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rollin298 · 02-03-2004, 09:19 AM

Centramatic

HI Folks
I'm a bit new to this board posting stuff but not to giving my $.02 worth…

I used a set of the centramatics on a pickup truck project I was working on a couple of years ago. I had a wheel shimmy problem and an issue with some
American Racing steel wheels I had recently purchased.
After several measuring sessions with a lath I determined the problem was in wheel eccentricity. so idecided to try the Centramatic.
Well the short of it is the balancers worked fantastic from about 18-20 mph on up.
They did make a shoosh shoosh sound bellow that. I contacted American Racing Directly (Houston Distributor) and explained the problem with the wheels. He suggested I go with a set of aluminum wheels as they are stronger and have tighter
Run-out specs (look good too). He gave me a full refund on my steel wheels toward the up grade. (PLUG: American Racing wheels are the only way to GO…

.
I ran the truck with and with out the Centramatics and the new wheels. The truck would pass
through several minor shimmy points at speeds up through about 110 without the Centramatics.
With the Centramatics I tried hard for several weeks and a shimmy I could NOT find…
However, the differences in the "true/well balanced rotating mass" with out the Centramatics
and the same WITH was not great enough to warrant the $200.00 price for this particular application, especially at normal tow speeds, so I returned them.

However, after careful consideration, where I did consider machine shop work/hub balance I have decided to go with the Centramatics for my trailer. They are an all aluminum spin-formed
unit now. I can rotate the tires, replace them
or a hub and run a spare at any position. Also the balancers may go with me to the next trailer
and will prolong tread life. Also they can be had with more than one bolt pattern on each unit.
AND in talking with Centramatic I suggested they contact Airstream, they were
also receptive to the suggestion that an incentive be considered for a group/quantity purchase from people on this forum. (Someone with TIME might work this part up.)

SEE YA

Inland RV Center, In · 02-03-2004, 10:18 AM

Tinsel Loaf.

A running gear balance is usually done in combination with a "major brake" job. That should be done every 10,000 miles.

Airstream uses Henschen axles that are equipped with a #42 spindle. That spindle can safely carry a maximum of 8000 pounds per axle, depending on the size bearing used with it.

The bearings used by Henschen are LM67048 and 25580. With that bearing set up, a maximum safe weight that can be used is 5500 pounds per axle.

Considering that the spindle and bearing setup that Henschen uses is really overkill (much more than needed), hubs can safely be switched from one location on the trailer to another.

That being the case, assuming the running gear is in balance, any hub and drum along with the tire and wheel can be installed on any spindle on that trailer. It does not matter.

There seems to be some misconception as to which trailers are more sensitive to vibration than others.

Hub and drum assemblies, for the last 10 years or so, have been made with much closer tolerances than ever before. So have tires for that matter. Newer coaches therefore are not nearly as likely to be damaged from vibration as the older units.

Balancing is always an "owner obligation." Hummers, Porsches, as well as any other expensive car, all have the same needs. The cost of the vehicle has nothing to do with balancing. The same is true for travel trailers.

However, once again, the newer the trailer, the less balancing becomes critical.

Older trailers, it's a must.

Andy

markdoane · 02-03-2004, 10:27 AM

I agree with the experts regarding switching the hubs. Be sure to re-adjust the brakes to offset any difference in brake linings. It's also great that you are inspecting, repacking the bearings and replacing the seals at the same time.

bake315 · 02-03-2004, 10:58 AM

Also not an endorsement, but rather an impression. At about $200 a pop they seem pricey, but if they're still viable after well over a million miles as they claim they seem worth it. The demo video was most convincing. I guess I'd get them for my TV as well as my A/S, after getting the running gear balanced.

I expect I'll be one of those pulling my A/S over a million miles, so it's nice to know a set would last that long!

mtbob · 02-03-2004, 03:59 PM

Andy

Does Henschen have a permanent lubricated bearing set similar to Dexter's Nev-R-Lube available?

Tinsel Loaf · 02-03-2004, 04:48 PM

Thanks Andy.
What would we do without your experiance and knowledge you bring to this forum.

Streamsaver · 02-03-2004, 04:51 PM

Andy,

Quote:

However, once again, the newer the trailer, the less balancing becomes critical.

Older trailers, it's a must.

We just purchased a complete axle setup for our 63' tradewind from Inland. Will a new axle on a older trailer reduce our worries about vibration? It seems to make sense that newer equipment made with tighter tolerances will be far superior than trying to balance older equipment.
Not to mention the added bonus of getting the whole assembly balanced and ready to bolt on. I rode for about 5 miles in our 68 overlander on its way to the welders. It was quiet enough to talk on the cell phone. Mild vibration, and the only thing sliding around was the sliding bathroom door with the broken latch. We never got over 25mph. I could only imagine the damage happening at 60 mph. This made us realize the importance of balance. It is a eye opening experience to ride for just a short trip around the block in your trailer.

