hubcentric ring sizes...

Deep6

Registered User
I have a small problem.

I have a new rim with a hub bore of 70.8mm. Of course my stock SC hubs are 63.9mm or thereabouts.

I have a set of 72.6mm to 63.9mm hubcentric rings from a previous set of 17" wheels that I had. They of course are just a smidge too big to fit into the new Cobra rims that I have.

I have looked high and low for a set of proper hubcentric rings and I've been in correspondance with a couple of different people.

Basically the 70.8mm outer diameter doesn't exist as a common size. I would either have to try and get my exisiting rings (or a new set of custom) machined.

The closest I've been able to find is a set of 70mm to 63.9mm. The company that is willing to machine the outer diameter of my rings cannot garuntee exact measurments due to "triangulating a small part on the lathe".

So my question is this, should I take my chances to get my exisiting set of rings properly machined to 70.8mm or at least very close, or would I be OK with a set of rings that are 70mm?

What is your guys advice and opinions?
 
First, are you experiencing vibration that you can't isolate? Don't get me wrong, I am very sympathetic to using rings as I have been through a nightmare trying to get "lug centric" cobra R's to run on my Dad's MVIII w/out vibration. But, if you have no probs, forget it for now is my advice. If you are intent on using the rings, then you are obviously, like me, wanting everything to balance out perfectly. In that light, I would not tolerate the .8 mm as your lug centric wheels probably wil get you that close. We had to end up machining the bore of the rim to get it to fit like centering rings should. The rings we are familar with are made out of a ultra hard plastic and the machine shops would not even try. That's my opinion based on the journey we have recently experienced. Larry
 
Re: Hubcentric Rings

I'm probably the only person here who doesn't know what these are, so would somebody be so kind as to explain them to me?

Are they some sort of wheel spacer?

Confused 68COUGAR
 
They are rings that ride over the hub flange and inside the bore of the rim. they remove any difference in inside bore diameter and outside hub diameter. Your rims are Lug centric, not hub centric which can cause the vibes especially if the rims and lug nuts have been on and off a million x's like mine. Larry
 
Hub-centric vs. lug-centric

LarryH said:
Your rims are Lug centric, not hub centric which can cause the vibes especially if the rims and lug nuts have been on and off a million x.
IC, so they are to correct an incorrectly machined part.

Wouldn't they also require different lug nuts? Cuz wouldn't taper seat lug nuts, try to pull the wheel back to the lug-centric position?

OR are these special rims that require hubcentric rings & special lug nuts?

Still a little confused, but I'm learning!

68COUGAR
 
no prob. No, use same nuts. They would try to pull rim but could not as the rings are hard palstic or aluminum and have little to no play. L
 
Bend or Un-seated?

Do they bend the lug, or just not seat totally in the lug taper in the wheel?

Is there a web site for these rings?

68COUGAR
 
There are actually quite a few sites that support the rings. It seems that they don't make just any size you need though. I gave Joe a handfull of places to look into and last I knew he had no luck finding the size configuratione he needs.

I myself run Lugcentric with 17X9 Bullitts and have no issues at all and doubt I will ever use the rings. Although I may end up using them later if I run into problems I suppose.

Joe...Maybe you can let me know what kinda luck you have ahd finding rings..

Cheers


Brad
 
Some answers...

68cougar: Take a look at your wheels, they have a big hole in the center of the 5 lugs. when they mount on your hub face (actually your disc brake rotor) the hub bore of the wheel perfectly matches the protruding hub center in the middle of the rotor/hubface. Bolting down the rim is simple.

Many aftermarket wheels have a larger hub bore. This is to accomodate as many OEM hubs as possible and thus increase the market applications for the wheel manufacturer. When you bolt one of these rims up to our applications, the wheel is not perfectly centered around the hub, but rather the lug nuts. There are slight variations and sometimes a lug nut/wheel stud is not enough to pull the wheel perfectly centered around the hub, at least on some micro measurment scale.

The end result is that the wheels will rotate with a high spot and a low spot, kinda like the way a clown's Jalopy car with offset hubs will ride at a circus. (the clown's car is specifically built that way and is for entertainment value only).

The hubcentric rings take up that lost space and help to center the ring better.


Larry H: What were the inner and outer diameter you used? Were they outer: 70.8mm and inner 63.9mm?
I don't have any REAL vibration. I guess I want them more for "peace of mind". But I do feel a little grainyness at higher speeds and would like everything on my side to eliminate it.

