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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 08-03-2005, 06:49 PM   #13966
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Quote:
Originally Posted by yellow15
Sorry to bring back an old post, but i just read from this site (http://wcrccc.v21hosting.co.uk/setup%20theory.htm) it says:

Also, the bigger he caster angle, the bigger the camber difference induced when the wheels are steered. This camber difference is to compensate for the chassis roll and tire squirm when the car is cornering. Hence, a lot of caster will provide more steering in high-speed corners, where chassis roll is more pronounced, and whilst turning in. It will also make the car more stable in rough conditions, and the car's straight-line stabili ty will also be improved. A small caster angle will provide more steering in low-speed corners, and less turn-in.

So my understanding is, castor will give you more camber in high speed corner and help steering


So with the 10 degree blocks, the castor DECREASE at high speed corner so it should mean turn-in progressively softer not harder?

I'm confused now
Youíre close! The thing you forgot to remember is that under braking, with the 10 deg reactive caster blocks, the castor decreases when you are decelerating or applying the brakes because the front spring compresses. This reduction of cast will make the car turn more as the car slows down. Upon accelerating, the springs return to their uncompressed height and the caster increases again, making steering easier as the car accelerates.

If you look at a top fuel dragster, they have so much castor that sometimes when maneuvering in the pits, the wheels will flop over to one side or the other because there is so much caster designed into the front end. At 300 plus mph, you need all the steering you can get!

Clear as mud, huh?
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Old 08-03-2005, 07:35 PM   #13967
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ok i broke down iam getting an rc12l3. Can some one help me on a set up body, tires etc. Is there a web site that is nothing but 1/12 th scale? thanks
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Old 08-03-2005, 07:46 PM   #13968
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Quote:
Originally Posted by Crashby
Youíre close! The thing you forgot to remember is that under braking, with the 10 deg reactive caster blocks, the castor decreases when you are decelerating or applying the brakes because the front spring compresses. This reduction of cast will make the car turn more as the car slows down. Upon accelerating, the springs return to their uncompressed height and the caster increases again, making steering easier as the car accelerates.

If you look at a top fuel dragster, they have so much castor that sometimes when maneuvering in the pits, the wheels will flop over to one side or the other because there is so much caster designed into the front end. At 300 plus mph, you need all the steering you can get!

Clear as mud, huh?
Those are actually "rudders" on 300 mph dragsters.

Make up your mind! Is it caster or castor??? I say caster...he, he...

j/k
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Old 08-03-2005, 07:55 PM   #13969
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Quote:
Originally Posted by Crashby
Youíre close! The thing you forgot to remember is that under braking, with the 10 deg reactive caster blocks, the castor decreases when you are decelerating or applying the brakes because the front spring compresses. This reduction of cast will make the car turn more as the car slows down. Upon accelerating, the springs return to their uncompressed height and the caster increases again, making steering easier as the car accelerates.
Thanks, so which block will give you a better lap time, on a large outdoor track and on a small carpet track respectively? Or it doesn't really matter as long as and it's more like a personal perference thing?
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Old 08-03-2005, 08:26 PM   #13970
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Hi all, I have got an issue with my RC12L4.

I was rebuilding the car recently, trying to make everything as smooth as possible to increase the efficiency thus increase the run time.

I am a bit puzzled with the rear axle of the RC12L4. It just doesn't seem to rotate freely.. felt gritty. I have cleaned up the 2 axle flanged bearings very well and they are in very good condition, and i haven't really assemble anything else on the axle, the axle just doesn't spin very freely when put through the 2 height adjusters.

Any clues what might caused this? Uneven bulkhead heights? uneven bearing holder heights? or maybe a bent axle?

Thanks for looking, all help appreciated.
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Old 08-03-2005, 08:35 PM   #13971
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make shure you have the same number adjusters in. Then sand the edges of the adusters until the go in and out with little force. If nether of these is the issue then just replace the bearings.
Just my 2 cents
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Old 08-03-2005, 08:37 PM   #13972
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Quote:
Originally Posted by yellow15
Thanks, so which block will give you a better lap time, on a large outdoor track and on a small carpet track respectively? Or it doesn't really matter as long as and it's more like a personal perference thing?
I want to answer this in a somewhat roundabout way...maybe somewhat over simplified but these three areas seem to be key to your question.

mod motors require stability = 10 degree blocks
stock motor require less stability = 0 degree blocks
Those that go back and forth in classes = 5 degree blocks (compromise)

long tracks require stability = 10 degree blocks
short tracks require quicker initial steering = 0 degree blocks
medium tracks are in between = 5 degree blocks (compromise)

new 1/12th scale drivers = 10 degree blocks (slows initial steering)
intermediate drivers = 5 degree blocks
advanced drivers = anything they want

Pick your needs and divide by 3 for general range of caster degrees...Sorry, can't help the advanced boys.
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Old 08-03-2005, 08:51 PM   #13973
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Quote:
Originally Posted by JRX-S Bill
Those are actually "rudders" on 300 mph dragsters.

