Observations on the NASCAR change to single center lock lug wheels

[rrrr]

While watching the Daytona 500 on Sunday, I paid particular attention to the new wheels and any difficulties encountered by tire changers during pit stops. There were a bunch of them. I'm going to sort out the issues and comment on what was done wrong.

But first I'll discuss the new wheels and how they will affect braking.

As everyone knows, NASCAR made a significant change to tire and wheel combinations for 2022. The wheel size has been enlarged, from 15" to 18" bead diameter, and the five lug nuts on last year's wheels are being replaced by a single center lock attachment.

The wheels are forged aluminum, replacing heavy steel units. The tires now being provided by Goodyear will generally be made with a softer rubber compound with more grip, and because of the reduced sidewall dimension, inner liners will no longer be used.

The larger brake rotors, made possible by the 18" wheels, increase the rear brake rotor friction surface area from 53 square inches to 105 square inches. The front rotor friction surface area increases from 41 square inches to 78 square inches. While this appears to mean a much more aggressive brake package, the advantages are not as large as one might think.

The limiting factor in stopping power is tire adhesion, so now it's much easier to lock up the tire under heavy braking. Where the advantage really lies is the brake rotor's ultimate temperature gain under racing conditions. The larger rotor surface area means that peak rotor and pad temperatures on short tracks will be much less than before, which will greatly reduce rear wheel hop during heavy braking, and brake fade attributable to rotor heat will decrease. Rotor explosions are likely a thing of the past.

Next: The center lock single lug wheel and pit stops

 

[rrrr]

The new aluminum center lock single lug wheels have advantages over the legacy five lug steel wheels. They're obviously lighter. The single wheel lug attachment theoretically makes for faster pit stops. But in practice, there are issues, and I spotted several of them during Sunday's Daytona 500.

The single wheel lug nut is a hardened steel unit, with high helix threads. Around its outer perimeter are two concentric rings, spaced about ½" apart, with tangential fences between them, spaced around the diameter. The inner ring has a lip contour that provides a locking surface that interfaces with the wheel gun socket. The socket has corresponding fingers with spring action.

When the socket is fitted to the wheel lug, the spring fingers engage the inner ring lip and clamp onto it, providing a firm attachment between the socket and wheel lug. It is critical that the socket is pushed onto the lug ring without any axial deviation. It must be aligned straight in all axes, so the fingers engage the wheel lug equally around the perimeter. This assures the wheel lug will stay clamped to the socket when it is spun off the male threads on the wheel hub.

When the wheel lug is replaced, it again must be axially aligned, so the wheel nut does not crossthread on the hub. Once the the wheel lug is tight, a push down on the wheel gun will overcome the locking fingers' clamping force on the wheel lug and it is released.

Now that you understand that the socket physically locks onto the wheel lug, we can discuss the things that can and did go wrong during pit stops.

First, and most importantly, the wheel gun socket cannot be turning when the tire changer attempts to lock it onto the center wheel nut. The technique used on the five lug nut steel wheel dictated the wheel gun would be spun up before it contacted the first lug nut, and the trigger would stay depressed while the socket was moved from one lug nut to another. As the new wheel and tire were placed onto the hub, the crewman would reverse the rotation of the wheel gun, hold down the trigger, and tighten the lug nuts one after another.

With the new equipment, the wheel gun socket cannot be turning while the crewman is locking it onto the wheel nut. It can't engage the fingers while turning. I saw several tire changers prematurely depress the wheel gun trigger while both removing and replacing the wheel nut. They then had to wait until the wheel gun spun down to zero RPM so the socket could be locked onto the wheel lug.

When the wheel gun removes the lug, it can be spinning at speeds up to 10,000 RPM. The crewman must modulate the trigger "on" time to keep rotation speeds within reason. If the crewman is careless about speeds and in placing the wheel gun on the ground while the socket and wheel lug are still spinning, the wheel lug can be knocked loose from the socket. The wheel lug will take off, and can travel ten feet or more away from the gun.

