1o80b

Specs :
18" x 9"
5/120
Offset : 20mm
$185.99

http://www.1010tires.com/wheel.asp?w...eelmodel=R-505


I will need speacers right ?

CharcoalBird

iTrader: (4)

Rear you won't need a spacer, the front you will need a 3/4" spacer to get it back to 0 offset...you could probably pull off a 1/2" though.

Make sure to get hubcentric rings also.

87350IROC

iTrader: (2)

Not to mention the bolt pattern is off. Our cars are 5x120.65mm. You will need to consider how you are going to deal with this situation.

If you are getting spacers anyway, I would recommend getting custom ones that adapt the car's 120.65mm to the wheel's 120mm.

rlewi771

really? thoses?

1o80b

It know but 0.65MM is not very much :O it will stress the stud just a little no?

1o80b

I have those bolt...

it might be ok!
http://www.ebay.co.uk/itm/PCD-WOBBLY...item4398456360

CharcoalBird

iTrader: (4)

I've never seen those before. Good find. I will do some research on them just incase.

87350IROC

iTrader: (2)

Wobble nuts are great as long as you can be assured that you have a very good hub-centric fit on the wheels. Can you be sure of that?

I'll go out on a limb and assume they are not hub centric to our hubs since they don't even have the correct bolt pattern.

So now your hubs aren't locating your wheels, and your lugs aren't locating your wheels. So what is? .... Nothing.

I would do what //<86TA>\\ did and re-bore the lugs correctly. If you are not comfortable with this operation, pay a machine shop to do it.

https://www.thirdgen.org/forums/whee...t-pattern.html

kickass92z

I ran a set of these on a 99 T/A. The bolt difference is not enough to affect it if you get the right hub centric rings. Contact the guys at Wheelsnext in Cali. That's where I bought mine....

87350IROC

iTrader: (2)

Man I get tired of typing this several times a month. But my conscience leaves me no choice.

Hub centric rings have no affect on the strength of the studs. Their sole purpose is to locate the wheels.

Wheels studs are no different than any other fastener, in this case a bolt. Bolts are designed to take load in tension, pulling along the long dimension. Their job is to hold a joint together so the joint can take the load. They can be visualized as a clamp. They simply clamp up parts. In the case of wheels studs, they hold the wheel to the hub such that the friction between the wheel and the hub is sufficient to carry all the forces through the wheel.

Bolts are not designed to be loaded in bending. When you use the wrong bolt pattern, the studs must be bent to compensate. The lug nut pulls the stud sideways into the wheel seat which bends the studs. The strength lost due to the bending is strength that is not longer available for the stud to do its main job, clamping up the wheel to the hub. So now you have a situation where you have removed a bunch of the safety factor designed into the joint.

I'm not going to say it is guaranteed to fail, but you have basically increased the risk from nothing at all, to something tangible. Obviously there are lots of people running around without problems. But that does not mean that there won't be problems tomorrow. For me spending $100 on doing it right is a small price to pay considering all the blood, sweat, and tears I have in my car. Not to mention, the value of my life and anyone I hit when my wheel flies off.

//<86TA>\\

iTrader: (14)

Find a metric ruler and look at how large that is. Its much more than people think, there is a pic in my thread that 87350IROC posted of a lug hand tight on a 5x120 bolt pattern wheel, look at the gap, its large enough to be worrysome.

If you want to do this job right, and want to spend some time making a
simple jig, I can rent you the tools to re-bore the lug holes to the proper pattern.
You will need longer, hardened wheels studs of you plan to use a slip on spacer anymore than 1/4" thick or so.

bsporty

I have these on my 85.I got them from Wheelstudio.http://www.wheelstudio.com/
I did have to use spacers and the front center caps don't fit but I didn't care just painted it silver.


