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Topic: Leffler accident caused by rf stop falling off
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June 21, 2013 at
12:35:47 PM
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Im not much of a fan of adding 4 long pcs of soft all-thread to my car but here is some ideas I have had for a few years, if the torsion bar mfg. would make the bars about 1/4" longer on each end and put a 1/8 inch hole thru the bar you could put a clip in just like the end of rear axel. Or machine a groove and just put a snap ring on the end of the bars. While there at it they can make the splines shorter so on the backside of the arm and stop they will quit cutting into the bushings.
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June 21, 2013 at
01:35:43 PM
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Reply to:
Posted By: sprint2j on June 21 2013 at 12:35:47 PM
Im not much of a fan of adding 4 long pcs of soft all-thread to my car but here is some ideas I have had for a few years, if the torsion bar mfg. would make the bars about 1/4" longer on each end and put a 1/8 inch hole thru the bar you could put a clip in just like the end of rear axel. Or machine a groove and just put a snap ring on the end of the bars. While there at it they can make the splines shorter so on the backside of the arm and stop they will quit cutting into the bushings.
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This is an excellent idea. I would be completely for a slightly longer bar with a little less spline on the inside. It is like killing two birds with one stone. I would prefer a pin over a snap ring however. Of course that is because I am old and blind and seeing a snap ring hole in the dark to remove it might be difficult, but that is just me. This is something that bar manufacturers should really consider. As for the rest of this, we are not going to prevent ALL potential problems that might result in someone getting hurt or killed, but most of them can be prevented and an effort should be made to do so. Not by sanctioning bodies or the government however. It is time that racers and manufacturers fix their problems and police themselves. It is our responsibility to be safe.
Never hit stationary objects!
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June 21, 2013 at
01:50:20 PM
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Reply to:
Posted By: MoOpenwheel on June 21 2013 at 11:10:05 AM
What does titanium have to do with it? I've seen this happen when the pinch bolt doesn't have enough threads. It torqued down on the shoulder of the bolt before it pinched the bar enough. Cost a friend a couple cars and some pain before they figured it out.
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I'm just guessing that its because ti is so hard and slippery untll its hot enough to glow that there is less friction.
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June 21, 2013 at
01:54:43 PM
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Posted By: sprint7chuck on June 20 2013 at 10:01:00 PM
According to sources at Maxim the right front stop fell off the car causing the accident.The stop was found and the bolt was tight. This is a problem that no one wants to fix. Why dont the sanctioning bodys mandate the use of some kind of retaining system. The fix only costs $50 from Speedway Motors for both front bars. I would like to know if anyone has had this happen to them. This safety concern needs to be addressed before we lose another driver.
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An other item is being made that would replace allthread. It has not been tested yet, but will have Univ. of Iowa test it as to how many pounds it will hold.
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June 21, 2013 at
02:00:39 PM
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I am using the threaded rod set up because that is available today. Another idea i have is to thread the torsion bar and put some kind of bolt with a washer on it. The bolt could also be tie wired for safety.if you are wanting light weight make it out of titanum.
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June 21, 2013 at
03:07:21 PM
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These are all good ideas to alleviate the problem. Would it serve a purpose to know what brand and type of stop it was, and that others are using.
Also, if you or a driver you know is using these, get rid of them.
The greatest knowledge is to know that you know nothing
at all.
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June 21, 2013 at
03:19:41 PM
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Reply to:
Posted By: sprint7chuck on June 20 2013 at 10:01:00 PM
According to sources at Maxim the right front stop fell off the car causing the accident.The stop was found and the bolt was tight. This is a problem that no one wants to fix. Why dont the sanctioning bodys mandate the use of some kind of retaining system. The fix only costs $50 from Speedway Motors for both front bars. I would like to know if anyone has had this happen to them. This safety concern needs to be addressed before we lose another driver.
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How can you publicly say something about buying a part that would have supposedly made this accident not happen? That is shameless for a person to point blame at people saying they didn't buy a $50 part. I have some more words for a person like you but I'll keep them private because this will go nowhere.