The crewman has another lug attached to the belt of his firesuit with a small lightweight cable tie. He has to break the cable tie, place the lug on the hub threads, and spin it to engage the threads. It he doesn't, when the wheel gun is used to finish tightening the lug, it can crossthread.

Next: More errors by the tire changer

 

[4Waters]

When did Nascar go open wheel?

 

[Bowtiepower00]

I don’t watch this Commie bullshit, nor do I watch the NFL or any other woke sports. And I hate these bullshit 1000’ NHRA dragsters!!! I’m an ‘MURICAN!!! Jk. Yeah a learning curve for sure. But I really dig the new gen cars and tech. Enjoyed the coliseum race and Daytona. Durability on the IRS appears to be a serious issue.

 

[Pivot]

Stupid.

 

[rrrr]

During the race I saw tire changers make just about all of the mistakes that can be made with a single wheel lug tire change.

The most common was timing errors made during removal and replacement of the tire. The wheel gun is capable of making a huge amount of torque with the compressed gas powering the gun (in IndyCar the gun uses nitrogen at 400 psi, I don't know the NASCAR gas or pressure used). It's critical to operate the gun for the proper amount of time to produce the proper clamping force on the wheel lug. If the lug is overtightened, on the next pit stop it can be next to impossible to remove it. The heat produced by the rotation of the tire and wheel at speeds approaching 195 MPH exacerbates the issue.

When the wheel lug is tightened, the gun should be allowed to hammer for a period of 1.1 to 1.3 seconds. Any longer than that can make the wheel lug difficult to remove. I saw several crewmen running the wheel gun for more than three seconds while tightening a wheel lug. Assuming a tire changer did that to both tires he was changing, that added about five seconds to the pit stop. Another error I saw was more egregious.

The right side wheel lugs have left hand threads, because the wheel lug is tightened by the direction of rotation on right side tires. On the left side tires, right hand threads provide the opposite and tightening force. A crewman I saw changing the left rear ran the wheel gun for at least five seconds without results. He released the gun, raised his arms in a WTF gesture, then pounded on the lug some more. He had the wheel gun rotation in left, and was therefore tightening the wheel lug instead of loosening it. At this point the camera broke away, but I can assure you it took a long time to break that wheel lug free once he discovered his error.

Next: The proper method for attaching the wheel, and how it went wrong

 

[Travmon]

They will get it figured out, They will learn to slow down a bit where necessary as well as get used to the new process.. I too saw some issues that need to be honed.. Overall I would say the car performed extremely well for its debut with very limited testing for the crews.. THAT SAID , I do have a BIG problem with the car not being STEEL ! Not only did you just put a bunch of guys that love making shapes out of flat metal OUT OF WORK , your killing what this country is lacking in the worst way..People with skills !!! Now we get to see a bunch of flying plastic/composite ( un-recyclable ) shards flying all over during a wreck all assembled by robots..

 

[Crazyhippy]

I don’t watch this Commie bullshit, nor do I watch the NFL or any other woke sports. And I hate these bullshit 1000’ NHRA dragsters!!! I’m an ‘MURICAN!!! Jk. Yeah a learning curve for sure. But I really dig the new gen cars and tech. Enjoyed the coliseum race and Daytona. Durability on the IRS appears to be a serious issue.

Say it right... it isn't 1000ft, it is 305meters.


That should really ruffle a few feathers!

 

[rrrr]

The crew chiefs and tire changers on the cars driven by Kaz Grala and Justin Haley were assessed four race suspensions for losing a tire and wheel during the Daytona 500.

The wheel on Grala's car failed at speed and fragmented. Haley's wheel and tire departed the car at race speed. Losing a wheel and tire at speeds nearing 200 MPH could have deadly consequences. If the object is struck by another car, it could easily be punted into the stands.

The new forged aluminum wheels now being used in NASCAR Cup have a single center wheel lug, attached by a single wheel lug that is tightened by a 10,000 RPM wheel gun, operated by gas pressures near 400 PSI. The wheel has a circumference of multiple ⅝" blind holes drilled in its backside, which are used to make a positive interface with drive pins on the hub snout. The holes are outboard of the single 1½" hole which accepts the threaded wheel hub snout. The wheel hub has a corresponding circumference of drive pins that match the ⅝" holes in the wheel.