I got 18" up front and 19" outback.19" tires are $$$$ but I like the look and I had the money so I went for it.

cal30_sniper

iTrader: (16)

Yes and no. Hubcentric rings add a lot to the strength of this setup (good aluminum ones, not the el-cheapo nylon ones). With the hubcentric rings in place, the hub is taking the radial force being applied to the wheel, as opposed to it being distributed amongst the five studs on a non-hubcentric wheel. 14mm wheel studs are not going to bend ~.3mm so that the bolt pattern lines up. Instead, the conical seat nuts will simply not bear on their entire surface. As long as you tighten the lugs up progressively, in a star pattern, with hubcentric rings, the studs will stay straight. The conical seat nuts will bear on most of their outer surface, and the wheel will be on like a glove.

Somewhere in a notebook is the stress/strain calculations I did using the measurements from my BMW rims when I first did this swap. Conclusion was, the slight increase in bending moment is still negligible compared to the stress imparted by tightening up the lugs to full torque. (Especially considering that these lug designs are going to have a Factor of Safety that's much higher than 1.0 from the factory).

Conclusion and Cliff Notes: A .3mm difference in bolt pattern on a hub-centric wheel places less stress on the wheel studs than a non-hubcentric wheel of the appropriate bolt pattern. How many millions of aftermarket wheels have been run in the last 100 years that were not hub-centric? (hint: all but the super-expensive ones aren't hub-centric) If you want a feel-good extra factor of safety, just press out your old, rusty studs and drop in some new ARP or other quality studs in their place. If you're going to be pushing your vehicle WAY beyond its design limit (Poly-Motorsports T/A kind of stuff), then you should be looking at the lug pattern rebore. If you're going to daily drive/autocross/drag race your car, the difference is negligible.

-cal30sniper

cal30_sniper

iTrader: (16)

Don't get me wrong, I'm not saying that it doesn't increase the stresses, I'm just saying that properly executed, there's a lot worse things out there that you could be doing to the integrity of your wheel/lug/hub interface, and running a non-hubcentric wheel is one of them.

This is also the reason that I hand tighten my wheels, in the air, in a star pattern, with a torque wrench. When you start letting Joe-Schmucatello at the tire shop spin down your lugs with an air wrench, your situation suddenly got a bit more hairy. Not saying that the lug re-bore isn't a worthwhile mod for someone with the tools and experience (I'll be doing it when I get ahold of a spare axle and the right tools), but a hub-centric BMW rim is not going to of-its-own cause your wheel studs to shear off. You're going to have to take way more serious missteps to cause that to happen.

Think of it this way, if you're the sort of person that has to worry about whether your wheels are cast or forged, or will be pushing your car to limits beyond the wheel strength of your standard ARE, Cragar, Eagle, you name it lower-mid brand wheel, then you are the person that needs to be concerned about a re-bore. If you're just looking for a good-looking wheel for a great price on a daily driver, then get some hubcentric rings, good wheel studs, and your BMW wheel of choice.

cal30_sniper

iTrader: (16)

Absolutely. And I wouldn't advise ever running a slip on spacer thicker than 1/2" (I personally wouldn't go over 3/8"). There are wheels out there that will fit within these constraints. If you need to go larger, then get an adapter that bolts to the hub, and then the wheels bolt it it separately. If you're going this route, you can order pretty much whatever size adapter you want, and do the lug-size conversion and hub-centric ring right in the adapter itself. That's going to significantly eat into your savings of going with the BMW wheels in the first place.

I would strongly advise finding a wheel that's close to the specs you need to begin with. You want as close to a 0mm ET front and 0 to +15mm ET rear wheel setup as possible. This will put you in factory specs, and alleviate the need for a spacer. Wheels designed to fit a 760 series will have +13mm front and +25mm rear ETs. 10mm spacers front and rear (or a 1LE hub upgrade up front), will put you right back at factory specs. Also, you want to keep close to factory specs for more than just appearance. Handling and road-worthiness can suffer drastically as you move away from the proper offset, and it can play heck with your wheel bearing life.

-cal30sniper

87350IROC

iTrader: (2)

Cal, this is not accurate.

In a bolted joint, the friction between the two mating surfaces takes the load. As long as the load is less than the frictional force, neither the bolts or the hub see any extra load. Bolted joints are designed so the frictional force is always higher than the load. You almost never design a joint to slip and induce shear in the fastener. Its just bad practice.

