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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!
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


Reflex Racing/RSD:


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Old 05-21-2003, 10:14 PM   #2986
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One more thing I want to clear up...... the Carpet Knife uses the same front suspension as the L3 and 6 pack right? The Associated design, it looks like it but looks can be misleading . Boy am I excited about getting this car and not the L3! No tape either! Yay !!!
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Old 05-22-2003, 03:23 AM   #2987
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Default Racerdx6

Its an associated Front end.

Tires cost about 12 to 15 for Green and a 17 to 20 for "exotic compounds".

Again I bought the plain jane one. I also bought a set of exotic tires. I wore out the green compound ones learning to drive the thing. I am an offroad guy so it was quite the learning curve.

CRC has bumpers, I recomend one, they will save your exotic tires. Its 4.99. I also recomend getting the side spring and center spring kits. You will be amazed at what changing the center spring does for handleing.

Sounds like a new Bloody Knife for you.

It does not come with a body, or pinion. I have a set from 23 to 32 teeth in 64 pitch. Start with the smaller ones with new tires.

Have fun
David Root
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Old 05-22-2003, 04:05 AM   #2988
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If you are looking at a non-tbar car, i would highly suggest you look at the Speedmerchant Rev. 3. Its a very similar design, however it has some small design advantages.

The CK' rear end pivots are not adjustable really, its two nuts you tighten town right next to the pivot point. However the Rev. 3 has side links that are adjustable and thus much more precise and consistant.

Also the CK has alot of cut outs in the chassis near the batteries, which does make a noticable difference in how much it flexes, whereas the speedmerchant does not. and chassis flex is bad, it allows the car to get tweaked much easier and reallys messes up your traction and handlings, it makes it inconsistant.

Also if you go to www.teamspeedmerchant.com it explains in further depth the advantages as well.

also reguardless of whatever car you get, a bumper isnt a good idea. I run one on my sedan, but not my 12th, because.... if the bumper hits the wall it will automatically stop the car and stuff it into the board. however if you arent running a bumper you have a little be of leway when you hit the wall, and while the body might crumple a little bit, you can keep on racing. I have never broken a front wheel, EVER, i have chunked em, but thats not something a bumper would help.
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Old 05-22-2003, 05:35 AM   #2989
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The Speedmerchant car also has adjustable battery positioning, and the Rev.3 comes with the "Old Skool" Associated front-end, which I feel is infinitely superior to the AE dynamic strut. The strut fornt-end is difficult to build properly, is easily bumped out of adjustment, and wears out at rate about 5 times faster than the "Old Skool". Plus, it's not as durable,and it weighs a ton more!
Team CRC, PowerPush, Access Race Place, US Indoor Champs, CD SUPERPRO, RK Designs, TxDSkingraphix, Cypress, Founder and lead instructor of the Ian Ruggles Negative Reinforcement Driver Training Program, enroll now.....
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Old 05-22-2003, 09:56 AM   #2990
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The old skool front end is better and more consistant on carpet, smooth surfaces, where as the dynamic strut front end is better for outdoor, bumpy tracks.

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Old 05-22-2003, 02:07 PM   #2991
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A good substitute for a plastic bumper is a foam bumper. I cut down a TC bumper and drilled holes to slide it over the body posts. It holds the pins on the dynamic strut front end in, and it helps the car bounce out of wrecks.
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Old 05-22-2003, 03:02 PM   #2992
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I do have to agree I fit a bumper on my Trinity car and it made all my meetings with the boards a much more enjoyable experience.
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Old 05-22-2003, 03:24 PM   #2993
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A TC3 bumper will fit onto a rev. 3 (the holes match) however alot of trimming is requires. the only advantage to a foam bumper i have really seen is that the body lasts a little longer, since it keeps it from compressing and cracking the wheel wells.

