# Slow down



## trackman (Aug 5, 2006)

I would like some input on slowing my 1/10 scale off road trucks down.

It seems that many ideas come to mind but what would be the best?

#1 Gearing down; Stock gears are 88/20 , biggest gear could be a 90t with a 15t pinion. I have tried it and it seems that it is hard on the diff gears and ends up stripping the diffs.

#2 Charging batteries at a lower amp for a slower battery charge.

#3 Less Battery cells per pack. The stock esc in the trucks require 6/7 cells and would require me to buy new esc's that could handle 4 or 5 cell packs.

#4 More turns in the motor. Stock truck comes with a 20t single , while we stepped to some name brand stock 27 turns they were actually as fast or faster than the stock 20 turn that came in the truck.

#5 What if I were to try some 35 or 50 turn rock crawler motors?
Would this allow me to use the stock esc (rated at 20turn 6/7 cell) with the required 6 cell packs with some gear mods (between ratios as listed above in #1)?

Reason for these slowing downs are to give some kids oppurtunity to do some raceing in groups that are not as lucky as most and actually to do it without destroying my trucks. The stock trucks normally run about 20 to 25 MPH and I am looking for about maybe 10 to 15 MPH.


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## Mike D. (Mar 4, 2009)

gearing down, you said 15t spur, i think you meant pinion?? i would try the highest spur and lowest pinion, and a 7.2v battery pack, never really thought about slowing down....lol, or set throttle lower on radio (depending on radio). or just buy parts for you cars so you can replace when break...lol


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## trackman (Aug 5, 2006)

inferno said:


> gearing down, you said 15t spur, i think you meant pinion??


Correct, pinion was intented.

Not many try to slow down, but as you said radio adjustment was a consideration but not enough to do the job. Even thought about jammin /blocking the trigger to limit the speed. But they seem to figure that one out and before you know one starts zooming around the track faster than the others. Dang Monkeys.


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## Mike D. (Mar 4, 2009)

lol, put road tires on, and let them race on the dirt, that will slow-em down...lol


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## KDarc (Apr 23, 2006)

I started my kids with 90spurs and 12 pinions with 4 cell packs I had from the winter carpet season. I also took some stock motors and put non silver brushes with soft springs on them. This also helped take the torque and wheel spin away so they could drive the trucks straight. I also adjusted steering travel out of the radio's to help with them sawing the wheel back and forth. Good luck and thanks for doing this for these kids!


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## Hick (May 22, 2007)

Try these, Spec Motors for Legends Class:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXNL80&P=7.

Ooops! They have gone up in price. 

Or something along these lines which are a little bit cheaper; 

http://www3.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=&FVSEARCH=TAMIYA+540+MOTORS++&search=Go. 

I maybe talking out of turn, but my limited experience with these motors, these motors just aren't that fast. These or something similiar came in my first car, a Chevy Stadium Truck.


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## hankster (Jan 1, 1998)

You can turn down the throttle end point on the transmitter so you only get about 1/2 throttle when the trigger is fully pulled.


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## CClay1282 (Jan 5, 2006)

hankster said:


> You can turn down the throttle end point on the transmitter so you only get about 1/2 throttle when the trigger is fully pulled.


Thats if he has a computer radio.

This would be the best option if your radio has that available.


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## trackman (Aug 5, 2006)

CClay1282 said:


> Thats if he has a computer radio.
> 
> This would be the best option if your radio has that available.


That would be nice if I had that option but I don't think my radio's have EPA.

Is EPA available only on computer radio's?


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## CClay1282 (Jan 5, 2006)

Usually. On some though there is a little dial.


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## trackman (Aug 5, 2006)

I have duratrax Evaders ST's and the RTR radio systems.

The radio's have 3 knobs on the top;

#1. The back one is " D/R " , I think that one limits the steering for more or less.

#2. Then the next one is " ST.TRIM " , I think this one adjusts the steering for straight or slightly steer left or right.

#3. This one is " TH.TRIM " Now this knob can actually be turned and make the car go backwards or forward without even mashing the trigger.

These trucks do have a programmable ESC that came with RTR trucks.

Maybe this can help out in the speed adjustment ?

Does number 3 sound like a EPA or is it just an adjustment drag knob or something?


