Foam Tire Mysteries Explained – Vintage Tech Tip

Foam Tire Mysteries Explained – Vintage Tech Tip

With all the different families of foam tire now available for radio-controlled cars it is often difficult figuring out what the compound terminology means and what the differences are. This article is a tutorial that will provide you with the knowledge required to make intellegent decisions on what tire you should be running for your particular application.

CRC's New White Dished Wheel for TC 26mm and 30mm

Purple,
Pink
, Grey,
Green
, R4, F3,
Black, Magenta….

What are all these
names for foam tires? HELP!

The folks here at CRC are hereto explain it all. Read this summary to better understand the various names that tire manufactures attach to the rubber. This will help you decide which tire you need and why.

CRC's New White Dished Wheel for TC 26mm and 30mm

Tires are grouped intowhat we call “families”. These groups are designated based on chemical compounds of the actual rubber/foam mix.

Lets take a look…….

Japanese F

The Japanese rubber primarily used for front tireson asphalt is called Japanese “F”. This rubber is tough as nails with a very high content of rubber and less foam. It wears like iron and is difficult to true and cut. The grip is fairly good but the tough design of the rubber prevents it from biting the surface like some other compounds. Rather than wear off in small chunks or pebbles of foam, this tire is known to melt and get very sticky under high heat. This makes this compound a great choice for asphalt, but not a good choice for carpet. The high friction of carpet racing causes these tires to get “sticky” and pick up grip during the race. If pushed even further, instead of wearing down, this rubber develops a sticky surface picking up debris and actually lowering grip levels.

Soft Medium Hard Very Hard Rocks
Typical
Shore
<30 30 – 35 36 – 42 42 – 49 50+
CRC
Designation
F2 F3 F4 F5 F6
Other
mfgs designation
30 35 40 – Red 45 – Red
50

Japanese R1/12th Purple fronts for 1/12th scale from CRC

The Japanese rubber typically used for rear tires is Japanese “R” rubber. This rubber has small pore structure and is very high grip and low wear. The rubber is used on the front in carpet racing and as a rear in asphalt racing. This rubber wears more than “F” type, but is much tougher than American or European rubber. When the rubber cures very hard, it makes for an excellent front tire.

Soft Medium Hard Very
Hard
Rocks
Typical
Shore

22 – 29
30
– 35
36
– 40
41
– 47
47+
CRC
Designation
R2 R3 R4 R5 R6
Use
for Front
NA NA On
Carpet
On
Carpet
On
Carpet or Asph.
Use
on Rear
Carpet/Asphalt Carpet/Asphalt Carpet/Asphalt Carpet/Asphalt Not
used often
Other
mfgs designation
Pink Magenta Purple Purple Double
Purple,X-50

Japanese CCRC Grey mounted rears for 1/12th Scale

Japanese C rubber is typically used for carpet racing. The foam is very light with decent wear. It is tougher than American foam and also has better grip. It does not last as long as F or R rubber.

Soft Medium Hard Very
Hard
Typical
Shore
<33 33-38 39
– 44
45+
CRC
Designation
White
– C2
Grey-C3 Black-C4 Double
Black-C-5
Use
for Front
NA NA NA On
Carpet or Asphalt
Use
on Rear
Carpet/Asphalt Carpet/Asphalt High
bite carpet
Other
mfgs designation
White Grey Black

American Rubber

Foam rubber dates back to the early days of racing on foam rubber tires. The foam rubber is very affordable. The compound provides decent grip but the life is low as they are typically high wear. Common names for America foam is green, blue, orange, yellow.

Soft Medium Hard Very Hard
Typical
Shore
<30 30 – 35 36 – 45 45+
CRC
Designation
NA Green Green Blue
Other
Mfgs
Yellow Green Blue Orange

European/Italian

The Europeans and their love of 1/8th scale gas racing pushed the limits of American foam tires. The European (especially the Italian) companies were eager to find a better tire with more grip and less wear to handle the horsepower of the .21 engines that they were producing. The result is a unique “wet” dense rubber that provides more grip than American rubber on asphalt. The European rubber doesn’t work very well for carpet racing. It is also the heaviest of the foam rubber tires.

