By now I'm sure you've all seen or heard of the first recalled, then backordered Speedway Tubular Control Arms for G Body and S10 but here's a picture just to remind everyone what I'll be discussing:
I'm lucky enough to have a set on hand which allowed me to experiment with different bolts to find the best possible fitment. You're provided 4 sleeves each of 2 different I.D.s that naturally require 2 different sized bolts and nuts... but you have more than 2 choices. Allow me to explain.
The factory bolts for the front position of the LCA spec out at M12- 1.75 x 110. The rear position of the LCA calls for M12- 1.75 x 95. These will fit the smaller of the 2 sleeves provided in the kit. The larger of the sleeves call for 14 mm fasteners of the same length.
The large sleeves have an actual I.D. of 0.555", the smaller sleeves measure 0.510", and the I.D. of the sleeve is what truly dictates the appropriate fastener O.D. for the best fit with the least amount of slop. I broke out a Vernier caliper my grandmother used to help build Air Force One to take my own measurements. The face is scratched, not cracked, and that occured long before its most recent calibration.
Looking at this chart will expose the overlap in size between SAE and Metric fasteners, and that overlap is why we have more than just 2 choices when it comes time to bolt these arms into our cars.
The chart reveals that while the job calls for 12 mm bolts they'll be a bit sloppy in their homes when compared to an SAE fastener of the 1/2" variety. The metric bolt has a clearance of 0.038" which doesn't sound like much but it's more than enough to allow the bolt to wobble in the bore. Of course, your frame mounts should prevent such wobbling but they'll do nothing to stop the arm from slamming up and down against the bolt as the suspension cycles, and I've read of people nearly going nuts before tracking a sound to this very cause. A 1/2" bolt in the same sleeve will only have 0.010" clearance provided that it has an actual O.D. of 12.7 mm-- some cheaper ones are simply made to an O.D. of either 12 or 13 mm, so choose carefully. I highlighted 13 mm and 9/16" in red since both are just barely too big to fit by only 2 and 8 thousandths respectively.
I remember a time when I had twice the selection and did half as much driving to find what I needed but my fantastic fastener forage took me to multiple stores with each one seeming to specialize in one type over the others. Atwoods hardly had any SAE selections outside of the 5 most common bolts but reigned supreme when it came to metric. I found SAE flange nuts but no Prevailing Torque/ Torque To Yield (PT/TTY) nuts like should be used on the control arm bolts. Feel free to reuse your old ones, as that can be done a couple of times before they should be tossed due to wear at the pinch point. My plan includes brand new fasteners across the board.
Ace/ True Value had a decent selection of bolts that weren't strong enough but lacked what was necessary to complete the job. A locally owned spot (The Big Tool Store) had some 14 mm bolts but not all of them or even the correct length, and like Atwoods had only half of the necessary 1/2" diameter bolts which were now in a 3rd color with no other options of the correct hardness. The 14 mm bolts would ring up at over $7 each and the 1/2" versions would be between $3 - $4 each.
Due to immediate availability as well as cost I elected to stick with the 12 mm fasteners which were originally called for, though I would have much preferred to use 1/2". Now that we know the I.D. of the sleeves as well as the O.D. of the bolts it's clearly the better choice. I don't believe I'd benefit from using 14 mm nor did I wish to pony up for them, and couldn't find everything in SAE but the metric stuff is rated at 8.8 and costs a mere $0.88/ lb..
You may notice that an M12 bolt with an 8.8 hardness rating sports a tensile strength of 120,000 psi (120 ksi). That's important if you wish to utilize the proper PT/TTY nuts mentioned earlier. Those nuts will come stamped to indicate their strength rating and the correct PT nuts will be rated B (3 marks). As seen below those call for a bolt with a tensile strength of 120 ksi. How convenient.
Perhaps you want to try and use shorter bolts for appearances, to shave weight, or due to availability. You really want to avoid having the threaded section contact the inside of the sleeve so shorter bolts are not recommended. In the following photo you'll see the rear mount of the front LCA, and that position calls for a bolt 95 mm long. The store had 90, 100, and 110 mm lengths available and those are present as well.
Holding the 90 mm bolt close to the CA reveals that the threads will be just inside of the sleeve by about 2 threads before we introduce the thickness of the frame mounts.
Since that's not desirable the next option is the 100 mm bolt.
That may appear to be a lot of real estate that needs taken up but the frame mounts and a single washer will take care of it. It's my understanding that none/ almost none of these cars came with washers on them but apparently the books occasionally show one on the bolt head side.
