What Are the Different Motocross Classes? MX, SX, Amateur, Kids & More

Whether you are thinking about starting MX racing or watching motocross and supercross on TV, you are going to need to know the different categories and classes so that you can follow along with the action.

Motocross racers are divided into many different classes to put similar racers together and create equal opportunity. This is done primarily by the size of the engine in the dirt bike and by the age of the rider. Some of the larger classes are further broken down into ability levels of A B C and D. 

For some explanation of the different ways racers are broken down into classes, check out the next section. However, if you are just here for some hard data about the class names in specific race series, then just scroll ahead to the tables.

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Classes Quick Guide:

These are the pro classes you will see on TV in the United States. Pro Motocross runs outdoors in the summer, Supercross runs in stadiums from winter into spring, and the SuperMotocross World Championship (SMX) playoffs combine both.

MX is short for motocross, raced on outdoor tracks, and SX is short for supercross, raced on tracks built inside stadiums. The 250 Supercross class is split into West and East regions. For the full comparison, see our motocross vs supercross guide.

Motocross Classes	Supercross Classes	SuperMotocross (SMX) Playoffs
450 MX	450 SX	450 SMX
250 MX	250 SX West & 250 SX East	250 SMX
Women’s MX (WMX)	No women’s class	No women’s class

 

Motocross/Supercross Number Plate Color Classifications:

On TV, the plate color tells you a pro rider’s class: white for 450, black for 250, and red for the points leader. The yellow plate is for amateur B riders.

450 Class (Pro)	250 Class (Pro)	B Class (Amateur)	Current Points Leader (Pro)
White with black numbers	Black with white numbers	Yellow with black numbers	Red background with white numbers

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What Are the Dirt Bike Racing Classes?

Imagine for a moment that you are an established track owner and race promoter and you are going to hold a major race. You are expecting hundreds of racers to show up for this event and you know that it will bring in a very diverse crowd of riders.

You will have the 4-17 year old demographic that wants to be the next Eli Tomac or Ricky Carmichael and are probably ripping anything from a 50cc up to a 250F. Even though these riders have the same goals, and potentially some share similar skill levels, it is not logical to place them in the same class.

A racer's abilities are categorized by using a scale of A, B, C, and D. 

• A is the top amateur level (pros race on a separate pro license)
• B is the intermediate group
• C is the entry level in the AMA rulebook
• D is the beginner group some tracks and districts add when they have enough new riders

The naming conventions used above aren't as important as remembering that the A designation at the end of a class means that’s the best of that engine/age class and everything after A is progressively easier. Some races do not have enough riders for both a C and D class, which results in combining the classes and the C class becomes the beginner class.

As we’re already on the topic of class variation and add-on designators I should mention you will also see words like ‘limited’ added onto the back of some classes. Limited means that you are required to keep your bike basically bone stock. You can change the graphics, air filter, sprockets, suspension settings, and the mapping on the stock ECU, but the exhaust and engine internals have to stay stock.

Also showing up on a day of motocross races will be a large group of younger riders and kids of all ages. Because of how different each kid can be during those growing years the classification options are very large. This is also because there is a diverse field of bike sizes and engine sizes for those younger riders.

You will find classifications groups like Micro (formerly Peewee), Schoolboy, and College for age groups and also class names like 65cc and 85cc that are more specific to the bike size/capabilities. See the class list below for the full youth category names. If you are still deciding when your kid should start, read what’s a good age to start motocross.

Another large group of riders will be the older crowd, and in motocross, riders 25 and over move into the veteran classes, referred to as the Vet, Senior, and Masters classes. These groups can include 25+, 30+, 35+, 40+, 45+, 50+, 55+, and 60+ classes.

What about the ladies?

Much like the other classes, there are specific classifications for the women racers as well. The girls have a couple of age groups for the younger riders and then all major competitions will have a Women’s MX category or will compete in an Amateur category.

The sport of motocross happens to be a more male-dominant sport, but that doesn’t mean that there aren’t opportunities for women. With the sport being less popular among women, the need for several classes is not there. There is an open Women’s class for teen and adult riders, and a Girl’s class for the females between the ages of 11-16 at Loretta Lynn’s (the AMA rulebook splits it into Girls Junior and Girls Senior, shown in the table below).

