[GMCnet] Lug Centric Wheels: Pros and cons?
Shan Rose
I know the conventional wisdom here speaks to only running hub centered wheels, but I am wondering if anyone has run lug centered versions. as I will be needing tires at some point in the future I wanna update the wheels to alloys, but the offerings I have seen are kind of bland, and I would like to run something a bit more fitting to my personal tastes.
I found these wheels by KMC as seen here
they meet the load rating as they actually exceed the eagle and alcoa rims by 500# so I know they would hold the coach, but they are lug centric rather then hub centric. I suppose I could get someone to spin some adapters, but that would add to the price. the 16" version of these rims runs around $160 a peice, and they look generally badass, and will fit with the paint scheme I have cooked up for my coach.
so basically I just wanna kno the pros and cons of a lug centered setup....
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Charles
Maybe you might want to consider 16 inch steel wheels.
Here is a portion of an email I receioved today.
Charles
>I checked with Southwest Wheel in Dallas for a "new" rim price.
>They indicated the new stock number for the Accuride ZX
>wheel is 29587 as the old number 27994 has been discontinued.
>The new wheel sells for $110.95 FOB Dallas. It has a hub
>diameter of 4.560 and a bolt circle 6.500 inch.
James Hupy
negative. If you use the flat flange type of lug nuts like our coaches were
fitted with from the factory, It is extremely difficult to get the
wheel/tire combination to run concentric with the hub. I tried setting up a
pointer like I used to do when I laced up custom motorcycle spoke wheels and
rims, and the wheel tire combination is so heavy that it is really hard to
do. I also had my tire store try it and my coach would shake the front end
so hard at 60 mph that it would rattle everything in the coach including the
occupants. Some wheels use a chamfer in the lug hole and tapered lug nuts.
That helps center the wheel on the studs, but it reduces the nuts ability to
clamp the wheel to the hub and the concentration of stresses I believe can
lead to cracking the wheel. There is no assurance that the lug centerline is
concentric with the hub wheel mounting flange, so even if the tapered lug
nuts do center the wheel with the studs, it may not be centered with the hub
center. That is why I made the hub spacers pictured on gmcmhphotos.com. I
will take some more pix and post them to show the spacers and hub extenders
that I made. My 78 Royale will now track straight without wheel vibration at
80 + mph. Sure didn't without being hub centered. Hope this gives you some
perspective.
Jim Hupy
Salem, Or
78 Royale 403
Shan Rose
well to be honest I hate the way steel wheels look, expecially when they rust! and I love the black anodized KMC wheel...
Charles wrote on Thu, 01 July 2010 22:30
James Hupy
the egg? Which is more important, Form or function. Ugly women function, but
so do beautiful ones. Your choice, that is what makes America great. We pays
our money and takes our choice.
Jim Hupy
Salem, Or
78 Royale w/powder coated steel wheels, they don't rust for a long time.
Ken Burton
James Hupy wrote on Thu, 01 July 2010 22:42
I thought ALL lug centered wheels used tapered nuts. If they don't, how does the wheel get centered? What am I missing in this discussion?
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Mike Miller
Ken Burton wrote on Thu, 01 July 2010 22:12
> I thought ALL lug centered wheels used tapered nuts. If they don't, how does the wheel get centered? What am I missing in this discussion?
Some Aluminum wheels (like the Eagles JimK sells) use a lug nut that has a sleeve that goes INTO the wheel at a very tight tolerance. I have always called these "Mag Wheel nuts." This lug nut centers the wheel on the lugs and provides very good clamping. RickD has wheels with this type of nut and seems to be happy with them. I haven't heard of any problems with this type of wheel and lug nuts.
Other lug centered Aluminum wheels and most lug centered steel rims use cone nuts to center the wheels. (Many OEM pick-up wheels are like this.) Some have used these wheels, but others report issues.
The OEM flat style lug nut is only good for hub centered wheels of the correct pilot size.
JimK's hub centered Eagles are BOTH hub AND lug centered. Belt AND suspenders!
--
Mike Miller
`73 26' X Painted D.
`78 23' Birchaven
Hillsboro, OR
Ken Burton
Yes, I am very familiar with the Eagles. I have them on my coach. I got some of the first sets Jim sold. They are marked right on the box that they are HUB Centered. You are correct that they also end up centered on the lugs because the the lug design but they are indeed hub centered as designed by Eagle.