The front position of the LCA calls for a bolt length of 110 mm, and the following photo again shows all three.
Much like the 90 mm bolt in the rear position, a 100 mm bolt up front comes up a little short and the threads will again be inside the sleeve.
The 110 mm bolt that is called for looks a bit too long before adding a washer to the head.
Adding another to simulate the thickness of frame mounts proves that washers are not necessary when utilizing the appropriate length fasteners, but 5 mm can be enough to call for one.
So while I'll only require them on the 100 mm bolts in the rear positions I'm going to use washers on all 4 bolts.
I also chose to replace the nuts that hold the upper control arm in place but intend to leave the bolts, as they're splined and stay in the frame unless they need replaced. If so, they're M12 - 1.75 x 66. I did purchase new flanged Nyloc nuts for them though.
When you go to bolt your control arms to the car don't forget about the offset cross shaft!
For the shocks you can rely on the usual U Clips / Speed Clips but Rivnuts are another option. You'll want steel ones- not aluminum- and they're M8 - 1.25 requiring an 11 mm hole which is slightly larger than the one that comes predrilled. Welding a nut to the top of the LCA is yet another option.
That pretty much leaves just the bumpstops, and we can improve upon those as well. The ones provided are rock hard and there's no doubt that bottoming out would be a rough experience. Enter the ZQ8 bumpstops (part # 31064), which are a softer composition and are intended to not only soften the impact but provide a bit of spring for the rebound as well. Really. They come in an off-white but 45 minutes in a jar of Rit dye on the stovetop can change that.
The size difference is quite obvious when placed next to the snubbers provided but the ZQ8 pieces thread right in and clear the coil springs. They clear mine anyway. The Speedway units measure 1 5/8" from mounting surface to tip, and their replacements are a solid 1" taller. The additional height is of no concern unless you've lowered your car multiple inches, and even then I'd rather have that extra cushion.
So to recap: Use 1/2" fasteners in the 12 mm sleeves for the tightest fit that still moves freely. Go with 14 mm if you think you really need that much heft, but be prepared to pay around $50 for them. And it seems that utilizing 12 mm fasteners will be the cheapest option that's quite possibly the easiest to locate as well.
Hopefully this information is useful to someone still waiting to receive their Speedway Tubular Control Arms.
I'm lucky enough to have a set on hand which allowed me to experiment with different bolts to find the best possible fitment. You're provided 4 sleeves each of 2 different I.D.s that naturally require 2 different sized bolts and nuts... but you have more than 2 choices. Allow me to explain.
The factory bolts for the front position of the LCA spec out at M12- 1.75 x 110. The rear position of the LCA calls for M12- 1.75 x 95. These will fit the smaller of the 2 sleeves provided in the kit. The larger of the sleeves call for 14 mm fasteners of the same length.
The large sleeves have an actual I.D. of 0.555", the smaller sleeves measure 0.510", and the I.D. of the sleeve is what truly dictates the appropriate fastener O.D. for the best fit with the least amount of slop. I broke out a Vernier caliper my grandmother used to help build Air Force One to take my own measurements. The face is scratched, not cracked, and that occured long before its most recent calibration.
Looking at this chart will expose the overlap in size between SAE and Metric fasteners, and that overlap is why we have more than just 2 choices when it comes time to bolt these arms into our cars.
The chart reveals that while the job calls for 12 mm bolts they'll be a bit sloppy in their homes when compared to an SAE fastener of the 1/2" variety. The metric bolt has a clearance of 0.038" which doesn't sound like much but it's more than enough to allow the bolt to wobble in the bore. Of course, your frame mounts should prevent such wobbling but they'll do nothing to stop the arm from slamming up and down against the bolt as the suspension cycles, and I've read of people nearly going nuts before tracking a sound to this very cause. A 1/2" bolt in the same sleeve will only have 0.010" clearance provided that it has an actual O.D. of 12.7 mm-- some cheaper ones are simply made to an O.D. of either 12 or 13 mm, so choose carefully. I highlighted 13 mm and 9/16" in red since both are just barely too big to fit by only 2 and 8 thousandths respectively.
I remember a time when I had twice the selection and did half as much driving to find what I needed but my fantastic fastener forage took me to multiple stores with each one seeming to specialize in one type over the others. Atwoods hardly had any SAE selections outside of the 5 most common bolts but reigned supreme when it came to metric. I found SAE flange nuts but no Prevailing Torque/ Torque To Yield (PT/TTY) nuts like should be used on the control arm bolts. Feel free to reuse your old ones, as that can be done a couple of times before they should be tossed due to wear at the pinch point. My plan includes brand new fasteners across the board.
