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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 10-26-2005, 12:33 PM   #15181
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Quote:
Originally Posted by Crashby
I think the YRX-12WE (silver chassis) is the best asphalt 12th car available!! This is the car that OD, JRRC and I run at all the asphalt races. The reason it works so well on asphalt is that the batteries are placed out from the centerline of the car further than any other 1/12th car. By moving the weight out away from the centerline of the car, you get better traction on surfaces with less grip due to better weight transfer to the wheels on the outside when cornering. On carpet, which has much higher grip that asphalt, you want to move the weight closer to the centerline of the car. Yokomo does make a black chassis for the YRX-12, which has the batteries in closer to the centerline of the car. I will check my inventory when I get home and see if I have one still in the package with a part number
Awesome....and like you said, I might need that chassis.....cause there will be NO outdoor 12 scale here, especially with SNOW coming...LOL
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Old 10-26-2005, 02:09 PM   #15182
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Quote:
Originally Posted by rayhuang
CHassis and battery trays.
awesome thanks
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Old 10-26-2005, 03:00 PM   #15183
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Quote:
Originally Posted by Rookie Solara
Awesome....and like you said, I might need that chassis.....cause there will be NO outdoor 12 scale here, especially with SNOW coming...LOL
What I would do with that YRX-12 WE that you just bought from Mr. Shookie, would be to put a 12LR chassis, lower motor pod plate and rear chassis cross brace under it. Yokomo does not make a thick chassis. While the black Yokomo chassis does move the batteries in, it is still a thin chassis, which does not lend itself well for carpet racing. In the winter for racing on carpet, just throw the 12L4 chassis pieces under the Yokomo. In the summer, when you go outdoors, put the YRX-12WE chassis pieces under the rest of the Yokomo kit and you will have the best of both worlds!
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Old 10-26-2005, 03:41 PM   #15184
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Quote:
Originally Posted by Crashby
What I would do with that YRX-12 WE that you just bought from Mr. Shookie, would be to put a 12LR chassis, lower motor pod plate and rear chassis cross brace under it. Yokomo does not make a thick chassis. While the black Yokomo chassis does move the batteries in, it is still a thin chassis, which does not lend itself well for carpet racing. In the winter for racing on carpet, just throw the 12L4 chassis pieces under the Yokomo. In the summer, when you go outdoors, put the YRX-12WE chassis pieces under the rest of the Yokomo kit and you will have the best of both worlds!
Very much like everyone just told me........but it is hard to find 12L4 chassis (not even Tower has it).....
About Lower motor POD plate....exactly, what is that..? The whole lowering pod like those from IRS...?
And the Rear chassis cross brace......what exactly is that...?
There are several carbon fiber on a little car like that, and I am kinda lost track whcih one is called which....

If I am using this one for carpet........can I just use the 12L4 chassis..? Or I have to get the rest items to match the chassis...?

It almost sounds like it is cheaper to buy a used 12L4 afterall...thanks for your info....
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Old 10-26-2005, 04:06 PM   #15185
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Quote:
Originally Posted by Rookie Solara
Kevin....once I am ready to be back at IRP, I will constantly bothering you about almost everything of 12th scale...just like last year with the pro 4.
(p.s....I might need idea about foam TC....right now, I have no cars and don't know what to get...)
No problem "Bunchbob"... Any of the new cars out there are good....
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Old 10-26-2005, 04:13 PM   #15186
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Quote:
Originally Posted by Rookie Solara
Very much like everyone just told me........but it is hard to find 12L4 chassis (not even Tower has it).....
Towerhobbies has it. Do a search "RC12L4". They have HEAPS of L4 parts as well.

But their search engine is really crappy. You really need to see your luck if you want to find something. The best is to enter the item# directly than 90% of the time you can find it.
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Old 10-26-2005, 04:18 PM   #15187
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I'm looking at getting a 2nd 1:12 for indoor carpet race only.

I'm driving a L4 at the moment and i want to try something different and i have my eyes on the CRC cars. Which CRC car do you guys recommend? I'll be racing mod and this car will be for indoor carpet only.

Our indoor track has quite low traction (probably lower than the our medium traction outdoor asphalt track) and no traction compound of any sort is allowed at all.
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Old 10-26-2005, 04:34 PM   #15188
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Quote:
Originally Posted by yellow15
I'm looking at getting a 2nd 1:12 for indoor carpet race only.

I'm driving a L4 at the moment and i want to try something different and i have my eyes on the CRC cars. Which CRC car do you guys recommend? I'll be racing mod and this car will be for indoor carpet only.