I do not have the ones that Jim had made special for the .031" smaller center hole that our GMCs have. You are correct in that they still mount centered with the larger center hole.
I still contend that true lug center wheels use tapered lug nuts. But what do I know?
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Rob Mueller
Do you have a link to "these wheels?"
Regards,
Rob M.
USAussie
Steven Ferguson
Jim K., Duane Simmons, myself, and many others have run lug centered
wheels for many years. I believe Duane still has his. All of us ran
Weld Alum 16.5 wheels with no problems. I still see a set or two of
them on coaches at GMC rallys every now and then.
On Thu, Jul 1, 2010 at 8:08 PM, Shan Rose <defc...@gmail.com> wrote:
>
>
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
Rick Denney
Duce Apocalypse wrote on Thu, 01 July 2010 23:08
> so basically I just wanna kno the pros and cons of a lug centered setup....
There are three methods by which wheels are centered on the hub while the nuts are being installed.
The first is by machining the center hole to precisely fit on a shoulder of the hub itself. GMC used this method for most of their vehicles back in the 70's. This approach does make it easier to center the wheel when it is being installed, such that you only need one nut to hold the wheel in place while you install the other nuts. The reasoning behind this design was to make it easier for the inner wheel in a dually setup to remain centered during installation. My '74 GMC pickup (non-dually) had wheels like this.
The second method is by sizing lug holes to fit precisely over a straight sleeve that is part of the nut. These are called "mag wheel nuts" and they provide the centering. These are little harder to install, because you must install two nuts to provide centering for the other six, and you have to wiggle the wheel around some to get those two to snug up without resorting to an impact wrench. Also, the nut is sometimes a bit tight in the hole and if the wheel is still a little crooked it might bind and gall. A little anti-seize lubricant on the sleeve of the nut prevents this.
The third method uses angled seats on the wheel and a tapered nut. These are common on passenger cars, but can't be used on dually applications because they won't align the inner wheel. Even though the GMC motorhome doesn't use the dually arrangement, it DOES use dually wheels to provide the necessary negative offset required by the front wheel drive. This option is therefore not available on any wheels intended for our application, because those wheels are also intended for dually applications.
All of these methods work fine. I know of no application where only flange friction on the nuts is used to center a wheel, or where one is expected to center the wheel on the lugs manually before being tightened down. If such an application ever existed, my first suspicion would be that the incorrect nuts were being used, or that a sleeve for the hub was required and not used. Some aftermarket wheels were provided with plastic sleeves to provide hub-centering on some applications, proving that hub-centering is only an alignment aid during installation.
The original steel wheels and the Alcoa replacements use the first method. The Eagle wheels come in two versions. The cheaper version has a larger center opening and uses the second method only. The more expensive version is a custom run for our application with a center opening that fits tightly on our hubs, and therefore uses BOTH the first AND the second method. All of these work fine on our coaches. I have the cheaper Eagle wheels (the hub-centered versions were not available when I bought mine) and they remain centered even after driving on rougher roads than just about anybody here would dare attempt. Again, wheels that use the first method are easier to install, but once the lugs are properly tightened there is no difference in function.
Rick "KB is temporarily confused--his wheels used the second method only" Denney
--
'73 Glacier 230 "Jaws"
Rob Mueller
This subject comes up over and over and over. Rick patiently writes up a
detailed response over and over and over.
I have not checked your website but if it is not posted there I'll bet Rick
would be grateful if you put it there! ;-)
Regards,
Rob M.
USAussie
-----Original Message-----
From: Rick Denney
Duce Apocalypse wrote on Thu, 01 July 2010 23:08
> so basically I just wanna kno the pros and cons of a lug centered
setup....
There are three methods by which wheels are centered on the hub while the
nuts are being installed.
Rick "KB is temporarily confused--his wheels used the second method only"
Denney
Mike Miller
Robert Mueller wrote on Fri, 02 July 2010 06:40
There was a picture on the first post... on the forum. As you, like most forum members, use the TEXT ONLY email... you did not get the picture. (Duce, make note... Provide links! Keep an eye out for the footer in the message... those posters use the email list.)
Back to the wheels.
Here is the same type wheel on the summit web site:
<http://www.summitracing.com/parts/KMD-77576082799>
Note they use 60 degree cone lug nuts.