Now a factory 12mm stud / nut torqued to 80ft lbs has a clamp up of about 8000lbs. Now we have 5 studs, so 40000lbs of preload in the wheel/hub interface. Obvious you won't product that much load on an inside tire in a turn so we don't have to worry about the joint coming loose in tension. Now radially or circumferentially we need to calculate the friction force. The coefficient of friction between iron and aluminum is roughly 0.6. So the load to slip the joint is 40000*0.6=24000lbs. I think we can agree that is not going to happen in service.

With that said, no axial or circumferential load is taken by the lug/stud/hub.

Now regarding the studs bending. Yes, they will bend. Everything in our world is made of rubber bands, its just a question of how stiff the rubber band is. Again if we know each stud produces 8000lbs of clamp up, I find it hard to believe it won't move over and completely seat in the wheel. So for an 8000lb clamp up I figure the side load on the stud produces a maximum deflection of around 0.032". Whereas the stud only has to move 0.013" to line up with the BMW wheel. So I say the lug will indeed seat itself in the bore once torqued up. Granted this is a quick and dirty calculation.

Either way, its really not a good idea to side load a stud. And I don't care how many people successfully run BMW wheels. It only takes one time to ruin someones life. Take the advice or leave, its up to the reader to make a hopefully informed decision.

I would MUCH rather run a lug centric wheel with the correct pattern than a hub centric wheel with the wrong pattern.

cal30_sniper

iTrader: (16)

I'm following your calculations up through the .032" of deflection. I'm not seeing where that's coming from. The calculations are great, but you need to take a step out of Sophomore Strengths of Materials and look at this from a real world perspective.

The fact remains that these were designed to take way more abuse than a properly torqued, perfectly patterned, brand new wheel stud could ever possibly see. The engineers behind these designs had to take into account decades of heat cycles and corrosion, improper torqueing, *gasp* tolerance stacked wheels that aren't perfectly on pattern, etc. Have you ever watched a guy tighten up your lugs at a tire shop? He doesn't torque them down with a wrench, and he doesn't tighten them on pattern. He runs around the pattern in a circle, tightening them to whatever rough setting the air wrench is set up. Now you've designed a stud design that will take that kind of abuse, for 20 years of Michigan winters, because you introduced a slight bending moment to them. Then again, you've got the guy at home spinning them on with a lug wrench. Who knows what he's torquing them to? 80 ft-lbs? 30 ft-lbs? 110 ft-lbs? Chances are, he doesn't really know or care, but that's what they're designed to compensate for.

So lets assume 8,000 lbs of pre-load in each stud (they are studs, not bolts, different loading). In a 12mm wheel stud, that puts it under about 60,000 psi of strain. Now, a grade 10.9 wheel stud is proofed to 120,000 psi of strain, and has a yield strength of 136,000 psi. That's a Factor of Safety of 2+ just for the proof. Adding a bending moment increases the maximum strain in the bolt, but it does not do so magically. It rotates the maximum stress element within the bolt, increasing it as it does so. However, given the angles at play, you can see how the increase is going to fall well within the proper FS. Not to mention, by your own calculations, the hub/wheel interface is static as soon as they're tightened down, so we're not talking about fatigue stress from bending back and forth here.

For a final look, put the engineering aside and look at it from a common sense perspective. Aftermarket wheels are going to have patterns that are drilled within a specific tolerance, as are the hubs that are manufactured over decades at plants on different sides of the country. Improper tightening or poor torquing of the lugs after years, and years of service on a wheel that has no hub-centricity to help it center up on the studs is going to cause just as many, if not more problems than the slight bolt pattern difference of 120-120.65. Now think of the worst loading that wheel could ever possibly see, a violent crash. Now how many violent car crashes (with aftermarket non-hubcentric, factory, or high-end hubcentric rims) do you see where the wheel lugs shear off and the wheel goes flying off? You don't. The either break off at the spindle/balljoint/control arm area (high grade or factory wheel), or the spokes/rim of the wheel shears (low-grade aftermarket). That's because the studs are much stronger than the ball joint shaft or control arm bolts (which are in shear), even if they aren't perfectly and properly torqued. That's what they're designed to withstand.

