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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 02-03-2006, 06:33 PM   #17236
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i just got a 12l4 and i wanted to know what upgradesdoes the car need to run good on asphalt? if not necessary but maybe just recommanded?
chris
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Old 02-03-2006, 06:56 PM   #17237
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Quote:
Originally Posted by crimson eagle
Tens,

Actually before I did this I thought the same way. However I did some research and the skin effect only applies to AC and not DC. Check out the link.

http://www.allaboutcircuits.com/vol_2/chpt_3/6.html

If the skin effect was in play a tube would be better than flexible cable as when the individual wires run in and out of the bundle the current will constantly want to jump to the strands on the outside.

Chris
crimson, well i'm not one to read one web article by an unknown source and jump the fence. so i did some research of my own and found many people saying what you are. i did however find a couple of things. some audio guys thinks it relevant. also it appers to be frequency driven. so i guess now i am wondering if our speed controls would have any effect on it.
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Old 02-03-2006, 09:14 PM   #17238
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Quote:
Originally Posted by Ntensweapon
crimson, well i'm not one to read one web article by an unknown source and jump the fence. so i did some research of my own and found many people saying what you are. i did however find a couple of things. some audio guys thinks it relevant. also it appers to be frequency driven. so i guess now i am wondering if our speed controls would have any effect on it.
There definitely is a frequency part of this however, what is the frequency at full throttle? This of course is the most relevant time as it will be when the most amps are drawn.

Chris
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Old 02-03-2006, 09:22 PM   #17239
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Quote:
Originally Posted by crimson eagle
There definitely is a frequency part of this however, what is the frequency at full throttle? This of course is the most relevant time as it will be when the most amps are drawn.

Chris
Actually the amperage that the fets see while on is the same at part throttle under load as it is at full thottle under load but due to the switching of the speedo the average amperage over time appears to be less on an amp meter.

EX:

At full thotttle: 30A--------------------------
At 1/2 throttle: 30A-0A-30A-0A-30A-0A-30A-0A-30A.... an amp meter would read that as 15A
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Old 02-03-2006, 09:43 PM   #17240
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Quote:
Originally Posted by AdrianM
Actually the amperage that the fets see while on is the same at part throttle under load as it is at full thottle under load but due to the switching of the speedo the average amperage over time appears to be less on an amp meter.

EX:

At full thotttle: 30A--------------------------
At 1/2 throttle: 30A-0A-30A-0A-30A-0A-30A-0A-30A.... an amp meter would read that as 15A
I see the accuracy here but not the relevance. Maybe to clarify it would be better stated this way -

During full throttle is when the highest overall amps are draw.

And to expand a little -

This is when you want the maximum volts applied to the motor. (volts = rpm = speed).

And as you pointed out, when at full throttle there is no frequency as it is at a constant current. This would therefore mean that the full cross sectional area of the conductor will be utilised.

Futhermore I think there is be a difference between AC frequency and DC switching off and on as the current does not get reveresed only interupted. So saying I think it is more than possible that even when at partial throttle there may be no "skinning" in the conductor.

Chris
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Old 02-04-2006, 12:03 AM   #17241
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Quote:
Originally Posted by chrisw
i just got a 12l4 and i wanted to know what upgradesdoes the car need to run good on asphalt? if not necessary but maybe just recommanded?
chris
No real upgrades needed. Generally lowered pod plates (IRS and CRC make some) and lowered front suspension arms (IRS) allow you to run your tires down to the rim.
Generally: keep your tires stored in sealed bags or boxes. If they dry out they don't provide much traction and wear faster on apshalt.
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Old 02-04-2006, 07:33 AM   #17242
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Crimson Eagle - the characteristic of a DC electric motor is that is draws LEAST amps at full throttle! It draws most amps at 'stall', or zero rpm. The bigget current draw is when the load is highest, not the motor speed.

What does happen is that drivers apply too much throttle, the car cannot accelerate fast enough, and the current draw shoots up. If the gearing is not good, this can be seen as drawing lots of current at full throttle, but that is only because the motor is still carrying a heavy load and running at a lower motor speed (rpm). The energy has to go somewhere, so it is turned into heat.

If you gear a 12th motor two teeth lower than normal, it comes off the race very much colder, because at full throttle it has the lowest load, and it accelerates easily - it overcomes the load easily. If you overgear, and drive no more than half throttle, the same thing happens. However, if you overgear and use full throttle, the motor does not have the power to get to full speed, it sits at a lower speed with a big load, and it gets very hot!

The wire size is about being able to get a lot of current to the motor at low motor speeds, and high load, not at full throttle. HTH
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Old 02-04-2006, 08:36 AM   #17243
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Quote:
Originally Posted by SlowerOne
Crimson Eagle - the characteristic of a DC electric motor is that is draws LEAST amps at full throttle! It draws most amps at 'stall', or zero rpm. The bigget current draw is when the load is highest, not the motor speed.