Cudaz101: Brad, I've checked around and one of the places you gave me refered me to another retailer. They are the ones with the 70mm rings. I posted this also in the suspension forum and duffy feels that trying to run the rings that are .8mm too short is basically pointless. I pretty much concur as I don't want to make any more stupid mistakes again.

Brad, I'm not really experiencing a major vibe like I was last time with the 17x7.5" rims. I think that the tires fit better and balanced up better with the 17x9" wheels. I've tightend everything down and gone for a drive or two (haven't gotten to use it much, been beating on the wife's Saturn SC2 mostly). Basically there is no vibe at 55mph. No vibe at 60mph. A slight "grainy" feeling at 65-70mph though. At 75-80mph there is a very small occilation.

I do think though that I should properly retorque the lugs, but while I'm at it, I might as well get the hubcentric rings to eliminate that as any possilbe variable.

If someone can post back their results with a proper sized ring, and possibly where they got it or had it custom made and cost, that would help. Anyone in NY?
 
Deep6

Ahhhh!!!! Thank You for explaining it so clearly. I get the picture now.

I had thought that the rings were to correct for a wheel that was drilled off center. I see now that they only take up the space between the hub & wheel bore.

Wouldn't they have to be custom machined? OR do custom wheels have "standard sizes" of center bores?

See, an "Old Dog" can learn new stuff!

68COUGAR
 
Custom machine...

68cougar: I'd probably have to get these custom machined. Like everything else on our cars, NOTHING is standardized. Much less offsets, lug pattern and hub bores.

For the most part, Most manufacturers will use a 72mm hub bore and up. Many of the on the market hub rings are usually 72 or bigger outer diameter with a varying size for the inner.

The cobra rims that I got (and just about everyone else here who has cobra R's from dante designs) have a 70.8mm bore. (they had to be different for a reason) No one seems to have this size ring. So I'd have to get it custom made.

There is a shop that I've been in contact with that can make them for me, I was quoted $30.00 per ring. I just want to make sure that I have all of my measurments correct.
 
Deep 6
Have you tried Prestige Wheel Access (800 854 6770) for hubcentric rings? Their chart shows 64mm for the MN12 hub size and they can machine wheel center bore to wide varity sizes. Price was reasonable $30.00 comes to mind).
 
Thanks for the tip...

Dick Hughes: Thank you for referring me to them. No I have not tried them yet. Do they have a website? As far as machining the actual wheel bores is concerned, that means having to ship the wheels out for the machine work. It would be better for me to just have the correct size ring made. Easier to ship.

Also, I've used the 63.9mm hub ring, but does anyone here think that a slightly smaller inner diameter like let's say a 63.7mm inner diameter would fit a bit tighter? I seem to remember there being a slight amount of play...

I'll probably be contacting a shop shortly on making a custom ring for me, I just want to make sure I have "perfect" measurments.
 
Deep 6
64mm inside hub deminsion rings work fine and fit. I wouldn't be concerned about .1 of a mm one way or another. you don't send your wheels. Just have the inside wheel centerbore measured in mm and Prestige Wheel Access cuts them to measurement and mails them back. I can't find the price but I think it was under $50 for all 4. Someone refered me to Prestige Wheel. By the way, their rings are an estremely hard plastic of some kind. Hope this helps.
 
I must be missing something here...Or maybe I'm not...I don't see how you can get your wheels machined from a 70.8MM to a 62 point anything...Are they adding metal somehow or what?

Joe why not just try and file off the excess of the rings you have and try to make them work?


Brad
 
Ummm...

Dick Hughes: It would be great if they can make me some hubcentric rings out of hard plastic for less than 50.00. I already know the measurments I need. All they need to do is make them up.

Cudaz101: Brad, I've thought about filing the existing rings I have down.... but I thought that would be bad, IE, they would be unbalanced and uneven. Maybe I'm wrong, but does anyone else have any comments about "self-machining" the existing hub rings I have?

I just got a new 90º right angle die grinder with various stones for x-mas???
 
Joe,
I don't see what you are afraid of...As long as they fit snug to the wheel center they should be fine. If you could protract a mark of the amount you need to take off of the existing ring, you would be pretty damn close. Close enuf to accomplish the purpose of the ring anyway...They are worthless to you as they are now anyways...:D

I am still trying to figure out my other question about machining the wheels hub from 70MM to 60 somthing...:confused:


Brad
 
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