Replace your wheel studs, follow correct procedures for torquing the down, and you will never have a problem with your wheel studs that something else doesn't break first. Having a properly centered lug-pattern prevents vibrations from an off-center wheel, just the same as a good hubcentric hub does. Having a perfectly centered bolt pattern just makes it much easier and less hassle to properly put the wheels back on after you've taken them off. You get more into the realm of letting the tire shop put your wheels on instead of doing them yourself. That being said, who out there that goes to the trouble of re-boring their own wheels is then going to turn around and let the shop put them on?

-cal30sniper

cal30_sniper

iTrader: (16)

You are completely right about the radial shock-loading being taken up by the friction though. Way too many hours of combustion on my mind when I went through that last night. Under driving conditions, a hubcentric and properly centered lug-centric wheel will experience the same forces. However, when improperly tightened, the lug-centric wheel can easily experience the same kind of bending moment in the studs as a hub-centric wheel with a slightly different bolt pattern. The studs are designed with that in mind.

Twin_Turbo

iTrader: (25)

I have been running bimmer wheels on my cars forever and nevr brok a stud, using hard plastic hubcentric rings. I probably run mine harder than most, twisty roads here and a lot of 100+ mph runs on the autobahn and such. NEVER had a failure, it's a non issue.

Johnny Blaze

iTrader: (15)

Bimmer wheels here too. Almost went with the RPM but found a set of Sterns that did not need any spacers.

87350IROC

iTrader: (2)

The 0.032" calculation is an idealized beam bending problem with built in support. Like I said, I made some rough assumptions, I wouldn't analyze my stuff without a better idea. If I get around to it, I'll work on it some more.

I'm not following. No doubt they the factor of safety includes considerations for things you have mentioned. However I can be pretty certain they are not designed with the assumption you will use wheels with the wrong bolt pattern. Regarding tolerance stack up. We are talking about a lug centric wheel where one of the studs is the datum point. Linear tolerance of the worst CNC mills is ~0.003". I highly doubt even the worst aftermarket wheels out there are going to be off by more than 0.005".


I calculate 46ksi. Radius = 6mm.

Area=(6/25.4)^2*pi=0.1753 in^2
Stress=P/a=8000/0.1753 = ~46000

I doubt every stud is proof loaded, but I could be wrong. I honestly don't assume anything, until I do the calcs.


No doubt, but those cars in the accidents you reference have the correct bolt pattern wheels on them. Not to mention the wheel is not highly loaded in most accidents in such a way to cause studs failure. Perhaps if you ran over a curb at high speed.

Again, you are forgetting friction. Control arm bolts are not in shear. They would only ever be in shear if the friction is overcome. At that load, the control arm shearing off is the least of your worries. That is another basic rule of bolted joints. Do not put bolts in shear or bending.

A bigger wheel stud will no doubt help the situation. Agreed for cases where you run the wrong bolt pattern, a hub centric fit will make it easier to center the wheels, that it though, it doesn't make the joint any stronger.

Look, I don't want to get in an argument. So far this is civil, which i appreciate. I'm just trying to share information so people can make their own decisions. Clearly you have though this through and are comfortable with the risks. However I cannot fathom how you have put so much blood sweat and tears into a car to run the risk when its so easily defeatable ($100).

cal30_sniper

iTrader: (16)

I'm all about civil discussion of a problem. As far as I know, this problem has never actually been aired out with calculations from both sides, perhaps its time to put some numbers and percentages down with the risks involved here. It's for the better knowledge of us all, and the safety of many of us. I am honestly not biased towards the answer at all, and it would certainly be for my benefit to put some figures to paper here. I did my original calculations years ago, and I've learned quite a bit since then. Perhaps it's time for a rework.

Just a few counterpoints from before:
The diameter of the stud is 12mm leading to an area of .1753, but the diameter at the root of the thread is less. The actual diameter at the root of the thread is only ~.388", leading to an area of 0.118in^2. That's 67ksi. If you use the Tensile Stress Area of the stud, you'll get a diameter of 0.407in, and an area of .130in^2 (ksi = 61.5). That's why I went at ~60k. The failure area is never as big as the shank area of the bolt/stud.

