- Sat Jul 07, 2007 5:43 pm
#13387
I thought I'd post this so that others may learn from my mistakes...and the results. 
Our commute to and from events is usually 2+ hours...one way. So, like many other racers, we change to our r-comps when we arrive.
Recently, I picked up a used set of Stock Class legal wheels for my r-comps from a 1989 Isuzu. Aside from ordering a set of Volk's for $2,000 +/-, these are the LIGHTEST 14x5 wheels around.
However, the offset for these wheels is 46mm, compared to 40mm for OEM. So, to push the wheels back out, I ran 5/16th spacers. I also used the OEM Honda lugs on the Isuzu wheels.
In addition to changing wheels/tires twice at each event, I also torque the lugs to 80 ft/lbs. Further, I re-check the torque after nearly every run.
I'd just re-checked them before this run. Here's the result...
What happened??? The lugs failed and the RF wheel came completely off the car. The lugs were described as "bullets." Thankfully, no course worker was injured.
Here's some more pictures of the damage.
Note the stud and nut for the lower balljoint...
Here's the driver's side for comparison...
Also, the tie-down and plastic covers saw the asphalt.
HOW did this happen???
I'm no Mechanical Engineer, but I do have my theories.
First of all, I think metal fatigue was a factor. These were the ORIGINAL studs and lugs. Also, consider if a racer makes 10 events a year, that's TWENTY wheel changes. That's as much component wear as a street car would see in 10 YEARS...IF the tires were rotated properly.
Further, consider that many repair shops simply set their air guns to 100 ft/lbs and leave them. Over the life of the car, there's no telling how many times the lugs were over-torqued.
Another factor was using Honda lugs on Isuzu wheels. Hondas lugs/wheels have spherical seats, compared to conical seats for nearly every other manufacturer. Thus, I ended up with a "round" peg for a "square" hole, if you will. This improper seating would allow the wheel to "squirm."
Still another factor was the size of my wheel spacers. The THICKNESS of the spacers prevented the lugs from getting enough "bite" on the studs. Although I had the recommended "4-5 finger turns," that obviously wasn't enough.
The failure occurred just after a short, but very firm, braking zone, followed immediately by a LH turn. I'd just turned in when it happened. Given the weight transfer, the RF was FULLY loaded when it failed. Additionally, using r-comps allowed for more even lateral force on the suspension.
How could this have been prevented???
-New, longer studs and lugs at ALL corners.
-Additional set of proper lugs for the race wheels.
Experienced racers consider lugs/studs to be wear items and replace them yearly. I fully understand why, now. Again, thankfully, no one was hurt. Replacing these items is CHEAP insurance. Perhaps someone can avoid MY mistakes from reading this.
Remember..."Civic spelled backwards is "civiC"
Our commute to and from events is usually 2+ hours...one way. So, like many other racers, we change to our r-comps when we arrive.
Recently, I picked up a used set of Stock Class legal wheels for my r-comps from a 1989 Isuzu. Aside from ordering a set of Volk's for $2,000 +/-, these are the LIGHTEST 14x5 wheels around.
However, the offset for these wheels is 46mm, compared to 40mm for OEM. So, to push the wheels back out, I ran 5/16th spacers. I also used the OEM Honda lugs on the Isuzu wheels.
In addition to changing wheels/tires twice at each event, I also torque the lugs to 80 ft/lbs. Further, I re-check the torque after nearly every run.
I'd just re-checked them before this run. Here's the result...
What happened??? The lugs failed and the RF wheel came completely off the car. The lugs were described as "bullets." Thankfully, no course worker was injured.
Here's some more pictures of the damage.
Note the stud and nut for the lower balljoint...
Here's the driver's side for comparison...
Also, the tie-down and plastic covers saw the asphalt.
HOW did this happen???
I'm no Mechanical Engineer, but I do have my theories.
First of all, I think metal fatigue was a factor. These were the ORIGINAL studs and lugs. Also, consider if a racer makes 10 events a year, that's TWENTY wheel changes. That's as much component wear as a street car would see in 10 YEARS...IF the tires were rotated properly.
Further, consider that many repair shops simply set their air guns to 100 ft/lbs and leave them. Over the life of the car, there's no telling how many times the lugs were over-torqued.
Another factor was using Honda lugs on Isuzu wheels. Hondas lugs/wheels have spherical seats, compared to conical seats for nearly every other manufacturer. Thus, I ended up with a "round" peg for a "square" hole, if you will. This improper seating would allow the wheel to "squirm."
Still another factor was the size of my wheel spacers. The THICKNESS of the spacers prevented the lugs from getting enough "bite" on the studs. Although I had the recommended "4-5 finger turns," that obviously wasn't enough.
The failure occurred just after a short, but very firm, braking zone, followed immediately by a LH turn. I'd just turned in when it happened. Given the weight transfer, the RF was FULLY loaded when it failed. Additionally, using r-comps allowed for more even lateral force on the suspension.
How could this have been prevented???
-New, longer studs and lugs at ALL corners.
-Additional set of proper lugs for the race wheels.
Experienced racers consider lugs/studs to be wear items and replace them yearly. I fully understand why, now. Again, thankfully, no one was hurt. Replacing these items is CHEAP insurance. Perhaps someone can avoid MY mistakes from reading this.
Remember..."Civic spelled backwards is "civiC"
I couldn't find a weight for them on any of the published lists I've seen.