When the wheel is placed over the hub snout, it must be rotated slightly so the hub drive pins engage the drive pin receptacles in the wheel. Once the wheel is seated properly on the drive pins, the tire changer moves the wheel gun, with the wheel lug attached to its socket, to the hub snout, and depresses the wheel gun trigger to thread the wheel lug onto the hub snout. As I mentioned above, once the wheel lug contacts the wheel opening, the crewman operates the gun for 1.1 to 1.3 seconds to apply the proper torque to the wheel nut.

When Haley's car lost a wheel and tire assembly, it happened at race speeds. I think, based on experience, that the drive pin holes in the back of the wheel hub weren't properly matched with the drive pins. This prevented the wheel lug from being properly seated, and once the car was on track the wheel lug backed off, and the wheel and tire separated from the wheel hub.

The incident with Grala's car was more complicated. The wheel actually failed. It appeared the wheel hub shattered.

I've never seen that happen in IndyCar. The wheels in that series are magnesium, not aluminum. I don't know the relative yield and ultimate load strengths of the two metals.

Watching the crews adapt to the single center lug wheels will continue to be interesting.

 

[rrrr]

I haven't priced out a wheel gun in years, so I went looking for one. A racing buddy pointed me to this Paoli DP 6000:

You think your impact has big torque numbers? Check out these specs:

1" Drive
4200 Nm (3100 ft/lbs) Maximum Torque
3.54kg (Aluminium cover), 3.50kg (Carbon cover)
14,700 Rpm Free Speed @ 25 bar pressure
198mm Length
3/8" BSP port

25 bar is 367 PSI.

Cost: $7,650.00

That doesn't include the wheel nut socket. They're another $375.00:

The wheel nuts are $725.00 each:

Are you beginning to get an idea why it costs so much money to go racing? A typical IndyCar team will have the following pit equipment just to change tires for each car:

• 10 DP 6000 wheel guns $76,500.00
• 10 wheel nut sockets $3,750.00
• 30 wheel nuts $21,750.00
• 8 HP nitrogen regulators $4,880.00
• 16 50' 600 PSI HP hoses $8,240.00
• Total for the above $115,120.00

 

[Crazyhippy]

I haven't priced out a wheel gun in years, so I went looking for one. A racing buddy pointed me to this Paoli DP 6000:

$7,500+

Does Harbor freight make one yet?

 

[LargeOrangeFont]

$7,500+

Does Harbor freight make one yet?

Yep. Just run down there and get an Earthquake impact for $100

 

[ChiliPepperGarage]

I think the people that run NASCAR are completely clueless as to who their real fans are. They keep making changes to try to capture a new audience but none of it works.

I've said this here before but I think the single best thing they could do to gain new viewers is to dump the current cars and go back to real stock cars. Camaros, Mustangs and Challengers in stock form. All three of these cars have more than enough power to put on a good show. Stock bodies with stock engines. Interiors can be gutted and cages installed. Other minor changes would be allowed like shifters, headers, etc. They could have two classes; N/A and F/I.

I think the manufacturers would like this too. Win on Sunday, sell on Monday!

 

[LargeOrangeFont]

I think the people that run NASCAR are completely clueless as to who their real fans are. They keep making changes to try to capture a new audience but none of it works.

I've said this here before but I think the single best thing they could do to gain new viewers is to dump the current cars and go back to real stock cars. Camaros, Mustangs and Challengers in stock form. All three of these cars have more than enough power to put on a good show. Stock bodies with stock engines. Interiors can be gutted and cages installed. Other minor changes would be allowed like shifters, headers, etc. They could have two classes; N/A and F/I.

I think the manufacturers would like this too. Win on Sunday, sell on Monday!

Just start watching Sports Car racing if that is what you want to watch. About all of that already exists.

The new NASCAR cars are light years better than the old cars, and much better equipped for road racing.

 

[CLdrinker]

Nascars hay day is long gone. The 80’s and 90’s was its prime.

