When putting tires on a personal vehicle it’s always recommended to tighten the lug nuts in a star or criss-cross pattern, yet when you see pit crews for nascar they just go around one by one very quickly in a circle, why can they get away with doing it that way even though they’re driving much faster so things like a loose lug nut or vibration should be a pretty big deal, but it’s recommended that I always do a star or crisscross pattern?
In: 20
Its a difference in tools and use. The driver they are using to tighten the lug nuts is set to stop before it over tightens to a damaging level. Putting lugs on the car may be the only thing that tool is used for. They don’t care about getting it to a specific ft-lbs because longevity of the lug threads isn’t a concern. They would rather just replace them than spend precious seconds saving the part for long term use. So they will just slam them on to a level that won’t come loose, but may damage the threads over time. For your car you want the threads to last the life of the vehicle. So more care is taken to get them to tight, but not too tight.
Because they use an impact gun and torque the shit out of them. The reason to use the star pattern on your car is to make sure the wheel is seated evenly to the rotor/hub and so the lugs aren’t on so tight that they damage the nuts or become unable to be removed.
This is a sport where tenths of a second count, and wheel studs are replaced every race. Lug nuts don’t stay on long enough to rust or seize. The wheels also experience many times the forces the wheels on your Civic do.
On balance, it is far more advantageous to use an impact gun and do it in the most efficient pattern to get the car out ASAP.
The center hub of the old Nascar wheels were nearly the same size as the center of the wheel. This serves to align the wheel on the hub. When you tighten in a star pattern, it does two things, helps correctly align the wheel and second, applies a consistent and even torque to the lug nuts across the mating surface between the wheel and rotor.
In the case of Nascar, they use high torque high speed impacts. These will easily apply 100lbs+ of torque to the lug. Most street cars lugs would strip or break when applying the same amount of torque which is why lugs are both very high quality and commonly replaced. So because the lug nuts are over torqued for their need and the wheel is already aligned and centered, it doesn’t matter if you go in a star pattern. Going in a circle vs a star saves time and making up time on pit road can significantly impact your finishing position.
That being said, at times the wheel would hang and not fully seat when the first lug is torqued. This would often result in one or more lug nuts remaining lose. It’s up to the tire changer to detect this and hit the lug again before the car leaves the pits. It’s a compromise and why Nascar teams train. When changing tires outside pit road, we would still use a star pattern and a torque wrench like you would typically do on a road vehicle.
Also, lugs don’t strip often as some would assume. Unlike a street car, the lugs used have about a two inch threadless section at the end that the lug nuts align to before they engage the treads.
Cause they don’t care if the brakes get warped. They’re either replacing rotors or have a floating rotor that won’t be effected.
They are trying to change the tires as fast as possible. Nascar had to make a rule to require 5 lug nuts be installed on each wheel because teams were only putting on 4 trying to shave fractions of a second on tire changes. They do sometimes get a loose wheel and vibration might get so bad they have to pit again.
The race cars races around a track in relatively known and observed condition for a short amount of time, the wheels will be replaced or serviced within minutes to a few hours of the last fitment. Most race teams will even have a tyres and wheel team member that
Watches the wheels via an under chassis camera set. A race tyre will only do about 200-800km in its life.
The home car will be used for long periods of time where no one checks the wheels for seasons. The home wheels will endure thousands more heat cycle events,wet/dry weather cycling events, Freezing thawing and many more miles of constant vibration, most doing 10,000 to 40,000km unchecked. Now most drivers will say “I check mine every bla bla bla…..” but in reality alot… too many people just don’t check tyres or anything for that matter. Thus more rigid expectations should be had for the home game.
These all roll alongside you one roads and streets carrying families and individuals at high speed everywhere.
The commercial tyre is another level again, these in most countries with road rules have huge requirements on wheel lug torque, this is due to them doing even more heat cycling and longer durations of vibration, with life spans expecting 100,000km+.
Sometimes pointers called lugnut flags are used to indicate no lug movement.
Could be a lug centric setup as well. In a lug centric the nuts it’s center the wheel where as a lot of standard cars are hub centric where the brake rotor or wheel bearing centers the wheel. Lug centric would be easier to slam on fast and not be worried about it seating properly.
Latest Answers