Ace/ True Value had a decent selection of bolts that weren't strong enough but lacked what was necessary to complete the job. A locally owned spot (The Big Tool Store) had some 14 mm bolts but not all of them or even the correct length, and like Atwoods had only half of the necessary 1/2" diameter bolts which were now in a 3rd color with no other options of the correct hardness. The 14 mm bolts would ring up at over $7 each and the 1/2" versions would be between $3 - $4 each.
Due to immediate availability as well as cost I elected to stick with the 12 mm fasteners which were originally called for, though I would have much preferred to use 1/2". Now that we know the I.D. of the sleeves as well as the O.D. of the bolts it's clearly the better choice. I don't believe I'd benefit from using 14 mm nor did I wish to pony up for them, and couldn't find everything in SAE but the metric stuff is rated at 8.8 and costs a mere $0.88/ lb..
You may notice that an M12 bolt with an 8.8 hardness rating sports a tensile strength of 120,000 psi (120 ksi). That's important if you wish to utilize the proper PT/TTY nuts mentioned earlier. Those nuts will come stamped to indicate their strength rating and the correct PT nuts will be rated B (3 marks). As seen below those call for a bolt with a tensile strength of 120 ksi. How convenient.
Perhaps you want to try and use shorter bolts for appearances, to shave weight, or due to availability. You really want to avoid having the threaded section contact the inside of the sleeve so shorter bolts are not recommended. In the following photo you'll see the rear mount of the front LCA, and that position calls for a bolt 95 mm long. The store had 90, 100, and 110 mm lengths available and those are present as well.
Holding the 90 mm bolt close to the CA reveals that the threads will be just inside of the sleeve by about 2 threads before we introduce the thickness of the frame mounts.
Since that's not desirable the next option is the 100 mm bolt.
That may appear to be a lot of real estate that needs taken up but the frame mounts and a single washer will take care of it. It's my understanding that none/ almost none of these cars came with washers on them but apparently the books occasionally show one on the bolt head side.
The front position of the LCA calls for a bolt length of 110 mm, and the following photo again shows all three.
Much like the 90 mm bolt in the rear position, a 100 mm bolt up front comes up a little short and the threads will again be inside the sleeve.
The 110 mm bolt that is called for looks a bit too long before adding a washer to the head.
Adding another to simulate the thickness of frame mounts proves that washers are not necessary when utilizing the appropriate length fasteners, but 5 mm can be enough to call for one.
So while I'll only require them on the 100 mm bolts in the rear positions I'm going to use washers on all 4 bolts.
I also chose to replace the nuts that hold the upper control arm in place but intend to leave the bolts, as they're splined and stay in the frame unless they need replaced. If so, they're M12 - 1.75 x 66. I did purchase new flanged Nyloc nuts for them though.
When you go to bolt your control arms to the car don't forget about the offset cross shaft!
For the shocks you can rely on the usual U Clips / Speed Clips but Rivnuts are another option. You'll want steel ones- not aluminum- and they're M8 - 1.25 requiring an 11 mm hole which is slightly larger than the one that comes predrilled. Welding a nut to the top of the LCA is yet another option.
That pretty much leaves just the bumpstops, and we can improve upon those as well. The ones provided are rock hard and there's no doubt that bottoming out would be a rough experience. Enter the ZQ8 bumpstops (part # 31064), which are a softer composition and are intended to not only soften the impact but provide a bit of spring for the rebound as well. Really. They come in an off-white but 45 minutes in a jar of Rit dye on the stovetop can change that.
The size difference is quite obvious when placed next to the snubbers provided but the ZQ8 pieces thread right in and clear the coil springs. They clear mine anyway. The Speedway units measure 1 5/8" from mounting surface to tip, and their replacements are a solid 1" taller. The additional height is of no concern unless you've lowered your car multiple inches, and even then I'd rather have that extra cushion.
So to recap: Use 1/2" fasteners in the 12 mm sleeves for the tightest fit that still moves freely. Go with 14 mm if you think you really need that much heft, but be prepared to pay around $50 for them. And it seems that utilizing 12 mm fasteners will be the cheapest option that's quite possibly the easiest to locate as well.
Hopefully this information is useful to someone still waiting to receive their Speedway Tubular Control Arms.
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