 

[ChiliPepperGarage]

Just start watching Sports Car racing if that is what you want to watch. About all of that already exists.

The new NASCAR cars are light years better than the old cars, and much better equipped for road racing.

The difference between sports car racing and NASCAR is the tracks, not the car. Sports car racing is road racing, not ovals. NASCAR runs what, two road courses?

I said Mustangs, Camaros and Challengers because they are all front engine, rear wheel drives cars so they fit into the traditional NASCAR STOCK car configuration. There is no reason why they couldn't run oval courses. the big three don't make any other vehicles in that configuration unless you want rucks or SUVs.

<y point is, fans are going to relate to seeing cars they can buy or already own, racing.

 

[playdeep]

NASCAR has lost it's way...
Spec racing. All chassis come from NASCAR.It's obvious they didn't bother to check out the health of the IROC&Trans Am series which is who they've modeled their current program under.
Banjo Mathews,Junior Johnson&Smokey Yunick are rolling over in their Graves.
I check in to see how the dirt guys are doing but watching a full race is as boring as watching golf.
...I'll stick to sprint cars&midgets on dirt.

 

[DUN]

They've turned it in to Indycar with fenders. The suspension is way too fragile but the bodies are way stronger.


That said, a race car is a race car and as long as they are fun to watch making laps, I don't discriminate.

 

[LargeOrangeFont]

The difference between sports car racing and NASCAR is the tracks, not the car. Sports car racing is road racing, not ovals. NASCAR runs what, two road courses?

I said Mustangs, Camaros and Challengers because they are all front engine, rear wheel drives cars so they fit into the traditional NASCAR STOCK car configuration. There is no reason why they couldn't run oval courses. the big three don't make any other vehicles in that configuration unless you want rucks or SUVs.

<y point is, fans are going to relate to seeing cars they can buy or already own, racing.

That was the point of the new car, It looks more like the street car. Also they run several road races per year now.

 

[240Hallett]

Back to the point of the thread…
Has anybody heard anything about the Penske/RFK wheels that were confiscated by NASCAR? They obviously saw something they didn’t like and the Fords seemed to have better pitstops during the duels. My uneducated guess is that they might have put a little more chamfer on the backside of the wheels to help the drive lugs engage a little quicker.

 

[Ducksquasher]

Like the new cars...hate the single lug (miss the zoom, zoom, zoom and challenge of the multiple lugs) and I can't stand the stages. Love NASCAR and racing...I get the need to try new things though to broaden the audience. The Clash showed well with new demographics and there are a few shows showing the local college kids and new to the sport peeps enjoying it.

I am over everyone's pandering and woke crap and catering to the smallest minority to make them happy in every situation. As a society we can learn, grow and "evolve" without having this huge pendulum swinging back and forth.

I boycotted the NFL for the last 3-4 years and I certainly do not like the sideline and end zone messages as I do not live my life having to be reminded that racism is bad thing...I take people for who they are? If you are a good person, you are a good person. If you are an asshole, you are an asshole regardless of what race or color you are!

I am a huge college football fan as it is a better game with more excitement, more tradition and is simply just a better product than the NFL. With that said, the NFL playoffs and Super Bowl were all great games and the best I have seen even when I was a diehard NFL fan.

 

[Canuck 1]

Maybe they should give trophies to all the drivers and crew, they could just polish the cars on the front straight instead of risking driving around the track


Iroc sucked 30 years ago and what napcar is doing now isn't any better, put the people back into the racing, throw out the computers and aero

 

[LargeOrangeFont]

Maybe they should give trophies to all the drivers and crew, they could just polish the cars on the front straight instead of risking driving around the track

If Canada had a racing series, that is surely what they would do.

 

[hallett3]

They took the competition out of the pit crews. They have to wait on the gas man because changing the tires is so much faster. Very boring to watch.

