Kla strut brace
11-12-2003, 11:14 PM
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Kla strut brace
I just recieved my KLA strut tower brace today and have to say I am a little dissapointed. The bar is nicely made but very, very flimsy. You can grab this thing and bend it like a bow. Maybe i should have shelled out and purchased the welt...
11-12-2003, 11:19 PM
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I really like the look of the KLA but I had wondered about the strength. Maybe I'll go for the Brey-Krause, which looks the same but is about three times as thick.
11-13-2003, 11:02 AM
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This is a response based on a question about the strength of our bar.
That is a very good question. When I designed the bar I did take the shear load and potential flex of the bar into account. I would like to address each of the components separately. The flexing and the resultant stress loads of the strut towers are a function of the ultimate side loading on the tires before they break loose and how that stress is placed into the shock tower. I took into account the geometry of the front end and the bending moment of the tower and determined the expected tension and compression on the bar, joints, ends and the hardware.
The center bar and end joints are not in a shear or bending load. As the shock towers try to flex in and out the joints and bar are in either tension or compression. I have selected the material and thread design that will have an ultimate tensile strength that is over 20,000 psi or 20 ksi using the SI unit of measure. This is many times the maximum tensile load that the tires can exert onto the towers. The bar does not flex because it is not in a bending moment. It is fully compression and tension.
The mounting plate was designed to also carry many times the calculated stress. If you look at the design, the mount base and the vertical member are welded in suck a way as to carry the shear load down the full length of the weld. In other words, the shear loading is carried over the entire length of the weld an in the longitudinal axis of the vertical member. The material that I selected for these parts has very good shear and tensile strength but also have great weld characteristics. When calculating the shear strength of this part, even taking into account the slight reduction in strength in the weld heat effected zone (HAZ), the ends shear and tensile far exceed the strength needed to maintain the front end geometry of the car without failure. According to the United States Steel Corporation (USS) Handbook Of Plate Products, the material we selected has an ultimate strength if 24,000 PSI or 24 KSI using the SI measure. The smallest area of material under load is approximately ½ resulting in that area maintaining a minimum of 12,000 pounds of ultimate strength. The material is also very ductile and therefore not susceptible to vibration cracking.
The last area of consideration was the selection of a 3/8 grade 8 bolt. The bolt is the smallest part that is in shear loading. In reviewing the ASTM table for grade 8 bolts, the 3/8 bolt has a body shear strength of 9,940 Pound Feet (lbf) of strength. The threads are not in shear so their strength was not calculated. With the placement and selection of the bolt, its shear strength far exceeds the calculated stress.
Thread Size Tensile Strength Yeild Strength (0.2% offset) Shear Strengtht (lbf) Tightening Torque
ksi lbf ksi lbf Body Thread lbf.ft Nm
1/4 - 20 UNC 150 4770 130 4130 4420 2860 11.7 15.9
5/16 - 18 UNC 150 7860 130 6810 6900 4720 24.2 32.8
3/8 - 16 UNC 150 11630 130 10080 9940 6980 42.9 58.1
In final summation we should look at the car as a whole. The car has a total weight of 3115 pounds. The cornering loads are primarily maintained within the structure of the cars thin sheet metal frame. This camber truss is designed to be a secondary stiffening devise to hold the loads that the frame cannot maintain. The weakest part of the truss can maintain over 9,940 pound feet of loading. In reality the weakest part of the cars front end is the sheet metal that is used to build the shock towers and they do not seem to have many problems.
In the final analysis we could lift the weight of four 944s off the ground and suspend them without a fear of failure. I hope this answers you question about the design methodology and strength.
My background is all-aerospace. The flight controls on many airliners use the same theory of putting bars, like our center bar, in compression and tension. The design parameters I used in selecting the material is the same as is used on a commercial airliner. In other words this bar has the same strength as does the push-pull tubes on the aircraft the carry passengers for every airline in the world. I am very aware of how to design lightweight components that will have the strength (plus a 150%) safety factor to carry the stresses. Also, we have several bars being used by PCA racers (full race prepped cars) with no problems. They like the bars because of the strength and weight savings.
