Center Bore

[zoomzoomers]

In my personal experience you don't absolutely NEED hub centric rings, but if you do a lot of tracking or a lot of hwy crusing then I'd suggest you spend the money and get the rings. I've run with and without them. The one time I had issues while running without them was when I was doing a lot of hwy cruising on a daily basis. I'd say I'd daily do 120 miles +. What ended up happening was a catastrophic failure of one of my front tires which caused a bad spin out on the fwy. The blow out caused me to lose control of the vehicle and I ended up doing a several, I think 3 to 4, 360's on a 5 lane fwy finally coming to a stop in front of a very large group of oncoming traffic.

Let me just say it wasn't pretty. I nearly caused a huge pile up at best and loss of life at worst due to me losing control of the car. Thank God nothing happened. In either case, I contacted Michelin about it and they actually sent out an investigative team with engineers to study the event. They eventually said that my lack of having hub centric rings caused a slight imbalance of my wheel which caused unnecessary heat, vibration and stress on the tire causing the rubber of the tire to seperate from the steel belt, which caused the catastrophic failure and blow out of the tire.

[Anaxilus]

Originally Posted by zoomzoomers

In my personal experience you don't absolutely NEED hub centric rings, but if you do a lot of tracking or a lot of hwy crusing then I'd suggest you spend the money and get the rings. I've run with and without them. The one time I had issues while running without them was when I was doing a lot of hwy cruising on a daily basis. I'd say I'd daily do 120 miles +. What ended up happening was a catastrophic failure of one of my front tires which caused a bad spin out on the fwy. The blow out caused me to lose control of the vehicle and I ended up doing a several, I think 3 to 4, 360's on a 5 lane fwy finally coming to a stop in front of a very large group of oncoming traffic.

Let me just say it wasn't pretty. I nearly caused a huge pile up at best and loss of life at worst due to me losing control of the car. Thank God nothing happened. In either case, I contacted Michelin about it and they actually sent out an investigative team with engineers to study the event. They eventually said that my lack of having hub centric rings caused a slight imbalance of my wheel which caused unnecessary heat, vibration and stress on the tire causing the rubber of the tire to seperate from the steel belt, which caused the catastrophic failure and blow out of the tire.

Interesting, so the wheels and lugs were fine but the tire blew out. Here I was about to give Michelin another chance after all the near fatalities they've caused in racing by pushing safety to the curb for that 'edge'. Now I hear this. I wish I could hear another story like this from say Bridgestone or Goodyear as Michelin's credibility w/ me is pretty much shit.

Tbh, I've run some piss poor balanced tires due to shitty old rubber shedding off shoulders from buying cheap closeout model tires (Avon). I've seen Kumhos and Sumitomos run on thread w/ uneven wear. For all the imbalance scenarios, I've never seen or heard of a tire blowout due to lack of rings causing imbalance.

Did you feel a severe imbalance from that corner when driving? Did you get to see the the flat spot on the tire that caused the rupture? I'm actually seriously concerned as I might back off my Michelin purchase and put them back on my blacklist.

Put it this way, if you have to ask, just put rings on your car.

[switchlanez]

Originally Posted by Anaxilus

You're not convinced? You mean I'm not convinced. You're the one speculating and have the burden of proof by offering a hypothesis that those pics are the result of operating w/o a hub ring. So it's your burden to prove your argument, not mine. I'd like you to try to explain how shearing forces from the road managed to only snap 3 of the 5 studs off and left two others perfectly intact. You also forget these wheels are supposed to be attached to working independent suspensions.

That said, I don't see how we really disagree tbh. I'm in the recommended but not 'needed' camp. If you want to put 35lb crap wheels that cost $10 to make from China, then good luck, maybe hubrings w/ reduce the rate of stress fracturing so you get an extra 3 months out of that garbage. I bet I'd ROLFMAO after doing a road force variance test on those wheels off that SC430, assuming they are even actually round. Hubrings also sure as hell won't prevent idiots from overtightening the wrong type of lugnuts w/ a 1/2" breaker bar on the wrong type of wheel. Nor will they stop morons cutting their springs w/ a torch thus altering the spring temper so their car rides like a 50's pickup truck.

Like I said, do what makes you comfortable. Maybe some people like racing w/o a condom, I don't know. I'm not going to ask. If you don't know what you are doing, then go for it. I can also tell you a bunch of stuff manufacturers do that I don't. Using 40lb batteries, carrying dead weight spares, TPMS, heavy wheels, piping in crap sound inductors, simulating engine noise via Bose, nerfing throttle response for CAFE, installing useless back seats, etc, etc.

So you talk about what's 'likely' to happen. I don't see that you've demonstrated operating properly w/o hubrings makes it 'likely' all your lugs will shear off.

Annnd still doesn't change the physics.

