Community Forums

TimmyB · 02-10-2021, 09:33 AM

Quote:

Originally Posted by joelsplace

Someone asked "why put pretty aluminum wheels one the inside?"
The answer is around 100lbs weight savings per axle. It makes the ride better and allows another 100lbs of capacity if you are at your maximum legal weight.
That brings up another question. How much do Centramatics weigh?

Not much at all, apparently. Looking at them on Amazon, shipping weights are between 11 and 20 pounds and they come two to a pack, so 5-10 pounds each. That's lighter than I thought they'd be.

EagleTampa · 02-10-2021, 09:42 AM

Quote:

Originally Posted by TimmyB

Not much at all, apparently. Looking at them on Amazon, shipping weights are between 11 and 20 pounds and they come two to a pack, so 5-10 pounds each. That's lighter than I thought they'd be.

I have a Tiffin Allegro Red 38KA on order, should be delivered by May, I already have my Centramatics in the garage waiting for the arrival, I'm hoping LazyDays in Tampa will put them on for me during the closing process.

TimmyB · 02-10-2021, 09:51 AM

Quote:

Originally Posted by EagleTampa

I have a Tiffin Allegro Red 38KA on order, should be delivered by May, I already have my Centramatics in the garage waiting for the arrival, I'm hoping LazyDays in Tampa will put them on for me during the closing process.

Is the weight of your package pretty much what I saw on Amazon? (Congrats on your new rig, btw!)

EagleTampa · 02-11-2021, 05:37 AM

Quote:

Originally Posted by TimmyB

Is the weight of your package pretty much what I saw on Amazon? (Congrats on your new rig, btw!)

I put them on a scale, both rear axle units (2) are a total of 20 pounds, the front are significantly less. The difference in front and rear are because the rear are drum brakes the front are disk. The weight difference is probably the expected load weight on the rear axle.

tderonne · 02-11-2021, 06:11 AM

Quote:

Originally Posted by joelsplace

Someone asked "why put pretty aluminum wheels one the inside?"

The answer is around 100lbs weight savings per axle. It makes the ride better and allows another 100lbs of capacity if you are at your maximum legal weight.

That brings up another question. How much do Centramatics weigh?

The Dana S135 axle assembly in my motorhome weighs 750 pounds. 245/70R19.5 wheels and tires are another 500 pounds. While 100 pounds sounds like a nice weight savings, it’s less than 10% of the unsprung mass.

tarnold · 02-11-2021, 07:08 AM

So, if you add centramatics, do you have to remove the lead weights already mounted? Or leave them on?

TimmyB · 02-11-2021, 08:04 AM

Quote:

Originally Posted by tderonne

The Dana S135 axle assembly in my motorhome weighs 750 pounds. 245/70R19.5 wheels and tires are another 500 pounds. While 100 pounds sounds like a nice weight savings, it’s less than 10% of the unsprung mass.

That may be true, Tim, but as we know, many manufacturers leave a woeful amount of OCCC and many unsuspecting buyers (newbies) don't realize that until it's too late. For those people, that 100 pounds might make a huge difference in what they can pack instead of leaving behind. An expensive solution, to be sure, but not much else they can do to shave weight off the rig itself.

TimmyB · 02-11-2021, 08:06 AM

Quote:

Originally Posted by tarnold

So, if you add Centramatics, do you have to remove the lead weights already mounted? Or leave them on?

From what I have read, lead weights are ok because they are static. What they strongly tell you to NOT do is have the balance beads, as those (like the Centramatics) are dynamic and you'd have two systems changing trying to counteract each other.

joelsplace · 02-11-2021, 11:13 AM

Yes around 50lbs per wheel savings for aluminum vs steel.
I don't know how noticeable it is but aluminum wheels usually have less runout and are more rigid than steel or at least cast and forged aluminum wheels are. Alcoa sells some light weight wheels that I think save another 5lbs.
Spun wheels may not be as rigid but I think all that is available for MH/truck use are forged. The lower you can get your unsprung weight the better the ride will be.