Finally keep in mind, if you don’t like the bar send it back for a full refund.
Ken
That is a very good question. When I designed the bar I did take the shear load and potential flex of the bar into account. I would like to address each of the components separately. The flexing and the resultant stress loads of the strut towers are a function of the ultimate side loading on the tires before they break loose and how that stress is placed into the shock tower. I took into account the geometry of the front end and the bending moment of the tower and determined the expected tension and compression on the bar, joints, ends and the hardware.
The center bar and end joints are not in a shear or bending load. As the shock towers try to flex in and out the joints and bar are in either tension or compression. I have selected the material and thread design that will have an ultimate tensile strength that is over 20,000 psi or 20 ksi using the SI unit of measure. This is many times the maximum tensile load that the tires can exert onto the towers. The bar does not flex because it is not in a bending moment. It is fully compression and tension.
The mounting plate was designed to also carry many times the calculated stress. If you look at the design, the mount base and the vertical member are welded in suck a way as to carry the shear load down the full length of the weld. In other words, the shear loading is carried over the entire length of the weld an in the longitudinal axis of the vertical member. The material that I selected for these parts has very good shear and tensile strength but also have great weld characteristics. When calculating the shear strength of this part, even taking into account the slight reduction in strength in the weld heat effected zone (HAZ), the ends shear and tensile far exceed the strength needed to maintain the front end geometry of the car without failure. According to the United States Steel Corporation (USS) Handbook Of Plate Products, the material we selected has an ultimate strength if 24,000 PSI or 24 KSI using the SI measure. The smallest area of material under load is approximately ½ resulting in that area maintaining a minimum of 12,000 pounds of ultimate strength. The material is also very ductile and therefore not susceptible to vibration cracking.
The last area of consideration was the selection of a 3/8 grade 8 bolt. The bolt is the smallest part that is in shear loading. In reviewing the ASTM table for grade 8 bolts, the 3/8 bolt has a body shear strength of 9,940 Pound Feet (lbf) of strength. The threads are not in shear so their strength was not calculated. With the placement and selection of the bolt, its shear strength far exceeds the calculated stress.
Thread Size Tensile Strength Yeild Strength (0.2% offset) Shear Strengtht (lbf) Tightening Torque
ksi lbf ksi lbf Body Thread lbf.ft Nm
1/4 - 20 UNC 150 4770 130 4130 4420 2860 11.7 15.9
5/16 - 18 UNC 150 7860 130 6810 6900 4720 24.2 32.8
3/8 - 16 UNC 150 11630 130 10080 9940 6980 42.9 58.1
In final summation we should look at the car as a whole. The car has a total weight of 3115 pounds. The cornering loads are primarily maintained within the structure of the cars thin sheet metal frame. This camber truss is designed to be a secondary stiffening devise to hold the loads that the frame cannot maintain. The weakest part of the truss can maintain over 9,940 pound feet of loading. In reality the weakest part of the cars front end is the sheet metal that is used to build the shock towers and they do not seem to have many problems.
In the final analysis we could lift the weight of four 944s off the ground and suspend them without a fear of failure. I hope this answers you question about the design methodology and strength.
My background is all-aerospace. The flight controls on many airliners use the same theory of putting bars, like our center bar, in compression and tension. The design parameters I used in selecting the material is the same as is used on a commercial airliner. In other words this bar has the same strength as does the push-pull tubes on the aircraft the carry passengers for every airline in the world. I am very aware of how to design lightweight components that will have the strength (plus a 150%) safety factor to carry the stresses. Also, we have several bars being used by PCA racers (full race prepped cars) with no problems. They like the bars because of the strength and weight savings.
