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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 05-23-2003, 07:54 AM   #3001
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racerdx- The merchant is cheaper to buy and maintain since it doesnt have the pain the @$$ dynamic strut front end. However if you really want to run that front end, you can buy it from AE for like $30-40 for everything (however you might need new servo mounts for it). however it really isnt that much better, and also unless you build it perfectly (which takes alot of time to make sure it all pivots freely and is at the correct angles and such) then it will be worse than the old school, since they bind up and do all sorts of stuff you dont want, very easily.

As far as parts for the old school front end, i would just get an extra set of arms (like $4). and you can get them fron hobby etc as well. also get the black center shock spring (its actually a repacked wolfe spring. its 17lb, the AE black spring is 4lb, so dont buy that one by mistake, like i did, lol)

and yes you have to drill holes in the chassis, but its not that bad, and only takes like 10 minutes. the adjustable servo mounts on the crc can move in a shunt unless you glue everything down.
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Old 05-23-2003, 08:22 AM   #3002
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Default thanks for the speedy advice!!!<!!!>

Salutations Earthlings!
to David Root and Newracer, thanks for the advice!
i don't think i can get a promatch pack here over here in Singapore but i'm sure i can solder a similar pack using loose cells.
so i'll just plug the recv pack into the rx and leave the esc switch off?
i always thought the esc switch prevented the esc from operating....not the rx.... have to try this though! thanks a bunch!
i used to have a kawada m300se which i really enjoyed playing with <mostly because it used stick packs which i could share with my touring car.> but i have since converted to 4 cells.if you guys haven't tried, the kawada tires are an excellent compound if you drive outdoors! they are soft, grippy and last forever!<well... maybe in dog years...>
btw, does anyone have any reccomendations for a good/excellent esc for 4 cell use?
most esc i find on the market are meant for a minimum of 6 cells.
i have found the postings about the front end quite informative and have gotten myself a old skool front end<mostly cause i was too lazy to build the strut front>and am itching to have a go with that.
i do know that for 6 cells, motor wear is quite low as a high turn motor is usually used, but is it the same for 4 cells?
is motor comm wear high?
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, 10:19 AM   #3003
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If anyone is still looking for the Yokomo YRX-12 Worlds Edition let me know by
e-mail as I have found a distributor that has some in stock. I do not know how many they have though.

KT Hobbies
There is great need for a sarcasm font.

You never know when it will strike, but there comes a moment at work when you know that you just aren't going to do anything productive for the rest of the day.

Sometimes I post just to look at my avatar.
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Old 05-23-2003, 02:24 PM   #3004
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Originally posted by racerdx6
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 !!!
to each his own, but one of the reason i got the CK is the tuneability of the rear end... also, i really don't like relying on tape alone ( i use the o-ring and tape)...

Plus the fact that the guys at team CRC are quite helpful...

CK is 64 pitch... 98 tooth spur
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Old 05-23-2003, 02:26 PM   #3005
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Originally posted by newracer
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
how long can i play with this pack?
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Old 05-24-2003, 05:46 PM   #3006
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I don't want to drill holes in my chassis because I will most likely screw up and have to buy a new chassis. I also hate using servo tape. So I want to get the CK. I also want to get the old skool front end for it. Would this work? I wouldn't need to drill any other holes or anything? What parts would I need to get? Has anyone ever done this or heard of anyone doing this? Could someone give me the part #'s or just the parts names of things I would need to order?
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Old 05-24-2003, 08:49 PM   #3007
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The Carpet Knife V3.1- Professional Four Cell 1/12th Scale Multiple On-Road Champion. With Retro-Front End + 3 bolt rear wheels $149.99

How about this option.... call or e-mail CRC for the P/N
G's RC Raceway- Best off-road track on the east coast...period!!!

Pitman for Team Dallas Austin...
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Old 05-25-2003, 06:59 AM   #3008
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you dont need to drill holes if you are running the old style front end. you can shoo goo your servo to the chassis (just make sure its properly orented, ie not crooked, or too far to one side or the other.

and going from the old style to dynamic strut just requires unscrewing on, and putting the other one on.
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Old 05-25-2003, 12:50 PM   #3009
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Ok here's what I'm gonna do........ I'm gonna get the Carpet Knife standard version (because I don't want to spend all the extra $$$ ), an "old skool" front end (I found a complete old style front end kit from Hobby Ect. for 20 bucks). I'm guessing that it will just bolt on from what Stormperson said. I'll find out what tires are right for my track and order them from some place that's cheeper . Here's another question I've come up with, what servo do you guys use? The only servo company's I will use is either JR or Airtronics. I had a Hitec servo and it died after not very long for no reason . And all the Airtronics or JR servos that I've had are all still goin strong . I've had a JR servo in my Rustler for 3 years, now it's in my xxx-t, and I've never had any problems with it except I stripped the main gear once because it's plastic. I want to get a high speed servo with metal gears. I probably sound pretty picky right now, but when it comes to servos I like to have good ones. I also don't want to spend more than around 60 bucks. But all I really want to know is what servos you guys like and their specs (speed, torque, metal gears, price, ect.). Thanks!
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Old 05-25-2003, 12:53 PM   #3010
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The JR servo to have is the 3550. Its a mini servo, about .13 s @ 4.8 V, and enough torque to turn the wheels at speed, and hold them. Its plastic geared, but then again, so are most mini servos. The only 1/12 servo Ive ever seen with metal gears is a Hitec

I dont think MG is really necessary, either. Its just extra weight.
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Old 05-25-2003, 01:03 PM   #3011
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I think I'll be fine with a plastic gear servo. I'd rather get a nice plastic geared servo than the Hitec . Where can you get it from? Thanks!
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Old 05-25-2003, 01:10 PM   #3012
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racerdx- the rev. 3 is 160 and it COMES with a old school front end, and then you will end up saving more money since you wont have to pay for shipping from two different places, AND you will also get a better car and as far as the servo issue, the merchant comes with very good instruction as to how to mount the servo properly, and if you shoo goo it (which works just as well as drilling) then you can also re-do it later, and it takes just as much time as screwing it onto the mounts on the CK

as far as the servo... why sir you might just be in luck! in a 12th scale you never use a standard servo (its too heavy and you dont need that much grunt), you use a mini servo, and there are only like 3 total choices out there, and one per company. i have run the airtronics one for the past few years and loved it. the number is like 91514 or something like that (it has a 9,1,4,5 in the number i think ) and its $60! lol. and make sure to get the small kimbrough servo saver for it, or else you steering geometry will be messed up.
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Old 05-25-2003, 01:57 PM   #3013
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I have a Multiplex digital metal geared servo in my corally. The most popular servo in the UK is probably the Sanva 141. This will be the same as something from airtronics but no idea which one.
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Old 05-25-2003, 02:13 PM   #3014
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i think u'll find its the 94143 airtronics your after.
i run the KO 947 digital mini servo, got everything, metal gears, speed, torque, i really like it, sounds sweet too!! (which is what counts!! lol)

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Old 05-25-2003, 02:21 PM   #3015
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Sanwa 141 is the same family as the Airtronics 94141, 94142, 94143, 94144, and 94145. The 94145 is .07 sec time to rotate 60 degrees at 6.0 volts. The 4.8 voltage transfere time is .09 seconds. There are NO other servos out there with those specs.

They are heavier and little bigger than the JR, but they still fit the car and don't weight it down.
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