Soft Medium Hard Very Hard
Typical
Shore
<30 30 – 35 36 – 45 45+
CRC
Designation
Silver Gold NA NA
Other
Mfgs
Silver,
Gummy Bear
Gold,
70D

Combinations

Sometimes, combining thin rings of 2 different rubber types will give performance features unique to only a dual compound tire. The Orange/Purple combination on the front of a touring car is known as CRC Dual X-firm. These are great for the front on Carpet. Other manufactures
designations are Plaid and Orange/purple.

CRC's White Dished and 5-spoke wheel for Touring Cars

CRC
tire Suggestions


Electric Touring Car – White Dished
Wheel

Track Front 1st Choice Front 2nd choice Rear 1st Choice Rear 2nd choice
High Bite
Carpet
#2129-26mm
Dual X-firm”Plaid”
#2134
-26mm R6 “Double Purple”
#2135
-26mm R4 “Purple”
#2136
– 26mm R3 “Magenta”
Low Bite
Carpet
#2134
-26mm R6 “Double Purple”
#2135
-26mm R4 “Purple”
#2136
– 26mm R3 “Magenta”
#2135
-26mm R4 “Purple”
High Bite
Asphalt
#2130
– 26mm F6
#2131
– 26mm F5
#2135
-26mm R4 “Purple”
#2136
– 26mm R3 “Magenta”
Low Bite
Asphalt
#2132
– 26mm F4
#2133
26mm F3
#2139
– 30mm R3
#2138
– 30mm R4

Electric
Touring Car –
Yellow
5-Spoke Star Wheel

Track Front 1st Choice Front 2nd choice Rear 1st Choice Rear 2nd choice
High Bite
Carpet
#2114-Dual
X-firm”Plaid”
#2120
-R6 “Double Purple”
#2119
– R4 “Purple”
#2117-
R3 “Magenta”
Low Bite
Carpet
#2120
– R6 “Double Purple”
#2119
– R4 “Purple”
#2117-
R3 “Magenta”
#2116
-35mm R3 “Magenta”
High Bite
Asphalt
#2110
– F6
#2112
– F5
#2119
– R4 “Purple”
#2117-
R3 “Magenta”
Low Bite
Asphalt
#2112
– F5
#2120
– R6 “Double Purple”
#2118
– 35mm R4 “Purple”
#2116
-35mm R3 “Magenta”

Nitro
Touring Car – White Dished Wheel

Track Front 1st Choice Front 2nd choice Rear 1st Choice Rear 2nd choice
High Bite
Asphalt
#2130
– 26mm F6
#2131
– 26mm F5
#2137
– 30mm R5
#2138
– 30mm R4
Low Bite
Asphalt
#2132
– 26mm F4
#2133
26mm F3
#2138
– 30mm R4
#2139
– 30mm R3

Nitro
Touring Car – Yellow 5-Spoke Star Wheel

Track Front 1st Choice Front 2nd choice Rear 1st Choice Rear 2nd choice
High Bite
Asphalt
#2110
– F6
#2112
– F5
#2119
– R4 “Purple”
#2117-
R3 “Magenta”
Low Bite
Asphalt
#2112
– F5
#2120
– R6 “Double Purple”
#2118
– 35mm R4 “Purple”
#2116
-35mm R3 “Magenta”

1/12th Scale

1/12th Purple fronts for 1/12th scale from CRCCRC Grey mounted rears for 1/12th Scale

Track Front
1st Choice
Front
2nd choice
Rear
1st Choice
Rear
2nd choice
High
Bite Carpet Road Course
#2325
– Purple
#2326
– Magenta
#2345
– Grey
#2305
– Green
Low
Bite Carpet Road Course
#2326
– Magenta
#2303
– Blue
#2345
– Grey
#2342
– Pink
Carpet
Oval
#2303
– Blue
#2325
– Purple
#2305
– Green
#2345
– Grey
High
Bite Asphalt Road Course
#2325
– Purple
#2326
– Magenta
#2342
– Pink
Low
Bite Asphalt Road Course
#2326
– Magenta
#2345
– Grey
#2342
– Pink

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