Do I need to balance my RV tires?

 I was recently asked about tire balancing.

Reasonable question but as always the answer starts off wit "It Depends"

Vibration can be because of a tire/wheel suspension component is out of balance. Vibration can also occur because the tire or tire and wheel assy is not "round". On a small (14' to 16") tire you can see and measure out of round when the tire & wheel are placed on a spin balancer.   I have shown that you can "balance" a square cement block

  so you need to be sure your tire & wheel assy is "round within at least 0.030"

The person asking the question, said that they had done some research and learned there were three methods. They wanted to understand the advantages of each and which they should use for their Class-A RV.

The basic method is static or "bubble balance". as seen in this  video   https://youtu.be/hp3ShyNzK84

The mounted tire is placed on a balance and the heavy spot is counter balanced with weights.

This static balancing is lower cost but does not provide the best balance. This method is not usually done any more by full service tire stores as it only affects the "static" imbalance and with today's light weight cars the driver is more likely to feel even a minor imbalance. I once had a car with one front tire 1/4 oz out of balance and on a very smooth portion of the interstate on my way home from work I would occasionally got steering wheel movement. A re-check at the store solved the problem. The car was a small light weight sports car and it just happened to be sensitive at that level. My one-ton dually pickup was not sensitive at the two ounce level on the rear axle.


The next best method would be with the mounted tire on a "spin balancer", This rotates the wheel and tire at speed and electronically calculates where to place the weights.
When you buy a new passenger or pick-up truck tire, this is the method they are normally talking about.

But truck/bus size tires can also be balanced using a heavy duty version of this type of machine.

Spin balancers measures the up-down imbalance and the side to side balance and tells the operator how much weight to place on both the inside and the outside of the wheel to counteract forces in both directions.

 Finally there would be "On-Vehicle" spin balance this would give the balance for the tire, wheel and the brake drum and hub of the vehicle so if the drum was slightly out of balance it would be included and weights would counter balance all the spinning components. If you get this type of balancing done it is important to mark the wheel position on the hub if you ever remove the wheel to check brakes and to re-mount the wheel in the exact same orientation. A downside to this method is that it can't be done to tires on drive axles.

Many drivers of Class-A do not balance their tires as they do not feel the imbalance. Some others always balance the fronts because the driver & co-pilot are sitting almost on top of the tires. On-vehicle spin would probably give the best results but this would be for the front only. Here is a video showing the process on a Corvette
 but RV tires would be the same process but with HD bigger equipment.

I see little reason to balance the rear duals on a Class-A as you will not feel the balance problem unless something was very out of balance.

Some additional info in another post.

https://www.rvtiresafety.net/2011/11/do-you-need-to-balance-your-motor-home.html

BOTTOM LINE
For Class-A I think you can just take the RV out for a quick test drive on a nice section of smooth Interstate. If you feel shaking either through the steering wheel or floorboards then you would go and have the front tires "on-vehicle spin balanced".

For Class-C and smaller vehicles using 16" diameter LT type tires I would spin balance all six assemblies.

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Have you considered "sealant" or "flat-proof" or other stuff to prevent a flat tire?

 Just read a tale of woe from a motorhome owner that appears to have been sold a tire treatment that caused nothing but problems. Names have been changed to protect the "innocent".

"We purchased "anti-flat" tire sealant for the 6 tires on our motorhome, to provide some protection from tire leaks on trips.  Our RV has had vibrations running at highway speeds, and based on forum feedback, it was recommended we try a "road force balance" on the tires.
We took our RV to "Billy-Bob-Jo's tire Emporium", which has road force balance machines - and they were unable to balance the tires - the machines got a different reading after each spin. They assumed their machines couldn't handle the motorhome rims.

 Then we took the motorhome to the nearby dealer for the company that made the RV chassis (since the front two tires were no longer properly balanced), and they called us about the "goo" they found inside the tires - because they were also unable to balance the tires.
Once they removed the tire sealant (about 45 minutes per tire), they were able to get all 6 tires balanced.  It cost us around $1000 for the "anti-flat" treatment and another $500 to get the treatment removed and the tires balanced."

