# To Restrict or to NOT Restrict pickup shoes



## Reaper (Jan 17, 2005)

Here is a slo-mo video I made while testing pickup shoe restriction on drag cars launching. Aurora t-jet motor & magnets in car. Pickup shoes are BSRT. 
The car had faster scale 60' times with pickup shoes unrestricted and 3/4 turn cut off a set of BSRT pickup shoe springs.


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## mowyang (Mar 24, 2008)

Informative video!
For fray-type road cars, my assumption has always been that restricting travel is most helpful in the curves, a speed limiter that helps keep you in the slot. Very interesting to see its effect on acceleration.


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## Reaper (Jan 17, 2005)

From my experience I probably wouldn't consider it so much of a speed limiter that keeps you in the slot as less of a lever to toss you out of the slot in the corner. Restricting the shoes improves handling but at the cost of speed.

I've got one Stock class car that I race (when I do make it to a club race) that has NO restriction on the pick up shoes. It flies on the straights and I nurse it through the corners. Seems to work well - the chassis likes that particular body with that shoe setup. 

For fray cars it's trial & error as each car is somewhat different on how much spring pressure and shoe restriction they like.

However for drag cars (without braided pickup shoes) it seems that no restriction is best. If rules allow adding weight to the nose of the body that is good but you have to test them a lot to get the optimal weight depending on tire grip, track voltage...


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## Hornet (Dec 1, 2005)

edit.


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## slotking (May 27, 2008)

I am strong believer in restrictions! Just ask my kids!!!!!!!!

I have done a lot of testing with this myself, but for road racing only!
without fail, from T-jets to my 6 mag unlimited Cheetah!

I get better times with restricted travel!
this way the shoes are not helping g-forces to push the car out of the slot.
it basic physics (which I never took) :freak:


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## Hornet (Dec 1, 2005)

edit.


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## slotking (May 27, 2008)

think about it
if it take say 500 grams of g-force to lift the car car out of slot
your shoes are say 200 grams of lift
you will now only need 300 grams of g-force to now push it the height of the shoe travel


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## SDMedanic (Apr 21, 2011)

From the video my opinion is that your shoes are not restricted enough. The front wheels should not visibly lift off the track. 0-60ft may be one comparison but in road racing you don't have that severe acceleration and restricting travel will help as opposed to hurt.


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## slotking (May 27, 2008)

ok, finally saw the video,

the reason the restricted shoe racing is slower is that the car is lifting the shoes from the track, thus losing power and slowing down the car.

if you add a wheelie bar that issue should be solved and help all the way around.

if you have an adjustable power supply, set it to say 14 volts, drive at full speed into a 6" turn, if you come out back off to 12 and repeat till the car sats in. then up it a hair a few times till the car de-slots, run the test 10 times seeing if the car de-slots.

now restrict the shoes, so you get maybe 3k of travel.
retest


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## Boosted-Z71 (Nov 26, 2007)

I think you also have too much weight after the back wheels, I would try to lighten the body in the rear section as well as lower it on the car. As the car just bounces, and never really settles, more than likely neither of these will help as much as a wheelie bar

Boosted


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## Reaper (Jan 17, 2005)

This car in the video was originally setup to race in a 'Super Stock' drag racing class at 13.8 volts. Adding weight in the nose was allowed but NO wheelie bars were allowed. NOT restricting the pickup shoe travel on this particular rule setup ALWAYS resulted in faster et's & faster mph... always. It may appear to hop higher when coming off the line but I found if you added too much weight to eliminate the hop then the et & mph suffered at the far end of the track, not enough weight and it would hop way too much and not get off the line fast enough. It came down to TONS of runs and varying the weight until you got it just right. Timing system was a TrakMate DragPro 3000 which had 60', 1/2 track and trap speed times & all the other bells & whistles.

I also found that the body didn't really make a big difference on the performance as long as you could add weight to the nose of any body that you used. What did make a difference was rear wheel clearance as you were not allowed to trim the body weight or the wheel wells at all so you had to find a body that was wide enough to fit the tires you ran. The car in the video had tons of torque (stock t-jet motor & gaussed/matched motor mags) so I needed to make the rear tires as large as possible diameter (within the rules) but still fit inside the body.


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## Bill Hall (Jan 6, 2007)

This is great stuff! 

I'd really like to see a comparison using stock springs and shoes AND then use the shoe hook bend trick to adjust the teeter totter effect out. I'm wondering how things would turn out if ya werent boinging around...?

How about a nice static picture of the car too?!


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## slotking (May 27, 2008)

try using a make shift slip diferentila

ie
silicone slip on tires that spin on the hub
you lose some lunch, but can reduce hop

i have done this on an inline, and a t-jet with a lot of motor
makes a difference


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## Reaper (Jan 17, 2005)

slotking said:


> try using a make shift slip diferentila
> 
> ie
> silicone slip on tires that spin on the hub
> ...


