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This is a place to share knowledge related to 1/12th scale racing. It is not to be used for conversations.

KITS:
Click links to go to manufacturer product page. If any are missing please add them!

TIRES:
Pre-mounted tires readily available in the US:
Pre-mounted tires readily available in the Europe:
  • Hot Race ??

Gluing your own donuts:
https://www.youtube.com/watch?v=hm7z1rz-74s - Special thanks to Edward Pickering!
Truing tires:
https://www.youtube.com/watch?v=8wqHOLWq6Uc - Special thanks to Edward Pickering!

The following information came from HERE, with some editing and information added. Thanks Christian!

THIS MAY NEED UPDATING FOR THE NEW BLACK CRC CARPET

Brands:
BSR, CRC, Jaco:
Pro One is no longer selling to the public, but it and the brands above are all mounted by BSR and use the same foam. The nomenclature of the BSR vs Jaco/CRC is a little different in a few instances but is otherwise the same. The BSR foam consists of three families, and can be identifed as synthetics, naturals, and blends.

Synthetics - The old school, light weight, easy to true "dry feeling" tires. These include tires like CRC/Jaco Yellow (BSR White), Black, Gray, etc. These tires offer the highest wear rate and lowest grip. Many racers continue to use these nder high bite conditions.

Naturals - These tires are usually the best alternative for low bite and asphalt. They include Pink, Magenta, Double Pink, Lilac (BSR Team Purple), Purple, and other tires. These tires provide a ton of grip, but tend to get sticky in high bite conditions. This rubber does not wear as easily, and the cars will pick up gunk and fibers from the carpet under most high bite conditions. This is especially bad if the humidity is high.

Blends - These are the tires most people run today. They were initially called "JFT foam" by some, as it was believed that the tires were the same as the JFT tires. We can divide the blends further into two groups: high rubber and low rubber content. The high rubber would be the new rear Orange and Red from the BSR family, and the low rubber would be the Green and Blue varieties. When, asked about the difference, John Foister from BSR Tires said they came from the same "family" of foam, but they offered different grip. According to John, the Green/Blue has more bite than Orange/Red, but from track testing Oranges offer more bite than Green (being equivalent to in hardness) when the grip is high and absolutely no grip when it is lower. The Orange foam has a denser pore structure and the tire is not as prone to chunking. It is also important to note is that BSR Blue rears are not the same as the BSR Blue fronts!

JFT:
JFT stands for Japan Foam Tire. They started the new wave of foam tires we are all using now (Blue/Blu, Green/Greene, Dbl Blue, etc). These tires are a little different than the BSR tire family, but work in very similar conditions. They offers four varieties A (asphalt), C (carpet), S (???), and R (???). This does not mean that those types only work on that surface, but this is what they recommend.

JFT uses the same foam for fronts and rears if the color is the same.

A: Used on asphalt, considered close to the natural rubber variety and are named consistently with other natural tires.
C: Used on carpet, considered a blend.
S: Used on carpet?, tires are ???
R: Used on carpet?, tires are ???

For setup, the JFT foam seem to generate more bite than the BSR, therefore the car tends to be a little more aggressive.

Ulti:
Ulti is another Japanese brand that offers an array of compounds. They have their own way of rating tires, and are difficult to equate to other brands. They have 4 different varieties, each in varying degrees of hardness.

J: High rubber content tire, similar to Pink/ Magenta. Soft would be close to a pink. These offer the most bite and are great for asphalt/carpet front tire. (J hard being very popular)
X: "Balanced" blend, similar to JFT Blue/ Green. Soft is equivalent to Green, medium to Blue in hardness. Great for carpet!
Y: High synthetic blend with lower grip, and is not a very popular variety.
Z: A very expensive "special" foam that is supposed to be magic on asphalt. Only make it in soft shore.
European tires:
There are many great European foam tire brands that use their own types of foam, as well as traditional foams. SOmeone with more knowledge about them will need to fill this in!

