Hubs (balancing)

[Sue&Von]

Von and I know what a tire is, and what a wheel is, and what a drum is.

It seems feasable that the wheel and the drum can be balanced in various ways we guess.

the tire can not be balanced alone !... right??, (only as a part of the wheel__ i.e. mounted.)

Now if the wheel/tire unit is balanced and for some reason the tire is dismounted and remounted, a new balance would be needed , right?

Now how can anyone balance the hub?
Isn't this the piece that is inserted (almost permanently) in the axle with the lug studs on it?
Inland Andy removes the wheel/tire amd the drum to balance them on his Snap-on Device so how does he (or anyone) balance the "hub"?

How many forms of balancing are there?
And could someone define each please.
(dynamic,bubble and what others)Von thinks Andy uses a different form than either of the above mentioned. What is it called?
Thanks
Sue & Von [finally gettin a
round toit]

[uwe]

The hub and the drum are one piece on the Airstream axle.
A hub is normally the rotating part of the wheel system that holds teh bearings and seals. A hub can be a standalone part with a brake drum slipped over the wheel studs, or it can be an integral part of the brake drum (or brake disc, for clarification)
A "composite" hub, is a hub that can be separated from the brake drum or disc.
I can remove the brake drum on my truck, and have the hub and axle stay in place.
i can remove teh brake disc from the front axle of my car and have the hub and bearing stay on the front suspension spindle.
On the Airstream, if i remove the brake drum, all the bearigns and seals come off with it. A heavy assembly, all one piece.
This assembly might be more or less out of balance, depending on ????
Also, an Airstream steel wheel with a bis ply tire weighs 69lb, without the hub cap, which can create a huge imbalance when it spins at freeway speed.
Oscillations will go through the trailer that can destroy the integrity of it over time. Interior wall separation, frame problems, loose rivets etc. can be visible evidence of either bad axles or unbalanced running gear.
I know this from first hand experience. My old wheels and hubs were so out of balance that the wheel would swing to a certain position like a pendulum ona clock. I would end up with open cupboards and a total mess aftera trip of a few hundred miles.
Balancing the running gear basically makes the trailer roll smooth and solid, instead of it oscillating and vibrating at speed.
The problem is, I don't kow of anyone but InlandRV doing this procedure.
I also believe that the next best thing are light weight wheels and Marathon tires, with a precision wheel balance, like tire stores do. This at least eliminates the wheel imbalance from the equasion.
Spin balancing and dymanic balancing are similar. The wheel spins and a sensor measures the weight it needs to be in balance, taking into consideration wheel width and weight postioning inside and outside of the rim.
Bubble balancing works like a scale, the wheel lays flat on a pivot, and one adds weight until it swivels at level.
I guess Andy's system would be static balance, but in steps.
Find teh heavy side of the hub, then the wheel, and mount them opposite, then balance the assembly.
I hope this helps.

[markdoane]

There are at least four forms of balancing that I know of:
1. Bubble method-wheel and tire are hounted on a horizontal plane and balanced while stationary.
2. Static method-basically same as #1 but done vertically
3. Dynamic-used by most tire stores- Wthe wheel and tire are spun on a machine which calculates and tells the technician where to mount the weights. Can be very good or bery bad, depending on frequency of calibration and operator attention.
4. Stobe method: tire, wheel and hub are spun on the car with a stobe light to detect imbalance. Very accurate, but does require mounting the same wheels in the same position on the same studs, or balance is lost.
An alternative is to find a dealer with a Hunter GSP9700, this is the latest technology which puts a load on the tire to replicate the loading that occurs while on the road. This is mostly used to diagnose vibration problems.

As regarding hubs. I am putting a new axle under my trailer. I took the new hubs, dry mounted them on the axle, and spun them by hand to determine the heavy spot. One of the hubs was over 40g heavy on one side, the other was about 20g. I plan to balance them myself. This requires a lot of time, effort, and mathematics.
If you live in or near a large city, you may be able to find a brake, clutch and U-Joint shop that can do this for you.

[Sue&Von]

Good info fellas. We are learning.

How do they mount the weights to the drums/hubs?

Also wouldn't spin balancing take care of the drrum/hub balance all in one operation?
And the weights could all go onto the wheel.