 

[mjc]

Back to the point of the thread…
Has anybody heard anything about the Penske/RFK wheels that were confiscated by NASCAR? They obviously saw something they didn’t like and the Fords seemed to have better pitstops during the duels. My uneducated guess is that they might have put a little more chamfer on the backside of the wheels to help the drive lugs engage a little quicker.

they said they cleaned up the wheels so they wouldn't get stuck on the hub. They told nascar what they were going to do long before the race and never heard back from them so they did it.

Penske Addresses NASCAR's Confiscation Of Wheels - SPEED SPORT

Daytona 500 winning team owner Roger Penske addressed the wheels that were confiscated by NASCAR officials after last Thursday night’s Bluegreen Vacations Duel qualifying races.

www.speedsport.com

 

[mjc]

They took the competition out of the pit crews. They have to wait on the gas man because changing the tires is so much faster. Very boring to watch.

they changed the nozzle in the gas can to slow down the fuel flow, so now the gas is the slowest thing during a pit stop.

 

[spectra bash]

150,000 people at the Daytona 500. Viewership 8 million. California will be packed. They must not know what they are doing. Some of you must still watch black and white tv’s and use rotary phones. Jeezus complain much?

 

[Ziggy]

That was the point of the new car, It looks more like the street car. Also they run several road races per year now.

Depending on the tracks they run I'd be more inclined to watch em run a road course. Not just some chicanes in the middle of an oval but a real road course.
Me likey to Zig n Zag

 

[RaceTec]

When Haley's car lost a wheel and tire assembly, it happened at race speeds. I think, based on experience, that the drive pin holes in the back of the wheel hub weren't properly matched with the drive pins. This prevented the wheel lug from being properly seated, and once the car was on track the wheel lug backed off, and the wheel and tire separated from the wheel hub.

The incident with Grala's car was more complicated. The wheel actually failed. It appeared the wheel hub shattered.

I've never seen that happen in IndyCar. The wheels in that series are magnesium, not aluminum. I don't know the relative yield and ultimate load strengths of the two metals.

Watching the crews adapt to the single center lug wheels will continue to be interesting.

All very good observations, and I agree with every point. Having worked on single central nut systems in everything from F1 down, I found the issues almost comical. One question, the hub and length of the studs must be deigned wrong to allow that wheel to come off? Every system I have worked with had at least two spring loaded locks to retain the nut and wheel in just this case. The nut would go over the locks depressing them as engaging the threads and even if the studs were not properly located in the wheel the threads were not long enough to allow the wheel nut to "bite" thus preventing exactly this failure. Dimensionally it doesn't make sense to me? Poor design in my opinion, I would have to look at it... Picture attached of IRL system, you can see the locks depressed and that the wheel nut is just partially on.

 

[LargeOrangeFont]

Depending on the tracks they run I'd be more inclined to watch em run a road course. Not just some chicanes in the middle of an oval but a real road course.
Me likey to Zig n Zag

The Nascar race in Sonoma was the most exciting race I've been to.

 

[77charger]

Its known that the centering pins are not perfectly fitted right now.They may have this solved real fast was also hearing that if the centering dowells are to big that its just as bad being that the wheel can move and work loose.

I rather see the simple 5 lug deal these are 3400 pound cars with alot of force on the wheels what works in indy or other series may not be the best fit for nascar

 

[LargeOrangeFont]

Its known that the centering pins are not perfectly fitted right now.They may have this solved real fast was also hearing that if the centering dowells are to big that its just as bad being that the wheel can move and work loose.

I rather see the simple 5 lug deal these are 3400 pound cars with alot of force on the wheels what works in indy or other series may not be the best fit for nascar

They will be able to figure it out. The Australian Supercar series runs center lock wheels as well and has for over a decade. The new cars are 3200 lbs, the Australian Supercars are 3075 lbs.

We talked earlier about running cars that looks like cars on the showroom... what car today runs 15" steel wheels?

 

[rrrr]

All very good observations, and I agree with every point. Having worked on single central nut systems in everything from F1 down, I found the issues almost comical. One question, the hub and length of the studs must be deigned wrong to allow that wheel to come off? Every system I have worked with had at least two spring loaded locks to retain the nut and wheel in just this case. The nut would go over the locks depressing them as engaging the threads and even if the studs were not properly located in the wheel the threads were not long enough to allow the wheel nut to "bite" thus preventing exactly this failure. Dimensionally it doesn't make sense to me? Poor design in my opinion, I would have to look at it... Picture attached of IRL system, you can see the locks depressed and that the wheel nut is just partially on.

