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Tyco Pro – Three Mods
by Terry Flynn (contact by email)

This series covers three modifications to a Tyco Pro brass pan chassis. One is a modification to run a solid front axle. This can be done to salvage a chassis with worn front axle stubs or to simply increase handling. The second is for using an early steel pan style hinged guide flag for the later brass chassis. This allows a worn out late model flag to be replaced by an early model. The third is for large crown gears that do not fit the chassis pan. This allows for later model cross-brand gears to be used.

These modifications can be used independently and in conjunction with each other and additional modifications such as magnates. The final example in here uses all three modifications here, plus magnates and a Johnson brass can with a hot stock Wizzard armature.

List of parts Photos .01 and .02

1) Tyco Pro brass pan chassis.
2) Factory early style hinged guide flag.
3) Later style brass pan guide flag keeper-weight.
4) Factory repro copper wiper pickups from Toybaron.
5) Factory button style guide flag for salvage parts.
6) A flexible keeper supplied by Toybaron to hold an Oscar the Track Cleaner guide flag into a Riggen 3000 chassis.
7) Solid or independent front axle set. Large, thick o-rings have to be used to obtain the proper track contact. .460 is the final mounted diameter in this example.
8) G+ or Super G Plus gear set. This example is based on a factory Tomy Super G Plus axle, crown and pinion.
9) BSRT narrow rear hubs for Super G Plus. BSRT T-Jet silicone tires. . 450 is the final mounted diameter in this example. Other types work well if properly selected. Wizzard Radical Radials would be another good choice.
10) .063 Tomy rear axle. .063 axles require that the rear axle retainers be relieved or sufficiently worn to allow friction free rotation.
11) Mabuchi can motor. Select a good spinner if possible. A hot stock arm could be used or a Racers Edge can as well.

.03; .08 – Modifying the front axle. Use a sharp razor knife to cut off the factory front axles stubs flush. Use the knife point to locate the stubs’ previous center. Rotate the knife back and forth to create a ‘pilot’ hole for the drill bit.


Use a drill bit equal to the axle’s diameter and chuck into a hobby drill. Rotate the chuck and bit BY HAND to punch through the plastic. Once both sides are done, run the bit through both axle holes to ‘line bore’ the holes.

.09; .16 – Modifying the rear gear box. Use a sharp razor to cut out the rear gear ‘sump’. Cut a little at a time to avoid cutting out the rear cross-member. Use a hobby drill with a cutter to finish out the rough spots.


Trim a small amount off of the crown gear’s hub as shown in photo .14. This is to allow fine fitting of the gears. Mount the crown on the axle and test fit into chassis. You will have to relieve chassis material till proper, free clearance is obtained.

.17; .19 – Modifying the Keeper-Weight. Hold the keeper-weight with a pair of pliers. Use a hobby drill with a cut-of wheel to cut the keeper’s rear portion off. Cut a little into the open center hole – photo .19.

Super Glue the trimmed keeper-weight onto the chassis – photo .24. The object is to allow the solid front axle to freely turn without the interference of the weight.

.20; .29 – Fabricating the Flag Keeper. Use the cut-off wheel to cut the button out of a button-style guide flag. The object here is to salvage the brass ferrule out of the flag. Cut the bottom off of the ferrule to release the top portion from the flag. Photo .23 shows the salvaged part.


The brass ferrule will now act as the top keeper for the early style flag. Place the flexible Oscar keeper over the shaft of the guide flag. – photo .26.



Press the flag up into the mounted keeper-weight. Use hot-melt glue to bridge across the brass ferrule and the flag post. The flag and ferrule will know rotate together.

.30; .35 – Final assembly. Fit any required poly or steel armature washers to take up side play between the crown gear and the gear box. Test run with a 9-volt battery. Fit tires and rims to rear axle. Check for track clearance on a piece of loose track. There should be no rail contact with the chassis. All of the chassis weight should be on all four tires.

Using the chassis magnate modification will negate small errors in pickup wiper adjustments. But the chassis weight must still be carried by the front tires and none by the guide flag. The car will not run or handle good nor will the pickups wipers stay positioned properly if the chassis weight is not fully supported by the front tires.


If the car experiences severe rear wheels hop under maximum acceleration, the rear chassis motor clip is probably not holding the can motor fast in place. Apply hot-melt glue at the back of the chassis motor clip and onto the can. Contact cement might be used as well.

With a little thought, a short wheel-bass lexan body can be fitted. The example here is a Riggen Porsche 917 from Toybaron.

The final example here is THE fastest and best handling chassis modification I have done to date on a brass pan Tyco Pro.