Then the RV owner asked  "Has anyone encountered balance issues when using tire sealant???"  and then added  "If we don't have any vibrations on the next road trip, we probably won't put any sealant back inside the tires."

  Clearly the material used either was in-appropriate or improperly applied. Also I do not understand why the owner felt it was necessary to even use such a product rather that use a TPMS and sign up for road service and save some money never mind avoid the aggravation of bad ride and lost time.

 ##RVT982

 

Can't "Balance" your tires? Bad ride?

Can't remember the number of times I have seen someone post about the "bad ride" they had in their Motorhome and that they took the vehicle to their RV dealer but was told they could not "Balance" the tires or that they were balanced and the ride was 'What it is".

The ride can be affected by a number of different contributing factors.

1. One or more tires may be out of balance
2. The tire may not be properly mounted to the wheel
3. The wheel could be out of round
4. The brake drum/rotor may be out of balance
5. The wheel may not be mounted to the hub correctly
6. The tire may be out of round
7. The tire may have internal structural "uniformity" problems.

Many times people jump to the conclusion that the tire must be "Out Of Balance" and they want to ignore all the other possibilities.

Back in Nov 2011 I covered a number of possible contributing factors when I answered the question of Do You Need To Balance Your Tires? Obviously, those that just focus on "balance" did not review this blog post.
In that old post, I said it was possible to balance a cinder block. You might consider reviewing this post as it has some good pictures of the other conditions that can give poor ride.

I have used this comment a few times in my RV Tire Seminars but I bet few believed me. Well here is the proof.

This first shot is of my "Bubble" Balancer and my test cinder block. Yes, the balancer is old ( from the 70's) but I have balanced hundreds of tires.








Even those used on my Camaro race car

where high speed (125+) would quickly show up if the tire was out of balance.

Now first I confirm the balancer is adjusted to a near-zero level of out of balance itself. We can see the bubble is very near to perfect balance with it right at the center point.

Next, I loaded the cinder block onto the balancer. I chose to not try and pile standard wheel weights on the block, so just grabbed some hand wrenches. After some moving these "balance weights" around I ended up with a

very acceptable level of balance.

I do hope this clears up some of the confusion on Ride vs Tire Balance. 

##RVT960

The Use Of Internal Balancing Materials and/or Coolants In MICHELIN® Truck Tires

I hope this answers the questions some have about the use of alternate materials for tire balancing.


+++++++++++++++++
The Use Of Internal Balancing Materials and/or Coolants In MICHELIN® Truck Tires
(Revised)

The use of internal balancing materials and/or coolants (such as powders, liquids, gels and/or beads) in MICHELIN® Truck Tires does not automatically affect the tire warranty unless the internal balancing material and/or coolant has a high water/moisture content or that it is determined that the internal balancing material and/or coolant has adversely affected the inner liner, casing plies, or the performance of the tires.

Prior to using any type of internal balancing material and/or coolant, Michelin strongly recommends that the customer make sure the internal balancing material and/or coolant has been tested and certified by the internal balancing material and/or coolant manufacturer as being safe for use in tires. Water/moisture content testing should be included in the certification process. Any product with a water or moisture content greater than 3% as measured by the Karl Fisher Method (ASTM D6304) will automatically void any mileage, number of retreads and/or time warranty.

In addition to the forgoing, please refer to the Michelin Truck Tire Operator’s Manual and Limited Warranty (MWE40021) for a general discussion of what is and is not covered by the warranty.

NOTE: Please consult Michelin prior to using internal balancing materials and/or coolants in any MICHELIN® tires that have sensors in them. The internal balancing materials and/or coolants may adversely affect the performance of the sensors.

For additional information, please contact your local Michelin sales representative or contact Michelin using the website at www.michelintruck.com.
++++++++++++++++++


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Another post on "Calculating" inflation to avoid a blowout or tread separation

It seems this will be a never ending task of explaining the "Why and How" of setting tire pressure on RVs.

