TECHNICAL Bulletins
WHY MICROBEADS?
HARD-TO-BALANCE MUDDER TIRES
BALANCING LOW PROFILE TIRES
WHY MICROBEADS?
The theory of
balancing tires by installing moveable balancing material inside the tire
was first established back in the fifties. Early versions included using
liquids, metal shot and even golf balls. Balancing truck tires however did
not really start to catch on until the eighties, when roads and rigs had
improved to such a degree that balancing truck tires to maximize tread life
was beginning to make good economic sense.
The introduction of tire balancing compounds in the late eighties overcame
the economic disadvantage of fixed weight balancing for truck tires, which
requires that the tires should be rebalanced at regular intervals of about
30,000 miles,
M. & R. Tire Products Inc.
patented the use of microbeads in a tire balancing compound in 1992. Until
that time, the most successful dry balancing product was a finely-ground
granulated material that was installed in the tire. However, we felt that
microbeads could improve on the use of a granulated material as a balancing
material in two areas – flowability and durability.
Flowability, because we felt that the better the material moved in
response to the forces of imbalance generated inside the tire, the quicker
it would neutralize the imbalance and give a smooth ride. (To understand
more about the importance of free flowability of a balancing material, just
watch our 4-min video – How Magnum Plus Works - on this website).
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And durability, because we wanted the
balancing material to retain its physical shape and size throughout
its working life, since any change of its physical properties could
affect the consistency of the balance. |
With these criteria in mind, we developed our original Magnum tire balancing
compound, using microbeads that were round, smooth and durable, plus
some additional materials. The roundness and smoothness of the microbeads
resulted in the shortest response time to the forces created by the heavy
spot in the tire, and the durability of the microbeads ensured that the
balancing compound would remain effective throughout its life. (This has
meant that all Magnum balancing compounds can be re-used in a retread tire
at no additional cost).
Testing by an
independent laboratory also confirmed that Magnum microbeads flowed
over twice as fast as other granulated materials, using the ASTM D
1895-90 standard for measuring the flowability of a material,
thereby demonstrating the superior flowability of our microbeads
over other balancing materials.
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Finally, we added additional components to eliminate any electrostatic
cling between the microbeads and the inner liner of the tire,
since anything that slowed down the free movement of the
balancing material inside the tire would detract from its
ability to neutralize quickly the forces created by the
imbalance. In other words, if the microbeads were sticking
to the inside of the tire rather than free-rolling, then greater
force would be required to move them to a new position for
neutralizing the imbalance. (This can be seen clearly in our
video.) |
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The introduction of tire pressure
monitoring systems created an additional problem, in that any
powdery material used in a balancing compound would run the risk of
blocking the TPMS sensor holes.
To avoid this, in 2006 we introduced our latest tire balancing compound, Magnum
Plus, which is fully compatible with tire pressure monitoring systems.
Magnum Plus uses much larger microbeads than before, and all
powdery materials have been eliminated. The microbeads we have
developed for Magnum Plus are nearly twice as large as before, are 98%
round and are carefully calibrated for consistent size. They are also
coated to avoid static cling and moisture, which would inhibit their
free movement within the tire.
Magnum Plus
extra-large superior microbeads also have two other advantages.
Firstly, their durability (as measured by a standard Newton compression
resistance test) is almost twice that of microbeads that are half their
size, Secondly, the larger microbeads create even less rolling
resistance within the tire over smaller microbeads, since their surface
contact with the inner liner is less than that of smaller beads. Also,
they resist humidity even better than smaller beads.
So with Magnum Plus tire balancing
compound, you really do get the best of all worlds. You get the
superior flowability and durability of ultra-smooth microbeads over
granulated balancing materials, plus increased flowability and
durability over products using smaller microbeads, as well as
compatibility with tire pressure monitoring systems.
Plus the extra savings from re-using
Magnum Plus in retread tires!
HARD-TO-BALANCE MUDDER TIRES Magnum Plus tire balancing compound can be used to successfully balance many hard-to-balance tires, such as heavy-lug off-road mudder tires.
With many larger mudder tires, the amount of imbalance can vary tremendously between tires, which makes it difficult to predict the correct amount of Magnum Plus to use. In these cases, a useful method is to determine the amount of static imbalance in the tire and rim assembly, and then to install approximately the same amount of Magnum Plus. If the static imbalance falls between two packet sizes, then choose the smaller quantity.
If you do not have an electronic tire balancer, you can use a simple bubble balancer. Just place the tire assembly on the balancer, then place some packets of Magnum around the side of the tire, until the bubble is centred - then go with that amount of Magnum Plus balancing compound. 
Final note - there are a few times when Magnum Plus may not give a satisfactory balance in off-road, specialty or custom wheels - factors vary enormously, and are hard to predict. If a fitment has not worked out for you, and you have followed our guide-lines, then we will gladly reimburse you the cost of the Magnum Plus.
BALANCING LOW PROFILE TIRES Low profile specialty tires and custom rims for light trucks and SUVs represent a growing market, but also pose some special problems for tire balancing. In particular, ultra low-profile light truck tires are hard to balance, since most custom rims will not accommodate fixed weights at the rim, but require that the weight be installed somewhere in the centre of the rim itself. If the heavy spot on the tire lies roughly in the centre of the tread, then you will likely get a satisfactory balance. However, if the heavy spot lies over towards the shoulder area, then a good balance may be difficult to achieve. In many cases, Magnum Plus balancing compound may be able to help you out. Firstly, if the tire is 60 series or higher, then Magnum Plus on its own should provide a satisfactory balance – just follow the regular instructions for installing Magnum Plus.. However, for light truck tires of 55 series profile or less, Magnum Plus alone may not give you a satisfactory balance, for the same reason as described above – namely, that since Magnum Plus tracks roughly around the centre of the tread, then it may have difficulty in correcting for a heavy spot located in the shoulder area of a low-profile tire. In these cases, we recommend a combination balance. That is, you combine Magnum Plus with a static electronic balance. 
Just open the appropriate Magnum Plus INSERT™ packet along its seam, and place it into the tire during installation. Then carry out a static balance of the wheel assembly. In most cases, the Magnum Plus microbeads will disperse quickly enough around the interior of the tire so that the reading for the static balance will not be affected. However, to make sure that the reading is correct, you should take two or more readings for the static balance, to ensure that these are consistent. Then fix the static balance weight in the appropriate location. If however the static balance readings are not consistent, then Magnum Plus would have to be installed after carrying out the static balance. Magnum Plus is compatible with tire pressure monitoring systems. However, you must use the nickel-plated valve core that we supply, to prevent any problems of electrolysis between the valve core and the TPM unit. NOTE
Magnum Plus is not recommended for balancing high performance tires. | 