[aCab]

Thread is stupid. A plastic hub ring aint gonna do shit but help center the wheel when you're installing it. If you tighten the bolts while the car is off the ground, the lugs center it. End of story. Hub rings have nothing to do with supporting the weight of the vehicle.

Hub rings ensure proper installation and center of the wheel, but are not necessary as mentioned before. If you know what you are doing and take the time and care to ensure that you install and tighten your wheels correctly, then you're not going to have an issue. Anyone who says differently is seriously misinformed, just like a lot of garbage posts on this forum.

[zoomzoomers]

Originally Posted by Anaxilus

Interesting, so the wheels and lugs were fine but the tire blew out. Here I was about to give Michelin another chance after all the near fatalities they've caused in racing by pushing safety to the curb for that 'edge'. Now I hear this. I wish I could hear another story like this from say Bridgestone or Goodyear as Michelin's credibility w/ me is pretty much shit.

Tbh, I've run some piss poor balanced tires due to shitty old rubber shedding off shoulders from buying cheap closeout model tires (Avon). I've seen Kumhos and Sumitomos run on thread w/ uneven wear. For all the imbalance scenarios, I've never seen or heard of a tire blowout due to lack of rings causing imbalance.

Did you feel a severe imbalance from that corner when driving? Did you get to see the the flat spot on the tire that caused the rupture? I'm actually seriously concerned as I might back off my Michelin purchase and put them back on my blacklist.

Put it this way, if you have to ask, just put rings on your car.

No didn't feel anything out of the ordinary, until right before the blow out. It felt like I was rolling on a imbalanced or oblong tire on the passenger side. Then the blow out. The techs said that what I felt was the catastrophic seperation of the steel belts and the rubber treads. The wheel and lugs were in serviceable condition after, but I ended up just buying a new wheel for that corner.

Lilke someone said previously, it was most likely due to improper mounting that caused the chain of events leading to my accident.

[switchlanez]

Originally Posted by aCab

Thread is stupid. A plastic hub ring aint gonna do shit but help center the wheel when you're installing it. If you tighten the bolts while the car is off the ground, the lugs center it. End of story. Hub rings have nothing to do with supporting the weight of the vehicle.

Hub rings ensure proper installation and center of the wheel, but are not necessary as mentioned before. If you know what you are doing and take the time and care to ensure that you install and tighten your wheels correctly, then you're not going to have an issue. Anyone who says differently is seriously misinformed, just like a lot of garbage posts on this forum.

So basically what you're saying is physics is garbage. Lug-centric mounting relies on the studs' ability to withstand shear forces to suspend the car along with some friction. Hub-centric mounting not only employs the above but also leverages the axle via the hub. Suggesting a flimsy ring = nothing is plain incorrect as both sides are *mated* to the hub/wheel allowing direct transfer of normal forces between hub/wheel. With no hubring, normal forces cannot transfer across air.

20 tiny studs are designed to hold wheels onto the hub. 2 MASSIVE axles are designed to hold the weight of the car on ground; hubrings make that possible. Would you rather suspend your car in the air by 20 tiny studs or the 20 studs and 2 massive axles?

[White64Goat]

Of course there is a LOT of missing information from the picture(s). It was run without rings and this damage happened because???

Hit a curb?
Went around a corner at 120 mph?
Wheel broke and rotor hit the ground?

If the studs 'just broke' during normal straight line driving then I'd have to say way over-torqued. (or tightened without a torque wrench).

Rings do center the wheel on the hub and cars run without them (some, not all) have experienced wheel balance issues.

[switchlanez]

Read the following piece of purely mythical garbage :

"...wheel nuts are simply there to hold the wheel on, NOT support the weight of the car. Also, as there is nothing to centre the wheel, you'll notice the wheels go in and out of balance because as you drive around, they'll move around on the hub.

Bingo! Three broken studs. The wheel vibrates, wobbles and the other studs work loose once some studs are sheared through. See the rusty ring around the middle? That is roughly where the spigot (hub) ring should go supporting the wheel on the hub. The studs cannot support the wheel force - they can only hold the wheel on the hub. Studs are one and half times weaker in shear than tension. Once a stud shears it places more load on the other studs. Usually the wheel wobbles nuts off before all the studs shear."

[switchlanez]

Originally Posted by White64Goat

Of course there is a LOT of missing information from the picture(s). It was run without rings and this damage happened because???

Hit a curb?
Went around a corner at 120 mph?
Wheel broke and rotor hit the ground?

If the studs 'just broke' during normal straight line driving then I'd have to say way over-torqued. (or tightened without a torque wrench).

Rings do center the wheel on the hub and cars run without them (some, not all) have experienced wheel balance issues.

http://www.planetsoarer.com/offset/studs.htm

[White64Goat]

I'd say running without the rings on those wheels was a mistake.

