Pro12 (1/12th scale RWD pan cars)

Anything with an Electric Motor can be discussed in here.
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Matt van der Haas
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Mon Apr 07, 2008 9:59 am

thought i'd start off a pro12 thread.

If you want some advice at all about pro12s also, go ahead and ask 8)

BRILLIANT (highly recommened read) Xray pro12 setup guide http://www.teamxray.com/teamxray/showfi ... le_id=5057

Heres my Manawatu Setup from the 2009 Electric On-road Nationals (1st place)
Image

Heres my CRCCC Setup from the 2010 Electric On-road Nationals (1st place)
Image

setup guide: from crc manual (these setup tips can be applied to most pro12s)
Springs:
The Gen X comes with .50mm front springs. Going to a softer front spring will allow the car to roll
more, which will yield more overall steering, but will be most noticeable on corner entry. Using a stiffer spring will
do just the opposite. The car will stay flatter and transition less weight side to side giving you less total steering,
but again most noticeably on corner entry. Preloading the front springs should not be used as a tuning aid (if you
need the front end to be stiffer, use a stiffer spring), but rather just to correct ride height. As an example,
sometimes when using soft front springs, you will notice that the car sits down into the spring (or “sags”), creating
a gap between the spring and lower pivot ball, causing loss of ride height. You do want the car to “set” into the
spring slightly (never bound tight at the top of its travel). But if this gap is more than .010” (or .25mm), you can
preload the spring slightly (either by turning the king pins in farther, or adding a thin shim) to get the ride height
back up.


Caster:
Caster is the angle of the king pin in relation to vertical when viewing it from the side of the car. Zero
caster is having the king pin perfectly straight up & down. Adding caster tilts the king pin back (top of king pin
towards rear of car). Caster is adjusted on the Gen X by moving the white spacers on the upper hinge pin forward
or back. Moving them back adds caster. Adding caster adds more mid-corner & exit steering. Decreasing caster
makes the car react faster off center (or also called making it “twitchy”), but decreases mid & exit steering.

Dynamic Caster: This refers to the angle of the upper arm hinge pin in relation to the lower arm hinge pin (in
this case, since there is no lower hinge pin, it is always in relation to level, or horizontal). (This would vary on other
vehicles such as off-road or touring cars where the lower arm hinges as well and the angle of kick-up/anti-dive is adjustable.)
This is adjusted on the Gen X by changing the upper arm mount blocks (or, dynamic caster blocks). The car
comes with all 3 options in the kit. The 0 degree block, or 0 degrees of dynamic caster, is having the upper hinge
pin parallel with the chassis so that when the suspension compresses, the upper arm pivots straight up & down,
having no effect on your caster setting. Increasing dynamic caster (changing to the 5 or 10 degree blocks) tilts the
front of the hinge pin down toward the chassis. By increasing this angle, the upper arm pivots forward slightly,
decreasing the amount of caster as the suspension compresses. This option is designed to give you the “best of
both worlds”. (see above section on effects of Caster.)


Camber:
Camber refers to the angle of the wheel/tire in relation to the track surface when viewing from the front
or rear. Negative camber means that the top of the tire leans in toward the chassis. Positive camber means the
top of the tire leans out, away from the chassis. Camber can be precisely measured with after market camber
gauges, sold at a local hobby shop. It can be measured roughly using any square (to the ground) object (such as a
credit card, business card, hotel door key, etc.) by checking the gap between the square edge and the top of the tire.
Increasing negative camber (in the range of 0-2 degrees) will increase steering. Changing the camber has a
tremendous effect on the handling of the car. This is, most often, a very critical adjustment in tuning your car.

Camber Gain: Camber gain refers to the amount of camber that is added as the suspension moves through its
range of motion. This can be adjusted by changing the height of the upper arm hinge pin and/or changing the
length of the upper arm (by moving the upper arm mount in/out). The stock location for both height and length will
yield the most camber gain. (Both height & length are only adjustable with the addition of optional parts.) Moving the
upper arm hinge pin upward or inward will decrease the amount of camber gain. Running the upper arm mount in
the stock location gives the most on and off-power steering, however the car may seem a little aggressive to
some drivers. If the upper arm hinge pin is raised, or moved inward, the car will lose some steering but will feel
smoother and easier to drive.