Tire Diameter:
If you are racing on carpet, you have to evaluate how much grip your track has. If your track is low to medium grip, you can run bigger tires. If you are on higher bite you have to cut them smaller, there is simply no way around it. Bigger tires are needed for asphalt, especially in the rear. The larger tires provide much needed lateral bite.

Carpet (mm):
Low - Medium Bite
Front: 42.0 - 42.5
Rear: 42.5 - 43.00
Medium - High Bite
Front: 40.5 - 41.0
Rear: 41.5 - 42.0
Big Race
Front: 39.5 - 40.0
Rear: 40.5 - 41.0
Asphalt (mm):
Parking Lot
Front: 43.0 - 44.0
Rear: 44.0 - 45.0
Prepped High Bite
Front: 42.0 - 43.0
Rear: 43.0 - 44.0

Tire Saucing:
Most facilities have moved towards odorless traction additives such as SXT. Some of additives evaporate very quickly and some do not. This seems to be something that is also dependent on tire compound and ambient temperature. For example, saucing a Green compound seems like it never dries, especially when tjhe temperature is lower. We have found that wiping the tires off 15 minutes before we go run allows the sauce to cure, which makes the car come in much quicker with Green rears. Blue compounds on the other hand, do fine when wiped off right before hitting the track.

Saucing half front and full rear is a good initial starting point. If the front of the car is too agressive you can sauce les than half, or for a shorter amount of time.
Tire Fuzzing:
In conditions of increasing grip, foam tires will somewtimes get sticky and pick up fuzz and debris from the track. This is highly dependent on the rubber sedan tire that is being run at your local track and the compound/ type of foam you are running on you car. The softer the sedan tire and the harder/higher rubber content in your foam tire, trouble with fuzzing seems more likely to occur.

There are ways to get around fuzzing under most conditions, and usually involves the selection of the correct foam compound. The more fuzz you get, the softer/lower rubber content you want to run.

Examples:
Problem: Car fuzzes with Lilac/Team Purple fronts and car starts pushing.
Solution: Use a softer front tire and or different family of foam. Replace it with Blue or Double Blue front.

Problem: Car loses rear bite 6 minutes into the run. Blue rear tires look almost clean but have small carpet hairs.
Solution: Use Green rear tires. The softer compound wears instead of getting sticky, minimizing fuzz.

Tire Selection:
Starting out, pick 2 tire compounds for the front and rear. The following should have you covered 99% of the time.

Front - Green and Blue (BSR) or Green and Light Blue (JFT)
Rear - Blue and Double Blue (BSR) or Blue and Dark Blue (JFT)

You may wonder about other compounds out there and if they might be better, trust me, they probably won't be. Even if there are other tires that can be as fast, the synthetic family wears out really fast and the high natural rubber will probably fuzz on you over an 8 minute run. The blends family seems to be the most versatile foam type available today. They last awhile, and sticking to them will make your process of tire selection simpler.
Tire Charts:
BSR/CRC/Jaco



Contact



Corally



JFT (Japan Foam Tire)



Ulti



Enneti (Xceed)



ELECTRONICS:
ESC:
As of now, ROAR is staying 1S (3.7V nominal; 4.2V fully charged) for 1/12. There are many 1S ESC's with a built in BEC so nothing else is required to power the receiver and servo.

If you don't want to lock yourself into a 1S specific ESC, you do have other options! It is possible to use your 2S ESC without a booster or receiver pack, and the ESC simply supplies the lower voltage. If that does not appeal to you, you will need to use an Rx pack or booster. The Rx pack and booster will both supply the receiver with a higher voltage than the 1S pack.

If you decide to use an Rx pack, MAKE SURE TO REMOVE THE RED WIRE FROM THE ESC PLUG THAT GOES INTO THE RECEIVER!!!

If you choose to use a voltage booster, it works exactly how it sounds. Instead of plugging the ESC into the receiver, it plugs into the booster, and the booster plug goes to the ESC, supplying the higher voltage.

1S ESC:
If there are any missing please add them!!

