Are the 5x5.5 hubs/wheels hub centric or lug centric?

Good morning gentlemen,

Does anybody know the answer to that question? And if you know the answer, do you know if there's much difference between hub and lug centric wheel balancing? (With regards to the bolt pattern in the title).

My 1984 came with factory Ford wheels that were not original to the truck. All I have had installed since are aftermarket wheels, so I don't know whether the factory Ford wheels were tight on the hub or not.

A guy told me one time that as far as manufacturing is concerned, there can be no difference between hub and lug centric. His claim was that if you are machining something, the circles are all based off the same center (or the same registration point) and therefore cannot be different. The discussion at the time was regarding aluminum wheels. Steel wheels that are stamped/punched/welded together are a different animal obviously.

I had a Toyota Tacoma years ago and they issued a TSB regarding a specific set of aluminum wheels that required special (at the time) lug-centric balancing, and I know that the higher end wheel balancers do have cone mounting (hub centric) and special lug centric adapters.

Have any of you had any experience with Road Force Balancing machines?

Anything with conical nuts is lug centric.

My alignment guy has a road load balancer, but I've never used it.

I've asked our resident tire balancer, Steven Fox aka FoxFordsomethingorother, to respond to this.  But, he's busy balancing tires so it may be a while.

I am on lunch, so quick and dirty:

Most aluminum wheels or mag wheels begin with machining the hub hole, and are therefore hubcentric. Most balancers are made to be hubcentric as well. There are hubcentric plastic rings that act as centering spacers in the case of the wheel hub hole being larger than the hub. That way a hubcentrically balanced wheel won't cause vibration. I've never balanced a wheel that couldn't be hubcentrically balanced, but we do have the lugcentric adapter.

Roadforce balancers roll the tires on rollers, emulating the tire making road contact, therefore it can be a (not much) more accurate balance, and also detect hard spots or imperfections in the tire.

All that was part of the discussion on the original question, but the answer is: a bit of both. That technician was kinda right, since the lugs are based on the hub, it is officially hubcentric first, but in practical application, when you run the lug nuts down, it's a beveled shank through the aluminum with a wide washer. Technically it's the hub which centers aluminum wheels and the bevel on the lugnuts that centers steelies. The hubs and lugnuts are made to support both.

FoxFord,

Thank you sir. I'm a little late getting back to this topic, but since I've now solved some engine issues I was having, I'm now putting a bullseye on my wheels and tires...well, as much as I can this time of year, which isn't much.

I bought this truck in 2017, and very early on installed a set of 275/60R15 tires on 15X8 Cragar Soft-8 steel wheels. The wheels were nothing special, just black steelies. I had all 4 balanced with the hammer on weights inside and outside. This combination worked very well. They were smooth on the road, and wore nice an evenly. No complaints at all.

Fast forward to winter (early) 2019. I bought a new set of wheels...15x8 again, steel/chrome. I had the same 275/60R15 tires installed, at a different shop. The young fella offered to balance them with weights only on the inside, and I said sure, why not.

Now this combination has a definite shake, most noticeable at 70 km/hr or 45 MPH. They don't feel like an out of balance shimmy...it feels like the tires aren't round...or more specifically, it feels like tires have flat spots. So I took the truck back in to the same shop, and had them re-balance the tires and wheels again, with weights on the inside and outside like normal, and it made zero difference. The wheels balanced relatively easy too...no crazy amounts of weights.

Still, the truck has a wheel shake in it at 45 MPH. It seems to settle down a bit over 45 MPH, but if I let off the gas and decel, it shows up again at 45 MPH even coasting, and then goes away again at 40 MPH or so slower.

So I've been trying to come up with a plan to get this rectified, and if I can get some input from the experts, it might save me some time and trouble;).

So, what are the most likely scenarios?

My tires actually DO have flat spots? The truck does sit for months at a time...
One of my wheels is not round...or several of my wheels are not round?
I need to go to a different shop to try a different balancer, or try Road Force?
Or I need to try a lug-centric balance?

This probably makes it seem like I'm making a mountain out of a mole hill, but what I'm trying to avoid is replacing stuff that doesn't need to be replaced. I don't want to buy 4 new tires only to find out one or more of my wheels is not round. Also, I don't want to buy 4 new wheels only to find out my tires have flat spots, etc.

I have no problem buying hub centering rings...or having custom ones made for that matter, but these aftermarket wheels all have those loose center caps...you know the ones that are almost falling out as soon as you pull the wheel away from the lugs? They just don't seem like they'd work well with centering rings, but if that IS the answer, I'll get on it right away!

How were the wheels bolted back on the truck,n with the impac or by hand and torq wrench?
Did they do the cross or circle when tightening the nuts?

I would loosen all the wheels and tighten in a cross pattern.
Before you put it on the ground get out your dial indicator and try and see how much run out you get on each wheel.

Also when spinning look at the tread to see if it is in line and if not then the belts broke.
What you posted sounds like broken belts in a tire, you only feel it a certain low speed.
Dave ----

FuzzFace2 wrote

How were the wheels bolted back on the truck,n with the impac or by hand and torq wrench?
Did they do the cross or circle when tightening the nuts?