The unique thing about motocross is the girls still have every chance the guys do! They can race in every class the men and boys race in, as long as they meet the age, skill level, and engine rules for it. 

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Official Race Series and their Class Breakdowns

FIM Motocross World Championship Classes

Class	Engine/Motor Size & Type	Number Plate Colors
MXGP	Over 175cc up to 250cc for 2-stroke, over 290cc up to 450cc for 4-stroke	White background & black numbers
MX2	Over 100cc up to 125cc for 2-stroke, over 175cc up to 250cc for 4-stroke	Black background & white numbers
WMX Women	MX2 bikes: over 100cc up to 125cc for 2-stroke, over 175cc up to 250cc for 4-stroke	Blue background & white numbers

MXGP is open to riders 16 to 50, MX2 to riders 15 to 23 (women are exempt from that cap), and WMX to riders 15 to 50.

 

 

AMA Motocross Championship Classes

AMA Pro Classes (Adult)

These are the pro classes in AMA Pro Motocross. Supercross uses the same two classes with slightly different four-stroke ranges: 249cc to 450cc in the 450 class and up to 250cc in the 250 class.

Class	Engine/Motor Size & Type
450cc	150cc - 250cc for 2-stroke, 251cc - 450cc for 4-stroke
250cc	0cc - 125cc for 2-stroke, 150cc - 250cc for 4-stroke
Women's (WMX)	122cc - 250cc

AMA Youth Classes by Age

The AMA youth division covers riders 4 to 17, and a rider’s age on January 1 is their age for the whole year. These are the youth motocross classes in the AMA rulebook. Big amateur races like Loretta Lynn’s split some of them further, like Supermini 1 (12-15) and Supermini 2 (13-16).

Class	Engine/Motor Size & Type	Wheel Size / Specs
Micro Jr. Limited (4-6 yrs.)	0cc - 51cc two or four-stroke	Single-speed automatic, 10” max wheel size, 24” max seat height, 14mm intake
Micro Sr. Limited (7-8 yrs.)	0cc - 51cc two or four-stroke	Single-speed automatic, 12” max wheel size, 19mm intake
Micro Shaft Drive Limited (4-8 yrs.)	0cc - 51cc two-stroke	10” max wheel size, 22” max seat height, 12mm intake
Micro Special Limited (4-8 yrs.)	0cc - 51cc two or four-stroke	Listed models only, 13mm intake
65cc (7 - 9 yrs.)	59cc - 65cc 2-stroke	12-14” front wheel
65cc (7 - 11 yrs.)	59cc - 65cc 2-stroke	12-14” front wheel
65cc (10 - 11 yrs.)	59cc - 65cc 2-stroke	12-14” front wheel
85cc (9 - 11 yrs.)	79cc - 85cc 2-stroke	17” max front wheel, 12” - 14” rear wheel
85cc (12 - 13 yrs.)	79cc - 85cc 2-stroke	19” max front wheel, 12” - 16” rear wheel
85cc (14 - 15 yrs.)	79cc - 85cc 2-stroke	19” max front wheel, 12” - 16” rear wheel
Supermini (12 - 16 yrs.)	79cc - 112cc 2-stroke or 75cc - 150cc 4-stroke	19” max front wheel, 16” max rear wheel
Schoolboy 1 (12 - 17 yrs.)	86cc - 125cc 2-stroke or 75cc - 150cc 4-stroke	19” min. front wheel, 16” min. rear wheel
Schoolboy 2 (12 - 17 yrs.)	122cc - 250cc 2-stroke or 126cc - 250cc 4-stroke	53” min. wheelbase, no mini or supermini, must be 14 to race a 250
Girls Junior (9 - 12 yrs.)	59cc - 85cc 2-stroke	17” max front wheel, 12”-16” rear wheel
Girls Senior (12 - 16 yrs.)	79cc - 112cc 2-stroke or 75cc-150cc 4-stroke	19” max front wheel, 16” max rear wheel
Mini-E Jr. Limited (4 - 6 yrs.)	1kWh battery, electric	12” max wheel size, 25” max seat height
Mini-E Sr. Limited (7 - 8 yrs.)	1.5kWh battery, electric	12” max wheel size, 28” max seat height

 