If anyone would like a need for a chart comparing the ESC's specs PM fenton06 and I'll get one made and put in here!
Voltage Boosters:
If there are any missing please add them!
Servos:
BODIES:
Black Art (CRC - US Dist):
  • Audi R8C - BA002 - .020 Thick



  • Black Market (Mohawk 12) - BA005 - .020



  • Lola B10 - BA006 - .020 thick
  • Toyota TS030 - BA008 - .020 thick

    Lola - black/red, TS030 - green/pink


PROTOForm:

Reflex Racing/RSD:

SUSPENSION ADJUSTMENTS:

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Old 06-06-2005, 07:47 PM   #13231
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Quote:
Originally Posted by yellow15
hi all,
built my RC12L4 about 2 weeks ago and had a few runs so far. This is my first 1:12 pan car and i'm running a 8T motor (will soon be getting a 10 double) outdoor. Using Jaco purple front and Pink rear.
I noticed the car is VERY sensitive to the steering compare to my touring car, just a little bit steering and the car will response instantly.. I've already tuned the steering exp on my radio down quite a bit (-40% i think) but it's still a bit too sensitive to me.. i just wonder what can i do to make it a bit more "stable" , maybe getting a thicker/thinner T-bar? or should i get a thinner one? i know nothing about setting up 1:12 car so any help would be great.

also, i remember seeing someone mention some of the bearings will worn out quickly but i can't find that post again? so which one is it?
If you are running on carpet, you would usually want a thicker T-Bar, asphault you would want a thinner one. 12th scale's are vary different then touring cars and are supposed to be able to turn fast.
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Old 06-06-2005, 08:03 PM   #13232
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Quote:
Originally Posted by yellow15
hi all,
also, i remember seeing someone mention some of the bearings will worn out quickly but i can't find that post again? so which one is it?
It is the outer flanged bearing in the right side hub that is the problem. Car takes a hit to that side and the bearing is kaput!

Absolute best way to deal with this is to buy a Slapmaster assembly which replaces the cone and Belleville washer assembly which rest on this bearing. Since getting the Slapmaster (in both of my 12L4s), I haven't touched that outer bearing and my diff action is absolutely perfect! Cost is $30.

Bill
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Old 06-06-2005, 08:43 PM   #13233
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Quote:
Originally Posted by yellow15
hi all,
built my RC12L4 about 2 weeks ago and had a few runs so far. This is my first 1:12 pan car and i'm running a 8T motor (will soon be getting a 10 double) outdoor. Using Jaco purple front and Pink rear.
I noticed the car is VERY sensitive to the steering compare to my touring car, just a little bit steering and the car will response instantly.. I've already tuned the steering exp on my radio down quite a bit (-40% i think) but it's still a bit too sensitive to me.. i just wonder what can i do to make it a bit more "stable" , maybe getting a thicker/thinner T-bar? or should i get a thinner one? i know nothing about setting up 1:12 car so any help would be great.

also, i remember seeing someone mention some of the bearings will worn out quickly but i can't find that post again? so which one is it?
i run purple fronts/pink or grey rears on asphalt or carpet

try setting the:
-front camber to -1.5
-toe in to -.5 or -1
-don't sauce the fronts at all
-go stiffer on the front spring .20 or .22 all play shimmed out.
-the AE front end has the option of going with 0deg, 5deg, 10deg, upper suspension mounts. i run 0degs because they are the least aggressive when it comes to the steering. if your running 10 go down to 5 and try it first.
-pack mounting on the 12L4 make sure the tray inserts are set so the cells sit in their aft most position.
-you may have to go down farther on the EXPO on your controller, i helped a racer awhile back with a YRX12 and for his driving style he ended up at -65% with a Airtronics M8...can't remember the servo, but it was too fast for him.

also on asphalt a 8-10T motor may be a little too much if your track isn't prepped such as blown off and sugar watered or VHT'd prior to each race, are you sure your car isn't breaking rear traction and actually steering from the rear? sometimes referred to as hooking.

Last edited by fast-ho-cars; 06-06-2005 at 08:54 PM.
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Old 06-06-2005, 09:40 PM   #13234
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RobS: Thanks, yeah it is very very different to TC so it'll take me a while to adopt to it but i like it a lot so far!!