Finally keep in mind, if you don’t like the bar send it back for a full refund.
Ken
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11-13-2003, 11:45 AM
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My problem with the bar is the steel end mounts that don't fit the sheet metal at the shock tower. I will have to reduce the size of the base of the part so that is will seat on the lowest portion of the strut tower. Specifically, the base of this piece is too wide on the engine side of the strut tower.
11-13-2003, 02:50 PM
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How far is the brace bottom from seating? On some cars that gap between the bottom of the bracket and the tower top has a gap of 1/32" or less before the bolts are torqued. On most cars this will seat properly when the bracket is installed. First you might try torqueing the bolts the 14 lb/ft using a cross pattern. Put the 4 nuts down by hand the lightly tighten each of the nuts in a cross pattern, bring then to 10 lb/ft of torque in the cross pattern and the to 14 lb/ft. If that does not seat the bracket then, if you want, you can draw with a sharpie the area that is not fitting and send the bracket to me. I will modify the bracket to fit and have it re-plated and ship it back. I will also pay shipping both ways. If you don’t want to try these we can refund your money and I’ll pay to have the bar shipped back.
Let me know what you want to do.
Ken
Let me know what you want to do.
Ken
11-13-2003, 03:14 PM
#10
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Dave,
Let me add...
This was noticed in the very early versions. When did you purchase yours? We've made a couple of changes since then. If you possibly have an early version, just send them back and I'll exchange them. Please email me and we'll work it out.
Let me add...
This was noticed in the very early versions. When did you purchase yours? We've made a couple of changes since then. If you possibly have an early version, just send them back and I'll exchange them. Please email me and we'll work it out.
11-13-2003, 03:46 PM
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Walgreens,
If you don't like it please send it back and we will refund you your $ including what you paid for shipping to get it. I'll pay the shipping back. All we really want are happy customers. You MUST feel like you got your $ worth or we are not happy. If we didn't make it right we would not be ethical. let me know how you want to handle it.
Ken
If you don't like it please send it back and we will refund you your $ including what you paid for shipping to get it. I'll pay the shipping back. All we really want are happy customers. You MUST feel like you got your $ worth or we are not happy. If we didn't make it right we would not be ethical. let me know how you want to handle it.
Ken
11-13-2003, 04:28 PM
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I bought it last spring, maybe february even, and never got around to trying to install it until a couple weeks ago. The piece is definitely not going to seat no matter how much torque I put on it, it sits about 1/4" plus above the shock tower. I will send them to you, with what I think would be the right shape marked with a marker, but I usually get close and need to keep cutting/grinding to fit something like this. I certainly in no way meant to imply that the guys at KLA are anything but standup businessmen and have other products they made and will continue to buy their stuff. I never tried to call them about the strut brace either, I was just too busy until recently, so my bad, not theirs. Thanks for your quick and thoughtful response Ken, I will try to get those out this week.
P.S. thanks for coming up with the adjustable end links for the rear bar, I was going to try to make a pair myself over the winter, but installed your version two weeks ago. On my wish list is a similar product to take the rubber out of the m030 bar mounts, not just the center two body mounts where I put the racer's edge delrin pieces, but the end links too. The movement requred due to the shape of the bar make would seem to make simple, inexpensive solutions unlikely, however.
P.S. thanks for coming up with the adjustable end links for the rear bar, I was going to try to make a pair myself over the winter, but installed your version two weeks ago. On my wish list is a similar product to take the rubber out of the m030 bar mounts, not just the center two body mounts where I put the racer's edge delrin pieces, but the end links too. The movement requred due to the shape of the bar make would seem to make simple, inexpensive solutions unlikely, however.
11-13-2003, 05:06 PM
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Originally posted by Ken From KLA Industries
This is a response based on a question about the strength of our bar.
