The Magazine For Slot Car Enthusiasts

6/15/06
Adjust T-Jet Pickups for Max Performance
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By John Kaufman
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 Special Thanks to contributing racers Frank Spena, "Hoss" Phoenix, Bob Lincoln, Rick Jocham, Vic Licausi, Tim Leppert, Hiram Durant, Jack Lamb, Trek Lawler, Walt Pierce, Gary Merrifield, Geoff Campbell and John Kaufman

Visit Scale Racers for more Information

Lots of discussion about Pickup Shoes recently, with folks throwing around terms like 'Limited Travel' and something called a 'Z-Bend".  We'll try to take some of the mystery out of what the latest tricks are and also take a moment to review some basics.

It also goes to say that most of these suggestions can be performed on Stock or AML TJet Shoes, A/FX Shoes or BSRT Ski-Shoes.  Unfortunately, the Johnny Lightning 500 Shoes don't seem to respond as well.  The Nickel plating that Playing Mantis uses is almost too hard.  Better results can be had by replacing these with Copper Shoes.

You'll need to do this with the wheel on, but this photo illustrates the front of the shoe in a slight 'nose up' position which will lead to the type of wear shown in the top photo.  Uneven contact with the rail means less electricity and LESS POWER!

Try to keep the surfaces even when looking at it from the front as well.  Flat, even lateral contact is the goal...

I
mportance for Pickup Shoes is insuring that maximum contact with the Track Rail is made.  Place the chassis, minus the body, on a piece of test track and visually inspect each Pickup Shoe.  Each Shoe should have maximum surface contact with the Track Rail.
 
Here's a good way to check for correct contact...  Clean the surface of the Shoes on the contact patch (where they  contact the Rail) then run a few laps around the track.  You'll get a better idea of where the Shoe is and isn't making Rail contact by inspecting the markings. If contact along the full length of the Shoe is not being made, tweezers or a needle-nosed pliers can be used to slightly bend the Pickup Shoe to increase the contact patch. Try to keep an even 'lateral' line when bending.

To improve performance, Shoe pressure is a primary consideration. Greater Shoe pressure usually results in an increase in speed. However, too much pressure can adversely affect handling and may cause to front of the car to lift and de-slot under acceleration or when cornering.  A careful balance between speed and handling is the ultimate goal.

As a “rule of thumb” set the Pickup Shoe tension to the balance point that the front of the chassis does not lift (but barely) when the body is not on the chassis. Then, when the body is mounted, the extra weight should keep the front end from rising under acceleration. 

When your spring tension is 'in the zone', it should only take the lightest touch to lift your bare chassis.  Try to rely on the body for the additional weight necessary to keep the pin in the slot.  This chassis has rear tires at .350 OD and fronts at about .325-.330 OD.

Shoe pressure, there are various techniques.  The most obvious is to changer the length of the Pickup Shoe Springs by stretching.  Gently stretch the Spring by securing one end with your fingers and pull on the other end with a pair of tweezers.  Again, gently!  TJet, A/FX & Johnny Lightning Pickup Shoe Springs are fragile - it's very easy to accidentally deform the Spring.

To test pressure increases, consider placing small phenolic or nylon Armature spacers (washers) under the springs.  By stacking a few & trying different stack sizes, you'll get a better idea of whether you need more or less pressure before bending.  Different rules sets have different levels of strictness - some allow bending, some don't - your final configuration should take rules language into consideration.
 
Yet another method is to bend the hook on the end of the Pickup Shoe. To increase the Shoe tension, bend the Shoe hook toward the front.  Remember, a little bend goes a long way!
 
 
Finally, the Chassis hanger plate may be bent down to increase pressure or bent up to relieve pressure. Bending the hanger plate will also provide alteration of Shoe tension. Something worth mentioning is that the lower you go in tire size, the more of a necessity altering the Pickup Shoe geometry becomes.  At about .335 OD, the front becomes so low that non-altered stock Shoes may hit the bottom of the chassis without some type of adjustment - avoid this vibration causing situation at all cost!

Remember, continually changing parts means essentially starting over each time.  Try to work with one car/chassis - adjusting existing parts.  This will increase your knowledge of what effect each change has, making you a better HO mechanic!

Notice the width of the openings, or 'Windows'.  General consensus has it that the bigger the better - however the most important thing is that both sides are similar in size, providing more predictability.

It has been found by numerous Racers that for optimal handling and performance, equal Shoe pressure on each side is the best set up.  Of course there are exceptions, like running on Banked Ovals.   Try to be be watchful of matching the Shoes.  There is great variation amongst Shoes in the “Window” area where the Shoe clips onto the front of the Chassis.  Try to use Shoes of nearly identical shape and identical Window sizes.

The condition of a Pickup Shoe is yet another factor to consider.  Grooved Shoes will dramatically hurt performance, especially on tracks with low rails.  Grooved Shoes translate into lost Rail contact and Lost Power!   But, fear not - because grooves are easily removed by filing a Shoe flat in the contact patch area.  A Rotary tool (Dremel) with a rubber wheel or fine abrasive attachment can also be used to file and clean the contact patch of a Pickup Shoe.