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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 01-22-2006, 08:46 PM   #16996
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The "original" RC12L dates to the mid-eighties ('87?). The shock was the same big fat gold-bodied shock that was on the front of the gold tub RC10s. The "old" front is the same as you see used now on some cars almost 20 years later. Same for the dampener disks.

I've still got a 410MXc and Futaba 132SH servo from my RC10L pan car. Pretty sure they were ca: 1990, maybe 1989.

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Old 01-22-2006, 08:49 PM   #16997
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I don't recall a gold full size shock on a 12L at any time. There was one on the 10L... the only shock I remember on the early cars were the length of fuel tubing on the threaded rod with the dampner plates.

I think the first actual shock on a 12L was a VCS. I'm sure there are people here with better memories than mine who can assist... Ike, you out there?

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Old 01-22-2006, 09:10 PM   #16998
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This shock is a VCS macro one.
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Old 01-22-2006, 09:46 PM   #16999
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My mistake--I'd forgotten all about the fuel tubing, wire and collars. MY RC12L has a humongous gold shock on it and I sure didn't recall "updating" it though I must have as I built it new. Just to be certain I grabbed the instruction manual(s) (glossy booklet w/pics, matte booklet with written instructions) and there's nary a mention of a "shock" in there.

Gotta love those "two pieces of wire and a collar" tie rods too. Ralphy Burch and Jay Halsey look like kids in their pics in the back of the book. Then again, they WERE kids. That RC500 is darn nearly as big as Ralph. What ever became of Tony Neisinger?

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Old 01-23-2006, 01:43 AM   #17000
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the scoop helps. just like you wrote before, the fan will be just below the bodyshell. by making some opening, the fan can have some breathing space to discharge the hot air. My friend suggested me this and I thanked him a lot for the idea because it solved my thermal shutdown problem. With 5.5 running at full blast, I need more than a fan to solve my problem.

Perhaps, with 4 cells and an air scoop, you may not need a fan anymore.
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Old 01-23-2006, 05:17 AM   #17001
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Originally Posted by mpetrich

I am using the Nomadio radio so I can measure motor temps and battery volatge and both have been absolutely fine. No chance of thermalling at this point.

Hope that helps. Let me know if you have other questions.
What version off the software are you runing in the radio Nomadio Sensor
and what servoe are you using digital og analog
and are you using the v2 reciver (Transceiver)

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Old 01-23-2006, 06:25 AM   #17002
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I don't run the fan or any additional holes in the bodywork, etc and don't come CLOSE to any thermal shutdown problems with my GTB/6.5 combo. After 8-minutes he motor and esc heat sink are above ambient temperature but not very much. I guess I could gear more aggressively but it just isn't neccessary--it's PLENTY fast.

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Old 01-23-2006, 09:56 AM   #17003
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Originally Posted by gmintimidator
I picked up a used RC12L this afternoon for $40 and it included 2 speedos (410 MXC and a Jem) and a Futaba 132H servo, all in working condition. I am not sure how old it is though I have a box kicking around from an RC12LW. It looks similar except that the one I picked up has a shock like the newer cars, but still has the old front end.

Any ideas what this is? I can get a pic.

Also, what tires are guys running? I am hoping to get this thing race ready for next weekend, a fellow racer gave me a complete rear axle for an L3 so I have the hubs for the tires. Is Jaco the only way to go or?

First 12l with a shock was the LW, it had a silver "delta style" shock, smaller than the VCS micros we use today, and included the old school front-end. It was the first evolutionary step of the L car, and the cells were closer together than the original. Next came the LS which had the new 3 screw top deck and dynamic strut front end. A ton of people use the Old-Skool front to this day. The best way to tell is if it has that hideously large nylon left bulkhead and a four screw top plate, it's more than likely an LW.

I run Parma tires, I like them better than the Jacos because the wheels are lighter and seem more durable. I haven't tried the Jaco two-stages though.
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Old 01-23-2006, 10:04 AM   #17004
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Default Novak brushless

I started running the 5.5 motot and GTB speedo in 12th a couple of weeks ago and I've never had a thermal shutdown. Even when I was really overgeared and only getting 7 minutes of runtime it was only about 125 deg on the speedo (no fan) and the motor was even cooler. If you're having a thermal shutdown you're definately overgeared.

From what I've seen so far, you need to gear way down with the 5.5 motor. Gearing down won't necessarily make the car lose top end but it will run a lot cooler and won't dump.

I had mine geared like a 9 turn and was dumping on carpet so it looks like you need to gear even lower (like a 1.30 rollout or less) for 4 cell 12th on carpet.
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Old 01-23-2006, 12:39 PM   #17005
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Originally Posted by Unregistered
From what I've seen so far, you need to gear way down with the 5.5 motor. Gearing down won't necessarily make the car lose top end but it will run a lot cooler and won't dump.

I had mine geared like a 9 turn and was dumping on carpet so it looks like you need to gear even lower (like a 1.30 rollout or less) for 4 cell 12th on carpet.
what's the size of the track you run on?
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Old 01-23-2006, 01:29 PM   #17006
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Default How much laptime difference does one tooth off equal?

I'm running 19 turn 12th. I don't get much track time or testing. I'm trying to pin down rollout on a new layout. New layout is more flowing and less technical than previous. Previous rollouts ranged between 48-50 mm depending on how smooth on the throttle.
I've heard others comment that the new track requires one tooth less than the old layout. Went with that recommendation and it seemed to work. Best lap 12.24 with no fade until last lap running OLD 3300's.
I went up one tooth and bolted in some really fresh 3800's and could only manage a best of 12.14 and with quite a bit of fade at last third, dropping to 12.4's. I'm not sure of the motor temp. It was warm, but I could keep my finger on it indefinitely. I know there are lots of variables at play - I'd like to hear from some of the guys that have narrowed this stuff down. When you find the "perfect" rollout, how much difference do you see in laptimes one tooth either direction?
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Old 01-23-2006, 01:57 PM   #17007
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Default Silva Centre shock

Can anyone tell me how to easily build/bleed a Silva centre shock?? I can't seem to get the correct amount of oil in it. Either too much and it obviously locks, or too little and clearly plenty of air - anyone got a good method.

If i can get this sorted, i have to admit it seems like a much better quality shock than the std one.

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Old 01-23-2006, 02:21 PM   #17008
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Can you guys let me know how to calculate rollout for 1/12th?

Muchmore l AHRP l Xenon l Futaba
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Old 01-23-2006, 02:32 PM   #17009
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Originally Posted by TFR
Can you guys let me know how to calculate rollout for 1/12th?

check out www.gearchart.com and you can print up rollout charts for any car and tire size.
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Old 01-23-2006, 02:35 PM   #17010
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Originally Posted by TFR
Can you guys let me know how to calculate rollout for 1/12th?

3.141592654 x tire size / spur gear x pinion
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