[aCab]

From TireRack:

The centerbore of a wheel is the machined opening on the back of the wheel that centers the wheel properly on the hub of a vehicle. This hole is machined to exactly match the hub so the wheels are precisely positioned as the lug hardware is torqued down. Keeping the wheel precisely centered on the hub when it is mounted will minimize the chance of a vibration. Some wheels are vehicle model specific and will come from the factory with a bore machined to match that vehicle. Some wheels are designed to fit multiple vehicle models and will use a centering ring system to reduce the bore size to match the hubs of different vehicles. These rings keep the wheel precisely positioned as the lug hardware is torqued down.

Some wheels are non-hub centric by design. These are known as lug centric wheels. With these wheels it is critical to torque the lug hardware with the vehicle on jack stands, off the ground. This allows the nuts or bolts to center the wheel and torque down without the weight of the vehicle pushing them off center.

http://www.tirerack.com/wheels/tech/...jsp?techid=91&

I see NOTHING about them supporting ANY load.

Also:

What is the purpose of centering rings? Are they required?

Some wheels are designed to fit multiple vehicle models and will use a centering ring system to reduce the bore size to match the hubs of different vehicles. These rings help to keep the wheel precisely centered on the vehicle hub as the lug hardware is torqued down. The clamping force of the lug hardware in the lug seats is what mechanically centers and secures the wheel in place on the hub.

[wparsons]

Originally Posted by switchlanez

http://www.planetsoarer.com/offset/studs.htm

Notice they talk about running flat seat lugs, which WILL NOT center a wheel. If that guy ran flat seat lugs without a centering ring, it's his own stupid fault.

Originally Posted by aCab

From TireRack:

http://www.tirerack.com/wheels/tech/...jsp?techid=91&

I see NOTHING about them supporting ANY load.

Also:

This!

AND...

Have a look at what a hub looks like:



then think about the offset of the wheel and how the forces would interact against that tiny lip (~10-12mm) on the hub. Unless you're running 0 offset wheels there will be a lateral force acting on the wheel mating surface just by setting the car down, and a large enough force will tip the wheel in or out (depending on +ve or -ve offset) and pull it right off the centering ring.

[Anaxilus]

Here is a nice thread discussing the issue, I recommend those interested read it. You'll find an explanation of how the lugs actually maintain the weight of the vehicle even w/ hubcentric wheels and rims. Also how the static distribution of weight is relatively minor compared to the dynamic load on the lug nuts in motion. I was going to ask about the amount of shearing from dynamic loads when you apply throttle and braking which put the stress on the lugs and not the hub center, but the link below clearly explains why lugs simply need to be able to handle all loads regardless of dynamic or static conditions.

From a couple of actual engineers:

http://forum.miata.net/vb/archive/in.../t-127227.html

Ergo, most problems w/ lugnuts shearing are installation or user error. Simple. Hub rings may prevent some of these issues but they are not the actual solution themselves. It's like putting plastic covers over your outlets so you don't stick you fingers in them.

In essence, If you or your installer do not know how to install lugcentric rims properly, use the rings. If you are still worried and want to feel better for peace of mind, use the rings. If you get what is actually happening in the physics model and confident in your understanding of how your car is maintained, you do not 'need' rings.

The reason manufacturers use hubcentric wheels despite increased material cost is ease of production. If you look at a modern assembly line, the wheel is placed centered on the hub and the axle holds it in place while the vehicle is suspended. This allows the installer to free both hands to install and torque down the lugnuts onto the wheels. Without the hubcentric design during assembly, you would loose access to one hand which would have to hold each wheel in place while you fumble about w/ the other hand. You'd have wheels flopping around and falling off the line all over the place. In the end, the added material cost is irrelevant to the massive cost saving from efficient assembly processes.

If you are worried enough about hubcentric rings, I'd recommend adding these to your cart too: http://www.summitracing.com/parts/ar...7716/overview/

[switchlanez]

Originally Posted by aCab

These are known as lug centric wheels. With these wheels it is critical to torque the lug hardware with the vehicle on jack stands, off the ground. This allows the nuts or bolts to center the wheel and torque down without the weight of the vehicle pushing them off center.

Please explain how we would torque our front wheels when they are completely off the ground, free-wheeling.

Originally Posted by aCab

I see NOTHING about them supporting ANY load.

Because they don't have to. Tirerack is in the business of selling wheels. If they go into load discussion, not only is it a tangent but it'll give people an inkling of why perfectly matched center bore is ultimately the only way to go when it comes to safety and they'll not want to buy aftermarket wheels from Tirerack.

Originally Posted by aCab

The clamping force of the lug hardware in the lug seats is what mechanically centers and secures the wheel in place on the hub

Agrees with what I already said: "20 tiny studs are designed to hold wheels onto the hub." But the hub supports the weight of the car and a hubring will transfer that load more directly.

Again, this entire debate boils down to this: Would you rather have 20 tiny studs holding your car up or 20 studs AND 2 massive axles?