I do that for certain road racing cars that I have - I use #10 (or something like that) 1/10 scale truck shock oil - clear silicone type stuff and I put it on only one wheel.


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## Hornet (Dec 1, 2005)

edit.


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## slotking (May 27, 2008)

I have put cars from SS to unlimiteds on the track, wondered why the handling is off and remembered i put new shoes on the car and did not restrict them.

NOTE
that is based mostly on CATs which have more flex than the other cars
which is why I run them
cause i can tune the flex for different tracks

My t-gets and g3's also like limited shoe travel
the key is finding the sweet spot

also the travel on the shoes does not have to be the same nor the shoe tension


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## Hornet (Dec 1, 2005)

I figure it's worth testing again.
Looked up my notes on when Lyle and i last did testing on restricting shoes,and it was way back in 00,so it's probably time for another test session on the idea
I'm working on shoes for Carter,and on half of his i did restrict them,the other half i left unrestricted,hey Rick feel like doing a test in the near future,he he :wave:.
Rick


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## slotking (May 27, 2008)

if find your losing power at spots, check the rail heights
I have seen some go from 13k down to 4k on the same track

but lets say you gonna race on a track with 12k rails pretty even around the track, use a 14k rail piece of track to set the car up with almost no travel (1 or 2 K)

that should get you around without losing contact if the track has even rails


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## Hornet (Dec 1, 2005)

I set my cars up super loose with roughly .005" or better of magnet float.
I think if you're set-up tight,the restricted shoes are an advantage,but on a loose set-up you got to run slightly more shoe travel to keep rail contact.
That was our findings years ago,but sometime soon i'm gonna go back to that test and re-do it,things do change in the hobby once inawhile


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## slotking (May 27, 2008)

yes, I drag the cars:dude:
nothing like magnet wear:tongue:

despite that, I still had enough speed to be the 1st 1 into the wall most times:freak:


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## Hornet (Dec 1, 2005)

Mike,i'm thinking us road racers got nothing on them drag guys 
By looks of some of them videos,those guys can hit the wall before they move,lol:wave:
I can't say i remember ever crashing before i was across the start line:thumbsup:
Rick


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## slotking (May 27, 2008)

check out the drag links

http://slotcar64.freeyellow.com/movies.html


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## Rick Carter (Dec 2, 2008)

Slick Rick,

Anytime -LOL! Shoe travel should be relative to your front tire height as to not to have too much travel nor too little in comparison with the wear pattern on the shoe. 

Your shoes/tension are the main areas of concern when it comes to your speed and handling. I restrict every shoe on my Storms and on my G's, it comes in the way of the spring tension selected.

All of my shoes are done in the same manner and can be used in all of the classes that I run without an issue.

(note). I hope that this makes sense because I'm sleepy as F$#@ but still trying to chime in a bit.


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## slotking (May 27, 2008)

> I hope that this makes sense because I'm sleepy as F$#@


is that 1 of the snow white characters:tongue:


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## Rick Carter (Dec 2, 2008)

Yes sir, LOL!


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## Hornet (Dec 1, 2005)

You guys might be right,as it's been quite awhile since i tested the idea.
Rick you'll have to try the ones i'm doing for you both ways.

Hey wasn't there one called Dopey too:wave:


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## slotking (May 27, 2008)

> Rick you'll have to try the ones i'm doing for you both ways


Come on man! let not get kinky on the BB here:freak:


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## ajd350 (Sep 18, 2005)

It appears that what is better for drags-unrestricted- is not as good for road courses. I do not run drags, but on road courses I set up restricted to drop just barely below the front tires at full drop. If the pattern is good but it cuts out through the turns, they are adjusted to drop a hair more until that clears up. Too much travel and the car becomes tippy at the limit and rolls out of the slot. Personally I prefer just a hint of slide at that point so I can better judge the limit before it's out and headed for the wall. It's all a balancing act and each car is different.


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## Rick Carter (Dec 2, 2008)

Yeah Mike, Rick wants me to try the Hermaphroshoe (Half Restricted/ Half Unrestricted).
LOL!

Ajd,

Yes, its a balancing act and there's definitely 2 different schools of thought between a drag car and a road car.

One of my boys mentioned to me a few years back in conversation when we were talking about the top racers at the time that the difference between them and us is that "we" build cars and "they" build race cars. The difference between the 2 are worlds apart. Since then, I've been building race cars and the restriction of the shoes is a major component in that equation.


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## slotking (May 27, 2008)

yes drag racing is really different!
the high heels is the toughest part:wave::tongue:


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## Hornet (Dec 1, 2005)

Mike practice makes perfect :wave:


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