Toe In/Out:
This is the parallel relationship of the front tires to one another. Toe-in/out adjustments are made
by changing the overall length of the steering tie-rods. Toe-in (the front of the tires point inward) will make the car
“lazy” around center and will decrease steering on corner entry, but will help the car to “track” better on long
straights. Toe-out (the front of the tires point outward) will make the car more aggressive and increase steering on
corner entry, but has a tendency to make the car wander on the straights. On the Gen X, we recommend setting
your toe between 0 (parallel) and 1 degree of toe-out at the most.
Tuning Guide
17


Bump-In/Out:
Bump-out (front of the front tires toe-outward under suspension compression) will result in more
off-power steering. This effect is obtained by adding washers under the ball stud on the steering block. Bump-In
(front of the front tires toe-inward under suspension compression) will result in less off-power steering and running
too much bump-in can make the steering feel very inconsistent. This effect is obtained by mounting the servo flat
on the chassis with the servo saver pointing upward. This method is NOT recommended. Testing has shown that
running the kit setup offers the most consistent performance, but adding bump-out in some instances can have
positive results.

Center Shock:
The center shock on the Gen X can be tuned just like shocks on other types of cars (via springrate
& oil viscosity). On a smooth track, a stiffer spring and oil combination will result in more overall steering, but
will be most noticeable from mid-corner to exit. If the track is bumpy, being too stiff here will cause the car to be
“bouncy”, losing contact with the racing surface and handling very unpredictably. Softening the center shock will
not only help the car perform better in the bumps, but it will also help generate more rear traction (exiting the
corner) on low to medium grip surfaces (such as asphalt), even when the track is smooth.


Shock Angle:
On the Gen X, you can alter the shock angle by adding washers under either of the two ballstuds
that the shock mounts to. Raising the front ballstud (on the antenna mount) will reduce steering slightly, but will
help make the car feel more connected to the track in bumpy sections. Raising the rear ballstud (on the rear pod
top plate) makes the car have more overall steering. Keep in mind that as you alter this angle, you will also alter
the rear pod droop. This can be corrected by shortening or lengthening the ballcups on the center shock.

Pod Plane Angle – Unloaded Droop: This refers to the angle between the rear bottom plate and the
chassis plate when the car is suspended in the air. Imagine a line drawn through the chassis exiting out the back
of the car, this is the chassis plane. With the rear pod hinging at the at the center pivot, unloaded droop is the
angle of this pod compared to the chassis plane. The shock length (and only the shock length), dictates the
amount of unloaded rear pod droop.
The car is set up with zero unloaded droop, when, with the car held in the air, the pod and chassis form a straight
line. Loosening the plastic ball-cups on the shock will increase its length, causing the rear pod to drop below the
chassis plane. This unloaded droop is best measured with a droop gauge like the Dynamite 2528 (Precision
Droop Gauge with Blocks). Placing the front and middle of the chassis on the blocks, you can measure the
unloaded droop with the gauge. Typically, the Gen X should be setup with about 1mm of pod droop. Adding
unloaded rear droop (up to about 3mm max) can give the car more rear grip and a more consistent feel on bumpy
tracks. Even without droop gauges, close inspection of the relationship between the rear pod plate and the
chassis will allow you to monitor and adjust for the proper unloaded droop.

Pod Plane Angle – Race Ready Droop: This refers to the angle between the rear bottom plate and the
chassis plate when the car is loaded, race ready, sitting on a flat level surface. This race ready droop is
dependant on the amount of shock spring preload. Increasing the center shock spring preload will stiffen the
shock, decreasing the amount the car settles into the suspension. Typically, with the unloaded droop set at about
1 mm, we set the race ready droop to zero, meaning when placed on the ground, the car settles into the
suspension 1 mm, enough to cause the rear bottom plate and the chassis to form a straight line.
Keep in mind, adjustments to these droop measurements effect the ride height of the car. Be sure to confirm ride
height settings after adjusting droop settings.


Side Springs:
Going to a softer side spring will give the car more rear grip and a smoother steering feel around
center. A stiffer side spring makes the car more aggressive off center, and in low bite conditions could make the
car loose, or oversteer. Preload on the side springs should only be just enough to get the pod to return to center
(about ½ turn per side), so you can accurately tweak the car flat. Just like what was mentioned for the front end –
if you want the sides stiffer, you should use a stiffer spring, not add more preload.