What does happen is that drivers apply too much throttle, the car cannot accelerate fast enough, and the current draw shoots up. If the gearing is not good, this can be seen as drawing lots of current at full throttle, but that is only because the motor is still carrying a heavy load and running at a lower motor speed (rpm). The energy has to go somewhere, so it is turned into heat.

If you gear a 12th motor two teeth lower than normal, it comes off the race very much colder, because at full throttle it has the lowest load, and it accelerates easily - it overcomes the load easily. If you overgear, and drive no more than half throttle, the same thing happens. However, if you overgear and use full throttle, the motor does not have the power to get to full speed, it sits at a lower speed with a big load, and it gets very hot!

The wire size is about being able to get a lot of current to the motor at low motor speeds, and high load, not at full throttle. HTH

You can hit full throttle coming out of a corner and not be at full speed. Full speed and full throttle are not the same. Yes when the motor is stalled and the throttle is on full is where Amp draw is highest, however this is irrelevant. If you want to get really picky you have the least amp draw when you are going into a corner with the throttle off and slowing down. However this is not what this is all about.

The middle two paragraphs are irrelevant and IMO the last sentence is innaccurate (it's my project after all). It's NOT about being able to supply the motor with enough amps. If this was ever a problem the wires would melt. Anyone seen this even with 16awg? I used it for a long time and had no problems with 16awg even in mod, if you exceed the wire's limits for safely delivering current it will burn up. The continuos ampacity of 16awg is around 35A, the continuous ampacity of 8awg is around 80A. Average current draw in a 12th scale is around 24 amps, if you ran any higher than that you would dump. The issue is voltage drop. Voltage drop is dependent on 3 things. The current, the distance and the conductor size. Two of those things we do not have much control over, the third (conductor size) we can do something about. Now the available voltage at the motor will determine the rpm and therefore the speed. Anyone out there measured the voltage drop on different sizes of wire?

Chris.
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Old 02-04-2006, 02:36 PM   #17244
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Has anyone out there done a heads up test of the CRC carbon t bar and the ASC. .075 t bar. Of so, When differences did you notice.
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Old 02-04-2006, 06:33 PM   #17245
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Hey guys, I just mounted up a set of purple fronts on my old scholl front end and it looks like I have about 2 deg. of camber. Is this normal for the fixed old school front end? Any tips or info would be greatly appreciated!! Thanks--Al
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Old 02-04-2006, 06:55 PM   #17246
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Quote:
Originally Posted by G Mills
Has anyone out there done a heads up test of the CRC carbon t bar and the ASC. .075 t bar. Of so, When differences did you notice.
G,

The CRC graphite t-bar is usually stiffer lengthwise than a .075" fiberglass t-bar, but has about the same amount of side flex as a .063" t-bar. The ideal conditions for running the graphite t-bar are smooth tracks where you can use lots of rear bite. Large sweeping tracks and ovals great for the graphite t-bar, as long as the track is not too bumpy.

The only down-side is graphite breaks more easily than fiberglass, so keep that in mind if you hit a lot of boards.

I have been running a graphite t-bar on my T-Fource for the last couple of weeks of club racing (at CRC raceway), and my car has been dialed.
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Old 02-04-2006, 06:58 PM   #17247
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Quote:
Originally Posted by big al
Hey guys, I just mounted up a set of purple fronts on my old scholl front end and it looks like I have about 2 deg. of camber. Is this normal for the fixed old school front end? Any tips or info would be greatly appreciated!! Thanks--Al
Yes, the Associated block front end has about 2 degrees of built-in camber. PSE used to make wedge shims to adjust the amount of camber/castor in the front end.
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Old 02-04-2006, 07:09 PM   #17248
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Does 2deg. affect the tire wear much? Seems a bit extreme.

On another note..how much toe-out (if any) is typically used on a carpet? I've heard that 12th scale cars have lots of steering by design already.--Al
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Old 02-04-2006, 07:18 PM   #17249
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Quote:
Originally Posted by big al
Does 2deg. affect the tire wear much? Seems a bit extreme.

On another note..how much toe-out (if any) is typically used on a carpet? I've heard that 12th scale cars have lots of steering by design already.--Al
Your tires will probably wear coned toward the inside with that much camber. I would rotate the front tires regularly to hopefully minimize the effect.

If you are running mod you might need to run a tiny bit of toe-out (1-2 degrees at most). If you are running stock, I would run the car with no toe-out at all, and then add as little as possible if you need more steering.
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Old 02-04-2006, 08:15 PM   #17250
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thanks G Ace!!
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