I've been messing around quite a bit with tjets the last few days.One thing I am messing around with is pickup shoes.

I remember reading awhile back of an optimum way to bend them for peak preformance.Anyone know what I am talking about and could poiint me there????

I've really gotten to spend some quality time with the JL tjet style cars the last few days.The more I race them,the more I am really liking them.


Mike

If you mean to tweak the shoes so you get as much contact with the rails, then all you need is a small piece of track to see how they sit. Depending on the angle the shoes go will determine how you need to bend them. If the shoes only hit at the front, you need to bend the rear step some. If they hit only on the rear, you have to hold the shoe(s) against the chassis and pull the front up a little.

Don't forget to limit the travel of the shoe by folding the front down and back on itself. (fold to the inside) They should hang about 1/16 of an inch below the front tires. They will deslot alot less. :)

There's also a tweak you can do to the top of the shoe where it snaps over the hanger on the chassis... if you fold the very top down to make the rectangular hole smaller, then you'll restrict pickup shoe travel and improve handling. The theory is that if you come into a corner fast enough to tip the car, the spring under the pickup shoe is helping it to tip. But if you restrict travel so the shoe loses contact with the rail right after the front tire loses contact with the track, then (a.) the spring is no longer pushing the car up and out of the slot and (b.) there's a "rev limiter" or "traction control" effect where the power is cut because the shoe loses contact... the car slows and in theory drops back into the slot.

Now, all that being said, be aware of a couple of things:
1. it's real easy to ruin pickup shoes bending them like that. They snap easily at that narrow point, and they're not all exactly the same so that some will bend too high or low... takes some trial and error.
2. There's another trick that I read recently on another board that effectively does the same thing... if you take a piece of small-diameter heat shrink tubing (I forget exactly what size, sorry) and slice it into little rubber bands, you can stretch them around the top of the shoe to limit travel in the same way. The shoe doesn't get ruined and it's even adjustable. i haven't tried it yet, but that's only because I haven't had the chance... sounds like a really good idea...

I know this might not be what you meant about bending pickup shoes; you were probably referring to rail contact. But this seemed like a good place to pass this along...

--rick

edit: sorry joez. guess i'm a little long-winded today... :D

Rick, that shrink tubing idea is GREAT! I have some that will be perfect for a trial.
Cudos to the guy who came up with that idea and to you too for sharing it with us! Thanks! :thumbsup:

I think Roger is the one that first brought up the shrink tubing idea.

What I've generally seen with all slot cars, TJets to magnet cars, is that they are EXTREMELY sensitive to pickup shoe tension. The more tension the better the current flow through the electrical joints and the more power and speed you'll get out of the car. I've seen lazy dogs wake up and run like greyhounds with a little adjustment of the pickup shoe tension. But the tradeoff is that when you increase the shoe tension you'll end up with less front-end weight on the front tires. You may lift the front wheels entirely off the track and lift the guidepin higher in the slot. Too much shoe tension and the handling, especially in the corners, falls way, way off.

It's this compromise between speed and handling that is the primary motivation for limiting shoe travel. If your sole concern is improving the handling you could simply use weaker pickup shoe springs. Hello lazy dog. But by limiting shoe travel you can increase the shoe tension (speed! speed! speed!) and still keep the front wheels of the car on the ground and the guidepin in the slot for good handling. What you're really doing is using shoe travel and tension to decide how the front end weight gets divided between the pickups and the front tires. This equates to trading off speed for handling.

TJets are more sensitive and take more trial and error to get tuned exactly right because all you have to work with is gravity and the magnetic attraction of the motor magnets to the rails (yes, even TJets have some magnetic downforce, especially when the chassis is lowered and equipped with strong magnets). Magnet cars have a bit more leeway because the motor & traction magnets are going to plant the car to the track for any reasonable amount of shoe tension. But with magnet cars you're still trading off downforce on the shoes vs. downforce on the tires and picking the right speed/handling tradeoff is still a non trivial testing & tuning exercise. Of course everything like track type, rail height, layout, body and chassis weight, chassis electrical connections, driving style, etc., all come into play. Permanently bending your shoes for one track and layout may render then ineffective on another, or at the very least, less than optimal.

