[scuderia_turini]

Tamiya Speed Checkers don't get much mention on here but can be very useful for tuning. They are intended for use with the Tamiya Mini-4WD models. These are 1:32 scale, free running battery powered vehicles which are raced on special tracks. Product code is "Tamiya 15183". In some respects these units are toys and the calibration may not be perfect but they provide a decent measure of improvements as you do the standard tuning stuff and reduce the hassle of running laps to check improvements (or otherwise). Obviously these units cannot replace actual lap test/trials but can help in the build up phase.

Using them for slot-cars means removing the front rollers, cutting a slot for the guide and fitting "rails" connected to a suitable power source. I added a digital voltmeter so I can get some consistency. For some cars it will be necessary to provide a spacer for the car nose to rest against so that the rear wheels are in a suitable position.

The car sits with the driven wheels on rollers that have electronic sensing.
Two functions are available:
1) Time taken for the rollers to rotate a fixed number of times (simulating a distance covered)
2) Speed measurement (in KpH)
Full instructions are attached.

As well as having these functions, the base and rollers make an ideal way to assess how "true" the driven wheels and tires are, as it is easy to observe them whilst they are rotating (especially with the body removed). If the wheels/tyres are significantly out of true the car will correspondingly jump around until you get the roundness better. With the body removed, the tyres/wheels can be sanded but probably best to do that with the tyres out of contact with the rollers.

Getting rare to find nowadays and as mine is quite old now, I recently bought a spare.
I don't know if/when they went out of production but they have always been rare in the UK as the related vehicles were not strongly marketed here. Both of my units are identified as 1996.

Leo

Brief Video here -

 

[Slotspeed]

Wow, I had forgotten about those cool little Tamiya 4WD’s that the cool kids had in primary school! Haven’t seen that speed checker before, nice mods for slot use.

 

[cbwho]

The Tamiya 4WD cars go crazy fast but they do break easily enough when going crazy on the house floor!

 

[MrFlippant]

Hehe, my friend and I, in college, bought a couple of those, and just had fun sending them across a busy street to see how many cars would hit them. It was amazing how rarely they were hit, and usually sent us clamoring to go grab them half way up the block. LOL

As for the speed checker, a little birdie told me that something similar, but more suitable to slot cars, will be on the market in the coming months. ;-)

 

[Abarth Mike]

I didn't cut a slot. I glued future board to raise the surface and create a slot. I only used it to measure the speed of various cars, only because I chanced across one.

 

[gsnopoint]

Built this a few years back. For a more "readable" measurement other than KPH, one of the rollers has a reflective tape that I can utilize a tachometer to get an RPM reading. My power supply has an amp ready to measure motor draw.
Plenty of uses for this gizmo when setting up a car.
Also made one for HO scale years ago.