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## CClay1282 (Jan 5, 2006)

The third one is just the center point adjustment for the throttle. You dont have an EPA adjustment. I would say a higher turn motor might be your best bet. One of the trinity spec motors like posted earlier would be a good buy probably.


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## shintastrife (Apr 26, 2009)

i would say chage the gears and put smaller batterys in them like a 1800mah

the d/r nob i think that might be like a F or R power to where you can give more power to going for word or back words. i say play with the nobs and see what they do.


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## trackman (Aug 5, 2006)

shintastrife said:


> i would say chage the gears and put smaller batterys in them like a 1800mah
> 
> the d/r nob i think that might be like a F or R power to where you can give more power to going for word or back words. i say play with the nobs and see what they do.


Yes the gears have been changed from a 88 spur /20 p to a 90 spur /down to 15p, Even tryed a 93 spur ( have to mod the gear gear cover for that ) ,

Still though part of the problem with that is to much tourqe and eventually strips the diff or idaler gears.

Far as smaller battery mah ; that has nothing to do with the speed , that's for the run time, where as the number of cells used can make a difference but the stock esc's have a requirement of 6 to 7 cells.

Really no need to play with the knobs as I do know that the D/R and the ST.TRIM are in reference to the steering and the number 3 knob was in question until I was informed that is just a center point adjustment , 

But thanks for the input.


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## shintastrife (Apr 26, 2009)

take the cover off, i run my ext with out one. try backing off the spring on the spur if its like the ext that will slow it down but it will all so eat the slipper pad up to. but there like 2-3 buck here for 2 of them. that will lessen the tourqe. all so try backing the screws off about a 1/4 turn on the gear box so they can spin more freely or just up gread to bearing as well.

i run a 5.5 t brushless in my ext, and the idel brakes more then any of them. but im running a 85sp and 32p i think. i know the pion is right.


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## LowClassCC (Apr 9, 2009)

i have a 4 year old son that i am slowly teaching to drive rc cars. the car i choose for him was a vintage rc10L due to the fact that the cars are very simply constructed and easy to fix. the car us running foam tires of an unknown hardness. the body is a truck that offers pretty much zero down force. and its driven on a standard unprepared blacktop parking lot.

so you can most likely imagine how uncontrollable the car was using a basic 27 turn stock motor. no less with a 4 year old at the controls.

i tried a 5 cell nicd. i tried gearing down. but that did not help all that much. gearing down may have actually hurt since the biggest problem was spinning out during takeoff. and teaching throttle control to a 4 year old is not likely going to happen. 

well gearing down did slow down the top speed but the torque still caused that car to spin as i had stated. i dropped in a vintage speed controller. one that has the 2 dials that you can adjust with a screwdriver. i adjusted that down and that really helped. but that alone did not give the throttle a very smooth feel but it did help. my next step was to drop a 65 turn crawler motor in it. i readjusted the speed controller to give it a little more but still not full power. the car is now running a 6 cell 1800 nicd stick pack and runs great. the speed has been drastically reduced to make it drivable yet it still maintains full throttle control. and lets not forget the fact that it would take someone with real skill to spin the car out now. 

65t crawler motor
vintage adjustable speed controller
geared down
6 cell battery

these changes have made it possible for my son to have an rc car that he can drive and do more with that don't involve donuts. it really brightened his thoughts of rc since he can now drive the car. 

and i almost forgot. the car now gets around 35-45 mins with the 1800mah 7.2v 6 cell nicd pack. just think how long a 5000mah lipo pack would last lol


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## trackman (Aug 5, 2006)

Thanks LC/CC for your idea,
What would you say your top speed is?

I was considering a 35Turn by hpi racing,,,
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWYE2&P=7

That motor is a direct replace for this 4X4 buggy by HPI
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXVZB2&P=V

Some rc reviews state that buggy does about 13 mph stock, but that is with a stock 65T spur and a 24T pinion.

If I have a 90spur and 15 pinion I may need to get a turtle shell for it:lol:

I have to agree I think a good quality stock motor escessively geared down will be to much wheel spin Unless I went with the Streak ESC with spin liminator, That ESC also has 4-10 cell capable .

