Tires are the single most important part of your chassis setup. Tires are the ONLY part of your chassis
setup in contact with the racing surface, and are the sole provider of directional forces such as
acceleration and steering. Generally speaking, the softer the tire is, the more grip that the tire can give.
However, if the tire is too soft, it may deflect or deform more under load and cause a reduction in
traction. The goal in selecting race tires is to run the softest tire you can run to achieve maximum
traction, while maintaining consistent performance throughout the duration of the race, without
excessive deflection, tire heat, and tire degradation. The softest, most hooked up tire combination is no
good if it does not last the duration of the race.
The best way to find out what tires you should be running is to go ask what the fast guys at your track
are running. Use this as a starting point for tire selection, but do not be afraid to try other combinations.
Each track typically has a known “go to tire” that works well. Asking the veterans and local fast guys is
always a good way to know what to start with.
Page 4 of 21
Foam Tires
There are two different “families” of foam tires; Synthetic Rubber and Natural Rubber.
Synthetic Rubber: These tires are best suited for tracks with moisture in them, and are usually the tires
of choice for wet clay tracks. These tires typically are softer than natural rubber tires, and create the grip
racers look for on wet tracks.
Synthetic Foam Tires
RC4LESS: Silver (25), Gold (30), Bronze (35)
BSR: Silver (25), Orange (25), Red (30)
Natural Rubber: These tires have higher rubber content, and excel on dry track surfaces. These tires are
harder than their synthetic counterparts, but offer longer wear, and better performance characteristics
on abrasive surfaces. Natural Rubber tires gain traction as the tire heats up and the rubber gets “sticky”.
Running too soft of a tire can cause overheating, excessive tire wear, and less overall grip. Running a tire
that is too hard can result in a tire that does not build heat, and creates less than desired grip levels.
Natural Rubber Tires
RC4LESS: Pink (30), Pink (35), Magenta (40), Purple (45)
BSR: Pink (30), Double Pink (35), Purple (40), Double Purple (45)
CW: V2 (30), V3 (37), V4 (45), V5 (55+)
Tire Grooving
Grooved tires generally provide more forward and side bite than do tires without grooves, but do have
higher wear characteristics and do require break in for maximum grip. Grooved tires that have not been
broken in will lack forward and side bite, until they get scuffed in. Generally speaking, on wet tracks, you
want a tire with radial grooves and cross cuts in rear, and radial grooves in front. On dry tracks, we often
run only radial grooves on all 4 tires. Radial grooves promote side bite by creating edges on the contact
surface that increase side bite. Cross cuts are used to increase forward traction, however if the track has
enough bite to run a harder compound tire, you typically are not looking for increased forward traction.
There is a point at which the grooved tire becomes too worn or feathered, and it should be replaced to
prevent a major loss in tire performance.
Tire Diameter
Tire Diameter is a huge factor in the amount of bite a tire produces. A good all-around tire diameter to
start with is 2.65”. The larger the tire diameter, the more sidewall the tire has. More sidewall creates
more side bite, and makes the tire feel like it has more grip than a smaller diameter tire of the same
compound. Taller tires can sometimes create too much bite, causing traction rolls, or tire chunking from
excess sidewall deflection. Typically, when bite goes up, you want to go to a smaller tire. Suggested tire
diameters range from 2.45” for slower spec classes on high bite tracks up to 2.80” for faster classes, on
lower traction surfaces. What is best for your application? Seek out the local fast guy and ask him!
Compound Selection
Foam tires do not have air in them; therefore you cannot adjust performance of the tire with air
pressure. Instead, we use softer compound tires on different corners to achieve different amounts of
traction. A common setup is to run 3 soft tires and a right front tire that is one step harder. This often
results in a more balanced feel, and smoother steering response. Sometimes, on abrasive tracks, racers
may opt for soft left sides, and one step harder right sides to balance out tire wear.
Stagger
Stagger is when your right side tire is larger in diameter than your left side tire. Some racers play with
rear stagger, but in general we do not. Our chassis race at scale speeds of 400mph around scale 3/8 mile
Page 5 of 21
tracks, lapping in 4 seconds. Our cars also feature independent rear suspensions, and differentials that
are not locked. The differential will usually absorb any difference in tire diameter by controlling diff
action on throttle. If the rear axle was solid and locked, stagger could be a helpful tool, but that is simply
not the case with our cars.