Make up your mind! Is it caster or castor??? I say caster...he, he...

j/k
Who need spell check when we have Bill!!!
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Old 08-03-2005, 08:54 PM   #13974
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Quote:
Originally Posted by DORIFT
Hi all, I have got an issue with my RC12L4.

I was rebuilding the car recently, trying to make everything as smooth as possible to increase the efficiency thus increase the run time.

I am a bit puzzled with the rear axle of the RC12L4. It just doesn't seem to rotate freely.. felt gritty. I have cleaned up the 2 axle flanged bearings very well and they are in very good condition, and i haven't really assemble anything else on the axle, the axle just doesn't spin very freely when put through the 2 height adjusters.

Any clues what might caused this? Uneven bulkhead heights? uneven bearing holder heights? or maybe a bent axle?

Thanks for looking, all help appreciated.
If you are using new height adjusters or even old ones for that matter that might be the issue. They are at times really tight on the bearing and will bind when inserted into the bulkheads, so some hand fitting might be needed. IRS make some really nice adjusters that fit quite well and help the axle spin more true. Or your bearings might just need to be replaced. The life of the axle bearings can be short at times if you have a bad wreck or something like that. Also you might have bent the bulkheads in a wreck or something as well. If you bent your axle you would see one end wobble....I have never seen one bend in the middle but it could happen I guess. What you can do is take the bearings out of the holders and put them on the axle and spin the axle while holding on to the bearings and see how they spin. If they feel gritty there then itís your bearings, if not try it with the adjusters on the bearings and so on so you can eliminate one thing at a time. I would guess that itís the bearings that are making it feel gritty.
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Old 08-03-2005, 08:54 PM   #13975
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Quote:
Originally Posted by JRX-S Bill
I want to answer this in a somewhat roundabout way...maybe somewhat over simplified but these three areas seem to be key to your question.

mod motors require stability = 10 degree blocks
stock motor require less stability = 0 degree blocks
Those that go back and forth in classes = 5 degree blocks (compromise)

long tracks require stability = 10 degree blocks
short tracks require quicker initial steering = 0 degree blocks
medium tracks are in between = 5 degree blocks (compromise)

new 1/12th scale drivers = 10 degree blocks (slows initial steering)
intermediate drivers = 5 degree blocks
advanced drivers = anything they want

Pick your needs and divide by 3 for general range of caster degrees...Sorry, can't help the advanced boys.
I may be wrong but for me the 10* blocks were the more agressive on turn in due to the greater caster change. I have since gone to 5's and arrived at a good balance. On the wifes L3, she begged for the car to be more old school, so her wish was granted, that car has the old front end with no reactivity at all, and is nice to drive, just does not have that agressive off throttle turn in. A very safe and easy car to drive.

PK
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Old 08-03-2005, 08:56 PM   #13976
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Quote:
Originally Posted by yellow15
Thanks, so which block will give you a better lap time, on a large outdoor track and on a small carpet track respectively? Or it doesn't really matter as long as and it's more like a personal perference thing?
It all has to deal with the way your car is handling. On large outdoor tracks, I will increase my caster as there tends to be less grip. On indoor carpet tracks, I run less caster to get enough steering to equalize the amount of rear traction.

A car that under steers is a safe car to drive. That's why Detroit designs all of their cars with under steer. Keeps the regular folks safe.
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Old 08-03-2005, 08:58 PM   #13977
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Quote:
Originally Posted by Crashby
Who need spell check when we have Bill!!!
What? I only charge $75 an hour for that!

I noticed that people in the UK tend to use the word castor and us'ins use caster. It may be legit; but, you used both in the same post...
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Old 08-03-2005, 09:02 PM   #13978
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Quote:
Originally Posted by Crashby
A car that under steers is a safe car to drive. That's why Detroit designs all of their cars with under steer. Keeps the regular folks safe.
Those suspension design boys in Detroit maybe drove an Austin Healey once and got scared by the "spinout king".

Hope I spelled AH right!
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Old 08-03-2005, 09:06 PM   #13979
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Quote:
Originally Posted by PMK
I may be wrong but for me the 10* blocks were the more agressive on turn in due to the greater caster change. I have since gone to 5's and arrived at a good balance. On the wifes L3, she begged for the car to be more old school, so her wish was granted, that car has the old front end with no reactivity at all, and is nice to drive, just does not have that agressive off throttle turn in. A very safe and easy car to drive.

PK
You are absolutely correct, PMK!

The reactive caster blocks only come into play when the suspension moves up and down. If you have the 0 degree blocks on the car and you move the suspension up and down... no caster change. 5 degree blocks equal about 2.5 degrees of caster change when the suspension is totally bottomed out. 10 degree castor blocks equal about 5 degrees of caster change when the suspension is bottomed out. The reactive caster suspension was created to give more turn in going into corners.
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Old 08-03-2005, 09:14 PM   #13980
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Are you guyís real rc racers, or did you just stay at a Holiday Inn.
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