Quick answer:
A. Trailers should follow the placard which is probably the tire sidewall pressure unless the size or type has been changed. BUT they should also confirm that no individuakl tire is overloaded due to un-balance.
B. Motorhomes should run the tire placard inflation unless they know the actual load on each tire.
C If a Motorhome owner knows the actual corner load he should consult the load inflation charts from the tire manufacturer for his brand in RV use. Select the inflation needed to exceed the actual load of the heaviest side of each axle and then inflate all tires on that axle to the minimum inflation plus 10%
D, If the tires on the trailer have been changes then the individual loads for each tire need to be known. Using load inflation tables select a tire with sufficient Load Range to carry that load and then set the cold inflation to the inflation shown on the tire sidewall.

Following the above should decrease the damage done by running a tire in overload and under-inflated condition. Hopefully this will also prevent Tread separations and Blowouts.

 I try and follow a few RV forums. Some are general and others are focused on a single brand or manufacturer. I would prefer it if I could simply post a few links to this blog so I don't have to spend time saying the same stuff over and over but some sites will not allow a link to this blog. (If you are reading this you should know that you can post a link to this blog but as the Blog writer I am not allowed to.)

Here is a recent post on a thread titled "Calculating the correct tire pressure". This forum is 95% trailer oriented.

 "A while back, we weighed our travel trailer on the CAT scales and got a total weight of 7,300 pounds, rigged for towing. Rigged for towing means with a full water tank, all of the misc. junk that we normally carry and weight distribution bars tensioned, but no clothing or food on board. On average, this translates to 1,825 pounds per tire.
Today, we were able to obtain individual wheel weights using portable scales. The results are (rigged for towing)

Left Front - 2,000 pounds Left Rear - 1,900 pounds

Right Front - 1,900 pounds Right Rear - 1,700 pounds"

We can immediately see the unbalance in this trailer with the heavy tire having 27% of the total. We also learn that the TT was not fully loaded with food or cloths which would add more weight. We also see that when the owner simply used the original CAT scale weight he assumed equal weight distribution of 1825# per tire.

In this case the owner was not aware of the special loading seen by trailer tires.

In this same thread we found one owner that switched from ST235/75R15 LR-D to P23575R15/XL ! giving up about 23% of the load capacity. This thread is at 85 posts and counting.

Clearly the need for more knowledge on care and maintenance of tires in RV application is needed. I hope I have provided helpful information here and in my seminars. Please spread the word. If you have a specific question you can send a question to   Tireman9   at  Gmail  dot com

"I don't want to weigh my RV"

That is the statement I occasionally get from a few who say they have no intention of getting their RV weighed each time they go on a trip so they see no reason to ever get the RV weighed as they are certain they know they are not overweight.

With over 40,000 data points RVSEF can show that over 55% of the units they have weighed have one or more tires and/or axles overloaded, I am pretty comfortable in suggesting that RV owners need to learn the individual tire position weights at least one time.
It is not unusual for an RV to be out of balance by 1,000# or more.
Trailer owners need to do this to confirm they are not overloaded due to axle to axle imbalance or side to side balance. They still need to run tire inflation at the tire max.

Motorhome owners need to learn the "corner loads" before they calculate the minimum cold inflation for each axle.

Once you have learned the actual loads and done the calculations and table look-up you are good to go unless or until you make some significant change to your RV such as adding a residential refrigerator or possibly granite counter tops.

Not understanding the difference between "Measurable and Meaningful" some incorrectly think I am suggesting that they need to get their RV re-weighed every time they go on a trip as they may pack different items. Not wanting to do this they just throw up their hands and don't get the RV weighed.

Improper inflation can lead to overloading and excess heat generation. This is bad for fuel economy and tire durability and in extreme cases could lead to blowout failure or tread separation.

I have had my small Class-C 2008 coach (seen above) weighed three times.

My first time was just after I bought the RV and not having access to corner weighing I still wanted to know what my weights were with the "stuff" I had loaded for my first trip.

I knew I would pass a CAT scale about 15 miles from home so pulled in and got the following results
Front 3,940#  Rear 6,580#   Total 10,520# Based on these results plus the margin of inflation pressure I wanted I then knew what to set as my cold inflation.