Damper Tubes:
The effects of dampening are not always the same and will change with different levels of grip
in the track. On high bite carpet tracks, where traction rolling is sometimes an issue, using a thicker damper tube
fluid will slow the side to side weight transfer and prevent traction rolling, giving a smoother, more consistent
steering feel. On low bite carpet (or on asphalt), too thick of a damper fluid will actually cause the car to be loose,
or oversteer, because the weight can not transfer quickly enough. Going to a thinner fluid here will tighten the car
up by allowing more weight transfer. Helpful Hint – A quick way to determine which way to adjust the dampening
is to go out and run a few laps (preferably on the clock), bring the car in and pull 1 of the tubes off and go back
out and run again. You can then make a decision (based on lap times and feel) on which way to go with your
dampening, saving yourself a couple of re-lubes.
Tuning the Chassis of the Gen X


Differential:
The diff on 12th scale cars (not only the Gen X, but all 12th cars) is NOT meant to be a tuning
option. There is ONE way to properly set the diff. The spur gear should be locked (meaning the motor can not slip
the spur gear), while still having free & smooth rotation of the rear tires (in opposite directions) while holding the
spur gear. The handling of 12th cars greatly depends on the smooth, free operation of the diff without it slipping at
all. When the diff slips, it flat spots the balls, making the diff action very “gritty” and this will turn a good handling
car into a poor handling car real quick. A low turn modified motor may require more tension on the diff nut than a
27T stock motor to keep the diff from slipping, but over tightening the diff nut will cause premature diff failure as
well, as this will crush the outer bearing in the hub. The key is to never have the diff slip on the track, while
maintaining that smooth, free rotation of the tires.

Battery Placement: The Gen X comes equipped with CRC’s ABP (Adjustable Battery Position) chassis (first
introduced as an option part for the CK3.2R). Testing has shown that moving the battery forward actually smoothes
out initial steering input and will help prevent traction rolling on high bite carpet. Forward battery will also make the
car rotate more from mid-corner to exit while on-power. Rear battery will actually steer more off-power on corner
entry, but does not rotate as much on-power.


Track Width:
The rear end of the Gen X is already maxed out at 172mm (when using CRC High Roller wheels &
tires), however you can alter the front track by adding or removing shims between the inner front wheel bearing
and the steering block. Widening the front track width is a good way to add some stability on corner entry as it will
slightly reduce front grip. This is especially helpful when there is a problem with traction rolling.

Ride Height:
This is the height of the chassis in relation to the surface of the track. Ride height needs to be
measured with the car “race ready” (all electronics, motor, battery, etc. installed). A higher ride height may be
used on bumpy or slick surfaces, improving overall handling by generating more weight transfer and chassis roll.
A lower ride height will make the car change direction quicker and should be helpful on high-bite surfaces such as
carpet. Testing has shown that offsetting the ride height, front to rear (running the rear ride height 1/2mm higher
than the front) will increase steering into the turn. Generally for carpet racing, the desired ride height is 3mm. On
lower grip surfaces, such as asphalt, the ride height is kept between 3.5 to 4mm. Please check with your local
track for their minimum ride height requirements.




tyre shore chart:

FRONTS:

Corally:
Corally Goldstar tyres front 1-12 - Shore 30 Goldstar front tyres 1-12 - Shore 30
Corally Green front tyres 1-12 - Shore 32
Corally Silverstar tyres front 1-12 - Shore 34
Corally Gold tyres front 1-12 - Shore 36
Corally Silver tyres front 1-12 - Shore 38

Kawada:
kawada (RS50S) 35 DEG
kawada (RS50WS) 35 DEG
kawada (RS250S) 40 DEG
kawada (RS250WS) 40 DEG
kawada (RS450) 45 DEG
link: https://sv18.wadax.ne.jp/~kawadamodel-c ... n_kate=705

CRC:
Magenta - 36-40 shore "soft purples." High grip, long life. Part of the pink / purple family of rubber. Great for 1/12th modified or asphalt.
Black - Long wear, high grip exotic racing rubber.
Red -Med-Firm 40 shore. . Exotic, super long wear, med. grip, high rubber content racing foam. . For front tires on asphalt. . Not for carpet.
Purple - Firm 45 shore. Exotic, long wear, high grip, high rubber content racing foam.

Dual Compound:
Magenta/Orange - Med. 35 - 39 shore. Exotic, long wear, high grip, high rubber content racing foam.
Purple/Orange - Firm 45 shore. . Exotic, long wear, high grip, high rubber content racing foam.