--
Mike Miller
`73 26' X Painted D.
`78 23' Birchaven
Hillsboro, OR
Shan Rose
there is an email list? yes those wheels use a 60* degree conical lugnut, which seems to me as long as you used 2 nuts to center the wheel, once all 8 nuts are on and tightened in order should center the wheels without much effort. I have seen these on a couple big duallys, and they really do look mean. they also have pleanty of backset so should have no problem clearing stuff like brakes. I plan a dark paint scheme for my rig and would love a set of anodized black wheels like these. plus a set of six is just under 1k delivered which means i I can get them to work without too much hassel, they would look great and be half the cost of Alcoas.
If they absoulutl had to be hub centered I guess one could have some rings spun to line'em up, but the big duallys seem to run them just fine without issues. they also have a lifetime warrenty.
Mike Miller wrote on Fri, 02 July 2010 10:57
James Hupy
GM Truck that is all wheel drive and I think that you will find extended
flanges on the front hubs to center the wheels. I have checked several GMC
MH hubs very carefully and on some of them the stud centerline is not
concentric with the bearing surface. Thats what I was concerned mainly with.
Jim Hupy
Salem, Or
78 Royale 403
Rick Denney
James Hupy wrote on Fri, 02 July 2010 16:27
> I have checked several GMC MH hubs very carefully and on some of them the stud centerline is not concentric with the bearing surface. Thats what I was concerned mainly with.
Really? No offense, but I think I would have to have that proven to me, with a definite example, and with an understanding of GMC's design and manufacturing tolerances.
My wheels don't have any axial runout that I can feel. And I bet any that might be measured with, say, a dial indicator would fall within their tolerances, and well within the normal tolerances of tire roundness.
The original wheels for the motorhome prototype were the dome-shaped wheels of the Toronado. But those proved too weak for the application, and were replaced with the 8-lug truck wheel. I would be absolutely floored to discover that the hub specification for the centering shoulder and lugs differed from their light dual-axle trucks at the time. And the wheels they used were certainly designed for the dually application, and were useful to them to get the center of the tire closer to the center of the bearing assembly. Non-dually wheels with that degree of negative offset were pretty rare in the early 70's, especially for truck wheels. But the wheels intended for dually applications were already a useful shape.
Finally, the bolt holes for the original steel wheels are not exactly drilled large--they are a close fit over the lugs. If the lug locations were not within tolerance, it would be pretty hard to get the wheel to seat on the hub, it seems to me.
Rick "politely skeptical" Denney
--
'73 Glacier 230 "Jaws"
James Hupy
the hub extension flange, and the O.D. of the hub extension flange are all
either precision ground as in the case of the bearing race, or they are
lathe turned centering up on the race. The holes for the studs are a
separate boring operation, probably on a multi-spindle mill that bores all
eight holes at once. All I am saying is that this is a separate machining
step on a different piece of equipment, and subject to some human
interpretation when it comes to set up. Yes, GM does have + or - tolerances
that are supposed to be adhered to, but in my experience as an automotive
machinist, stuff still happens. If GM made those hubs today, A robot would
make all the moves and all parts would be exactly the same. My wheels are
also true and concentric with the hub center. I only had to go through about
15 or 20 Truck Front Wheels and spun them on a tire balancing machine,
eliminating the ones that wobbled or were egg shaped. Mag type wheels are
much more precision than their steel counterparts in their construction and
they are certainly attractive, plus they have the added advantage of having
the correct back spacing for the GMC MH. Their only significant drawback is
their cost. I use the steel wheels because they are strong and inexpensive.
I have a lot of other places that are screaming at me for my di$posable
income when it comes to my coach, I think my entire investment in wheels,
powder coating, media blasting, spacers and hub extensions, trim rings and
hub covers cost me $575.00. I do have a life long friend in the tire
business and he cut me a good deal. Can you buy 7 Alcoa's for that? I guess
I'm just a cheapskate, but I feel that the coach still resembles the
original and that is important to me. I guess to each his own. I do
appreciate your comments.
Jim Hupy
Salem, Or
78 Royale 403
Chris Choffat
My head hurts...