Maybe if I went with the Streak esc I could run some 5 cell packs ,35T motor , Mod gearing and when some Jack ass comes along talking about how slow those cars are I could put a little wager on it and sneak TWO 5 cell packs in there and blow'em away:woohoo:


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## trackman (Aug 5, 2006)

*ESC Limitations*

My Stock esc has a 20 turn limit 6/7 cell, The Duratrax streak has a 12 turn limit 4 /10 cell limit.

Now My question is , If I were to go with a 35, 45 or 55 turn motor on an ESC as stated above will there be any limitation restrictions for the ESCs in the opposite direction as if running a lower turn motor specs limit?

Stock 27 turn is usually the norm, but are way higher turns such as 35, 45, 55 and 65 compatable with the ESC's such as the Streak with a 12 turn limit?


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## LowClassCC (Apr 9, 2009)

12 ad 20 considered modified motors. they are faster and run hotter than say a 27 turn stock. a 35 turn in turn is a slower motor than your 27 turn. 

basically it the esc has a limit of 20 turns don't put a 12 turn motor on it because it can not handle it. if the esc has a limit of 12 turn motors don't run a 10 turn with it. 

as far as running colder and slower motors like a 27 turn, 35 turn, 55 turn or 65 turn you are good to go with what you have. 

as far as how fast my rc10l is i'm not sure. its still more than twice as fast as the walmart toy rc cars the other kids in the neighborhood have. but slow enough to get laughed off an rc track trying to run against the stock guys. yet to the kiddo's around here it's lightening fast! lol


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## TOM MAR (Jul 24, 2008)

Do you know if you can use a receiver pack with your speed control ?


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## trackman (Aug 5, 2006)

TOM MAR said:


> Do you know if you can use a receiver pack with your speed control ?


One did'nt come with the system. I'm guessing probably not due to the primary battery connects to the speed control then the speed control sends a certain amount of voltage to the receiver to operate the steering servo and I would guess the reciever to recieve the radio signal.

But the receiver does have a battery pack connection point, Which I think most 2 channel receivers have.

Why; What's the idea behind that thought?


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## martian 710 (Jan 22, 2004)

The Sprint speed control is rated for 5-7 cells. So a 5 cell should work for sure. When my daughter first started racing I had a cheap Duratrax speed control in he car that was rated for 6-7 cells and it worked fine on 4 cells. I don't think I did anything to bypass the BEC.


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## trackman (Aug 5, 2006)

martian 710 said:


> The Sprint speed control is rated for 5-7 cells. So a 5 cell should work for sure. When my daughter first started racing I had a cheap Duratrax speed control in he car that was rated for 6-7 cells and it worked fine on 4 cells. I don't think I did anything to bypass the BEC.



Wow, thanks for that info on the ESC of 5 to 7 cells...
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAMN7

The manual for the Evader St always said requires 6/7 cell so I went from there,
But then again it has a 20 turn limit and I have ran 17 turns with 7 cells constatntly for many packs and it keeps on running....
I think they may have giving this ESC a big ol' safety net far as the specs.


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## TOM MAR (Jul 24, 2008)

trackman said:


> One did'nt come with the system. I'm guessing probably not due to the primary battery connects to the speed control then the speed control sends a certain amount of voltage to the receiver to operate the steering servo and I would guess the reciever to recieve the radio signal.
> 
> But the receiver does have a battery pack connection point, Which I think most 2 channel receivers have.
> 
> Why; What's the idea behind that thought?


With some sc's you could plug a 4 or 5 cell receiver pack directly into the receiver, allowing you to run very low voltage to run the motor. ( we did this in 4 cell oval) I was wondering if "a receiver pack pluged in to the receiver & a 2 or 3 cell pack hooked to the sc" would work & do what you were asking ?
I Have not tried this,Just wondering if anyone knows if this would work with this system.

If you try this make sure you DO NOT connect more than a 4 cell pack to the receiver until you have the specs on how much voltage your receiver & servo is rated at.


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## DJ1978 (Sep 26, 2001)

Simple way is to tape a foam stop to the handle so the throttle can not be pulled as far. 
That way you can just set the vehicles up properly and limit the throttle travel. 
Less cells would work.. but then you dedicate all packs you change to the lower voltage. 
If you just limit trigger travel, you can use the same vehicles for inexperienced drivers and take the stops off for more experienced groups.


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