failing is not considered normal or acceptable when working on an aircraft. I am not sure it is really ever acceptable, but why shouldn't we hold our cars to standards that are just as high. If the factory weld on the K-member failed, everyone would "go nuts" bitching about GM's quality. Right?

My thoughts.

 

Gotcha!!

 

This is a great example and makes you think, really makes me think because I just got off a plane a few hours ago from a 1200 mile trip. A failure on a large aircraft such as a 747 could take hundreds of peoples lives. I know our cars arent a 747 but shouldnt our suspension parts or any parts be approved of before shipping, such as a plane is before taken off? My post might not make much sense, but the point was that the quality of are items should be treated just as it is that important.

Now, here is my thoughts on BMR. Have you noticed lately that EVER online sales store (thunderracing, LMPerformance etc, etc) all carry BMR products, its like gold to them. Those are just 2 out of I am sure a hundred. Also it seems every new suspension ethusiast that signs this forum has a first post about getting BMR suspension items, BMR boxed or tubular sfcs seems to be the most common post. I am not ragging on any of you newer guys, I myself only new of BMR when I started getting interested in the suspension of our cars. So my thoughts are this, BMR is producing SO many items to send each supplier and feel each sell that the quality has gone down. Instead of running 50 sets of lower control arms as they most likely did when they started they are now running 1000's. Therefor there quality has gone down it seems. Is this ok, I dont think so at all. But thats why I feel all the problems. It seems most of the components breaking arent even under stress, such as the control arm breaking as pulling into a parking lot (this happened to a Impala I think). This means most likely this had a defect before it even left the shop.

Theres some of my thoughts on this

 

Well if BMR and PA have had trouble with k-members (being that they are the only aftermarket companies that produce them for LS1's, except for AJE) maybe it's more of a design issue than a build quality issue. Yes, I have seen a few BMR suspension failures, but like you said, they do sell more than any other manufacturer.

I'm not defending BMR here, just not agreeing with all the flames they're getting. That's like someone getting in a wreck while driving on ET Streets, and everyone jumping on Mickey Thompson's ***, because they're supposed to be drivable on the street. We take risks when buying aftermarket pieces and no product is 100% safe.

 

Another thing to keep in mind is inspection. If these were race cars with welded tube frame chassis they'd have to be inspected at regular intervals. Commercial airplanes are checked at regular intervals - often to the point where the whole tube is gutted and all areas checked for corrosion, fatigue, etc. IMO, a large sub-structure such as a K-member fabricated of welded members should also be subject to routine inspection. I know that the manufacturers of these parts generally make no mention of this kind of thing (with the exception of LG, in my experience) nor does the average enthusiast have the expertise to make such checks. But I see no reason that routine inspection might not turn up a problematic weld before it fails altogether.

[rant]

A PROPERLY DESIGNED piece can do all sorts of things. The factory piece was properly designed for the criteria that the designers and the OEM felt appropriate. An aftermarket piece can just as easily be designed for different criteria. Can somebody with no engineering experience weld up a good piece that meets all these criteria? Doubtful. There are a number of good FEM packages that can be had relatively cheaply (a company building and designing suspension parts, whose failure could be deadly, might want to strongly consider something like this) and IMO is a valid substitute for extensive track testing (supplemental to testing, of course, would be preferred). Personally, if it were me I would NEVER release a design to the public that I hadn't thoroughly tested. People are jumping on BMR's *** because their **** seems to be making a habit of breaking under far-from-unusual circumstances.

Also, for the record, titanium is no stronger than a good quality steel. It just has a better strength-to-weight ratio and tends to hold its strength better under extreme temperatures.

As posted above, the BMR site clearly states that these can be used for daily driver duty. A good quality weld can last a lifetime.

No disagreement there. The only caveat is that many enthusiasts aren't so well versed that they can tell when "can be used for daily driver duty" actually means track-only. Not that you'd want the damn thing to fail as you cross the traps at 120mph either, though, right?

No its not hard, its just time consuming and more labor intensive besides being good business practice. These are the kinds of things to consider when you compare a $200 part to a $100 part. Remember, more often than not things are cheaper for a reason.

Its the least they could do.

[/rant]

 

They sell more so some failure is acceptable? What?

And, you are right ... no product is 100% safe. So buy cheap and hope for the best, right? You use WalMart generic motor oil in your car, right? Same logic ...

 

I too have a BMR broken K member. maybe it was the third one they were talking about since you guys only listed two. But i'm a welder so i fixed it myself.

 

More often than not is correct. Some of the smaller companys have the resources to test this stuff as well as sell it a little less expensive.

 

[QUOTE=trackbird]I've never seen a Lakewood LCA fail (even though they seem to be cheaply made)QUOTE]

Very true, some of lakewoods stuff is flakey, but your right I have never heard of one breaking either.

 

Since you're an engineer I'm sure you know that software can be had relatively cheaply but the knowledge to use it is a completely different story. For instance, how do you properly mesh the part and what loads do you place on it? What kind of cycle do you put it through? What is an acceptable factor of safety?

These are the kinds of questions that are only answered through experience, and not just from books in college. If BMR hires someone with the resources and knowledge to help them improve their designs I can guarantee you their prices will go up. How close do you think their prices would be to LG's if that happened? A good consulting engineer gets at least $100 per hour. That adds up.

 

well I'm glad I got some people's opinions rolling... but honestly, all the aftermarket stuff I have on the car, I expect it to perform better, but I don't expect it to last like OEM parts. I realize that with performance comes more maintenance, which also means inspection. I inspect my rotors for cracking, I expect to replace the bearings in the 12 bolt more often than a 10 bolt (well, assuming the 10 bolt didn't break), I expect to have to rebuilt the motor more often than a bone stock motor. The point is, aftermarket stuff is meant to make the car perform better and such, but 99.9999% of the time, it is not designed with longevity in mind.

 

wow! i was looking to purchase the BMR k-member for my '89 so the a/c compressor would clear on the LS1 swap but now i'm not so sure about that.......

 

A welder can be had pretty cheaply as well, but the skill to use one only comes through experience. Ultimately, the question is do you feel comfortable saving a few $$ and by doing so decreasing your safety? Is the average consumer even aware that they're making that tradeoff?