Not every stud is proof loaded. They are batch tested to within a certain tolerance using probability distributions.

\

You'd be surprised. In 3 years of working on a wrecker during high school, in an area with a speed limit of 80mph, you see some wild stuff (and some extremely poorly manufactured aftermarket wheels too). The most common case of a wheel failure/separation is a high speed roll-over. As the vehicle skids 90 degrees perpendicular to its original direction of travel, the lower control arm bolts and ball joint shaft go into full shear (due to angles, the leading edge lower control arms bolts are carrying almost the full dynamic force of the vehicle). Note that the upper wheel studs would be in probably the worst case of tensile stress that they have ever experienced as the wheel tries to pull away from the hub. Here's a little schematic, with control arm bolt and ball joint shaft in red, and upper wheel stud in blue:


Note that even this is usually not enough to cause catastrophic failure. The coefficient of friction between the tire and road is low enough that it begins to skid before anything breaks. However, if the tire is in poor shape or under-inflated, the force of this skidding actually breaks the bead of the tire, or tears the tread from the sidewall. Then all hell breaks loose. The solid rim edge digs into the pavement, the forces go way up, and something breaks. On factory rims, this is where the control arm or ball joint lets go, and the whole assembly folds under the car. That, in turn, rips the upper control arm bolts out, and there gos your front hub. In contrast, with cheap cast alloy wheels (or even worse, cast alloy wheels with a screwed up heat treatment from somebody's coating job), the spokes or rim of the wheel break off the hub, and you get basically the same result: Catastrophic rollover. This is why double bolt pattern wheels are so inferior, their shear area is much smaller.

That being said, for the number of wheel separations I have ever seen, a wheel stud failure has absolutely never been the cause. In fact, I've never seen even one of the 5-6-or 8 break off before the wheel or control arm lets go. Intuition tells me that if a stud can take that kind of force, even with a perfectly centered bolt pattern, that a small bending moment from a .6mm difference in bolt pattern is not going to anywhere near the cause of a failure. Then again, intuition has been wrong before, so I will attempt to back up my thoughts with a little FEA and see what comes out.

Hopefully we can settle this. Now the little man in the back of my head has started questioning me about my own setup. I will find out and report back.

-cal30sniper

Ruckusz28

iTrader: (3)

Looks Great!

Homer23

These rims look surprisingly good on a Camaro. I will save that wheel pattern for a Corvette when I purchase one.

Johnny Blaze

iTrader: (15)

Be warned these wheels are heavy.

toomany

http://www.wheelstudio.com/view-whee...ll/vehicle-all

These the same? Only in 5x120.7mm. Only .05mm off.

Edit: Silver- http://www.wheelstudio.com/view-whee...ll/vehicle-all

Chrome- http://www.wheelstudio.com/view-whee...ll/vehicle-all

Edit again: After seeing bsporty's pics again...I'm really considering these for my next project.

87350IROC

iTrader: (2)

120.65mm is commonly rounded up to 120.7mm. I'm sure they are 120.65mm wheels.

kickass92z

I am very impressed by the level of maturity of this debate. And, I did look at the issue and weighed both ways before I decided to buy a set. I know numerous people who have run the 5x120 wheels, with no issues. But, I do also understand the thought of it only takes one screw up to get someone hurt. Now that they have the 120.7 it's a no brainer for me. I will be ordering a set for my 92 Z. I hate that we are so limited on wheels options for our cars, unless we can spend 3k on a set. Good luck with you choice whatever you decide....

kickass92z

I love these wheels, and have wandered what they would look like, now I know. What size are the front 8"?? I plan to get a set also, thanks for the input...

Ruckusz28

iTrader: (3)

The lip really makes these wheels pop out. love them on this car.

Homer23

You can also get used C5 or C6 Corvette rims and wheel adapters as an affordable option.

reride

iTrader: (1)

What size tires (275/35's, 295/30's)are you running front & rear? Also, does your car have stock front brakes? They do look great! Also, what offset would I need with a 4th gen rear?