That is a very good question. When I designed the bar I did take the shear load and potential flex of the bar into account. I would like to address each of the components separately. The flexing and the resultant stress loads of the strut towers are a function of the ultimate side loading on the tires before they break loose and how that stress is placed into the shock tower. I took into account the geometry of the front end and the bending moment of the tower and determined the expected tension and compression on the bar, joints, ends and the hardware.
The center bar and end joints are not in a shear or bending load. As the shock towers try to flex in and out the joints and bar are in either tension or compression. I have selected the material and thread design that will have an ultimate tensile strength that is over 20,000 psi or 20 ksi using the SI unit of measure. This is many times the maximum tensile load that the tires can exert onto the towers. The bar does not flex because it is not in a bending moment. It is fully compression and tension.
The mounting plate was designed to also carry many times the calculated stress. If you look at the design, the mount base and the vertical member are welded in suck a way as to carry the shear load down the full length of the weld. In other words, the shear loading is carried over the entire length of the weld an in the longitudinal axis of the vertical member. The material that I selected for these parts has very good shear and tensile strength but also have great weld characteristics. When calculating the shear strength of this part, even taking into account the slight reduction in strength in the weld heat effected zone (HAZ), the ends shear and tensile far exceed the strength needed to maintain the front end geometry of the car without failure. According to the United States Steel Corporation (USS) Handbook Of Plate Products, the material we selected has an ultimate strength if 24,000 PSI or 24 KSI using the SI measure. The smallest area of material under load is approximately ½ resulting in that area maintaining a minimum of 12,000 pounds of ultimate strength. The material is also very ductile and therefore not susceptible to vibration cracking.
The last area of consideration was the selection of a 3/8 grade 8 bolt. The bolt is the smallest part that is in shear loading. In reviewing the ASTM table for grade 8 bolts, the 3/8 bolt has a body shear strength of 9,940 Pound Feet (lbf) of strength. The threads are not in shear so their strength was not calculated. With the placement and selection of the bolt, its shear strength far exceeds the calculated stress.
Thread Size Tensile Strength Yeild Strength (0.2% offset) Shear Strengtht (lbf) Tightening Torque
ksi lbf ksi lbf Body Thread lbf.ft Nm
1/4 - 20 UNC 150 4770 130 4130 4420 2860 11.7 15.9
5/16 - 18 UNC 150 7860 130 6810 6900 4720 24.2 32.8
3/8 - 16 UNC 150 11630 130 10080 9940 6980 42.9 58.1
In final summation we should look at the car as a whole. The car has a total weight of 3115 pounds. The cornering loads are primarily maintained within the structure of the cars thin sheet metal frame. This camber truss is designed to be a secondary stiffening devise to hold the loads that the frame cannot maintain. The weakest part of the truss can maintain over 9,940 pound feet of loading. In reality the weakest part of the cars front end is the sheet metal that is used to build the shock towers and they do not seem to have many problems.
In the final analysis we could lift the weight of four 944s off the ground and suspend them without a fear of failure. I hope this answers you question about the design methodology and strength.
My background is all-aerospace. The flight controls on many airliners use the same theory of putting bars, like our center bar, in compression and tension. The design parameters I used in selecting the material is the same as is used on a commercial airliner. In other words this bar has the same strength as does the push-pull tubes on the aircraft the carry passengers for every airline in the world. I am very aware of how to design lightweight components that will have the strength (plus a 150%) safety factor to carry the stresses. Also, we have several bars being used by PCA racers (full race prepped cars) with no problems. They like the bars because of the strength and weight savings.
Finally keep in mind, if you don’t like the bar send it back for a full refund.
Ken
This is a response based on a question about the strength of our bar.
That is a very good question. When I designed the bar I did take the shear load and potential flex of the bar into account. I would like to address each of the components separately. The flexing and the resultant stress loads of the strut towers are a function of the ultimate side loading on the tires before they break loose and how that stress is placed into the shock tower. I took into account the geometry of the front end and the bending moment of the tower and determined the expected tension and compression on the bar, joints, ends and the hardware.