I have this problem with being vague.FOr some reason,I automatically assume that people know what the hell I am talking about.You guys figured it out and told me exactly what I wanted to know.


Very cool info.Exactly what I was looking for.The coffee is ready,must head down to the basement for a few hours and test out this new found knowledge.

See you guys later........... :wave:
Thanks again!!!!

Mike

For those that are intersted the best FRAY/VHORS TJETS I have seen have almost zero pickup travel and are restrited by one use American Line pickups and tweaking the U hinge part of the shoe that hooks up to the chassis.

Roger Corrie

I agree with Roger. Using American Line Pick-up shoes and tweaking the rear of the shoe at the 'U', is the way to go.

It's easy once you get the hang of it. No way would I mess around with shrink tubing or bending over the front of the shoe. That's entirely too much work!

Keep it simple! You'll enjoy it more!

NICK DANGER

Well...when you have more time than pickup shoes/money and have a drawer full of shrink-tubing PLUS the itch to fiddle with something, I still think it is a great idea. I will look into those shoes at my local shop. Thanks for the heads-up! :)

Just as a follow up to this since I last asked,I did some messing around with the pickup shoes.
Bending them to me was too much work,after three unsuccessful tries,I gave up.

But the shrink tubing idea,now that one works really good.
I picked up an assortment pack at Radio Shack,and the 1/8" stuff,cut into small bands and then hit real quick with a Bic lighter works like a charm.

A lot easier then bending for a guy like me who can barely see anymore.Next to My Dremel,the reading glasses I get at the dollar store are the most important tool in my tool box!!!

Give the tubing a shot if you haven't yet.Good hop up tip.

I think it was Rick who first gave me the heads up on that one.Thank you Rick!!!!!

Mike

for a guy like me who can barely see anymore.Next to My Dremel,the reading glasses I get at the dollar store are the most important tool in my tool box!!!
Rick!!!!!

Mike

Know what you mean. At my rate of degeneration, I 'll be graduating to 1/32 scale in a few years. ;) rr

Hi All:

I have not posted in several months, so here we go:

On the pick-up shoes contact problem:

Get one of the cheap $5.00 ( Hobby set ) of screw drivers at Wally World or Target. Cut of the top part of the drive, just below the head where it is all round. Use a dremel with a cut off disk. Most drives have a black shaft, keep this part and cut off the slot part. From the top, cutting down the shaft, cut down about a half an inch. Cut down the shaft, leaving one "finger" part on each side. Be sure to round off the sides. Use the new tool to help set your pick-up shoes. Place the tool with one part above the pu and one below. Now you can "twist" the tool to adjust the pu.

Next, get a fine point black sharpie pen. On a diagional to the pick-up shoe, mark down at angles, the shoe. Make a couple runs on the track. Look at the pu, and see if the marker has be taken off. This also helps tell if the pick-up shoe is centered on the track. Adjust with your new tool and do again until atleat 3/4 on the pick-up shoes contact area is touching the rails.

I think it was Rick who first gave me the heads up on that one.Thank you Rick!!!!!

Mike

i can't take much credit... it wasn't my idea, I just passed it along. I figured out that I first saw it on the Fray in Ferndale Bulletin Board (which, in turn, I think I was directed to by one of my racing buddies in the Baltimore area). When I went back just now to find the original post, oddly enough, it wasn't there. There were a few posts in response to the idea, though... apparently it caused some controversy when it was suggested that the tubing mod be made legal for Fray racing. Some folks worried that the tubing might fall off during the race and become a "track hazard"... others were against the idea of adding anything to the pickup shoes in the name of "pure" Tjets...

here's the topic if anyone's interested...
http://p087.ezboard.com/fthefrayinferndalefrm2.showMessage?topicID=22.topi c

--rick