Showdown Rolling Chassis Parts (1:25 Builds)

Introduction

The Home Racing World Showdown Chassis has become increasingly popular with 1:25 and 1:32 scratchbuilders. One of the great things about the Showdown Series is the chassis features a straightforward design that is relatively easy to build. This page describes parts commonly used for a 1:25 Showdown Chassis build. Note our goal is to provide first-time participants with a shopping list. The shopping list is fairly complete; however, there still may be some odds and ends not on the list. As we receive feedback, we are continually updating this section to make it as complete as possible. 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.

* NEW * Complete HRW 1:25 Showdown Chassis Kit!!!

We now offer a complete chassis kit with everything need to build a "roller" chassis for HRW 1:25 Showdown Chassis builds. Click on the thumbnail below for more information.

Section I describes parts that are common to 1:25 HRW Showdown Chassis builds regardless of the axle diameter you plan to use.
Section II describes parts used if you plan to use 3/32" diameter axles.
Section III describes parts used if you plan to use 1/8" diameter axles.
Section IV describes tools and accessories recommended to assist you when building an HRW Showdown Chassis.

Section I - Common Parts

This section describes parts commonly used for 1:25 HRW Showdown Chassis builds independent of the axle diameter (3/32" or 1/8") you plan to use.

Motor Bracket

At the heart of the 1:25 HRW 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

For the HRW 1:25 Showdown Chassis builds, you MUST use the Predator 20,500 RPM motor shown below.

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.

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 accommodate guides with a 3/16" diameter guide post. We offer narrow (1/2" wide) and wide (1" wide) guide tongues. If you want to keep things simple, the wide guide tongue is a good choice. It is the same width as the wide motor bracket (see above) making it easy to create a "box" with the chassis side rails. If you plan to bend the guide tongue, the narrower guide tongue will be easier to work with.

Guide and Braid

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.

Chassis Rails & Body Mounting

The front and rear axle assemblies are connected using chassis rails. 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. The Showdown how-to videos show examples of incorporating chassis rails and body mounts into your chassis build.

Section II - Parts for Chassis Builds Using 3/32" Diameter Axles

This section describes parts commonly used for HRW 1:25 Chassis Builds using 3/32" diameter axles.

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).

Front Axle Holders / Sleeves (3/32" Axle)

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 prefer the square tubing since the axle will only be contacting four (4) points inside the tubing and the flat surfaces may be easier to position and solder. We've provided links for both sizes of front axle sleeves below.

Section III - Parts for Chassis Builds Using 1/8" Diameter Axles

This section describes parts commonly used for HRW 1:25 Chassis Builds using 3/32" diameter axles.

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. Slot Car Corner 1/8" axles are perfect for Showdown builds. These are the same axles included in the 1:25 HRW Showdown Chassis Kits.

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. Parma makes a variety of high-quality 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 Parma 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 (1/8" 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).

Tires (1:25)

HRW 1:25 Showdown Chassis builds MUST use Paul Gage PGT (firmer) compound tires. While not required, some builders will sand tires to achieve a desired tire diameter or to ensure the tire contact patch is as smooth as possible.

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

Section IV - Tools & Accessories

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.

Soldering Flux

Acid core soldering flux will aid in soldering brass and other metals by removing oxide films which form on the surface of metals. Flux increases the "wetting" ability of solder, causing it to flow more evenly into joints. The acid core flux we offer includes a brush to make it easier to apply where it is needed. Acid core flux should NOT be used on motor lead wires.

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.

Tire Truer

A Tire Truer makes it much easier and faster to fine tune the tire diameter (if desired) and ensure the tire contact patch is perfectly flat.

Wire Bending Machine

If you are planning to use piano wire (sometime called "music wire") in your build, a wire bending machine can be very useful. The wire bending machine makes it much easier to bend the piano wire as required for your chassis build. The picture/link below also includes a video tutorial and useful tips.

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.