The center bar and end joints are not in a shear or bending load. As the shock towers try to flex in and out the joints and bar are in either tension or compression. I have selected the material and thread design that will have an ultimate tensile strength that is over 20,000 psi or 20 ksi using the SI unit of measure. This is many times the maximum tensile load that the tires can exert onto the towers. The bar does not flex because it is not in a bending moment. It is fully compression and tension.
The mounting plate was designed to also carry many times the calculated stress. If you look at the design, the mount base and the vertical member are welded in suck a way as to carry the shear load down the full length of the weld. In other words, the shear loading is carried over the entire length of the weld an in the longitudinal axis of the vertical member. The material that I selected for these parts has very good shear and tensile strength but also have great weld characteristics. When calculating the shear strength of this part, even taking into account the slight reduction in strength in the weld heat effected zone (HAZ), the ends shear and tensile far exceed the strength needed to maintain the front end geometry of the car without failure. According to the United States Steel Corporation (USS) Handbook Of Plate Products, the material we selected has an ultimate strength if 24,000 PSI or 24 KSI using the SI measure. The smallest area of material under load is approximately ½ resulting in that area maintaining a minimum of 12,000 pounds of ultimate strength. The material is also very ductile and therefore not susceptible to vibration cracking.
The last area of consideration was the selection of a 3/8 grade 8 bolt. The bolt is the smallest part that is in shear loading. In reviewing the ASTM table for grade 8 bolts, the 3/8 bolt has a body shear strength of 9,940 Pound Feet (lbf) of strength. The threads are not in shear so their strength was not calculated. With the placement and selection of the bolt, its shear strength far exceeds the calculated stress.
Thread Size Tensile Strength Yeild Strength (0.2% offset) Shear Strengtht (lbf) Tightening Torque
ksi lbf ksi lbf Body Thread lbf.ft Nm
1/4 - 20 UNC 150 4770 130 4130 4420 2860 11.7 15.9
5/16 - 18 UNC 150 7860 130 6810 6900 4720 24.2 32.8
3/8 - 16 UNC 150 11630 130 10080 9940 6980 42.9 58.1
In final summation we should look at the car as a whole. The car has a total weight of 3115 pounds. The cornering loads are primarily maintained within the structure of the cars thin sheet metal frame. This camber truss is designed to be a secondary stiffening devise to hold the loads that the frame cannot maintain. The weakest part of the truss can maintain over 9,940 pound feet of loading. In reality the weakest part of the cars front end is the sheet metal that is used to build the shock towers and they do not seem to have many problems.
In the final analysis we could lift the weight of four 944s off the ground and suspend them without a fear of failure. I hope this answers you question about the design methodology and strength.
My background is all-aerospace. The flight controls on many airliners use the same theory of putting bars, like our center bar, in compression and tension. The design parameters I used in selecting the material is the same as is used on a commercial airliner. In other words this bar has the same strength as does the push-pull tubes on the aircraft the carry passengers for every airline in the world. I am very aware of how to design lightweight components that will have the strength (plus a 150%) safety factor to carry the stresses. Also, we have several bars being used by PCA racers (full race prepped cars) with no problems. They like the bars because of the strength and weight savings.
Finally keep in mind, if you don’t like the bar send it back for a full refund.
Ken
Could you elaborate on that?
I had one on my car and was VERY happy with it.
11-13-2003, 05:44 PM
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I have typers cramp. It looks like you got a REV. A. if you will send the brackets back I'll get you a REV. B. Give Scott a call and he will give you the shipping account number or get you a pre-paid lable.
11-13-2003, 09:22 PM
#15
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I don't think you mean 20 ksi for UTS, Ultimate Tensile Strength. That would be extremely low for a carbon steel product. It's even on the low side for the Y.S., Yield Strength of an IF type carbon steel.
Alan C.
Alan C.