Inland RV Center, In · 02-03-2004, 05:28 PM

Older trailers with new axles will not have the lack of proper balance problems, as an old trailer with the original axles.

Andy

wahoonc · 02-03-2004, 05:37 PM

Andy,
This isn't a balance question but it kind of fits in. What is the reasonable life expectancy of the axle's on an Airstream. I realize that a unit that is towed, is going to be better off to a point than the one that just sits. But I was wondering if there is an age point when you would be better off just going ahead an replacing the axles. Mine are border line and will probably be replaced in the next year or so.

Aaron

Inland RV Center, In · 02-03-2004, 05:50 PM

Aaron.

Airstream and Henschen have no records of life expectancy.

They both say that there seems to be no limit in terms of miles.

Granted 74's and prior do have the rod problem. Also not using the trailer for years, even with the new type rods, will allow them to settle. Once that happens, the axles become history.

If an Airstream or Argosy trailer will not be towed for years, most of the weight should be removed from the axles. That can be accomplished by setting the chassis on "jack stands."

No one has any record, ever, of a Henschen axle wearing out, from mileage.

Andy

wahoonc · 02-03-2004, 05:57 PM

Thanks Andy,
I am used to products with a "design life". It is interesting to see a product built like the Henschen axles, that with proper care will probably last several lifetimes, if it is taken care of.

Aaron

JPAIRSTREAM · 02-03-2004, 06:06 PM

My axles on my 72 are still good they are sitting at a neutral angle under load.

You are can have up to 5 degrees according to Henchens under load. According to the call I had with them.

Inland RV Center, In · 02-03-2004, 06:10 PM

Five degrees up, fully loaded, is the absolute limit.

Watch for any unusual damages, just to be sure. That doesn't cost anything.

Andy

JPAIRSTREAM · 02-03-2004, 06:11 PM

Correct ANDY 5 degrees is the very worst they can go...

Joe62984 · 02-03-2004, 06:50 PM

I just purchased comple axles, hubs and drums from Dexter Axle. Your discussion prompted me to inquire with Dexter Axle as to whether or not their drums were balanced. This is their reply.

"Thank you for visting Dexter Axle website and sending me your question.

Dexter Axle does not balance the drums to compensate for any weight difference. The drums are machined to exact specifications for radial and lateral runout.

The assembly that may require balancing would be the wheel/tire once they are assembled together. Weights are added to the wheel mainly to compensate for the irregularities in the tire. The tire being the largest diameter of the system has the most significant impact on balance."

Christing Bachman
Application Engineer

Joe

markdoane · 02-03-2004, 09:42 PM

This is a fairly small sample of two.
I recently purchased a complete Dexter axle with 12×2 backing plates and hubs.

I set the axle up on a pair of sawhorses, and assembled the bearings and hubs with a light coating of oil (no seals and no backing plates).

I marked the circumference of the hub and proceeded to spin the hubs by hand to determine the balance. Each 'test' involved spinning the hub in opposite directions 20 times and recording the point where it stopped spinning.

By plotting the results, then adding temporary weights to the light side until the hub stopped a random location, I determined that one of the new hubs was off by 40 g. (1.4 oz) and the other was off by 20 g. (0.7oz).

Considering the small radius of the hubs, compared to the radius of tires, I think these results are acceptable.

Inland RV Center, In · 02-04-2004, 08:57 AM

Dexter Specs

Dexter "WILL NOT" provide any specs as to runnout limits on the wheels they make, or on their hub and drums.

All they will say when you send them the specs, is that they are within limits.

They claim that their specs are "proprietary" and therefore they won't release them.

We had a shipment of wheels that were made by them that were out almost 1/4 inch. They still said "within specs."

WOW!!!

We scrapped the wheels.

Andy

markdoane · 02-04-2004, 12:19 PM

Andy,
I am incredulous, to say the least. I would think Dexter would have paid you big bucks to send them back and never mention it in public.
Were the hubs you ordered from Dexter for a carnival ride, or one of those cars the clowns drive in the circus, with the square wheels?
BTW, what specs does Henchen adhere to?

Inland RV Center, In · 02-04-2004, 01:16 PM

markdoane

The wheel in question is the one we sell to Airstream owners, since it has a 2600 pound rating.

We have learned at this point, to inspect every new wheel we purchase for resale, on our balancer and check them for runout.

Andy

Pahaska · 02-07-2004, 02:50 PM

John hd asked me a few days ago to post a photo of a Centramatic balancer. I finally got around to taking a picture this afternoon.

They are one-piece spun aluminum. There is one place on the inside of the rim that is a cover for the orifice where they insert the weights and oil. You can hear the balls rolling arond when you rotate the balancer. Earlier units were assembled from several parts rather than being spun in one piece.