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June 21, 2013 at
04:05:31 PM
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Reply to:
Posted By: TA69 on June 21 2013 at 03:19:41 PM
How can you publicly say something about buying a part that would have supposedly made this accident not happen? That is shameless for a person to point blame at people saying they didn't buy a $50 part. I have some more words for a person like you but I'll keep them private because this will go nowhere.
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So he's supposed to keep it to himself or only privately tell a couple of his racer buddies... make sure they buy this $50 part and help prevent a crash, or worse... ?? This thread has over 1,500 views, some of them are likely drivers that lurk on the board. If there's a possible deficiency and there's a way to make these cars safer so nobody crashes, gets hurt, etc... the more people that know the better! jmo..
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June 21, 2013 at
04:08:30 PM
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I know of a design that will prevent torsion arms and stops from ever accidentally coming off, without adding ANY additional parts.....I would love to work with a manufacturer to implement it...
Member of this message board since 1997
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June 21, 2013 at
04:33:35 PM
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What about machining a recess in the bar and redesign the stop so that the torsion clamp bolt is further in on the stop to lock it on the bar.
The greatest knowledge is to know that you know nothing
at all.
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June 21, 2013 at
04:47:13 PM
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Reply to:
Posted By: sprint2j on June 21 2013 at 12:35:47 PM
Im not much of a fan of adding 4 long pcs of soft all-thread to my car but here is some ideas I have had for a few years, if the torsion bar mfg. would make the bars about 1/4" longer on each end and put a 1/8 inch hole thru the bar you could put a clip in just like the end of rear axel. Or machine a groove and just put a snap ring on the end of the bars. While there at it they can make the splines shorter so on the backside of the arm and stop they will quit cutting into the bushings.
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I am not commenting in reference to this particular accident, but why the need to build longer torsion bars to implement this idea. All that needs to be done is cut off .250 your existing torsion tubes, then cut 2 snap ring grooves in your existing bars and your set. 20 minuets per chassis, 8 per bar and $2.00 worth of snap rings and your good to go. I have seen a few teams doing this already. There is no real need to over engineer a simple fix.
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June 21, 2013 at
05:00:26 PM
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http://sports.yahoo.com/news/nj-mechanical-problem-caused-fatal-192729477--nascar.html
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June 21, 2013 at
05:40:49 PM
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I agree,add this to the safety list,contanment seats,blanket for driveline u joint,seat belts,run one season then have them redone or replaced,hans device,newer helmets.i would rather see a race team show up at the races with an open trailer,having spent there money on safety instead of bling.
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June 21, 2013 at
06:14:17 PM
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Reply to:
Posted By: sprint7chuck on June 20 2013 at 10:01:00 PM
According to sources at Maxim the right front stop fell off the car causing the accident.The stop was found and the bolt was tight. This is a problem that no one wants to fix. Why dont the sanctioning bodys mandate the use of some kind of retaining system. The fix only costs $50 from Speedway Motors for both front bars. I would like to know if anyone has had this happen to them. This safety concern needs to be addressed before we lose another driver.
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A retainer is being worked on now that does not use allthread. Might be ready in about 4 weeks. Schroader also makes torsion bars that are a little longer and use a clip or ring similar to piston pin retainer on each end
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June 21, 2013 at
06:16:34 PM
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Reply to:
Posted By: sprint2j on June 21 2013 at 12:35:47 PM
Im not much of a fan of adding 4 long pcs of soft all-thread to my car but here is some ideas I have had for a few years, if the torsion bar mfg. would make the bars about 1/4" longer on each end and put a 1/8 inch hole thru the bar you could put a clip in just like the end of rear axel. Or machine a groove and just put a snap ring on the end of the bars. While there at it they can make the splines shorter so on the backside of the arm and stop they will quit cutting into the bushings.
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Schroader already does this
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June 21, 2013 at
06:46:55 PM
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This message was edited on
June 21, 2013 at
06:52:18 PM by Hannity
In order to fix the problem, we need to better understand root cause. The threaded rod, snap ring, other, are all good ideas, but they ultimately fail to address root cause. If we're serious about figuring out how to keep the stops from falling off, then we need to better understand root cause.
