Showdown Rolling Chassis Parts

The Home Racing World Showdown Chassis has become increasingly popular with 1:25 and 1:32 scratchbuilders.  The chassis features a straightforward design that is relatively easy to build.  This page describes parts commonly used for a Showdown Chassis build.  Click on any of the product pictures for more information or to add the part to your shopping cart.

Before proceeding, if this is your first Showdown Chassis build, we STRONGLY recommend spending some time watching the excellent how-to videos put together by Harry Wise and George Pineda.  These videos provide detailed step-by-step instructions and show each of the various parts and components that make up a Showdown Chassis.  For convenience, we have provided a link to the videos below.

 

  

Motor Bracket

 

At the heart of the Showdown Chassis is the motor bracket.  The bracket not only secures the motor but provides an easy way to secure the rear drivetrain components and chassis rails.  The motor bracket shown below was specifically designed for Showdown Chassis builds - it works with both 1:25 and 1:32 chassis.  It requires no cutting and works with both short-can (FC-130) motors and long-can (FK-180) motors frequently used for these builds.

  

Motors

 

HRW Showdown builders have a wide selection of motors available.  If you're building a Showdown Chassis for a proxy or formal Showdown event, be sure to check the rules as they will often specify a specific motor or group of motors.

For 1:25 builds, long-can (FK-180) motors typically work best.  The extra torque these motors produce helps overcome the additional weight for the larger 1:25 builds.  The two (2) Predator long-can motors shown below are very popular for 1:25 Showdown builds.

    

 

For 1:32 builds, short-can (FC-130) motors are often used (the long-can motors shown above can also be used).  The two (2) Predator short-can motors shown below are popular for 1:32 Showdown builds.

    

 

Motors are secured to the motor bracket using motor retaining screws like those shown below

 

Motor Lead Wire

 

High strand motor lead wire is very flexible making it easy to route between the motor and guide.  Silicone insulation won't melt when soldering.

 

Rear Axle Assembly (3/32" Axle)

 

For the purpose of this discussion, the rear axle assembly will consist of bushings, axle, crown gear, pinion gear, and wheels.  The parts listed in this section are designed for use with a 3/32" diameter rear axle. 

Axles (3/32" Diameter)

Axle length will vary depending on the scale of your build, the body you plan to use and how wide you plan to set the rear track width.  In general, it is better to use an axle that is a little longer than you may actually need since you can always trim it to the precise length.  If you use an axle that is too short, you can't extend its length.  Here are some popular axle lengths for HRW Showdown builds.

        

 

Bushings (3/32" Axle)

The HW 1" Motor Bracket recommended earlier is designed for use with 3/16" OD bushings mounted inside a 7/32" brass sleeve (made from tubing)

    

 

Crown Gears (3/32" Axle)

Since the Showdown Chassis uses an inline motor configuration, you'll need a crown gear for a 3/32" axle.  Slot.It makes a variety of crown gears ranging from 23 teeth to 30 teeth.  The most common crown gear size used for the Showdown Chassis is 27 teeth which is listed below along with slightly smaller (26 tooth) and slightly larger (28 tooth) gears.

        

 

Pinion Gears

The pinion gear must match the motor shaft size (diameter) and have the same pitch as the crown gear to ensure proper gear mesh.  Slot.It makes several pinion gears designed for inline applications that are designed to work with the Slot.It Crown Gears listed above.  The 9-tooth pinion is most commonly used; however, we have also listed slightly smaller (8-tooth) and slightly larger (10-tooth) pinions.  Be sure to use a pinion tool when installing or removing a pinion to prevent damage to the motor and/or pinion (refer to the "Tools" section at the end of this page for more information).

        

 

Wheels (3/32" Axle)

CB Design Wheels are a popular choice for the Showdown Chassis.  We recommend a wheel with a center rib.  The wheel shown below is designed for use with a 3/32" axle.

 

Rear Axle Assembly (1/8" Axle)

 

For the purpose of this discussion, the rear axle assembly will consist of bushings, axle, crown gear, pinion gear, and wheels.  The parts listed in this section are designed for use with a 1/8" diameter rear axle.

Axles (1/8" Diameter)

Axle length will vary depending on the scale of your build, the body you plan to use and how wide you plan to set the rear track width.  In general, it is better to use an axle that is a little longer than you may actually need since you can always trim it to the precise length.  If you use an axle that is too short, you can't extend its length.  Here are some popular axle lengths for HRW Showdown builds.

    

 

Bushings (1/8" Axle)

The HW 1" Motor Bracket recommended earlier is designed for use with 3/16" OD bushings mounted inside a 7/32" brass sleeve (made from tubing)

    

 

Crown Gears (1/8" Axle)

Since the Showdown Chassis uses an inline motor configuration, you'll need a crown gear for a 1/8" axle.  Mid-America Raceway makes a variety of 48-pitch crown gears ranging from 26 teeth to 34 teeth.  The most common crown gear size used for the Showdown Chassis is 27 teeth which is listed below along with slightly smaller (26 tooth) and slightly larger (28 tooth) gears.

        

 

Pinion Gears

The pinion gear must match the motor shaft size (diameter) and have the same pitch as the crown gear to ensure proper gear mesh.  JK Products makes several pinion gears designed for inline applications that are designed to work with the Mid-America crown gears listed above.  The 9-tooth pinion is most commonly used; however, we have also listed slightly smaller (8-tooth) and slightly larger (10-tooth) pinions.  Be sure to use a pinion tool when installing or removing a pinion to prevent damage to the motor and/or pinion.  Refer to the "Tools" section at the end of this page for more information.

        

 

Wheels (1/8" Axle)

CB Design Wheels are a popular choice for the Showdown Chassis.  We recommend a wheel with a center rib.  The wheels shown below is designed for use with a 1/8" axle - note there are two (2) styles available.

