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I have 4 Borbet Xl 17" 7.5 wide rims with a bolt pattern of 114.3 and 40mm spacing that i used to have on my 2003 dodge stratus coupe r/t. I've read up on people being split on the idea of using 114.3 on 115 bolt patterns and whether its a good idea or bad idea. I'm trying to find sizing for a hub centric ring that would work to help minimize issues and help keep the rim more secure also. So if anyone has any comments or ideas it would be very helpfull. I have cooper studless winter tires i'm going to be putting on the car soon and figured it would be nice if i could still use my other rims for summer and the factories for winter.

My rims

 

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As you know, there are two schools of thought on that, and it looks like you've already done your research, so go with your educated guess.

Personally, i don't think it's an issue. 0.7mm is the width of the lead of a mechanical pencil. In all cars i've owned, without a hub centric ring, there's certainly more play than that.

That said, you certainly should get the correct hub centric ring. It'll center your wheel properly, reduce vibrations, and ensure proper distribution.

Inside/outside clearance-wise, you're good.
 

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Mismatch, even that small of a one is a bad idea. It will require each stud to "bend" as you torque up the nuts, and since hardened studs don't bend, it is likely to result in some broken studs. Really bad idea!
 

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Get the rings, metal ones and try mounting the wheel on the car before buying or mounting any tires on them, then decide.
 

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Great looking wheel, I can see why you want to use them.
 

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If the rim uses a tapered seat lug nut, I would advise against. If the rim uses a flat washer style lug nut, and it fits over the studs, a centering ring should take care of things. I know other people have used it anyway, and it works, but the tapered holes on the rim aren't really lining up with the lug nuts - I don't think it's a good idea long term.
 

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Personally, i don't think it's an issue. 0.7mm is the width of the lead of a mechanical pencil. In all cars i've owned, without a hub centric ring, there's certainly more play than that.
I had the Volt up on the lift the other day, with the wheels off, and think this is a good observation. If what centers the wheel is the hub-ring, .7mm may not matter too much in terms of balance. Your problem could then be the conical lug bolt seating properly. Each one is going to have a sheer forse pushing the bolt head inward, applied by the wheel's slightly smaller bolt center. I haven't played these distances (.7mm), but think it could be safe so long as you feel for vibrations and frequently check for all 5 bolts.
 

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Have you folks ever tried fitting tapered/acorn nut aftermarket wheels with the correct PCD but without hub centric rings? There's quite some play, the bolts through the holes are never a tight fit.

Anyway, this was interesting:
http://www.automotiveforums.com/vbulletin/showpost.php?p=6945048&postcount=4

I wonder if anyone here could do the same measurements on the OEM set-up.

For anyone looking for exact 115mm pcd's, most wheel manufacturers can custom drill wheels for you if they're not already available.
 

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Please please please dont use a conical bolt on those........your putting a hell of a shear load on the studs......35mm on each one. Simple solution is to use like i have offseting wheel bolts......horribly knkwn as wobble bolts. They are absolutely fine and will take the .35mm offset without putting shear loads on the studs.....also make sure you do get the correct size spigot rings.
 

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Please please please dont use a conical bolt on those........your putting a hell of a shear load on the studs......35mm on each one. Simple solution is to use like i have offseting wheel bolts......horribly knkwn as wobble bolts. They are absolutely fine and will take the .35mm offset without putting shear loads on the studs.....also make sure you do get the correct size spigot rings.
Mismatch, even that small of a one is a bad idea. It will require each stud to "bend" as you torque up the nuts, and since hardened studs don't bend, it is likely to result in some broken studs. Really bad idea!
Read this thread: http://www.cadillacforums.com/forum...012/253334-114-3mm-fit-115mm.html#post2880388

There are many others like it around the interweb. Some people do and get away with it. Others don't.

Oddly, people who've had a wheel fall off and died in the resulting crash, don't post all that often. Wonder why?

No advice here.... just some facts.

[1] 0.7mm = 0.028" (and 1/2 of that - which is the actual offset at each stud - is actually ony 0.014"). This is NOT an absolute, as there is a mfg tolerance which needs to be accounted for.

[2] You will need to determine how accurate (consistency) each hub is by actual measurements to know the tolerance in each wheel under manufacturing acceptance. This will give you a snse for the actual expected delta between the hubs stud rig and the wheels bolt hole ring.

[3] You'll also have to check the tolerance in he wheel mfg itself.

[4] You'll need to know the material stength to compare to the calculate loaded force stress value for the worst-case mismatch in the concentricty between the hub and wheel.

[5] Finally... you can calualte the stress induced at each stud. Be sure to dd back in the stress taken away by using the hub centric ring (so you'll need to know that too).

[6] now apply that to the calculated force expected on the "worst-case" cornering

Use:

As = P/A = P /(Pi*Db^2/4)

As = Average Shear
Db = Diameter of bolt (Minor Dia)
P = Load

And you'll have to calculate it to the force applied as the deflection of the stud (about 1/2 degree WCI) so AS * tan(<WCI)



... all this is really long to say this:

Is it "safe"? Well.... depend on the load being applied. The stud is there to hold the wheel "ON", and the hub - when fitted properly to the wheel (concentricity) minimizes the load de to vibration. So if you "race", expect MUCH GREATER stresses to be applied. For around town driving and low speed highway (like under 90 MPH), then the stress is propably negligable when properly mounted (using hub-centric rings) and torqued. But - there is some variablity due to the tolerances in manufacturing. That is accounted for by the mechanical engineers (and testing) to insure that such tiny (but acceptable) tolerance can be overcome. So - in essence - there is a engineered acceptble level of stress which can be tolerated.


Now.... it's up to you to find out exactly what that is. Like I said - the delta between 114.5mm and 115mm rings is .35mm at the stud it self (or 0.014"). What tolerance did you measure in your hubs?
 

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PS... I would expect that the wheel quality should be taken into account more so than the GM hub (and stud), as this is a more likely place to "discover" a failure. IE - cheap Chinese wheels probably do not stress really well.


YMMV
 
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