I would loosen all the wheels and tighten in a cross pattern.
Before you put it on the ground get out your dial indicator and try and see how much run out you get on each wheel.

Also when spinning look at the tread to see if it is in line and if not then the belts broke.
What you posted sounds like broken belts in a tire, you only feel it a certain low speed.
Dave ----

Dave,

All good points. I didn't see how the guys in the shop tightened the wheels, but they have been on and off the truck several times, and I personally have tightened them in the correct pattern. That didn't change anything.

And, I actually did check the wheels with a dial indicator...just on a flat surface inside the from the outer lip of the wheel, and they seemed to be pretty good. Three of them only had about 0.010"-0.015" variance, and one on the rear I believe was more like 0.030"-0.035" out. Now those numbers seem to be pretty low, and from the little bit of reading I did on the topic, the outer limit seems to be 0.025" variance.

I can't see any visible humps on the tires or anything, but there's definitely something wrong somewhere.

I think I have one or more egg shaped tires...lol, I just need to narrow it down.  

Anyone you know have a set of tires and wheels you could borrow to test?  If the size is close you could swap a tire on at a time to see if you have one bad one.  Or, how about your spare?

Im just gonna toss this in here and see if it floats. When was the last time you checked/ repacked your front wheel bearings?

old55pete wrote

Im just gonna toss this in here and see if it floats. When was the last time you checked/ repacked your front wheel bearings?

Well, the bearings and seals were all new last year, but I did re-tighten them earlier this year. Would they cause a problem like this? Which brings to another point...the rotors on this truck are original...I suppose they could be warped?...although I don't notice any issues with pulsations while braking...at least I don't think so.

Ok, a story with a moral. In 2008 I took the Bronco to Ca with my race car trailer in tow to pick up a 73 Rivera boat tail sport coupe. On the way back I got just out side Kingman Az and felt something funny in the front. Turns out, I lost a wheel bearing. I limped into Kingman to a Grand auto or some similar store and they had the bearings, races and seal. I bought everything I needed to get it going in the morning as it was around 7;30 pm and was getting dark. I put it all together the next morning and hit the road for the last fours of my trip. I noticed that I had a slight shimmie at around 45 and again at 70. I took it to have the wheels re balanced several times. Even changed the spare rim on to the road. Nothing helped. A few months later I had a guy bring a Peterbuilt into the shop with the same kind of story as my Bronco. Someone had put some brand of wheel bearings in it that I have never heard of and were made in china. You could actauly see where some of the rollers were out of round/ worn funny. I replaced them with Timptkin bearings and races and test drove it. Problem solved. I had driven the Bronco to work that day. I pulled it in the shop and pulled the left front apart and found the same thing. Replaced the wheel bearings and solved the problem.

The moral, don't buy parts based on price alone.

So my answer to your question is yes, the wheel bearings could be the problem.

old55pete wrote

So my answer to your question is yes, the wheel bearings could be the problem.

Ahh, OK...well that's good to know. I was thinking I'd replace the rotors in the spring of 2020 anyway, so when/if I do, I'll grab some new bearings while I'm at it, and I'll make sure they're Timkens as well. Thanks for the heads up Pete. I'll take whatever I can get in order to resolve this. I'm trying to get rid of all these little problems which will in turn make the truck much more enjoyable to drive.

You had said that you had recently adjusted the wheel bearings. I have always found it to be a good pratcise to not adjust them if they are loose enough to require adjustment. If that is the case, I pull them, clean them, inspect them and the races. If they are good, I repack them and put them in and readjust them. If they show wear, I replace them.

FuzzFace2 wrote

Also when spinning look at the tread to see if it is in line and if not then the belts broke.

Ok, so I just did a little test, and I put the end of a 1" wide straight edge very close to the center tread on each tire. I left a very small gap...almost touching the tire. All four tires have low spots...or flat spots. None of them have any high spots. On the worst one...the right rear tire, the flat spot is exactly where the tire was sitting on the floor.

They right rear is the worst, but the right front actually has what appears to be two low spots. It was a bit hard to measure...it wasn't as even as the other three at least. Maybe that one has a broken belt.

I marked each low spot with a paint pen, and then rotated the spot to the top before sitting it back on the floor. I'll leave it for a few days, and then check it again and see how they measure.

I might take the two worst offenders to the tire shop and get them to check them on a road force machine and see what they see. A fresh set of eyes on a different machine.

A broken belt can drive you bananas.  Been there, done that, replaced both the engine and transmission trying to find it - to no avail.  Had relatively new Michelins with multiple broken belts.  Haven't had Michelins since.

Gary Lewis wrote

A broken belt can drive you bananas.  Been there, done that, replaced both the engine and transmission trying to find it - to no avail.  Had relatively new Michelins with multiple broken belts.  Haven't had Michelins since.

Gary, I will be investigating everything, but I'm starting to lean more towards it being a tire issue. The tires being a problem would be more probable then wheels, etc imho. Could a wheel be out of round? Sure it could, but a tire (or tires) being out of round would be more likely. I've been reading that tires developing flat spots is still a common issue, but one that should clear itself up once the tires get warmed up after a few miles. Anyway, we'll see what happens after a few days of sitting on a different spot.

After that, I think I'll take the two worst ones in to a shop to be checked out.