Seems like it would be easy to mark and rehang wheels over same studs. Tire rotation of course would mean a new balance.

What about my question on remount?
Would tire have to mount to wheel absolutely on a mark? to maintain the balane?

Von says lots of service stations USED to have the spin balancers. Says he hasn't seen such a service in years. But then who has seen a service station lately.?
How rare are spin balance providers?

As for do-it-yourself I guess the trick is to buy one of the old units like Inland has on EBAY. They dont look too big or bulky. I wonder if they ever appear there?
What are they worth - ball park?
I only ask for information value as we will not attempt to do-it-ourselves.
But we are convinced it is real important.

S&V

[markdoane]

Q1. How do they mount weights on the hubs?
-I really don't know, but I have seen washers and other paraphenalia welded on. On my hubs, I use a grinder to remove metal from the heavy side. Need to be very judicious so as not to compromise the structural integrity of the hub.
Q2. Rebalance de-mounted tires?
-Remounted tire are normally rebalanced.
It's not hard to do and they can charge you again. If the tire has been in use, it probably needs rebalancing anyway. Tires get out of balance from normal wear and tear.
Q3. Used InlandRV style balancing equip?
Prev. threads have asked the same question. You can build your own- see homemade He also has a list of used tire balancing equipment.

[CanoeStream]

This thread has a nice, peaceful tone to it. It looks like you've done some research here and at Inland's site.

There is some good info in the following links. Some people have been able to get a list of garages in their region using the Snap-On balancer. Take the following with a grain of salt, read between the lines to find value, etc...

How to Balance Running Gear
Tire balance
Saggy Bottom ( rear end )

[markdoane]

Canoestream:
shhhhhhh.
(we don't want to wake up the sleeping dragons)

[SBS]

This past year, I have been thinking a lot about balancing the whole running gear.

Reading past posts on this forum, I am surprised at the antagonism a simple topic like that can generate, to the point that I start to doubt about everything I read on the subject.

Any idea why so much fighting?

I know it is very important to balance the tires, but this business about balancing the whole assembly does not seem to come up in other RV forums.

Is it really that important or is there some hype under that story?

Steve

[markdoane]

Steve:
People tend to lose perspective. I am balancing my hubs because they are new and it's convenient for me. An out of balance hub has less effect on running gear than an out of balance wheel and tire, because of the radius of the moment arm. Also, tire and wheels are more variable by their manufacturing method.
I would check any new equipment before I install it. You never know when you'll find a really out of spec hub/wheel/tire that made it past the QC inspector.
I'm also a very retentive engineer.

[biggerbadbrad]

Here is my method to check for balanced running gear on any trailer. Take your trailer for a test drive!!! If wheel balance is questionable, take trailer or tires and rims to a reputable tire shop (i.e. NOT Joe's Garage) and have them all properly balanced on a dynamic balancing machine. Then have assistant drive at highway speeds while you lay face down on the trailer floor over the axels to detect any vibrations. Sounds silly? Maybe. Sounds illegal? Definitely. But come on, we’re talking about a 10 minute drive. Does it work? Every time. I have yet to detect a serious vibration from a hub at highway speeds. In fact the worst vibration ever detected was due to some dried mud that had collected on the inside of one rim. Cleaned the rim and solved the problem. I do this every year so I will notice any changes in sounds and vibrations from year over year. And I’m surprised by how many other things I notice needing attention…loose brackets, poorly stored items, improper weather-stripping, bad shocks, etc. I agree with Markdoane that the radius of the moment arm for the hub is smaller than that of the wheel and would therefore have to be seriously out of round/balance to create a significant vibration.

bbb

[jaco]

Sue/Von I am finding this thread very interesting and very similar to a question I posed back in August.

I never heard a reply, so I thought I should ask again, so I hope Inland Andy is still looking these subject threads over.

BTW I don't know what folks mean by all the "antagonism” on the subjects. I read all those links and thought they contained great questions and viewpoints. Who in the world are the "sleeping dragons" Markdoane is referring to?
I, being a meat & potato guy, look forward to the subjects that ask the meaty tough questions and question the weak or fluffy answers.