I heard that the stop was tight, but that's not enough. Was the stop machined correctly? Was the stop worn or stretched? Was the bar worn or damaged? What kind of material was the stop made out of? Does the material affect the stops ability to adhere to the bar? Was the teeth on the bar or stop damaged? Was there grease between the stop and the bar? Was there a gap between the stop and the tube? Was the stop under or over tightened? Was there a manufacturing defect? Was the stop made to spec? Why is it always the RF? Are the stop/bar companies performing pull force testing?
I think you get the point...
We can come up with creative bandaid and or work around solutions. Fine... but I wanna know why the stops are falling off! Something is wrong and if we truly want to fix the problem, then we need to better understand root cause.
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June 21, 2013 at
07:15:50 PM
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Reply to:
Posted By: Hannity on June 21 2013 at 06:46:55 PM
In order to fix the problem, we need to better understand root cause. The threaded rod, snap ring, other, are all good ideas, but they ultimately fail to address root cause. If we're serious about figuring out how to keep the stops from falling off, then we need to better understand root cause.
I heard that the stop was tight, but that's not enough. Was the stop machined correctly? Was the stop worn or stretched? Was the bar worn or damaged? What kind of material was the stop made out of? Does the material affect the stops ability to adhere to the bar? Was the teeth on the bar or stop damaged? Was there grease between the stop and the bar? Was there a gap between the stop and the tube? Was the stop under or over tightened? Was there a manufacturing defect? Was the stop made to spec? Why is it always the RF? Are the stop/bar companies performing pull force testing?
I think you get the point...
We can come up with creative bandaid and or work around solutions. Fine... but I wanna know why the stops are falling off! Something is wrong and if we truly want to fix the problem, then we need to better understand root cause.
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Control arms, bell cranks and such (the equivalent of a torsion arm/stop) coming off on aircraft systems has never been an issue due to the inferior design of the spline/arm/stop design used on race cars. Clips, rods ect are nothing but band-aides for a poor design.
Member of this message board since 1997
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June 21, 2013 at
07:49:13 PM
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Hawker,
I don't believe that the design is the root cause.
We've been using torsion bars and stops for a long, long time. Something in the manufacturing process, the metals, the stack up of tolerance, the installation, etc... something is wrong.
We still don't have "root cause". If and when we can identify root cause, then and only then will we be able to ultimately fix the problem...
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June 21, 2013 at
11:06:54 PM
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Reply to:
Posted By: Hannity on June 21 2013 at 07:49:13 PM
Hawker,
I don't believe that the design is the root cause.
We've been using torsion bars and stops for a long, long time. Something in the manufacturing process, the metals, the stack up of tolerance, the installation, etc... something is wrong.
We still don't have "root cause". If and when we can identify root cause, then and only then will we be able to ultimately fix the problem...
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I am a Quality Assurance Manager for a large aviation company, I've also worked on a lot of sprint cars. I "live" and am VERY familiar with root cause analysis and design/process changes to prevent repeat occurrences. The fact is, there is no safety mechanism in the torsion bar/stop/arm design, only band-aides. Sure the occurrences are far and few between, but when it does happen, it is usually catastrophic (Ronald Laney). Sprint car suspensions are under much higher loads than ever, so you can't fall back on "it's been this way with no problems for a long, long time". A simple design change, like the ones we use on all splined aircraft spline assemblies would ensure that another stop or arm would never fall off unless is actually breaks in half. Aviation is a model for everyone to follow. 50 years ago, 70% of all aviation accidents were caused by mechanical failure. Today, nearly 80% is cause by human error. This is from using better designs, processes and materials. Our racing community can learn from this...After all, you use safety wire on your brake calipers, don't you?
Member of this message board since 1997
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June 22, 2013 at
12:15:07 AM
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I just have one question: was Jason Leffler wearing a HANS device? Does anyone know? The YAHOO article mentioned "blunt force neck trama".
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