Three months later I attended a large RV Rally and had RVSEF do corner weighing
LF 1,750  RF 1,850   Total Front  3,600#   -340#
LR 3,400  RR 3,250  Total Rear   6,650#   +40#             Total 10,250  +270#

It has been a few years since my RVSEF weighing and I have added a few items as "permanent" take along stuff and a few minor modifications to the RV that I felt had increased the load when preparing for a longer trip. I again decided to do a quick check so again visited a convenient CAT scale.
Front 3,820#   Rear7,020#   Total 10,840#   This indicates an additional 220# on the front axle and an extra 370# on the rear from the RVSEF weights

As you can see the RV has gained a some weight over the years, A bit like its owner I am sorry to say.

The good news is that the new weights do not require a change in cold inflation as the extra 320# is not large enough to put any individual tire into a higher inflation bracket. Plus my margin easily accommodates this change

As you can see it is easy to confirm that no significant change in weight has occured. There have been and will continue to be changes in the tire loading due to weight changes but those changes, while measureable are not meaningful so are not of concern. I also think you can see that excuse for never getting your RV weighed because you don't intend to or want to weigh the RV each trip is not a reasonable excuse.

"Danger, Will Robinson, Danger"

I think a good number of us remember those iconic words of warning from B9 the robot on the "Lost in Space" TV show from the 1960's. I repeat it here for I feel that just like young Will, many RV owners simply continue on and do not heed the warning. My message is of the importance of having adequate inflation based on the real tire loads. Without knowing the real load you can't use industry guidelines on how much air you need to have in your tires.
Too many RV owners simply and incorrectly assume that if they get on a scale and learn the axle load they can assume they know the tire load because they simply divide by 2 and think the result is the tire load. In reality few motorhomes are balanced side to side and even fewer trailers are balanced between axles so towables tend to be worse off as they start down the wrong path by taking the total load on all the trailer axles and divide by the number of axles and assume equal load distribution. They then compound their error and further assume equal side to side loading.

Now these assumptions might be tolerable if there is adequate (12 to 20%) "Reserve Load" ** but most RVs have no room for error and many have so little safety margin that they end up with one or more tires and/or axles overloaded.
Recently I did some research on a couple of forums to see if I could learn what the real load balance was.
Looking at 14 different Class-A motorhomes I found side to side variation on front axles ranged from 50/50 to 47/53 with no trend showing which side was heavier. The rears ranged from 50/50 to 54/46 but again there was no consistency as to which side was heavier. Here is a detailed breakdown of a group of Class-C motorhomes.

So here we see that while a majority seem reasonable balanced in the range of 48/52 or better we do see that some people are out with a split of 45/55 and this is on a vehicle that probably started life very near 50/50 which is what you would expect from a major mfg like GM or Ford.

For 5th wheel units,
I reviewed over 500 posts to a thread that asked what the "Real Weight" was but only found two owners know the actual tire loads. Searching some other threads I found a very small sample. I found that the best trailer had 50/50 on the front axle and 52/48 on the rear axle. This sounds good until you also look at F-R axle to axle split and find 61/39. If we look at the trailers with 50/50 balance between axles we see some as bad as 41/59 side to side.

The only trend I think might exist is that Class-B and smaller Class-C without slideouts might be a bit better for side to side balance than the rest of the RV community.

Important note. All of the above is simply looking at balance and not if any tires are overloaded. RVSEF has done over 35,000 RVs and recorded the individual tire load measurements. They point out in their seminars they have found some 57% of RV have an overloaded component.

While preparing this post I learned from an RV repair company that they find $7,000 worth of damage on motorhomes is normal when there has been a tire failure so clearly making the effort to either get your RV weighed at big RV events or finding a scale where you can get both individual axle loads and one side at a time is worth the effort if you want to avoid this unnecessary expense.