However one thing to watch out for, if you have it so the foam bumper extends infront of the wheels make sure the wheels cant touch the bumper (its not as obvious as it seems) or cant in the event of a hit, or else it will act like the wheel has a brake on that individual wheel when you hit a wall, which is bad (duh, lol). however sedan bodies are much stronger and dont cause the bumper to push back as much in a crash, however a 12th scale is a different story, since the body is so thin it moves alot in a crash and you have to make sure that it doesnt touch anything while it is moving around, or else when you tap a wall you might all of the sudden stop or the car will pull itself into the wall because that wheel locked up.
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Old 05-22-2003, 06:37 PM   #2994
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To each his own, but I like the bumper. When I did run with out it, I bent a king pin once and sheared off an axle in the main once. I figure its worth the extra effort to have it same my $20.00 a pair wheels. I have broken 4 bumpers so far, but I am getting to be a better driver. I keep a spare in my pit box.

Once it did bend down on both sides and cost me my steering because it was lifting the front end off the track, but that is what I get for hitting so many things.

Either way , enjoy the 1/12. Its an adventure.
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Old 05-22-2003, 10:05 PM   #2995
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The Rev. 3 looks pretty good. I really like the battary positioning, it trick. But the car costs 250 dollars if you buy from them. Does anyone know where else you can buy their kits from? How much would it cost from another place? I also need to make sure that my track carries replacements for the "old skool" front end. I'm almost positive they carry parts for the new version because they carry parts for almost every associated car. I'm going tomorrow so I'll check. I couldn't find any holes for the servo to mount. Mabey I just missed them or they arn't there. You don't have to drill holes or anything do you to mount the servo? The "bloody knife" looks pretty tempting though. The price on the speedmerchent doesn't though, but the car does . They're both good cars though? If I got the CK I wouldn't be disapointed right? Would the CRC bumper work on the Rev. 3? Heres the last question for right now: Does the Carpet Knife use 64 pitch or 48 pitch gears?
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Old 05-22-2003, 10:08 PM   #2996
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Actually I have one more question , where could I buy the "old skool" front end at? I'm considering buying the CK and installing the "old skool" front end, than if I went to a bumpy track I would have the new version one to install. How much could the whole front end cost?
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Old 05-22-2003, 11:11 PM   #2997
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Default need help! por favor!

Salutations Earthlings!
i have a 4 cell carpet knife with the following stuff on it.
-hitec mini servo
-schulze eagle 3 esc
-trinity D5 9t double
-micro recv from GWS
-futaba 3pj tx

the problem is that the esc is rated at 6-18 cells and the bec is rated at 4.5v min. the esc automatically slows down motion to conserve energy to the servo and rx when voltage drops to 4.5v
this is a prob cause using 4 cells, i already start at a pretty low voltage, and thesc performs inconsistantly during hard acceleration....or soft acceleration for that matter.
i am told that a recv batt is req.
so what do i do?
-what recv batt to get? what capacity and size?
-how do i connect it to the control circuit?
recv pack to recv, but if i connect the esc to recv, the esc may blow up!6v +4.8V=10.8V
-will it work if i disconnect the red wire between the esc and recv?
-finally, what gearing ratio should i use as a benchmark?spur is stock:98t/64p
all help will be appreciated!
thanks for looking in!
During heats, i use durex for both front and rear, with Hard inserts.

Sorex, i meant Sorex.
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Old 05-23-2003, 03:28 AM   #2998
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You really need a different speed control rated for 4 cells.

Putting a reciever pack in will not help acceleration problems when the 9 turn draws the pack voltage down.

Yes if you were to do it you would have to cut the red wire from the speed control to the reciever and use a pack plugged into another port on the Rx.

I reall do not think you will solve your problems unless you replace the speedo.

If your batts are 1.115 under load, (30 amps) you only will have 4.46 volts if you only draw 30 amps.

Racerdx6 64 pitch diff (spur) gear. 98 teeth.

David Root
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Old 05-23-2003, 05:01 AM   #2999
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You can get the Rev3 for a $160 at www.hobbyect.com And yes you can use a CK bumper on a Rev3, I do and it works pretty good. As for mounting the servo on the Rev3, you can either use servo tape and mount is flat with the tie rods on top or you could use some mounts and drill the holes and put the tie rods on the bottom.
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Old 05-23-2003, 07:07 AM   #3000
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you can use a pack like this one from Promatch

it is 5 cells and 160mah, commect it to the battery slot on the rx and do not turn on the esc switch and everything should work fine, it will power the rx and servo
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