Bill: you talking about the front right hub? or rear right hub? or both? why is it just the right hub but not the left? and where can i find that Slapmaster assembly you are talking about?? i need to find a online shop that ship international

fast-ho-cars: Thanks i'll try your setting. I'm using a KO 949 servo so yeah it probably isn't helping me at this stage
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Old 06-06-2005, 09:53 PM   #13235
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yep killer servo for the 12th. maybe aking the expo down more is the fastest cure to your problem
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Old 06-06-2005, 10:13 PM   #13236
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fast-ho-cars: yeah will do that, so in summary, is this what i need to make the car a bit easier to drive?

Harder front (springs)
Softer Rear (T-bar)
Shift the weight towards the rear of the car
Less front caster.


But i thought less caster will make the steering more responsive?
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Old 06-06-2005, 10:19 PM   #13237
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You started out in 12th scale with an 8t. I'd say drop a stock motor in for a while, the car will be much easier to drive and will still be fast. Once you get used to 12th, then drop in some power.
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Old 06-06-2005, 10:20 PM   #13238
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Quote:
Originally Posted by yellow15
RobS: Thanks, yeah it is very very different to TC so it'll take me a while to adopt to it but i like it a lot so far!!

Bill: you talking about the front right hub? or rear right hub? or both? why is it just the right hub but not the left? and where can i find that Slapmaster assembly you are talking about?? i need to find a online shop that ship international

fast-ho-cars: Thanks i'll try your setting. I'm using a KO 949 servo so yeah it probably isn't helping me at this stage
Bill is talking about the thrust bearing in the right rear hub. It takes a beating because that type of bearing is not intended to be used as a thrust. The Slapmaster unit is a true thrust bearing and will hold up better.
I don't use the Slapmaster thrust bearing because it does not make your diff better; it just makes the bearing last longer, but adds weight. And you can make the same thing for a few bucks with off the shelf parts, if that's what you really want. For me, I just replace the bearing every 3 or 4 races.

Rather than turning up the exponential on your steering, try slowing down the servo speed. This will keep the steering linear (which is good) but will make the car less "darty". I use 949's on my cars too, but slowing the servo mellows the car's handling considerably. I set the steering speed on my Futaba 3PJ to 60%, I think you can do this adjustment on most top end radios also (KO and Sanwa guys correct me if i'm wrong).

Welcome to 1/12th scale- once you get dialed you'll never go back to those lumbering 4 wheel drive cars again!
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Old 06-06-2005, 10:30 PM   #13239
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Quote:
Originally Posted by yellow15
fast-ho-cars: yeah will do that, so in summary, is this what i need to make the car a bit easier to drive?

Harder front (springs)
Softer Rear (T-bar)
Shift the weight towards the rear of the car
Less front caster.


But i thought less caster will make the steering more responsive?
this should clear it up more

the AE front end has more reactive caster change with the 10deg block than the 0 or 5's do. 0deg blocks with 2 shims with 2 shims to the rear (4deg of caster) of the will make it more consistent. 10deg blocks with the same shimming has 4-6deg of caster, up to 2deg shift depending on front springs ran and suspension movement. the 5deg blocks will put you somewhere in between

i run my Odeg blocks with 4deg of caster

softer t-bar will help in the rear traction department and roll/weight transfer. it may add more traction which may make the car push a little more. i have been running a .70 Doug Powell t-bar on my car on asphalt with a stock motor which is in between what AE offers

Last edited by fast-ho-cars; 06-06-2005 at 10:46 PM.
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Old 06-06-2005, 10:46 PM   #13240
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Thanks for the reply fast-ho-cars and odpurple. Btw, i can't find any shop selling the Slapmaster bearing?? i went to Towerhobbies and KT and a few other usual RC website but none of them is selling it.. and i did a google search and nothing came up as well?


fatdoggy: haa yeah call me crazy. but the real reason is... our local club only has one 1/12 class and it's open motor.. so everyone is using 9-10T motors. so i'm going to get a 10T double very soon once i got some spare $$$$ but in the main time, i'll be practising with the 8T and i'll be very gentle with the throttle
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Old 06-06-2005, 10:51 PM   #13241
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i just added/edited more info on the caster in the previous post.