If you want additional information on how to get your individual tire loads you can check this site. If you have a facility that can weigh individual axles and one side of the RV at a time you can download a worksheet to help you calculate the individual tire loads. Once you know the actual individual tire loads simply select the load on the heavier side, look up the minimum inflation needed to carry that load and inflate ALL tires on each axle to that level.  If you exceed the max for a tire you MUST move stuff around or out of the RV or you can expect to simply be another statistic.

 BOTTOM LINE Hopefully I have convinced you that you can't assume the weights on your RV are either balanced or under spec. The odds are that you have one tire carrying at least 5% if not 10% more than another but you can't guess which.

** Reserve Load. The difference between the tire load capability at it's cold inflation pressure and the actual load on that individual tire.

Do you need to balance your tires?

I was recently asked about tire balancing.

The person asking the question, said that they had done some research and learned there were three methods. They wanted to understand the advantages of each and which they should use for their Class-A RV.

The basic method is static or "bubble balance". as seen in this  video

The mounted tire is placed on a balance and the heavy spot is counter balanced with weights. This is normally done with the mounted tire in the horizontal but I have also seen it with the tire on a special spindle as seen with this motorcycle tire as seen in this video.

This static balancing is lower cost but does not provide the best balance. This method is not usually done any more by full service tire stores as it only affects the "static" imbalance and with today's light weight cars the driver is more likely to feel even a minor imbalance. I once had a car with one front tire 1/4 oz out of balance and on a very smooth portion of the interstate on my way home from work I would occasionally got steering wheel movement. A re-check at the store solved the problem. The car was a small light weight sports car and it just happened to be sensitive at that level. My one-ton dually pickup was not sensitive at the two ounce level on the rear axle.



The next best method would be with the mounted tire on a "spin balancer", This rotates the wheel and tire at speed and electronically calculates where to place the weights.
When you buy a new passenger or pick-up truck tire, this is the method they are normally talking about.

But truck/bus size tires can also be balanced using a heavy duty version of this type of machine.

Spin balancers measures the up-down imbalance and the side to side balance and tells the operator how much weight to place on both the inside and the outside of the wheel to counteract forces in both directions.

 Finally there would be "On-Vehicle" spin balance this would give the balance for the tire, wheel and the brake drum and hub of the vehicle so if the drum was slightly out of balance it would be included and weights would counter balance all the spinning components. If you get this type of balancing done it is important to mark the wheel position on the hub if you ever remove the wheel to check brakes and to re-mount the wheel in the exact same orientation. A downside to this method is that it can't be done to tires on drive axles.

Many drivers of Class-A do not balance their tires as they do not feel the imbalance. Some others always balance the fronts because the driver & co-pilot are sitting almost on top of the tires. On-vehicle spin would probably give the best results but this would be for the front only. Here is a video showing the process on a Corvette
 but RV tires would be the same process but with HD bigger equipment.

I see little reason to balance the rear duals on a Class-A as you will not feel the balance problem unless something was very out of balance.

BOTTOM LINE
For Class-A I think you can just take the RV out for a quick test drive on a nice section of smooth Interstate. If you feel shaking either through the steering wheel or floorboards then you would go and have the front tires "on-vehicle spin balanced".

For Class-C and smaller vehicles using 16" diameter LT type tires I would spin balance all six assemblies.

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Do you need to balance your motor home tires?

Do you need to balance your motor home tires?

There is some controversy on this topic. Some insist it is not necessary while others say you should always have your tires balanced. Here are my thoughts.
If you are not experiencing any vibration of your seat, through the floor boards or in the steering wheel due to the imbalance of your front end components, I see no reason to spend the money to have your tires balanced. Now if you have some vibration, one of the first things you need to do is to try and identify the cause. Is it due to tire wheel assembly imbalance and not some other front end component or source? To learn the answer you need to do a little investigation and give a little thought to what you discover.

