All General Rules apply
1. Motors must be commercially available, as defined in General Rules, Section IX, and must be specifically approved for the Box Stock 15 class on an as submitted basis. Approved motors are listed in the Boxstock approved components listing.
2. Can & endbell must be mass produced, of full dimensioned can type (full top, bottom, & 2 sides, without cheater tabs or other artificial attempts to meet the dimensional specifications) without modification. Inside can dimensions are defined as not less than:
Length - .925 inches (23.495mm)
Width - .835 inches (21.209mm)
Height - .560 inches (14.224mm)
3. Aftermarket components which are not identical replacements of original parts as approved are not allowed. This means endbells, hardware, cans, etc. must be original for that brand & type of motor with the following exceptions.
a. Approved single piece magnets may be interchanged. Any magnet approved for use in any manufacturers motor may be used in any other manufacturers setups
b. Manufacturers selling super magnets, or other components above the cost of original equipment replacement parts are not allowed. A super magnet at higher cost and identical in appearance may not be detectable in a car, hence manufacturers selling identical looking components at higher cost will lose approval for their motor (this would not rule out "matched" pairs of approved magnets).
4. Retail price may not exceed $34.84 US
1. Magnet Dimensions Plus Or Minus 10% Are As Follows:
a. Length: 0.500 Inches (12.70mm)
b. Width: 0. 150 Inches (3.81 mm)
c. Height: 0.550 Inches (13.97mm)
2. Magnets Must Be Commercially Available Through Major Distributors.
3. No Quad magnets allowed. Single piece ceramic only.
4. Magnets May Not Contain "Rare Earth" Materials (Defined As Elements With Atomic Weights 58 through 71).
1. Armatures must be commercially available as defined in General Rules, Section IX, and must be specifically approved for the class. Approved armatures are listed in the Box Stock 15 Approved Components
2. Must be machine wound with a minimum of 50 series wound turns of AWG #29 wire per pole. AWG #29 wire, excluding insulation, is 0.0 112 -.0114 inches diameter.
3. Group 12 or 15 armatures are permitted, must have a minimum stack length of .350 inches for 12 arms .440 for 15ís See Armature Stack Length section for clarification.
4. Armatures must be no less than .513 inches 13.03 mm) diameter.
5. Must be tagged with at least the number 12 or 15 indicating they were produced by a USRA approved manufacturer in compliance with these rules
6. Armatures may be reconditioned but not re-sized. Reconditioning includes: Cleaning, commutator re-truing, and rebalancing.
7. Retail price may not exceed $18.13 US
D) Can Modifications Anything not listed here is illegal.
1. Can bushing may be soldered in place but may not be reversed or moved from original position except as stated in #2
2. Diameter of bushing locator hole may be altered to allow the stock size bushing to be centered.
3. Outside diameter of bushing (excluding flange) may not be altered.
4. Magnets may be super glued in place but must retain OEM magnet clips.
5. Magnet zapping is permitted.
6. Single, one piece magnets. No quad or multiple piece magnets allowed.
7. Motor brushes and springs may be replaced and spring tension may be adjusted but, any 3-coil spring, brush, or bronze bushing may be used.
8. Prohibited Modifications
a. Cut outs or machine work on can or endbell.
b. Shunt wire or spring insulation
c. Adding endbell heat sinks.
d. Drilling holes in can or endbell.
e. Interchanging parts from one approved type of motor to another is not permitted. In other words, Box Stock motors must use the original can, endbell, and hardware. Armatures and Magnets may be intermixed between approved Box Stock 15 manufacturers.
f No post factory honing, shimming or polishing of magnets allowed unless delivered by the manufacturer in this manner.
1. Chassis for the Box Stock 15 class must be commercially available and be specifically approved on an as submitted basis, in accordance with the following parameters:
2. Chassis must be available in completed form, for a maximum retail price of $28.09 US.
a. Chassis must be commercially available separately, and may also be available in a completed car.
b. See the Box Stock 15 Approved Components for approved chassis 3. Chassis may be made of any material.
4. Chassis containing steel components, except steel wire and lead wire retainer
a. Must have a guide mount which is integral,
b. Must be made of a continuous piece of steel extending from the guide mount to the rear axle line and to which the pillow blocks are attached.
c. The bottom of the guide mount must be level with the bottom of the chassis with no offset.
d. Steel chassis may be sold as kits, but must be commercially available in an assembled form. Kits must be assembled in a manner identical to the assembled production chassis except as noted.
5. Front body mounting tubes must be rigidly attached to the chassis (no shakers)
6. Rear body mount may be floated on any steel chassis, but must remain in original location as the RTR car. Steel pin tubes may be used.
7. May only reposition front wheel mount location on any chassis but wheels must be able to be seen through body wheel well opening. No other component may be altered or repositioned from its original location in ready-to-run car.
8. Minimum weight of a completed, RTR car will be no less than 72 grams at all times during the racing
Pre-assembled chassis may be re-soldered, but components may not be altered or repositioned, chassis kits must be assembled the same as production chassis. Anything not listed here is illegal.
1. Static bracing, consisting of piano wire may be added to solder joints only.
2. Lead weight may be added.
3. On steel chassis brass may be used for weight.
a. Brass weights must be solid, and rigidly attached, and not used as a brace
b. May extend no more than 1" back from the center of the guide hole,
(1) No floating pans
(2) No modifying or bracing of chassis and calling it weight.
3. A lead wire retainer may be added.
4. A motor support tube or wire may be added, not to exceed 1.5 inches in total length behind the motor. Motor must be soldered to this brace or it will be considered a chassis brace.
5. May solder or glue oilites in place.
G) Prohibited Modifications:
1. Tie Wire
2 Changes in size, dimension, shape, or location of any component
H) Lightweight Components
Since the Box Stock 15 class is intended to be an entry-level class, many of the rules are designed to discourage the use of complicated, state of the art, or expensive components. Therefore, special lightweight components are specifically prohibited, including:
1. Magnet wire or magnet type wire as a substitute lead wire
2. Hollow or special lightweight axles
Any gear ratio or pitch is allowed. Drilled gears arc permitted.
J ) Axles
Axles with flats are allowed.
Front and rear wheels may be drilled.
No ball, roller, or other frictionless bearings are allowed.
All cars will be of it race legal weight of not less than 72 grams.