Slapmaster Thrust bearing...email blbodine@comcast.net
www.slapmastertools.com


on the motor, our track allowed any motor, but since it was only blown off, it was found that stock motors were the faster way to go. wasn't enough traction for anything 19T or lower

Last edited by fast-ho-cars; 06-06-2005 at 11:16 PM.
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Old 06-06-2005, 11:16 PM   #13242
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Quote:
Originally Posted by odpurple
I don't use the Slapmaster thrust bearing because it does not make your diff better; it just makes the bearing last longer, but adds weight. And you can make the same thing for a few bucks with off the shelf parts, if that's what you really want.
od,

Gotta disagree with your first point...With the Slapmaster, the diffs on my two 12L4s are smoother than I had achieved otherwise...Even with all ceramic bearings.

Your second point is correct about the outer ball bearing lasting longer...Haven't changed my bearing after a dozen runs. Adjusting diff is almost unnecessary.

I agree that the weight is marginally increased by one additional ball bearing. Otherwise, the Slapmaster replaces the diff thrust cone and belleville washer of the stock AE setup.

Crimson Eagle's similar unit seemed to involve a lot of precision machining by him. How does one make it with off the shelf parts?

Your experience is appreciated.

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Old 06-06-2005, 11:21 PM   #13243
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yellow15,

One of the reasons that 12th scale cars are so responsive is that they are light and the main mass (batteries) are close together. Try moving the batteries away from the t-bar. It may seem stupid, but I've done it with my L4. Move the batteries flush with the sides of the chassis. They will no longer sit flat in the battery tray and much be taped in very tightly as they no longer held in the tray. This increases the polar moment of the car, making the car less sensitive to steering inputs and a lot easier to drive.

Since I did that experiment with the L4 (I won the race that day) I have converted the L4 to a Yokomo YRX-12. The Yokomo chassis has the batteries as far away from the t-bar as any car and the wheelbase is longer than the L4 so it is much easier to drive. All you need to convert to a YRX-12 is the chassis and rear brace.
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Old 06-06-2005, 11:39 PM   #13244
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Quote:
Originally Posted by jrrc
yellow15,

One of the reasons that 12th scale cars are so responsive is that they are light and the main mass (batteries) are close together. Try moving the batteries away from the t-bar. It may seem stupid, but I've done it with my L4. Move the batteries flush with the sides of the chassis. They will no longer sit flat in the battery tray and much be taped in very tightly as they no longer held in the tray. This increases the polar moment of the car, making the car less sensitive to steering inputs and a lot easier to drive.

Since I did that experiment with the L4 (I won the race that day) I have converted the L4 to a Yokomo YRX-12. The Yokomo chassis has the batteries as far away from the t-bar as any car and the wheelbase is longer than the L4 so it is much easier to drive. All you need to convert to a YRX-12 is the chassis and rear brace.
Jim,

Interesting! And you were fast, fast, fast with your batteries setting like that!

Do you think that this will apply to carpet racing as well?

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Old 06-06-2005, 11:41 PM   #13245
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Quote:
Originally Posted by fast-ho-cars
this should clear it up more

the AE front end has more reactive caster change with the 10deg block than the 0 or 5's do. 0deg blocks with 2 shims with 2 shims to the rear (4deg of caster) of the will make it more consistent. 10deg blocks with the same shimming has 4-6deg of caster, up to 2deg shift depending on front springs ran and suspension movement. the 5deg blocks will put you somewhere in between
i run my Odeg blocks with 4deg of caster
hm.. what is the difference between REACTIVE caster and normal caster?
how come 0 deg block + 2 shims = 4 while 10 degree block + 2 shims = 4-6 degree??


jrrc: thanks for your suggestion, i may give it a try as well
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