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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 01-26-2004, 05:47 PM   #6361
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Default diff bearings

The outer, or thrust bearings on 12th diffs wear out much faster than the other bearings on the diff because they are not meant to take the side loads they are subjected to. Some guys like to use an expensive bearing thinking it will last longer but I agree with John- buy cheap ones in quantity and just replace it when a fresh diff feels gritty.
For what its worth, the stock AE diff isn't very good. No bearing inside the hub or spur gear and tiny diff rings. If you spend the money for a good big ring diff it will pay for itself eventually because you won't have to rebuild it as often. The small ring diffs were meant to save weight but they just don't work that well.
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Old 01-26-2004, 05:56 PM   #6362
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thanks oddpurple-i think i do that, buy a bunch of spare bearings as well as some other parts BTW would you recomend the irrgang diff? the only reason i have an AE axle and diff is because i had a brand new 12L3 and then bought a carpet knife conversion fo it. are there any fiberglass axles on the market?
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Old 01-26-2004, 06:05 PM   #6363
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Default diffs and bearings

Tower Hobbies has Duratrax bearings, 10 for about 30 bucks, they seem to work good for me.
The IRS diff (big ring) is great, I've got a couple of them-but if you want the Cadillac (or should I say Ferrari) of 1/12 diffs, get a Niftech...Sweet! (but really expensive)
As far as I know, all the axles worth buying are carbon fiber.
BTW CRC now specs a big ring diff in thier Red Knife kits, too.
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Old 01-26-2004, 07:20 PM   #6364
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Default axles and diff's

Does anyone know if someone makes an aftermarket axle for the yoke yrx 12? I heard that the 12l3 axle is not compatible with the yoke. I can't seem to understand that, the rear ends look identical to each other.
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Old 01-26-2004, 07:31 PM   #6365
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picco007--Just got in the door so I had to read all the posts I mised today. If you are going to mount your servo flat you should slide it forward a little. You don't need the tierods perfectly stright though a little rear sweep should be good. It will slow down the steering and the car won't feel as twitchey. If you leave them swept fowared like that it would cause all sorts of problems. As far as an axel goes get the IRS big ring diff. I know that a lot of guys will say to get the small ring for stock due to the lower rotating mass but its not that much differint and I can go a month or two between rebulids if I only run stock.
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Old 01-26-2004, 07:46 PM   #6366
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Default Re: axles and diff's

Originally posted by picco007
Does anyone know if someone makes an aftermarket axle for the yoke yrx 12? I heard that the 12l3 axle is not compatible with the yoke. I can't seem to understand that, the rear ends look identical to each other.
Have you tried a 12L axle? I have a spare and we can try mine next weekend. The only thing I can think might be different is if the Yok uses metric hub/bearings (but I doubt that). Does the left hub screw on like the L3's?
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Old 01-26-2004, 08:24 PM   #6367
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IRS sells complete axles for 12th scales that will work will yok's
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Old 01-26-2004, 09:02 PM   #6368
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Anybody know the part for the complete rear axle kit for the 12L3? Its either 4450 or 4550. Kinda confusing on ae site's parts list
Sometimes I post just to look at Kraig's avatar
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Old 01-26-2004, 10:37 PM   #6369
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I have a Hyperdrive 12th scale. I am using TQ purple traction compound (our track wont let us run Paragon so thats out of the question). I apply it to the whole rear tirer and to the inside 1/4 of the front. The oil I have in my damper tubes was the only good stuff avaliable at the time. Actually I'm not sure if its really that good. What do you guys think about diff grease? Would that work well? Has anyone ever tried it in damper tubes, I know I've heard of people using it in their damper discs before. Mabey associated green slime (the stuff to make shocks super silky) would work well. I dont think it would hurt to try any thing, you can always clean them off. Mabey I should try turning my dual rate even farther down. thanks for any more help.
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Old 01-26-2004, 10:48 PM   #6370
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How long were you leaving the traction compound on? You have to understand, our track has an insane amount of traction right now. Try leaving it on for 3 min instead of 5-10min.

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Old 01-26-2004, 11:54 PM   #6371
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it seems everyone has there own opinions. I will start with RC12L3 stock but with IRS chassis diff rings and axle. then after a while i will try the damper tubes so i can find out what the differences are for myself.

thanks for all your help
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Old 01-27-2004, 12:11 AM   #6372
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i seem to remember some posts about turning the thrust cone around or using a different one altogether, but i wasnt really paying attention-was that related to this problem?
I have modified my axle to take a thrust race and eliminate the side loading on the outer bearing.

Here is how it was done
Attached Files
File Type: pdf axle thrust race conv.pdf (44.9 KB, 206 views)
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Old 01-27-2004, 08:45 AM   #6373
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Originally posted by reynard55
2. the beam front axle off the G3 car will not fit the 12m, the distance from the front of the chassis to the front axle line is shorter on a 12M, get hold of some of the new alloy front wishbones off Corally, they will not break and they flex less.
Should I get the one piece beam or stick with the two piece set up. I am pretty new to 12th, but I have raced many different cars over the years. I am looking for ease of driving and durability, not necessarily the "hottest but twitchiest" setup.
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Old 01-27-2004, 08:51 AM   #6374
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Default What castor?

What caster blocks should I use for running on carpet?

I'm running my CRC 3.2 and I don't have good bite in the corners.
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Old 01-27-2004, 11:55 AM   #6375
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Hey guys, I'm looking for a bunch of 1/12 parts from Associated. Apparently AE is out of stock in what I need at the moment. Does anyone know who carries a lot of 1/12 scale AE parts in stock?
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