Center Bore
 

Question to the wheel gurus..If a wheel with 57.1 center bore was purchased for our cars we would then need "what" to allow it to fit properly? Thanks in advance for any assisrance :thumbup:

The hub bore for our cars is 56.1. You will need what is called a "hubcentric ring" to adjust for your difference. Talk to your local wheel/tire shops and see if they can get what you need.

If your wheels are lugcentric and lugs are conical w/ the right face and angle, using a proper star pattern installation at the proper torque spec, you do not 'need' hubcentric rings. Haven't used or needed a hubcentric ring in more than a decade. Of course you can put them on if they make you feel better.

If you do buy some, don't buy plastic unless you are comfortable throwing them away w/ your rotors after they melt onto them. Hubcentric rings are more necessary for German cars that use one piece lugbolts.

I'm no wheel expert but a quick Google search shows this (wheel basics):

"There are some people who will say that driving on lug-centric wheels doesn't really matter as long as the lugnuts are the self-centering cone type, as they will adequately center the wheel. These people are wrong. Driving on lug-centric wheels means that any impact will apply shear force to the lug studs, forces at 90 degrees to those the studs are designed to handle. This can cause the lug studs to bend, leading to a vibration in the car as the wheel slips around on the mounting plate, and possibly damaging the wheel's center bore if it has enough play to contact the axle. To prevent this kind of thing, aftermarket wheels will usually need hub-centric spacers, small rings of metal or plastic made with various inside and outside diameters so as to fit inside the wheel hub and then fit over the axle, making a lug-centric fitment into a hub-centric one."

The bit about unintended orthogonal forces acting against the studs, I do believe. Studied forces like that at a basic level in college then again when I got my EIT certification.

http://tires.about.com/od/understand...ric-wheels.htm

all the hub rings do is make it seat easier. Ive ran the plastic ones in my STi for years on autox and track days, and they never melted, even when i cooked my brakes.

Myself and others have beat up and tracked cars w/o rings and had no issues. Like I said, if it makes you feel better go for it. Of course everything is relative so people need to make up their own mind based on their own conditions. Since many of us have had no issues, I stand pat that they are not 'needed'. Recommended? Perhaps. I'd recommend a lot of things, like people actually using their fucking blinkers for example.

I have seen someone w/ a PoS 90's Camaro pull into a shop and have the wheel fall off right after it came to a stop, all the lugs were snapped. Personally I've had 5 cars and never had an issue, but I don't drive GM products nor am I redneck enough to Kentucky Windage my torque specs.

Well I certainly melted mine that I used for Kosei K1s on my old '92 Corolla ages ago. Does smoke billowing out under the front fenders count as cooked brakes? That was street driving btw. Of course, one would expect your STI to have more efficient brakes than a Corolla.

Here's a car from a reliable manufacturer that ran without hub rings:

http://planetsoarer.com/offset/4129.jpg

http://planetsoarer.com/offset/4686.jpg

http://planetsoarer.com/offset/4688.jpg

http://planetsoarer.com/offset/4739.jpg

http://planetsoarer.com/offset/5849.jpg

http://planetsoarer.com/offset/5851.jpg

You can certainly get away with running no hub rings. But why toy with death? Instead of thinking of it as $20 saved, consider it cheap life insurance. In the unlikely event that plastic rings melt, they're not impossible to clean off. Aluminum rings can seize but nothing a screwdriver can't pry off with a tap and WD-40.

Thanks for the help guys.. I meant to close this thread after I got some lesson from Google.. I'll be spending the $25 bucks if I chose to get those wheels.. It's looking like I'll be going with brand new wheels for next summer and should need the hub rings anyways.. Thanks again! ;)

For anyone claiming a plastic hub centric ring will prevent snapped studs, go look at how little meat there is on the ring. It's not going to do anything except hold the wheel centered while you tighten the lugs.

Over torqued/stretched studs are a far more likely cause for the snapped studs. Look closely at the picture, you can see that the stud sheared off in the middle of the depth of the spacer, not at either edge.

If you hit something with the wheel hard enough to snap good condition studs, ring or not those studs are going to shear and the wheel is going to be toast.

Get Aluminum Rings, call it a day.

Can you even get 1mm rings though? All the ones I've used in the past are like 56 --> 70+ mm hub centric rings.

56 --> 57 is tiny and minimal difference.

(Winter tires are from my old Jetta, 57.1mm)

Lol, I want to see what that wheel looks like. You have two perfectly intact lug studs w/ all that body damage? No freaking way that damage was caused by only losing three of five studs. If I had to guess, that big fat cheap ass, poorly cast wheel exploded or separated in half. That's why the rotor is only damaged in the same area. Half the wheel stayed on, the other half took a different trip. No hub ring will save a crap wheel from fracturing itself.

Also can't see what lugs he used and the design of the wheel lug seats. User error does not look unlikely here.

I'm still not convinced. All that speculation doesn't change the fact that, without hubrings, more shear force gets applied to the studs which aren't intended to take 100% of the forces in the vertical direction. Why don't OEMs use larger bore wheels? It'd be more universal and, hence, cost effective. Because a hub matched wheel distributes more load to the hub. That's why OEMs bother to match them and Tirerack ships their wheels with hub rings.