GRP:
GDY30S 37 shore, Magenta, 26 width, 48 diameter , use with asphalt/Carpet
GDY31S 42 shore, Purple, 26 width, 48 diameter , use with asphalt/Carpet
GDY32S 37+42 shore, Cyan, 26 width, 48 diameter , use with asphalt/Carpet
GDY33S 35 shore, Black, 26 width, 48 diameter , use with Carpet

Jaco:
Standard:
Green - Medium, standard
Pink - Medium-Soft, low wear
Double pink - Medium, low wear
Purple - Medium-Firm, low wear

Prism - Larger diameter:
Magenta - 32
Double Pink - 35
Lilac - 38
Purple - 40
Black - 40

REARS:

Kawada:
kawada[RS151S] 25 DEG -discontinued?
kawada[RS51S] 25 DEG
kawada (RS451) 30 DEG (shore rating)
kawada[RS551] 35 DEG

Corally:
Corally Green rear tyres 1-12 - Shore 28
Corally Orange (Outdoor Compound) rear 1-12 - Shore 28
Corally Gold tyres rear 1-12 - Shore 28
Corally Silver tyres rear 1-12 - Shore 30
Corally Pink tyres rear 1-12 - Shore 30


CRC:
White - Med. wear, high grip exotic racing rubber.
Green -30 shore Good old American foam rubber. Less expensive, good grip on carpet, but more wear than the pink/magenta family and more wear than the white/grey family.
Pink - 30-33 shore. High grip, long wear. The traction leader for rear grip. Great for asphalt. Wears like iron with great grip.
Grey - Long wear, high grip exotic racing rubber.
Magenta - 34 - 38 shore. High grip, long wear. Same family as pink, but firmer. Great for asphalt and carpet.Wears like iron with great grip.

GRP:
GTY30S 25 shore, White, 39 width, 53 diameter , use with Carpet
GTY31S 30 shore, Gray, 39 width, 53 diameter , use with Carpet
GTY32S 32 shore, Pink, 39 width, 53 diameter , use with Asphalt
GTY33S 37 shore, Magenta, 39 width, 53 diameter , use with Asphalt

Jaco:
Standard:
Green - Medium, standard
Pink - Medium-Soft, low wear
Gray - Medium, low wear
White - Medium-Firm, low wear

Prism - Larger diameter:
White - 25
Yellow - 30
Pink - 30
Magenta - 32
Gray - 35

Parma:

Standard:
white - 25
Pink - 30
Black - 35
Violet - 35/40
Purple - 40

Pro 38 - Larger Diameter:
Grey - 30
Magenta - 37
Purple - 42

Jaco, 1/12th scale tire chart.
Black - 40 shore: This is a low natural rubber compound. Special tire for insane traction carpet tracks. Does not get gummy like Purple. If you don't have insane traction you car will likely push with these.

Purple - 40 shore: This is a natural rubber compound. Popular front stock tire, carries good corner speed because it's firm. The foam this compound is made from gets more gummy late in a race. The more you run this compound the gummier and stickier it gets. A little more forgiving than some of the other fronts.

Lilac - 37 shore: This is a natural rubber compound. Great front tire for stock carpet or if dbl. pink is too much steering.

Double Pink - 35 shore: This is a natural rubber compound. This is the standard front tire for carpet in all classes. Its is used front and rear for 19T and Mod carpet and front and rear in all classes on asphalt.

Grey - 35 shore: This is a low natural rubber compound. It is just as hard as dbl. pink but it has FAR LESS traction. It is used to free up the rear of stock powered carpet cars for more efficiency and corner speed. This is the old standard rear carpet tire, most stock carpet racers use the softer yellow compound now for more forward grip.

Magenta - 32 shore: This is a natural rubber compound. Its softer than dbl pink so if you need more steering than dbl. pink use these up front. If you need more rear traction than dbl. pink use these in the rear.

Pink - 30 shore: Pink - 30 shore: This is a natural rubber compound. This tire is used in mod 1/12th on carpet and asphalt if the traction is low. If the traction is high it will lock in the rear of the car and make it push.

Yellow - 30 shore: This is a low natural rubber compound. It is the standard rear tire for Stock racing. It is used to free up the rear of stock powered carpet cars for more efficiency and corner speed.

White - 25 shore: This is a low natural rubber compound. It was the standard rear tire for 1/10th on road carpet racing. Its a little softer than yellow.
Last edited by Matt van der Haas on Thu Apr 10, 2008 11:10 pm, edited 4 times in total.

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REZRCT
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Mon Apr 07, 2008 10:01 am

Matt post up your awesome shore chart for tyres 8)

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Matt van der Haas
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Mon Apr 07, 2008 10:16 am

Hopefully I have it somewhere, will post it when i find it.