Piros1 · 02-11-2021, 11:37 PM

Quote:

Originally Posted by joelsplace

Yes around 50lbs per wheel savings for aluminum vs steel.
I don't know how noticeable it is but aluminum wheels usually have less runout and are more rigid than steel or at least cast and forged aluminum wheels are. Alcoa sells some light weight wheels that I think save another 5lbs.
Spun wheels may not be as rigid but I think all that is available for MH/truck use are forged. The lower you can get your unsprung weight the better the ride will be.

Just an FYI for those who are not familiar with the difference between steel and aluminum wheels. Aluminum wheels are thicker at the mounting flange and in most cases will require replacement of the lug studs. As a general rule when your wheels are mounted to your rig you should have three threads showing on the stud after the wheels are mounted and the nut is torqued. We had to change the studs on a couple of our company trucks that we got a warning ticket at a scale house.

EagleTampa · 02-12-2021, 05:17 AM

Quote:

Originally Posted by tarnold

So, if you add centramatics, do you have to remove the lead weights already mounted? Or leave them on?

From what the factory told me; the Centramatics will balance the wheels as you begin driving. The weights on the wheel don't matter, there is no need to remove them. However, the fellow that first showed me his, had removed the weights for cosmetic reasons. This fellow had the same rig as which I have ordered and is in the truck and heavy equipment repair business. I trust him. I am ordering a set for my trailer also. Maybe I won't be the poor guy on the side of the road with a trailer blowout.
Even when you pick up stones the Centramatics will make the minor rebalancing adjustments until the stone leaves.

skyking421 · 02-17-2021, 06:27 AM

I was having a front shimmy on our 35' Journey, with new Michelin 22.5 RV tires. Had all 6 wheels spin balanced and that cured the front shimmy, but still had a vibration/shake that would be annoying on a long trip.

I had Centramatics installed on both axles and the vibration was much less, but still there. I finally realized that the Crossfire rear tire pressure balancing system was not included in any tire balancing. The Crossfire regulator and hoses are mounted to the chrome wheel cover, which is mounted last.

After calculating the weight of the parts, the rim needed 7 oz opposite the system to provide a closer balance. With that the coach now drives with no vibration. A nice, smooth ride.

My point is, that even though the Centramatics helped a lot, the ride was better when the wheels were closer to balance to begin with. Also, the rears did need a good initial balance and the Centramatics.

deandec · 02-17-2021, 11:18 AM

Interesting thread.

Our experience is a little different than presented so far.

We have had the same 31,000lb MH for 19 years and @90,000 miles

3 sets of 14G tires. Toyo, Bridgestone, Toyo 10R/22.5 or 295/75R22.5 (Steer)

Balance only the Steer axle with Equal Powder (dry climate).

Wheels are Aluminum, stud pilot (Budd) type.

All tires purchased from Les Schwab Tires. (Did install a out of round set of Toyo tires that thankfully the Dealer ultimately replaced.)

Saddltramp · 02-18-2021, 12:27 PM

Quote:

Originally Posted by Dutch Star Don

There are really four ways to balance your tires, each being a little more expensive than the other.

First is a static balance, where they place the rim/tire on a bubble level and add weights (rarely used any more).

The second method is high speed spin balance, which I prefer on my cars, but not on an RV. As the tires wear, the balance changes. Since most keep their RV tires seven years or more, it can change quite a bit.

Third, is balance beads. Balance beads are added to the inside of the tire and balance the tire/rim every time you drive. The first generation of beads had issues with clumping and clogging valve stems, but really not an issue anymore.

The last method, are Centramatic wheel balancers. They're a metal ring that is placed behind your front wheel and in between your duals. The ring has beads inside and rebalance the entire assembly, hubs, brakes, tires and rim every time you drive. I prefer the Centramatics and have had them on my last three diesels. If you buy the same coach chassis, they can be removed and moved to the next chassis. They're about $150 - $175 per axle. The Centramatics are great for eliminating even the most annoying minor shakes.

Lastly, don't be frugal, balance all tires. Even though you may not feel any issues in the rear, you can end up with unusual wear and shorten the life of the tires.

wher would one get the Centramatics..Thanks