I read everything and anything Inland Andy writes about Airstreams. I agree with a lot of it. If he is the sleeping dragon you refer to then wake him up.
As for JPAirstream ,Overlander, Hex, Uwe, and Gordon Watt and others who spoke out in those linked threads, what would this place be without them? I hope they never go away and those that have I wish were back.
Steel tempers steel and those who are too timid for sharp contact end up with pig iron or pot metal.


Here is my previous post on the subject of balancing: I hope Andy can respond.

>>Snap-on Balancer I am seeking the snap-on balancer Andy uses.
>>I see it as a WBK-2C model Snap-on.
>>Has anyone else attemped to buy one? What seems to be the going prices of these?

>>Andy is there much or anything on that model that wears out?
>>On your website the pictures look like a new machine. Have you all repainted the base of the unit?

>>I have an old Snap-on catalog #CA circa 1971. This model does not show any attachment nor does the >>write-up mention hub. I thought the hub was part of the axle and could not be removed for off unit >>balancing. Where am I off on that?
>>It only shows 4 cones as accessories( 2 lg. for tire and wheel and 2 small for drums) and the protractor. >>Have you customized something or do you just use the stock Snap-on kit?

>>After you finish the job do you use an electric motor wheel spinner after replacing the wheel & tire?

>>Your webpage write up is excellent, many thanks. I'm on the other coast so must figure out how to do >>this myself.

jaco
__________________

[markdoane]

Jaco:
You call 'em like I see 'em.
I wasn't referring to anyone particular with the sleeping dragon comment, just the flames that were shooting about.
Mostly, I wanted to keep my response polite and informative without re-opening an old and somewhat agrumentative thread.

[Inland RV Center, In]

Jaco

The snapon balancer that we use is static.

There really is nothing to wear out. As with any equipment, taking care of them pays many dividends.

We did not paint the balancer. But we do try to keep our equipment clean.

A good tire repair shop will remount a tire in the same exact position when it was necessary to remove the tire, so as to minimize any possible change in the balancing.

We do not spin the assembly after balancing. But we do check the balance by rotating the assembly and making it stop in different positions, to make sure that it doesn't move, which would indicate some form of unbalance. Actually the complete assembly can be unbalanced, causing it to rotate, by adding a mens hankie to the top of the assembly, slightly offset from center. That will make the assembly move.

Thanks for the compliment about our web site. It will never remain the same, as many changes, additions, in time, will appear.

The next addition will be replacements for the thin Airstream Skylights of recent use, both the rectangular and square units.
Also we will have photo's and offer the Carrier Air Conditioner, that does not need a drain pan.

Molds are now being created for the refrigerator scoop that so many owners have asked for.

Andy

[Motoman]

Couldn't find the thread or post but I seemed to remember that someone, maybe Andy, said that failure to balance the entire rotating assembly would cause flat-spotting or a pronounced wear at one point on the tire.

Well we observed this on a Marathon on our 2005 CCD. The curbside front tire was replaced last October in Akron, Ohio at a Goodyear company owned store and spun balance at my request. The store installed a single weight on the back side of the rim to balance it (I would have preferred using two or four with two mounted on the front and two mounted on the back). Last week we experienced a flat on this tire coming out of Death Valley. There was no obvious damage to the tire and I haven't yet pulled the tire out of the carrier under the trailer to see why it went flat but I did notice that the tire had one area where the tread was worn down considerably when compared to the balance of the tread. The other three tires are original and have an estimated 25K on them, the two street side tires having the most tread, the rear curbside having less and probably needing replacement this Fall or next year.

If in fact the accelerated wear is due to an imbalance of the entire rotating assembly, and not poor workmanship by the mechanic who mounted and balanced the tire, why wouldn't it be better to pull all four drum/hub assemblies and have a drivetrain shop balance each so that: 1) new tires could be balanced on the rim alone; 2) tires could be rotated to another position on the trailer to equalize wear; 3) one wouldn't have to worry about remouting a tire exactly as it came off when packing the wheel bearings; 4) eliminating to the greatest extent imbalance that would cause damage and wear?

Has anyone had the hub/drum assemblies balanced, what type of shop and what cost range?

[dscluchfc]

Centramatic Balancers work for me.
I put them on after the tires were dynamically balanced and mounted.

http://www.airforums.com/forums/f438...ate-32907.html