Front stagger can be used to tune steering response and entry steering. Stagger will reduce
responsiveness at initial turn in, and reduce steering on corner entry. Reverse stagger is when the right
front tire is smaller than the left front. Reverse stagger will make your car more reactive at initial turn in,
and give you more steering at corner entry. Front stagger is a good way to fine tune steering, but is
recommended only as a fine tuning adjustment once your chassis is close.\
Rubber Tires
Rubber Tires are typically used on “Looser” dirt surfaces, although loose dirt has pretty much
disappeared from race tracks across the country. There are two distinct types of rubber tires: Street
Tracs and Buggy Tires.
Street Tracs
Street Tracs are a Spec style rubber tire that are not particularly high in bite, but when used as a spec
tire, can be a very good control tire. Street Tracs are available in two compounds, standard and high
bite. If you are racing on dirt and the rules allow, you will want to use the High Bite (HB) compound. If
you are running on a hard surface, the Standard compound will keep you from wearing out tires too
quickly. I suggest the CW molded inserts for use in the Street Trac tires. The lower the bite, the softer
your insert should be. The higher the bite, the harder you want. Yellow is soft, Orange is medium, and
Red is firm. A good all-around combination is HB tires with Yellow inserts.
Buggy Tires
There are two types of Buggy Tire racing: Open Tire and Spec Tire.
SPEC Tire
If you run SPEC Tires, you need to talk to the local fast guys at each track and figure out what the
handling tendencies are of the SPEC Tires. AKA “Rebar’s” are a common SPEC Tire. This tire is known to
have very little side bite, and a good amount or forward bite. This tire is designed and used in off-road
for super packed conditions, and is not the ideal tire for looser surfaces, but as a SPEC Tire, it is the same
for everyone. The three tricks with SPEC Tires right now are insert selection, tread depth, and tire
doping. Some tracks are so hooked up that foam tires would work very well, however certain parts of
the country are afraid of foam tires. This brings “ghosting” into play. Ghosting is the practice of
purposely wearing out your tires to make them have very little tread left, usually tiptoeing the fine line
between worn out treaded tire and slicks. I have one issue with SPEC Buggy Tire racing today, there is 2
different compounds allowed, and no limit on tire inserts, which allows racers to have 10 different
combinations of the same rear tire, which in the long run, saves nobody money. Throw in each tread
depth, and tire costs can be very high.
Inserts
Open cell foam inserts are softer than their molded counterparts, and usually provide a more hooked up
feel all the way around the track creating more side bite and more forward bite. Molded inserts are
usually more firm, and reduce sidewall deflection and carcass stretch under acceleration. This promotes
less side bite and forward bite, but in higher traction situations may give a more balanced feel by
allowing the car to better rotate into the corner, and rotate more on throttle during corner exit.
Page 6 of 21
Open Tires
Open Tire racing may seem like it would cost more than SPEC Tire racing, but there are a few tires that
are known to be ideal in most situations. There is not much to say about Open Tires, instead I will list
what Open Tires you should consider. Tire Insert selection is similar for Open and SPEC Tires. For best
performance, seek out the fast guys, and see what they are using!
Front Tires
Pro-Line – Narrow 4 Rib – M3 Compound (Good on looser tracks)
Pro-Line – Scrubs M3 – Compound (Good on Harder Tracks)
Rear Tires
Pro-Line – Inside Job – M3 Compound
Hot Bodies – Gigabite – Pink Compound
Tire Dope
I hate tire dope. It is made up of toxic chemical solvents, known in the chemical industry to cause
cancer, serious birth defects, and mutations. Somehow, the RC industry is allowed to sell such chemicals
without supplying proper safety precautions and use instructions, and without MSDS or ingredient
listings. Please avoid skin contact and inhalation of these products. Please do not use them indoors or
without proper ventilation. If RC Racers would push for a doping ban, we could eliminate the need to
have several $12 bottles of toxic chemicals in our pit boxes, increase tire life and lower tire bills, and
race in a much healthier environment.
If you want Tire Doping advice, seek out the local fast guy at your track, and do what he is doing.
In conclusion, for the fastest race car possible; TIRES, TIRES, and TIRES!!!!!! If your tires are not ideal for
the track conditions, you WILL NOT be as fast as you could be on the right tire. A poor chassis setup
racing on the right tires will often beat a well setup car on the wrong tires. For best results, do your
homework, come prepared, and look to the veterans for guidance.
Chassis Tuning 101
Matt Murphy’s Dirt Oval Chassis Tuning Guide