Vibration can be due to a number of different sources and depending on when and where you feel the vibration and if you can make the level or frequency change you will know what the possible source is.
Do you have a large generator up front as normally found in “pusher” Class-A? Does the vibration change or go away when you run or turn off the generator? If so then one of the areas I would first look into is the generator mountings. This can include the rubber bushings that attach the generator to the frame around it. Are the bushings old?
Remember the general advice to change your tires when they get to be 10 years old?
Well motor mounts are also rubber and that rubber can age or get oil soaked and sometimes even tear. Spend a few minutes with good lighting and check each mount to be sure the bolts are tight and the rubber appears to be in good condition and not overly soft or hard. If your generator can slide out for service, be sure the mounts of the slide frame are firm when the generator is locked in place for travel.
Next ask yourself; does the co-pilot feel the vibration or just the driver? Is the vibration felt mostly through the steering wheel? Does the wheel just “Buzz” or does it oscillate back and forth? Steering wheel motion can many times be traced to worn steering components so you need to do a thorough inspection of the steering shaft mounts, steering box and all the links that go to the front suspension.

Moving on, when there is vibration felt through the floor and possibly the seat when both the driver & co-pilot can feel it, does the vibration feel most pronounced at low speeds or above say 40 mph? Low speed vibration can many times be caused by tire “Flat Spots”. A Flat Spot is a localized condition where a tire has taken a set from long term parking and can be more pronounced when the tire was parked when it is hot. Driving on a tire that has a large flat spot sometimes is noticeable at less than 10 mph. Also sometimes a flat spot can go away after 30 minutes to an hour of highway speed driving after the tire warms up. You can minimize flat spotting by ensuring you are carrying more than the minimum inflation needed to carry the load. If you are going to park for a few weeks or more I would recommend you inflate your tires to the max pressure shown on the tire sidewall. If you have the ability to remove some of the load on the front tires that will also decrease the tendency to flat spot. Balancing a flat spotted tire will not solve the ride problem. Remember it is possible to balance a cinder block but I doubt you would ever get a smooth ride driving on one. Old worn shocks can allow normal short term flatspot vibration to get to the passengers so you might need new or better shocks.

Another possible source of floor vibration with front engine motor homes when not felt through the steering wheel could be problems with the drive-shaft, U-Joints or support bearing. These can be checked by any truck service company and with smaller Class-C units possibly a large Ford or Chevy dealer depending on the manufacturer of the original cutaway van chassis.

High speed vibration that changes as you increase speed does point to a rotating component. This is not always just the tire as the imbalance could also be the wheel or the brake drum/rotor or hub or even a wheel not properly centered on the hub. The rim hub fit should look as seen in this picture.









Also your tire might not be properly centered on the wheel. One thing you can check yourself is tire centering on the wheel. Most tires have what is sometimes called a Rim Centering Rib.




This is a feature molded on the sidewall which should be visible just above the rim and uniformly spaced around the tire.











If you see variation in the RCR to rim spacing you need to have the tire inspected and possibly de-seated and re-inflated to ensure the tire is concentric with the wheel. The tire shop that mounted the tire is responsible for ensuring the tire is properly seated. You should not attempt to fix this yourself as it requires the use of a tire safety cage.

Another thing to check is the run-out of the tire. This should be less than 0.035”. If there is more than this then you need to fix the centering or mounting issue that is probably causing the run-out. If all the components are properly centered then you might need to have the tire trued if the vibration is a real problem. Remember that cinder block.

If all else checks out then I suggest you have an on vehicle balance done as this will identify any imbalance in the rim, hub, brakes or tire. Off vehicle balance does not confirm the brake drum/rotor and wheel mounting or hub is in balance.
If you need to have the rotating assembly balanced external weights are usually used and may be needed on both the inside and outside of the rim to achieve full dynamic balance. If you choose to have the tire balanced by adding one of the products to the inside of the tire be sure to get a full warranty, in writing, that the balance material used will not damage the wheel, tire, valve or TPMS. If you use one of these products and have a TPMS valve you will also need to purchase a special valve core to prevent the material from plugging the small sensor hole.

I hope this clears up any confusion on how to achieve a smooth ride.

Some links with more information. NOTE I am not recommending any of these companies or products. Just showing you that a quick GOOGLE on truck tire truing will find the options available to you.
GardenSpot
Cooktire
TruckmodCentral
KeenTransport