Classic Steel Wheels are designed to look like a stamped steel wheel.  The narrower Classic Steel Wheels listed below are often used both front and rear; however, wider Classic Steel Wheels are also listed.

 

Insert Wheels are designed to use an insert which are available to a variety of styles.  The narrower Insert Wheels listed below are often used both front and back for Showdown builds; however, wider Insert Wheels are also listed. 

    

Wheel Inserts for 1:24 Insert Wheels

We offer several styles of wheel inserts for the 1:24 Insert Wheels listed above.  If you have purchased a 1:25 model kit, the wheel inserts included with the kit can often be used with the 1:24 Insert Wheels shown above.

         

   

Front Axle Assembly

 

The Showdown Chassis uses a no-frills front axle setup.  The front axle rides inside a brass sleeve that is used to set the desired wheelbase and front axle ride height.  The brass sleeve is then soldered to the two side frame rails.  Some builders prefer a square axle sleeve while others use a round sleeve.  We've provided links for both sizes of front axle sleeves below.

Sleeves for 3/32" Axle

    

Sleeves for 1/8" Axle

    

 

Front Axles & Wheels

In general, the front axle will be the same diameter and length as the rear axle (see earlier discussion).  Again, it is better to error on purchasing an axle that is too long since it can easily be cut to the required length.

Front wheels will usually be the same style as the rear wheels (see earlier discussion).

 

Guide Assembly

 

For the Showdown Chassis, the guide assembly consists of a guide tongue, guide and braid.  Motor lead wire was covered earlier (see above).

Guide Tongue

A guide tongue is used to provide a sturdy mounting point for the guide.  The guide post will be inserted through the hole in the guide tongue.  The guide tongue hole is designed to accomodate guides with a 3/16" diameter guide post.  We offer narrow (1/2" wide) and wide (1" wide) guide tongues.  If you plan to bend the guide tongue, the narrower guide tongue will be easier to work with.

    

 

Guides & Braid

When it comes to guide setups, there are a couple of options available.  Some Showdown racers will prefer a commercial 1:24 style guide while others prefer a 1:32 guide.  Which setup you use is strictly a matter of personal choice - both work very well with the Showdown chassis.  We list the parts for both options below.

 

Commercial Guide Setup

Guides used for 1:24 commercial raceway cars typically have a 3/16" guide post that is threaded.  With this setup, the guide post mounts directly to the guide tongue and is secured with a nut.  Braid with brass clips provide a connection point for motor lead wires.

    

 

1/32 Guide Setup

This setup will require a guide tube to hold the guide post.  While these can be fashioned from brass tubing, pre-made tubes are readily available.  1/32 guides will use different braid than the commercial guides.

        

 

Chassis Rails & Body Mounting

 

The front and rear axle assemblies are connected using chassis rails.  The Showdown how-to videos show examples.  Chassis rails are generally made from square brass tubing, piano wire, or a combination of both.  Body mounts can be fashioned using flat brass strip.

        

 

Tires (1:25)

 

1:25 Showdown builds can choose between silicone (Quick Slicks) or urethane (Paul Gage).  Both options offer two (2) compounds to choose from as described below.  Silicone tires offer outstanding grip on clean track surfaces.  Urethane tires are more tolerant of dust and are easier to sand.  Sanding can be useful when reducing the tire diameter and/or sanding the contact patch to ensure it is as straight/flat as possible.

Silicone Tires (Quick Slicks)

If you are planning to use a narrow 1:24 CB Design Wheel with a center rib (refer to earlier discussion of wheel options), Quick Slicks offers the HR01F (Firm) or HR01XF (X-Firm).

     

If you are planning to use a wide 1:24 CB Design Wheel on the rear of your car, Quick Slicks offers the HR11F and HR11XF.

     

Urethane Tires (Paul Gage) 

If you are planning to use a narrow 1:24 CB Design Wheel with a center rib (refer to earlier discussion of wheel options), Paul Gage offers two (2) sizes of tires.  The Paul Gage 28125 tire is approximately 28mm in diameter.  The 26125 tire is approximately 26mm in diameter.  Note these tires are only available in the "PGT" (firmer) compound.

Depending on your Showdown build (and any applicable rules), builders have several options:

  • 28125 front and rear
  • 28125 rear, 26125 front
  • 26125 front and rear

     

 

Tools

 

For best results, you'll need a few tools when building your Showdown Chassis.  Slot Car Corner carries some of these tools; however, some items like digital calipers and a soldering iron will need to be sourced elsewhere.

Chassis Jig

A basic chassis jig, like the one shown in the Showdown Chassis how-to videos, will help you layout and assemble the various chassis components.  The chassis jig has a honeycomb texture with hundreds of small holes.  Small metal pins are inserted into the holes to accurately position chassis components in preparation for soldering.

     

 

Pinion Puller / Press

A pinion puller / press tool is essential to install and remove pinions without damaging the motor and/or pinion.  We offer a couple of very high quality pinion puller / press tools.

    

 

Hex Drivers

Wheels and crown gears are secured to the axle using set screws.  If you plan to use 3/32" axles, the recommended wheels and gears use M2 set screws.  You will need a 0.9mm hex driver to tighten and loosen the M2 set screws.  If you plan to use 1/8" axles, the recommended wheels and gears use 4-40 set screws.  You will need a 1.3mm hex driver to tighten and loosen the 4-40 set screws.

     

 

Digital Calipers

Digital calipers are an essential tool to build the Showdown Chassis.  While we don't offer digital calipers for sale, we have included links to examples of digital calipers that are affordable and well-suited for chassis building.  We have no affiliation with these suppliers nor do we endorse them.