RULES

U4RC rock racing is edge of control racing that is sure to get your adrenaline pumping.  It pits everything from stock RTR 4 wheel drive vehicles, to full on custom rock racing and trail rigs, against some of the toughest obstacles R/C cars have ever seen. A U4RC track combines not only the toughest desert sections, but big technical rocks, silt/sand washes, the steepest hill climbs and of course terrifying descents. U4RC is heads up heat racing against your friends and family. Timed/scored heats let you know how you rate against the competition every day, and with competitors around the world. U4RC tracks can and do vary in layout and terrain.  In fact a U4RC track can be created almost anywhere there is open space and dirt, often utilizing existing terrain features as obstacles. On the other end of the spectrum is the permenant track.  Permenant U4RC tracks are being built and raced on literally all over the world. So whether you are a single person looking for a track, or you are part of a group looking to start your own U4RC series, this is the place to get started. Below are the U4RC official rules/vehicle specs.  You can expect to see these rules being run as written at major U4RC events.  Theses rules, or local versions thereof, can be used by all groups that are part of the U4RC family. Get out there, have fun and see what U4RC rack racing is all about.

 

All Classes:

Power: Electric, battery powered vehicles only.
Electronics: All electronics must be hidden with the exceptions being a transponder, an axle mounted servo, and the battery on the Twin Hammers.
Drivetrain: Vehicle must be 4 wheel drive and shaft driven, utilizing either a center transmission, or transfer case. No motor on axle.
Suspension:  Must be scale appearing. IE; 3 or 4 link, leaf sprung, trailing/leading arm.
Weighted Knuckles: Weighted Knuckles are allowed but must be of an integral weighted design. If the knuckle can still function with the weighted portion removed, it is not legal.
Tires: A tire for U4RC rock racing must be a scale appearing tire, either a licensed replica, or a non-licensed replica. No comp, short course, cut n shut, paddle, or pin tires are allowed. Removing material, or siping of tires is permitted.  Adding material, or combining portions of tires to make one tire is not.
Wheels: Wheels must be designed to fit a legal tire’s un-modified bead.
Bodies: Bodies must appear scale for rock racing. IE: Panels from an onroad car are ok attached to a tube chassis, but an onroad body itself is not. Vehicles with bodies must have at least 50% of the tires outside the body. The 50% tire rule does not apply to 1.9 Trail class. 
Tube chassis: Must be scale rock racing type and have interior with drivers. No rock bouncers, no dune buggies
Interior: All vehicles must have a minimum scale interior, with the exception of full bodied rigs.  
Drivers: Many classes REQUIRE scale drivers.  Please see individual class specs.
Center Differential: Not legal except in solid axle Trophy class vehicles.
Legal Vehicles: Rock racers or scale trail rigs. No shortcourse, monster trucks, or basher type vehicles allowed.
Race Director: It is always the race directors decision to choose the correct class for a given vehicle that meets the “All Classes” specs.
Tech: All vehicles are subject to technical inspection prior to the race, or at anytime during the event at the Race Directors discression.

Remember U4RC is more about Scale than Performance!

 

1.9 Trail 

This class is for 1.9” tire and wheel clad trail type vehicles that are stock through highly modified. Vehicles must have (2) solid axles. Truggy type vehicles require a minimum of a molded hood and cab, while full tube chassis require a molded hood minimum. This is an entry level 1.9 class, but will likely have faster, yet similar vehicles competing. Vehicle should resemble something you would see on a 1:1 trail, or at a 1:1 rock race in an entry level class. This is not for full blown race vehicles.

 

Class Specs:
1.9” Wheel Diameter
Solid Axles Only
Max Wheelbase: 13”
Max Width: 10.5”

 

1.9 Comp

This class is for 1.9” tire clad rigs, that are highly modified, and resemble full size race vehicles. Vehicle must be scale in appearance for rock-race style racing. The vehicle must have a driver figure or insert installed. 


Class Specs:

1.9” Wheel Diameter
IFS with solid rear axle Only
Max Wheelbase: 13”
Max Width: 11”

 

1.9 Trophy

This class is for 1.9” tire clad Ultra4 style rigs that are highly modified and highly resemble full size rock race vehicles. The emphasis in this class is appearance first and performance second.  IFS and IFS/IRS cars are required to have a metal cage attached to a custom metal skid/pan. Skid/pan is defined as a partial pan chassis, attached to a solid rear axle.  Rail style chassis are allowed when welded to the tube portion of the chassis. All upper shock mounts must be part of the metal chassis structure for all chassis types. A center differential is allowed in solid axle vehicles ONLY. Center differentials are not legal in IFS or IFS/IRS configurations.

