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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 03-23-2006, 10:26 PM   #17836
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Two other things to note in the pics of Frank's new Carpet Knife. There isn't a cap on the GTX and the shock is mouted upside down from what I would consider the normal position. I thought a cap should always be used on a GTX but maybe it's different with 4 cells. Sure would be nice not having to fit that cap somewhere. I wonder what the benfit is of mounting the shock that way.
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Old 03-24-2006, 10:06 AM   #17837
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B&B: There is nothing weak on the new CRC Knife prototype. I have looked at Tom Firsching's prototype car extensively, and it is built like a tank. If you notice, the car uses 4 standoff posts in the rear to support the rear tweak plate and damper tubes, so it is much stronger than a design that uses 2 standoffs. The 1-piece side links are also far stronger than the 3-piece type.

As far as a release date, there have been several different prototypes of the car kicking around the CRC "skunkworks" since the end of last summer. I would not expect Frank to release a new product until he is 100% satisfied that the new product has all the adjustability and user-friendliness that he demands, and that the new car has a performance advantage over the old car.

Rick: Mounting the shock upside down ensures the piston is always sitting as deep in the oil as possible. If the shock were to leak or there was an air bubble inside, it would be at the opposite end of the shock body as the piston. This is probably the same reason all off-road vehicles mount their shocks with the shock shafts pointing downward.

Not sure about the capacitor.

Last edited by G Ace; 03-24-2006 at 10:26 AM.
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Old 03-24-2006, 11:02 AM   #17838
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Wouldn't an air bubble in a shock travel to the highest point in the shock body?
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Old 03-24-2006, 11:14 AM   #17839
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Quote:
Originally Posted by odpurple
Wouldn't an air bubble in a shock travel to the highest point in the shock body?
exactly, which is why we mount our shocks "upside down" now. so the piston is not at the highest point where the bubble is. instead, it's at the lowest point of the body.
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Old 03-24-2006, 11:20 AM   #17840
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"probably the same reason all off-road vehicles mount their shocks with the shock shafts pointing downward."

has to do more with a Sprung/Unsprung weight issue and the adverse affects on handling it would cause by having the a-arms bear the weight of shocks and do dampening. now i have seen guys mounting shocks backwards on offroad cars converted to run oval...lowers CG is the reason they give.
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Old 03-24-2006, 11:23 AM   #17841
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Quote:
Originally Posted by johnnywhopper
exactly, which is why we mount our shocks "upside down" now. so the piston is not at the highest point where the bubble is. instead, it's at the lowest point of the body.
Sorry, you've lost me. If the shock is upside down then the bubble would be in the oil chamber of the shock, and would rise to what would be the "bottom" of the shock normally. If the shock is right side up the bubble is still in the oil chamber but would rise to the end with the seals.

Oh this is so confusing! Will "upside down" become "rightside up"?
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Old 03-24-2006, 11:24 AM   #17842
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G Ace: I was looking at the number of holes in the chassis and the closeness to the edges and each other. Less material equals less strength, increases the chances of breakage. The tweak plates each use 2 standoffs. Frank has modified battery o-ring posts on this car.



I agree on the shock piston in the oil but have to add to this that this installation adds unsprung weight to the rear suspension.



The Capacitor on the ESC acts as a buffer to help keep the supply battery voltage up above the BEC voltage under short high amp loads. In the stock classes where the motors do not draw the high amps like the low turn modifieds, a cap is not needed. The cap is easier to install and use than a receiver battery pack.
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Old 03-24-2006, 11:25 AM   #17843
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Quote:
Originally Posted by odpurple
Sorry, you've lost me. If the shock is upside down then the bubble would be in the oil chamber of the shock, and would rise to what would be the "bottom" of the shock normally. If the shock is right side up the bubble is still in the oil chamber but would rise to the end with the seals.

Oh this is so confusing! Will "upside down" become "rightside up"?

My head hurts....

-James
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Old 03-24-2006, 11:27 AM   #17844
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That car is pretty similar to the one I made to upgrade the Carpet Knife. I put the tweak holes in too, and extended the rear pod like the 12l4.
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Old 03-24-2006, 12:56 PM   #17845
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Thanks for the info guys. As mentioned, from my offroad racing I was concerned with the sprung vs. unsprung weight of moving the whole shock body vs. just the piston. Probably with the size of a 12th scale shock it's not as much of a concern.

Bear with me here. The oil chamber is the same size and the movement of the piston is the same regardless of which way the shock is mounted. So if there were an air bubble at the top of the chamber, my thought would be the piston would hit it regardless of which end was which. Considering the shock is more laid down than upright, the bubble would be more on the edge and not near the shock shaft. Maybe it has to do with the relative starting position of the piston. Iím not questioning anyone's information, just trying to understand what's happening as I'm looking at my car. I'd be curious to know if during the movement of the pod during a race, whether the piston is more at the bottom or the top of the oil chamber.

I guess the secret is to build my shocks without any air bubbles so I don't have to worry about it.

My head hurts....
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Old 03-24-2006, 01:27 PM   #17846
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Default brushless setups!

I am starrting to see alot of brushless setups in the 1/12th world but i dont know what the big deal is?Whats the diffrence between brush and brushless? does brushless give you an advantage?
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Old 03-24-2006, 01:48 PM   #17847
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Quote:
Originally Posted by JamesArluck
My head hurts....

-James
Mine too. I'm going to mount my shock sideways.
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Old 03-24-2006, 01:58 PM   #17848
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Do you need the cap with the GTX when running 4 cell stock?
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Old 03-24-2006, 02:10 PM   #17849
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Quote:
Originally Posted by T1bobo
I am starrting to see alot of brushless setups in the 1/12th world but i dont know what the big deal is?Whats the diffrence between brush and brushless? does brushless give you an advantage?
With brushed motors you have to remove the motor, cut the commutator and install new brushed every run to keep it fast (At least around here you do ).

With brushless you instal your motor and you forget about it. Every few months you take it out clean the bearings, oil them and put the motor back in. Brushess motors are about 10-20% more efficient than Brushed motors. This means run time is a lot less of an issue. The Mod 1/12th brushless guys are running full punch for 8 min with no worries about run time at all.

Brushless costs about $100-150 more than brushed systems but thats about 6 months of motor brushes if you race a lot.
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Old 03-24-2006, 04:58 PM   #17850
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I'll give the shock explanation a try.....

The shock on these cars is run very close to max extension at all times. Or "topped out". This is the key point......

If you run the body of the shock attached to the pod ("upside down"), the oil reservoir is the highest point. The shock piston is nearer to the lower end of the shock. Air bubbles will rise to the highest point. Which is the opposite end of the piston. So the piston will always be in oil.

If the shock is "right side up", and there is air in the shock, the piston will be in the air bubble, and move very freely for the first bit until the piston hits oil.

I'd rather have consistent shock action over lowering the unsprung weight a gram or two...but that's just me. Well, I'm lazy also, and can go a few more weeks without rebuilding the shock this way.......

Just last weekend a very experienced oval racer asked me why my shock was "upside down".......I told him about the air bubble, and he just looked at me like a deer in the headlights.......
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