I assume the NASCAR hubs have the same lock pins. I think the tire changers were probably in a rush to release the car and didn't realize the wheel nut was barely engaged and not past the lock pins.

The TV broadcast didn't show a wheel nut being picked up from the racing surface, but they must have been out there somewhere.

 

[DUN]

They will be able to figure it out. The Australian Supercar series runs center lock wheels as well and has for over a decade. The new cars are 3200 lbs, the Australian Supercars are 3075 lbs.

We talked earlier about running cars that looks like cars on the showroom... what car today runs 15" steel wheels?

On the contrary, what show room cars other than hypercars run single lug wheels?

 

[playdeep]

I assume the NASCAR hubs have the same lock pins. I think the tire changers were probably in a rush to release the car and didn't realize the wheel nut was barely engaged and not past the lock pins.

The TV broadcast didn't show a wheel nut being picked up from the racing surface, but they must have been out there somewhere.

Shiat...that center locking nuts been around since the 60's...old school stuff
Here's a picture of same basic setup on an early 70's sprint car I'm restoring...

 

[Racer56]

Shiat...that center locking nuts been around since the 60's...old school stuff
Here's a picture of same basic setup on an early 70's sprint car I'm restoring...

When are you going to start a restoration thread for all of the open wheel junkies on RDP?

 

[Racer56]

Personally, I love all of the changes Nascar has made. How long were they going to stick with truck arm suspension from the 50's, 40 year old transmissions and steel wheels. Nascar needed a modern race car that was relevant desperately!

My only disappointment is they should of lowered the minimum weight to under 3,000 lbs for a more nimble race car instead of a taxi cab.

 

[playdeep]

When are you going to start a restoration thread for all of the open wheel junkies on RDP?

I could do that...Here's my current project.
1975 Trostle chassis driven by sprint car legend &hall of fame Buddy Taylor.
rrrr&I grew up watching him race locally at Speedway Park..

 

[HTTP404]

Great analysis all you gear heads!

 

[rrrr]

I could do that...Here's my current project.
1975 Trostle chassis driven by sprint car legend &hall of fame Buddy Taylor.
rrrr&I grew up watching him race locally at Speedway Park..

Have you seen the photos of Taylor racing a midget at Cormit Speedway on KingNitro? Looking at the exhaust pipes, it appears the car was powered by an Evinrude conversion.

The track was on South Wyoming and Susan Ave, literally about a quarter mile from the block where my Dad's shop was and where I lived in a little stucco house as a small child, on Susan and General Chennault.

This Taylor sprinter rebuild sold at Barrett-Jackson Scottsdale in 2017 for $70K, and it's in the catalog for their next auction at Palm Springs in April. I don't think it had all of that chrome on it when Buddy drove it.

1962 AAA RADIATOR-BUDDY TAYLOR SPRINT CAR - Vehicle | Barrett-Jackson Auction Company - World's Greatest Collector Car Auctions

www.barrett-jackson.com

 

[rrrr]

Shiat...that center locking nuts been around since the 60's...old school stuff
Here's a picture of same basic setup on an early 70's sprint car I'm restoring...

You need to post a photo of the counterweighted bash wrench used to tighten those nuts.

Hint for everyone else:

It doesn't involve a $7,650.00 wheel gun.

 

[HTTP404]

How often do those wheel guns need to be rebuilt? They abuse the hell out of them on the Indy cars.

 

[rrrr]

How often do those wheel guns need to be rebuilt? They abuse the hell out of them on the Indy cars.

They're pretty stout. It seemed like we had to send one or two in for repair during the season when they acted up. All of them went in for inspection and refurbishing during the off season.

They do get thrown around a bit, especially the one used by the right front tire changer. Last year, one of the Penske guys started tossing it to the pit wall behind his back. Adding a little show I guess.