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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:
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 Chart:

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Old 09-04-2006, 12:19 PM   #20341
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Originally Posted by EAMotorsports
Hi Ral,

I dont have any 12th scale expereice but I can tell you that the KD's get HOT!! They pull huge amps and require a little different motor setup because of this. I cant help you out on Rollout as I dont race 12th scale but I can tell you that you can take a little off the edge of the brush either .010 off the trailing or .005 off the leading and trailing and it will reduce the amp draw a little and help with the heat.

But from my expereince I dont usually worry about motor temps as long as the motor is not fading more than normal during a 5 or 8 minute run and the motor is not burning up.

Hope this helps.

Hot on only 4 cells...Not my experience.
Constantly evolving CRC WGT and WGT-R/T...Carpet & Asphalt...All thanks to Team CRC.
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Old 09-04-2006, 02:08 PM   #20342
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Originally Posted by Still Bill
Hot on only 4 cells...Not my experience.
Jason's and my KD's are 190deg after a run...that pretty warm for 4 cells.
Adrian Martinez
What I run: Schumacher Mi5/Associated RC10R5.1/Associated RC12R5.2/Futaba/HobbyWing/Team EA Motorsports/BSR Racing
Where I run: Florida Indoor R/C Complex/Thunder Racing/Florida On Road State Series
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Old 09-04-2006, 03:44 PM   #20343
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but its all worth it!!
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Old 09-04-2006, 09:01 PM   #20344
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A quick question for all you 1/12th scale pro's, I ran my car today and it is suffering from off power oversteer what is the best way to tune this out of the car?
Thanks Brendan
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Old 09-04-2006, 09:18 PM   #20345
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Reduce your drag brake in your esc setting. If your car still oversteer when you let go the throttle, replace your motor with different motor or replace the motor can with less powerful magnet.
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Old 09-04-2006, 09:34 PM   #20346
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Azmio, thanks for the reply, I am not running any drag brake, the motor i am running is an orion revolution 9x2 what do you suggest to change with this?
Thanks Brendan
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Old 09-05-2006, 12:35 AM   #20347
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Originally Posted by mtmmotorcycles
A quick question for all you 1/12th scale pro's, I ran my car today and it is suffering from off power oversteer what is the best way to tune this out of the car?
Thanks Brendan
1) Keep a little throttle going into a turn to prevent the weight diving forward as much. Helps the car roll better through the corner anyway.
2) Use less droop on the rear pod
3) Use stiffer center shock spring
4) move batteries more forward
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Old 09-05-2006, 12:59 AM   #20348
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Default Brushless Motor on 4 cell

got a 3* & 4* to use

what do you guys run the rollout @ ?
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Old 09-05-2006, 01:27 AM   #20349
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Originally Posted by Slapmaster6000
Hi all!
I just wanted to poke my head back in hear to let everyone know that I am still here. Big news from the Slapmaster factory, I am nearing completion of a new work shop for production. In the '05-06 winter season, I to had lease a space which I vacated this past April. I made up as much inventory as I could to get through the summer knowing that a new shop would be built. The work benches are going in right now and lots of shelving. A really cool dust collection-ventilation system has been installed in the cut booth for cutting the chassis out. All the machine equipment will come out of storeage and get remounted in the next day or two. Production should start back up in the next couple of weeks.

I see that many are chatting about the thrust bearings. They continue to amaze me. So much, I am considering offering a lifetime guarantee. I have not been able to wear mine out. I ran my 3 year old diff's at Nats this year. Everyone I showed them to, couldn't beleive it. I have only heard of two that have failed that were likely used on a dusty out door track. Beyond that, I have not heard of any of the thrust races wearing out through normal useage. If anyone has worn one out, I would like to know: blbodine@comcast.net How many r/c products can you claim that have a unknown life expectancy? ... on the positive side!

BTW: the thrust race replaces the cone and bellevel washer, but the 1/4x3/8" bearing remains in the hub. It's now a radial bearing (like it was designed to be) and just centers up your wheel hub.

I have decided to do just a running change on the MS2.3 rather then a giving it a new designation. I will change the mold enough to get back to the smaller front tire diameter like the 2.2 used. It will be able to use a tire down to 1.60 whereas the 2.3 could only get to a 1.66 with common parts. I will also add two holes in the rear so that CRC upper chassis brace can be added. You will be able to mount the damper tubes near flat for those high bite race tracks. Down low for the med-low bite. Up high or flat for those high bite tracks.

Dan Garber is my latest driver piloting the MS2.3 at his local home track; Seattle Indoor Raceway. Dan has evolved from the Tamiya series. He has even taken Tamiya Series Championship a few years back. Dan's understanding of race cars is very impressive and together we should have even more refinements for the MS line up. You know that there will be some fun prototype stuff showing up from time to time.

Foam bumpers are still available. I knew that they didn't weigh very much, but I never checked them. I took 10 of them and put them on a gram scale... it showed 20 grams or 2 grams each. Amazing.

My website is still very stagnent. Someday I will get around to putting my latest products on there. You can still reach me through it. www.slapmastertools.com

Thanks for your support!
I always used thrust bearings on my oval cars.. super smooth, and dif last longer then anything else.. However, my thrusts i useoon 10th scale dont fit the 12th scale rims.. Do you sell them?? i would like to pick up one or two.. My email is boxerking1977@yahoo.com if you have any info on them.. thanks
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Old 09-05-2006, 03:29 AM   #20350
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Can somebody give me a good setup for a CK 3.2R on a very dusty outside track.

I got a SP12M but i want to try a link system.

thanks for your help.

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Old 09-05-2006, 06:46 AM   #20351
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Default Ceramic Bearings


How does one tell the difference between a "standard" metal-shielded bearing and a ceramic bearing? I bought a roller that is supposed to have ceramic bearings installed on it and have a complete second set of them. The loose bearings look pretty much like the ones that come with the CRC kits...

The bearings are supposed to be Boca.


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Old 09-05-2006, 06:54 AM   #20352
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I don't know how without taking off the sheilds, so it probably wont help. But if you take the shields off, it is pretty easy to tell the difference in the color of the balls.
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Old 09-05-2006, 06:59 AM   #20353
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Originally Posted by GrandeGixxer
Is there any way to get the front end grip to come down at the beginning of the heat, and stay consistant for the whole 8 minutes? For about the first minute and a half or so, the front grip is so high, it is on the verge of spinning out. After that, it is fine for the remainder of the race. Is there any way to make it the same for 8 minutes?
Make a small change to the car to make it understeer.
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Old 09-05-2006, 07:12 AM   #20354
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Sorry bro, I have switched to brushless motor a long time ago and no longer in touch with the latest brush technology. You can start by manually rotating the motor using your finger. If it takes a lot of torque to rotate it, you will sure have plenty of motor braking. Try several of them including the one with old magnet cause old can has weak magnet.

1/12 car is light and very sensitive to motor braking. Even with brushless motor, if I set it with too much drag brake, my rear end will become loose everytime i let go my throttle. Dont bother applying light throttle cause with a car that light, it's very difficult to determine how small is small until you're sure that the throttle is neutral.
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Old 09-05-2006, 07:45 PM   #20355
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Originally Posted by radio_car_racer
got a 3* & 4* to use

what do you guys run the rollout @ ?
35mm rollout for 3*
30mm rollout for 4*

This is for a large outdoor track (120ft straight), adjust down for smaller tracks.
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