AMA Amateur Classes and Age Groups

Class	Engine/Motor Size & Type
125cc	122cc - 125cc 2-stroke only
250cc	122cc - 250cc
14 - 24 yrs.	122cc - open
Open	122cc - open
Vet 25+	122cc - open
Vet 30+	122cc - open
Vet 35+	122cc - open
Senior 40+	122cc - open
Senior 45+	122cc - open
Senior 50+	122cc - open
Senior 55+	122cc - open
Senior 60+	122cc - open
Women (12+)	99cc - 250cc
Open B Electric (16+)	Electric

Most of these classes are split by skill level (A, B, or C) when enough riders show up. You must be 14 to race a 250cc and 16 to race anything bigger, and the AMA raises the minimum amateur age from 12 to 14 on January 1, 2027. Loretta Lynn’s uses its own names for the age classes: College (18-24), Junior (25+), Vet (30+), Senior (40+ and 45+), and Masters (50+).

 

British Motocross Championship Classes

These come from the Auto-Cycle Union (ACU) standing regulations, which British motocross runs under. The championship’s own rules can differ, so treat the plate colors as a guide.

British Adult Classes

Class	Engine/Motor Size & Type	Number Plate Colors
MX1	Over 175cc to 500cc 2-stroke, 251cc to 450cc 4-stroke, or electric up to 45kW	White background & black numbers
MX2	120cc - 250cc 2-stroke, 175cc - 250cc 4-stroke, or electric up to 36kW	Black background & white numbers

MX1 is the big-bike class and MX2 is the smaller one, the same split as MXGP and MX2 in the world championship.

British Youth Classes

Class	Engine/Motor Size & Type	Wheel Size / Specs
E4 (4-7 yrs.)	Electric, about 4kW max	10” front wheel, 10” rear wheel
Automatic (from age 5)	49cc - 50cc single-speed automatic, or electric up to 6kW	15” front wheel, 12” max rear wheel
65cc Junior (7-11 yrs.)	60cc - 65cc 2-stroke or 85 - 110cc 4-stroke, no electric	14” front wheel, 12” rear wheel
85cc Small Wheel (9-12 yrs.)	70cc - 85cc 2-stroke, 125cc - 150cc 4-stroke	17” front wheel, 14” rear wheel
85cc Big Wheel (11-14 yrs.)	70cc - 85cc 2-stroke, 125cc - 150cc 4-stroke	19” front wheel, 16” rear wheel
125cc (13-17 yrs)	120cc - 125cc 2-stroke	21” front wheel, 19” rear wheel
125/250f (14-17 yrs)	120cc - 150cc 2-stroke, 175cc - 250cc 4-stroke	21” front wheel, 19” rear wheel

The British championship also runs a women’s championship with girls’ youth classes. Check the ACU’s current regulations before you enter, since the youth age limits have changed twice in the last few years.

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Related Questions

What Are the Different Types of Dirt Bike Racing?

Motocross (MX), Supercross (SX), Arenacross (AX), Enduro, Cross Country (GNCC), Grand Prix (like WORCS), Endurocross, Trials, Hare Scrambles, Hare & Hounds, Hill Climbs, Ice Races, and Freestyle (FMX).

What is the Schoolboy Class in Motocross?

This class is referring to younger riders that are between 12 and 17 years of age. Schoolboy 1 is for smaller bikes (up to a 125 two-stroke or 150 four-stroke), and Schoolboy 2 goes up to 250cc.

What is the Difference in Motocross and Supercross?

Motocross is held on an outdoor open course and Supercross is held on a built track inside a baseball or football stadium, some open-air and some with a roof.

Final Thoughts

Whether you are lining up for your first race or watching motocross and supercross on TV, every class comes down to the size of the bike, the age of the rider, and how fast they are. Know those and you can find your class on the sign-up sheet, or tell the pro 450s from the 250s by their plate color.

Rules do change. Age limits move, classes get renamed (Peewee became Micro), and every big race publishes its own class list, so check it before you pay the entry fee. Kids race by age and bike size. If you are an adult new to racing, ask at sign-up where you fit; most newcomers start in C or a beginner class and let their results move them up.

Whichever gate you end up on, the AMA requires a full-face helmet, goggles, boots, chest and back protection, riding pants, and a long-sleeve jersey in every class. That last part is where our motocross riding gear comes in. See you on the line.

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