Class Specs:

1.9” Wheel Diameter
IFS, Solid Axle, IFS/IRS
Metal Cage Only
Scale Driver with Helmet
Max wheelbase: 13”
Max Width: 11
Min Weight: 7 lbs
Center Differential Allowed: Solid Axle Vehicles Only

 

Minimum Weight: 7 lbs
This is the weight of the vehicle ready to race.
Overall Chassis Minimum height: 5.00”
This is the measurement from the bottom of the skid/pan to the top of the roof without light bars etc…
Overall Chassis Minimum Width: 5.00”
This is the minimum with at the door panels extending the entire length of the door panel and window Opening.
Door Panel Minimum Length: 3.75”
This is the minimum length of the door panel.
Side Panel Minimum height: 1.50”
This is the minimum height of the side panels at the driver and passenger door area.
Window Opening Minimum height: 2.00”
This is the window opening Minimum height for both the driver and passenger side of the vehicle. This is measured from the top of the roof to the top of the side panel at the driver’s compartment.
Minimum Roof Panel: 2.75” x 4.00”
This is the front to back x side to side minimum roof measurement.
Minimum Overall Chassis Length: Wheelbase length from center line of axles.
This is the length of the overall chassis structure from front to rear excluding light bar mounts,
bumpers, stingers, spare tires, winches, etc…
Chassis Structure:
This is defined as the tubular portion that includes the driver compartment, upper shock mounting points front and rear, and engine cover area as part of the chassis.
Engine Cover Area: Panels and tube
This is a scale first, performance second class. The engine compartment, either front or mid, must be covered by panels (inner fenders). The vehicle must appear as though a scale 1:1 race engine is present. Scale motors or panel concealed areas where 1:1 engine would be located are required.
Driver figure:
Either molded driver interiors, or figures are required. Driver and passenger must both have helmets and an upper torso minimum.

 

2.2 Comp

This class is for 2.2” tire clad vehicles that are moderately to heavily modified. Vehicle must be scale in appearance for rock racing. This class includes vehicles running plastic chassis, metal chassis and roll cages or a combination thereof.  Either a molded driver interior, or driver figures are required. Driver and/or passenger must both have helmets and  and be an upper torso minimum.

Class Specs:
2.2” Wheel Diameter
Solid Axle Only
Max wheelbase: 15”
Max width: 13″

 

2.2 Indy

This class is for 2.2” tire clad vehicles that are moderately to heavily modified. Vehicle must be scale in appearance for rock racing. This class includes vehicles running plastic chassis, metal chassis and roll cages or a combination thereof.  Either a molded driver interior, or driver figures are required. Driver and/or passenger must both have helmets and  and be an upper torso minimum.

Class Specs:
2.2″ Wheel Diameter
IFS with solid rear axle Only
Max Wheelbase: 15”
Max Width: 13”

 

2.2 Trophy

This class is for 2.2” tire clad Ultra4 style rigs that are highly modified and highly resemble full size rock race vehicles. The emphasis in this class is appearance first and performance second.  IFS and IFS/IRS cars are required to have a metal cage attached to a custom metal skid/pan. Skid/pan is defined as a partial pan chassis, attached to a solid rear axle.  Rail style chassis are allowed when welded to the tube portion of the chassis. All upper shock mounts must be part of the metal chassis structure for all chassis types. A center differential is allowed in solid axle vehicles ONLY. Center differentials are not legal in IFS or IFS/IRS configurations.

 

Class Specs:
2.2” Wheel Diameter
IFS, Solid Axle, IFS/IRS
Metal Cage Only
Scale Driver with Helmet
Max wheelbase: 14.50”
Max Width: 12.75”
Min Weight: 8 lbs
Center Differential Allowed: Solid Axle Vehicles Only

 

Minimum Weight: 8 lbs
This is the weight of the vehicle ready to race.
Overall Chassis Minimum height: 5.25”
This is the measurement from the bottom of the skid/pan to the top of the roof without light bars etc…
Overall Chassis Minimum Width: 5.25”
This is the minimum with at the door panels extending the entire length of the door panel and window Opening.
Door Panel Minimum Length: 4.00”
This is the minimum length of the door panel.
Side Panel Minimum height: 1.75”
This is the minimum height of the side panels at the driver and passenger door area.
Window Opening Minimum height: 2.25”
This is the window opening Minimum height for both the driver and passenger side of the vehicle. This is measured from the top of the roof to the top of the side panel at the driver’s compartment.
Minimum Roof Panel: 3.00” x 4.25”
This is the front to back x side to side minimum roof measurement.
Minimum Overall Chassis Length: Wheelbase length from center line of axles.
This is the length of the overall chassis structure from front to rear excluding light bar mounts,
bumpers, stingers, spare tires, winches, etc…
Chassis Structure:
This is defined as the tubular portion that includes the driver compartment, upper shock mounting points front and rear, and engine cover area as part of the chassis.
Engine Cover Area: Panels and Tube.
This is a scale first, performance second class. The engine compartment, either front or mid, must be covered by panels (inner fenders). The vehicle must appear as though a scale 1:1 race engine is present. Scale motors or panel concealed areas where 1:1 engine would be located are required.
Driver figure:
Molded driver interiors, or figures are required. Driver and passenger must both have helmets and an upper torso minimum. No non-human figures.

 

Copyright 2016 U4RC – Revised 07/21/2016 -JG

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