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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.

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

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!


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 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 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.

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:



JFT (Japan Foam Tire)


Enneti (Xceed)

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 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.

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!


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Old 04-20-2014, 04:46 PM   #40636
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I just finished building the Yokomo R12 C3, everything came together perfectly. However, the one piece sway-bar is causing a minor tweak in the front suspension arm. I've done all I could to remedy the problem but it's still causing a slight tweak on the left suspension arm. The tweak is probably 0.2-0.5 mm.

Everything else in the suspension is spot on, all I need to do now is to figure out how to un-tweak the sway-bar.

I checked on the Yokomo Thread and there have been a few issues with the three piece causing suspension tweak, but mine is a one piece.

I was thinking of lightly sanding the ends of the sway bar which insert into the suspension arm. This would remove some material from the bar and maybe help correct the sway-bars imperfection.

Looky what I found !


Last edited by EDWARD2003; 04-21-2014 at 03:44 AM.
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Old 04-21-2014, 10:04 AM   #40637
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Thanks guys for answering my gearing question. Guess I'll get a 76 spur and stock up on pinions.

I just finished building my RC12R5.2

More photos at: http://www.apexattitude.blogspot.com...ll-almost.html

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Old 04-25-2014, 07:40 AM   #40638
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Figured this is a worthwhile bump. Some of you 12th scale-ers may appreciate this, and I've haven't seen any discussion of this chassis in this thread...

Just starting the build of my new Kawada M300 FX3. Anyone else out there running one of these? I've converted to 1/8 front axles and have different hubs and axle for the rear, as the stock wheels are proprietary.

I'm kicking myself for breaking one of the damper tubes while assembling. It probably won't see any track time until the fall!
- Steven Stewart - Kawada USA

Last edited by S.Stew; 04-25-2014 at 05:35 PM.
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Old 04-25-2014, 02:49 PM   #40639
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If you're waiting on a dampener tube, just get a Speedmerchant or CRC or any other dampener tube and sand the anodizing off it, and go racing.

That is a really cool front dampener design, i like it a lot.
I race toy cars for fun. If I need to explain, you'll never understand.
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Old 04-25-2014, 03:24 PM   #40640
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You don't sand off anodizing, put the part in a bag and spray some oven cleaner in there. Wait a few mins, wash off in water. Done
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Old 04-25-2014, 05:32 PM   #40641
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Originally Posted by DesertRat View Post
If you're waiting on a dampener tube, just get a Speedmerchant or CRC or any other dampener tube and sand the anodizing off it, and go racing.

That is a really cool front dampener design, i like it a lot.
I'm sorry, I should have been more specific. I broke one of the front damper tubes when pushing it into the arm

It's a unique part so I'll be waiting for parts from Japan. Just one of the joys of owning a weird Japanese chassis

Finished up the build tonight. fit and finish is really, very good. The shock is super smooth and the rear damper tubes are very precise (both stick and tube made from machined aluminum). I was just barely able to make 172mm width at the back with Pro-one hubs.

- Steven Stewart - Kawada USA
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Old 04-25-2014, 09:41 PM   #40642
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Those front dampers are cool! I like that!
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Old 04-26-2014, 07:52 PM   #40643
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Default R12C3 first outing.

The Kawada FXIII is a pretty sweet looking kit. The owner of the hobby shop I frequent to here in Japan just bought one. The front damper tubes are really neat.

You can buy the whole front end assembly. So if you're looking to convert your front end to this style of dampening you can. Kamui rc in Japan has them in stock.

On Saturday, I went out to my local asphalt track and did a few laps with my new R12C3. I decided to run both my Kyosho and R12C3 to compare lap times ect. Before I even put any laps down, my preconceived notion was the Kyosho will be the faster of the two. Considering I've never put any laps down with the R12C3. The Kyosho Ra should be the faster of the two.

Running setup, same tires for both rides. The R12C3 was running a D3.5 21.5 stock 12.4 rotor and the Kyosho a ORCA 21.5 stock 12.5 HT rotor.

On Track

The Kyosho was obviously the faster of the two with a solid 0.300 sec lap faster than the R12C3 for obvious reasons.

A-I've been racing this chassis for 1.5 years
B-The Kyosho has the ORCA motor which is hell ass fast.
C-R12C3 was running bone stock setup and it's the first run for this chassis.

After laying some laps down I noticed how easy it was to carve into the corners and all the while maintaining corner speed with the R12C3. I felt the car was really connected with the track in every way - entering, mid and exit of the corner. With my Kyosho there was always this "grey area" or "disconnect" with the track. It just never seemed like it connected or responded with the track. Therefore, I was a little unsure about the R12C3 and doubted if this "connectedness" was a good or bad thing.

By looking at the lap times and the on-track performance I decided to make a few changes for the next run.

After reading up on Mark Stiles R12C3 suggestions on R12C3 setup changes. I decided to change the steering ankerman position by changing the steering block from 0 to + 1.0. I decided to increase the damper roll oil from 100 wt to 130 wt. I also noticed the motor performance was different between the two cars. So I decided to switch out the motors. So now, the R12C3 has the ORCA installed.

The R12C3 managed to drop it's lap times considerably. The extra bit of power and the setup changes made I was able to be 0.200 seconds faster than the Kyosho. I managed to gain 0.500 seconds! Pretty impressive for it's first day out. I can't wait to test and tweak this bad boy in order for it to go faster.
I love the front suspension design, many people at my track complain about how complicated the front end is. I personally like having the ability to adjust roll center, damper tube rates, droop.

All in all. I am very impressed with the R12C3's performance and handling.
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Old 05-04-2014, 09:28 PM   #40644
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Hi Edward2003,

It is interesting to read that you run 2S - 21.5T in Japan.

I tried to browsed the website of JMRCA, but couldn't understand the language

Is there any link to learn the JMRCA's 1/12 technical rules in English ?

In addition, any youtube channel for 1/12 races being run in JMRCA or TCS in Japan ?

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Old 05-05-2014, 03:07 PM   #40645
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what is the best center shock to use on a 12R5.2?
The standard ones bends the shaft far to easy!
I no everyone uses the hot bodies one, but no one seem to be able to get that anymore and the stoped production.
The vbc one looks nice but the ae springs don't fit that or the xray one.

reflex racing team prime is never in stock either!

What's the go finding a decent shock that fits the AE springs???
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Old 05-05-2014, 04:03 PM   #40646
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Hmm...never bent the shock shaft of a 12R5. And I'd be one to do it!

Anyway, of all the shocks you mention, I'd say the CRC. It's readily available, builds up smooth, doesn't leak, and fits AE springs no problem. It's red, which may cause some cognitive distress once mounted, but there are drugs for that.

Pity about the Hot Bodies shock. It seems to be gone from global inventory.
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Old 05-05-2014, 04:16 PM   #40647
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Anyone have info about this and what springs fit on it?

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Old 05-05-2014, 04:25 PM   #40648
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Originally Posted by PROMODVETTE View Post
Anyone have info about this and what springs fit on it?

Associated springs. They were originally made IRS.
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Old 05-05-2014, 04:34 PM   #40649
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So is it a good quality shock or just looks pretty? I was looking all over for a hotbodies shock but they are gone. CRC doesn't fit on my xray
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Old 05-05-2014, 04:49 PM   #40650
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Kyosho Plasma Ra damper works with associated springs. The shock doesn't leak and it's super smooth.
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