This is a debate of what's likely/unlikely with physics as the rationale. Maybe 85% of people without hubrings won't run into problems. Among the remainder, maybe 14.5% will undergo undetectably faster wear than people with hubrings and 0.5% will have instant catastrophic failure. But among people with hubrings, maybe 99% will not see those problems. Yes, these are hypothetical values but illustrate the idea of odds. It's not 100% you will or you won't. In analog, a little over 1 million Americans have been diagnosed with HIV. That's not even 1% but a fraction of 1% of the American population. You'll likely never catch HIV if you never wear a condom your whole life. But the tiny odds are enough for people wrap it up. Why choose to increase the odds when lives (or cars) are at stake?

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.

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.

Annnd still doesn't change the physics.

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.

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.

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?

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.

Read the following piece of purely mythical garbage :rolleyes::

"...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.

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

From TireRack:


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

I see NOTHING about them supporting ANY load.

Also:

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.

This!

AND...

Have a look at what a hub looks like:

http://planetsoarer.com/offset/4686.jpg

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.

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/

http://static.summitracing.com/globa...-7716_w_ml.jpg

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

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?

^^ You clearly either missed or ignored the link to the miata site where actual engineers chimed in with real world numbers and clearly stated that with lug centric wheels/lugs centering rings do nothing but hold the wheel centered while you tighten the lugs.

Also keep in mind that the only time there is a purely vertical force on the lugs is if you're running 0 camber with 0 offset wheels while at rest. The dynamic forces are all over the place and all rely on the lugs to hold the wheel in place.

False choice, the 20 tiny studs are in fact what always puts the weight on the both axles. If the weight of the vehicle is actually on that plastic ring after installation, something is more than likely wrong. See above.

I never said hubrings are necessary; only that they're better especially when $25 can save cars/lives.

I used to believe hubrings were purely for mounting and not loading purposes. As recently as earlier this week, when I advised my friend that he didn't need hubrings for his Enkeis so long as he mount them perfectly centered. Til this thread prompted me to look into it.

I read through that Miata thread. Saw opinions stating 20 studs support the weight alone and people stating the studs combined with hubrings will help some. My hubrings have a conical tapering so they fit completely snug with NO play *before* I torqued down my conical lugs. Hard to believe no load gets transferred through fully seated hubrings with 0 gap fitment.

I still say 20 studs/conical lugs + hubrings > 20 studs/conical lugs alone.

@aCab, @Anaxilus, @wparsons, lug-centric front wheels must be torqued completely off the ground to properly mount them to the FR-S/BRZ. So how do you do it?

Torque down does not equal torqued to spec.

It's pretty clear that clamping force from the conical lugs is what puts the load on the actual hub and wheel mounting surfaces. If the hub center has to support any load after installation of a lugcentric wheel, something is mechanically wrong somewhere. The lugs mechanically position and glue the wheel to the hub, not the hub center. Deny it all you want, you'd be incorrect. But if the ring makes you feel better, go for it.

I admit I once found the task completely impossible for mere mortals, so I've since learned that sprinkling ground unicorn dust on my wheels does just the trick. :D

Hand tightening lug-centric wheels before dropping the weight of the car does not sound reassuring. Especially when it requires both hands to apply forces that pull the wheel off-center as you hand torque the lugs instead of using both hands to hold the wheel centered as it's torqued.I never denied clamping force plays a part. If it didn't, we'd have a serious problem. I also don't claim the hub center supports 100% of the load. I just don't see how no normal force (load) can get transferred when there's 0 gap at the hub rings. Especially when the clamping force applied by the lugs seats the wheel against the chamfer of the hub ring. :iono:

Does physics make me feel better than "pretty clear" speculated claims? Yes.

So when physics and engineering disagrees w/ you, it's just a speculated claim? Apparently ignoring real physics and engineering to rely on lucky charms makes you feel better too.

http://www.idsfa.net/miata/lugnuts/page1.jpg
http://www.idsfa.net/miata/lugnuts/page2.jpg

1) Please point out where he factors in shear strength of the studs. I might be overlooking where he included that. All his calculations focus on friction (tension) and that would be a huge oversight. Studs being 1.5 times weaker in shear than in tension (aka frictional clamping force) would make them the weakest link as demonstrated by the real life example I posted earlier; your guy seems to neglect shear force and focuses entirely on clamping force.

2) He assumes the thread's coefficient of friction mu and collar friction mu c to both be 0.15 with no reference to how that value was determined. An interesting coincidence: The textbook from my basic Physics for Engineering class used an assumed value of u=0.15 for the sample and homework problems in the chapter that introduced us to friction. Seems he used the same number here (aka pulled that number out of his ass). Actually quite hilarious and nostalgic (for me). :bellyroll:

Lack of calculations for shear and speculated coefficients of friction reduce his calculation to speculation making it invalid enough to ignore. Believing in how components are clamped against each other and transfer load (via hubrings) involves no luck nor odds.

When I made the first reply to this thread, it was one notch from being bumped to page 2 of wheels and tires and forgotten forever. I had NO idea it would spark such passionate debate. Think about this. Hours have been spent in this thread putting forth perspective and reason.

Amazing.

http://i2.kym-cdn.com/photos/images/...70/623/337.gif

My dilemma. TRD wheels 54.1 center bore against 56.1.


http://vid1164.photobucket.com/album...307_084325.mp4


would hubcentric rings be my solution? Thanks for any info provided.