--
-Chr$: Perpetual SmartAss
77 Ex-Kingsley 455, Power Drive, 3:21 FD, Quadra bag. The Engineer's Motorhome
Scottsdale, AZ
Photosite: Chrisc "It has Begun"
Rick Denney
James Hupy wrote on Fri, 02 July 2010 23:13
> My wheels are also true and concentric with the hub center. I only had to go through about 15 or 20 Truck Front Wheels and spun them on a tire balancing machine, eliminating the ones that wobbled or were egg shaped. Mag type wheels are much more precision than their steel counterparts in their construction and they are certainly attractive, plus they have the added advantage of having the correct back spacing for the GMC MH.
I used the steel wheels until my tires aged out, and then I changed to the Eagles (much cheaper than the Alcoas) so that I could get access to cheaper and more plentiful 16" tires. My steel wheels were a hodge-podge of later wheels--my '73 wheels weren't rated for radials but they had radials on them when the coach came to me. They were not all round. I cannot imagine what it would take to find 7 round ones--nor can I imagine how I would have done that for less than what the Eagles cost. But where I live, those alternatives are hard to come by. The new steel wheels I did find on the market were just about as expensive as the Eagles.
Rumor has it that GMC culled the wheels in their inventory to find the roundest and truest examples, because the ride of the motorhome was more important than the ride of a truck. Maybe Bill Bryant or someone else can confirm or deny that rumor.
But I'm still curious if you actually measured hubs where the lugs were not concentric with the hub shoulder or bearings by an amount sufficient to matter. Wheels are another matter, especially after decades of battering.
Rick "whose coach rides smoother than his cars" Denney
Shan Rose
Guess ill just have to try the wheels. Guess I could buy 2 of the KMC wheels and see if they run ok on the front, if so then get 4 more....
James Hupy
other. As little as 1/2 oz. wheel weight sometimes makes the difference
between smooth and shake. It doesn't take very much concentricity error to
have the same effect. The studless hub that I pictured in
gmcmhphotos.comwas rejected for MY use partly because it had enough
error between the two
to make me replace it, and also because the previous owner ran the front
brake pads down to the metal backing and the rotor and hub assy got so hot
that the backing welded itself to the caliper piston, melted the front brake
hose and destroyed the front wheel bearings, creating hairline crack
fractures in the hub. I used it for a template when making the hub extenders
and wheel spacers, and I checked it quite closely while chucked in a 4 jaw
chuck on a lathe. The lug centerline on that hub is not concentric with the
bearing race or the shoulder cuts on the center of the hub that the wheel
centers up on. The new one I bought to replace it was better than the
overheated one but the studs are loose enough that the wheel takes it's
centering from the hub like it was designed to do. I may be way more
particular than other GMC owners about machine work, I think that it's one
of the reasons I don't get as much done as I used to. Waay too much
procrastination and checking and what if'n time. When I was younger, I would
just do it. Still, them alloy wheels sure are pretty.
Jim Hupy
Salem, Or
78 Royale 403
Bob de Kruyff
""Rumor has it that GMC culled the wheels in their inventory to find the roundest and truest examples, because the ride of the motorhome was more important than the ride of a truck. Maybe Bill Bryant or someone else can confirm or deny that rumor.
""
That is true. All new vehicles are tested for tire unbalance and out-of-round sensitivity, and the GMC had very high sensitivity to tire/wheel disturbances--hence the selective wheel sorting. Unfortunately, when those things were done at the time, the part number was bever amended or given a sub designation. But there's much more to the overall story. GM steel wheels of that era were both hub centered and lug centered at the same time. Since they were steel, they would tend to become almost impossible to remove due to corrosion at the hub interface. The hub clearances were increased to help that problem and they gradually became lug centered. Given all that, what most people are complaining about is simply poor steel wheel concentricity no matter which approach was used. Steel wheels were stamped and coined--there was no machining of the wheel itself. Alloy machined wheels are dramatically better because of the wheel uniformity not because of how they are centered.
--
Bob de Kruyff
78 Eleganza
Chandler, AZ
Rick Denney
Bob de Kruyff wrote on Tue, 06 July 2010 23:36
> That is true. All new vehicles are tested for tire unbalance and out-of-round sensitivity, and the GMC had very high sensitivity to tire/wheel disturbances--hence the selective wheel sorting.
Thanks, Bob. That addresses the rumor I heard perfectly, and also gives insight into the issue.
Rick "who has resorted to a Very Big Hammer to remove hub-centered wheels from various trucks in the past" Denney
--
'73 Glacier 230 "Jaws"