Our indoor track has quite low traction (probably lower than the our medium traction outdoor asphalt track) and no traction compound of any sort is allowed at all.
yellow

i have been using crc cars for about 5years they are one of the best out there .i have a 3.2R bloody knife and love it i use it for stock and 19 turn
. if you have any more questions about any of there cars just give them a call ,they will tell you which one is best for you.
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Old 10-26-2005, 04:42 PM   #15189
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Hey guys,

Looking for roll out on 19t and stock motors. Track is 70 x 36. I'm sure its on this thread somewhere, but its a huge freakin thread, LOL. Also, could someone post up the formula for roll out one more time.
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Old 10-26-2005, 05:14 PM   #15190
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Quote:
Originally Posted by zinger77
yellow

i have been using crc cars for about 5years they are one of the best out there .i have a 3.2R bloody knife and love it i use it for stock and 19 turn
. if you have any more questions about any of there cars just give them a call ,they will tell you which one is best for you.
Thanks Unfortunately i'm from New Zealand so calling them isn't the best option for me

And i hope some CRC owner can tell me their real life experience/feedback like the advantage and disadvantage/weakness of each CRC car.
Btw, i notice the 3.2R has a graphite T-bar? would it still break during a crash?
And the carpet knife is using somethign like a rubber band to secure the batteries!?? how good is it?
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Old 10-26-2005, 05:18 PM   #15191
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rollout= (tire diameter x 3.14) / (spur/pinion)

not sure what 3.14 equals in MM though, sorry
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Old 10-26-2005, 05:22 PM   #15192
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Default CRC 3.1

I ran my first 1/12 heats in 16 years this past weekend and the car made me look MUCH better than I am. I qualified in the B-main after two heats (no practice) but bumped up with a time/total that would have qualified me second in the A-main!! On my third pack.

I'd forgotten how much I loved DRIVING 1/12. I only got out of it then because it was such a battery war with the 1200SC batteries we had back then. It was cheaper and less hassle to race 1/8th gas on-road, so that's what I did. Then took a dozen years off...

You won't be disappointed with the CRC. Wonder how I'll do with it when I actually get it set up.

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Old 10-26-2005, 05:27 PM   #15193
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Quote:
Originally Posted by Northeast Racer
rollout= (tire diameter x 3.14) / (spur/pinion)

not sure what 3.14 equals in MM though, sorry
25.4mm/inch, so:

3.14 X 25.4 = 79.76mm

BUT (and this is a BIG but) I don't believe you have to convert pi to metric , just the tire diameter. Pi is pi. Or pi are round, or whatever it is mathematicians say. Pi is a fixed ratio (thank goodness or highschool Geometry would have been even MORE fun). If you convert both pi and the tire diameter you'll end up with a number that likely won't show up on any roll-out charts. Or if you convert pi and not the tire diameter you'll be similarly in error. Unless your tires are 3.14" in diameter...but I digress.

The tire diameter is all I need as I've got roll-out charts that accept both inch and mm diameter inputs. BUT...if you're really jonesing for some math you can do it all yourself.

Examples?

1.7" (tire diameter) X 3.14 (pi) = 5.34" (tire circumference) X 25.4 (convert to mm) = 135.59mm (tire circumference).

Now, let's suppose your buddy told you the guys at your track are using about a 44mm roll-out (1.73") for their layout. Circumference (135.59) divided by desired rollout (44) gives you your target gear ratio (3.93:1). Further, let's pretend you've got a 100-tooth spur gear on your car... take 100 (spur gear teeth) divide by 3.93 (target gear ratio) and you get 25.45 (desired pinion size). Now, I've HAD pinions that have a half tooth, but they're really noisy and not terribly efficient, so in this instance you'll have to round up or down. OR if you're REALLY anal retentive you can try a different spur gear and see if it lines up better with your target gear ratio. A 96 tooth spur would give a target pinion size of 24.42. Hmmm...not much better. A 92 tooth would give 23.4. Well, if you're THAT much of a perfectionist I guess you'll have to true your tires down a bit. We could do the math to tell you how much to take off of them, but it's making my head hurt.

Take the lazy way out...measure tire od and plug it into the chart and compare with what your buddy tells you is a good roll-out number. Assuming HE knows what he's doing...

Scottrik

Last edited by Scottrik; 10-26-2005 at 06:40 PM.
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Old 10-26-2005, 06:28 PM   #15194
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Quote:
Originally Posted by Northeast Racer
rollout= (tire diameter x 3.14) / (spur/pinion)

not sure what 3.14 equals in MM though, sorry
Isn't rollout Tire Diameter X 3.14 X Pinion / Spur?
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Old 10-26-2005, 06:33 PM   #15195
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Both equations give the same answer...so I guess both are correct!
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