Your 12x was going good on sunday, congrats on 2nd 8)

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REZRCT
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Mon Apr 07, 2008 1:29 pm

Matt van der Haas wrote:Hopefully I have it somewhere, will post it when i find it.

Your 12x was going good on sunday, congrats on 2nd 8)


Thanks Matt, it was all your tips that helped me :D Congrats on 1st 8)

Alwyn
Posts: 152
Joined: Mon Apr 07, 2008 12:38 am
Location: Tauranga

Mon Apr 07, 2008 2:06 pm

hey guys, hows it going? seems like you guys had fun on saturday and sunday despite of the rain.. too bad i couldnt make it again.
congrats to rocky and matt... oh
and who got 3rd placE?

anyway, see you guys at the track on NHRCCC on sunday :) pray weather is good.

Edit: oh and rocky, i see that you have "world's fastest indian"... lol, dont forget to bring ur birthday card on sunday... lol show the guys ur achievments...

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REZRCT
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Mon Apr 07, 2008 2:08 pm

Alwyn wrote:hey guys, hows it going? seems like you guys had fun on saturday and sunday despite of the rain.. too bad i couldnt make it again.
congrats to rocky and matt... oh
and who got 3rd placE?

anyway, see you guys at the track on NHRCCC on sunday :) pray weather is good.


3rd Jason Marshall Team Associated RC12L4
4th Matt Whitmarsh Corally 12G3
5th Julian Morgan Corally SP12M
6th Sam Cooney Team Associated RC12L4

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Matt van der Haas
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Mon Apr 07, 2008 2:12 pm

from rcracing.co.nz

1st Matthew Van Der Haas (TQ)

2nd Rocky Ali

3rd Jason Marshall

4th Matt Whitmarsh

5th Julian Morgan

6th Sam Cooney

DNS Stephen Li


Sam did a few solid efforts to destroy his part of his chassis on the track markers :shock:

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Damon S
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Mon Apr 07, 2008 2:15 pm

I will be getting my 12th out again soon if all goes to plan.

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ed
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Mon Apr 07, 2008 2:17 pm

Matt van der Haas wrote:from rcracing.co.nz


Sam did a few solid efforts to destroy his part of his chassis on the track markers :shock:


i have a picture of the poor track marker in the collection Julie and I took.

i promise its less than 200 pictures this time.

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Matt van der Haas
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Mon Apr 07, 2008 2:27 pm

nice ed! I was surprised his car wasn't damaged more to be honest :shock:

Well pro12 is stronger than ever at NHRCCC, with a few more people in the pipeline getting 12ths, now is a good time to have some great competition Damon 8) I hope the hamilton 12th drivers come up and have a race, they said they will hopefully be able to :D :D

but ofcourse i'm going to be biased to this class, as I absolutely enjoy driving 12ths 8) :D

Alwyn
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Location: Tauranga

Mon Apr 07, 2008 5:11 pm

i need some help on my 1/12, its still running a little funny. still feel tweaked for some reason. its travelling in a straight line and takes off in a straight line too... but right turn feels different and its loose at one of the corners, while left turn is very steady. left right settings are the same.
anyone free on saturday or friday to give me a hand on my 1/12..

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Matt van der Haas
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Mon Apr 07, 2008 5:20 pm

do the coin trick (tests how even the front suspension is)

where you put a 10 cent coin on the top front tyres (slightly biased forwards) and put one of your tool drivers in the center of your chassis (from the front), then you leaver the driver up making sure it is in the middle is important, now the first coin to drop means that, that side is harder than the other side, so you either harden the other side, or soften that side until both coins drop at the same time.

It's hard to explain i might take pics and mike a mini tutorial in this thread.

ALSO check:
your tbar for any stress lines, that might need replacing.
and you have the same thickness / amount of side dampening in each side damper

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fatbear
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Mon Apr 07, 2008 6:18 pm

Damon S wrote:I will be getting my 12th out again soon if all goes to plan.


It's about time :lol: :lol: :lol:

JACO RACING
EXPRESS MOTORSPORTS
HARRIS RC
BMI RACING

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Stumpy
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Tue Apr 08, 2008 1:16 am

I got a kawada M300MSX on its way.. Can't wait to race it at NHRCCC with all the other fellow pro 12 drivers 8)
Last edited by Stumpy on Tue Apr 08, 2008 10:47 am, edited 1 time in total.

Alwyn
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Location: Tauranga

Tue Apr 08, 2008 8:59 am

hey stumpy, when will your car be ready?

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