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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.

KITS:
Click links to go to manufacturer product page. If any are missing please add them!

TIRES:
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!

THIS MAY NEED UPDATING FOR THE NEW BLACK CRC CARPET

Brands:
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:
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:
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.

Examples:
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:
BSR/CRC/Jaco



Contact



Corally



JFT (Japan Foam Tire)



Ulti



Enneti (Xceed)



ELECTRONICS:
ESC:
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 decide to use an Rx pack, MAKE SURE TO REMOVE THE RED WIRE FROM THE ESC PLUG THAT GOES INTO THE RECEIVER!!!

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.

1S ESC:
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!
Servos:
BODIES:
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


PROTOForm:

Reflex Racing/RSD:

SUSPENSION ADJUSTMENTS:

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Old 07-26-2011, 03:48 PM   #36106
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Quote:
Originally Posted by sdunnmcp View Post
I have been running the inline chassis from another MFG. since February. The car is faster in the turns. Lipo's have changed everything with these cars and I think we are still learning what is needed. Less side roll was achieved by moving the batteries towards the center but not completely centered. We also got more weight up front which helped with more steering.
Keep in mind these changes were for modified, although I think stock will benefit also. In mod there is so much power that a configuration change had to happen and this has helped.
Vegas will be a good test for all the new cars.

Steve Dunn
Indianapolis, IN USA
Unless you moved the cars center of mass up or down, it's impossible to have changed the amount of chassis-rotating force the mass of the car would exert in a corner of a constant G. What may have been changed slightly is the Y-axis polar moment of inertia, meaning that the energy that the car uses upon entering a corner to first accelerate the chassis Y-axis rotation, which once moving (twisting) the speed and inertia of the movement is slowed by your dampening and then, once maximum cornering G has been achieved for a fraction of a second, stops being relevant as the car has completely set-up and there is no movement in the suspension. At that time all of the potential energy which upon exiting the corner or slowing down will be used to uncompress the chassis back to flat has been absorbed by your springs, an energy quantity independent of the polar moment of inertia and dependent only on mass, height of the center of gravity, and cornering force. So overall, changes to that moment of inertia will mean the car requires less energy to compress itself into a turn and spring itself back from cornering forces, but the force exerted on the side spring at constant G will not be changed. Technically you could say that the reduced rotational inertia to be absorbed by the dampening system would reduce the chances of over-compressing the side spring and over-rotating, but there is no 1/12 scale car in service today that isn't far massively overdamped in terms of its pendulous motion. Another argument would be that because there is a greater inertia to be absorbed by the side dampening in a given amount of time that this could result in momentary over-loading of the outside rear tire upon entering a corner from the greater dampening, but I cant say if that momentary force is good, bad, or indifferent for the car's performance.
On the other hand, you HAVE increased the energy the car will require to rotate itself on its X and Z axis, meaning that weight transfer from front to rear will be slower but contain more energy, and the energy used to rotate the car itself will be increased, there is a tradeoff to be accounted for here, and I don't claim to know the answer but I have decent reason to think that none of these values have changed more than a few percent by turning your battery sideways and then mounting your heavy brick of a speed control, receiver, transponder, booster, or receiver pack next to it. I think I can safely say that it is not just "Less side roll is achieved" or "faster in the turns."
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Old 07-26-2011, 03:57 PM   #36107
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holy wall of text Batman, what have I done....
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Old 07-26-2011, 07:29 PM   #36108
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Evan, you're over thinking this. We don't have the kind of telemetry needed to actually measure the forces at work here. All we can do is try something and see if we get faster lap times. If Steve says he can turn faster lap times with the inline car, I believe him. I think if you could accurately measure it you would have a lower polar moment along the longitudinal axis, meaning weight would transfer from side to side more quickly in both action and recovery. That would give you better transition into and out of corners. When you concentrate the weight closer to any axis, you speed up the reactions of the vehicle. Nearly every other type of RC car has longitundinal battery placement.
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Old 07-26-2011, 07:44 PM   #36109
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I don't think hes lying, but I also don't think this is a magical formula that will transform 1/12 scale racing. I think that his potential advantage in the corners is more a result of a longer chassis with more weight on the nose that can be setup and driven with more aggression than a tiny change in the rotational moment on any axis. I guess if your going to make a chassis that can fit the battery between the servo and rear pivot, why not face it sideways?
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Old 07-26-2011, 08:38 PM   #36110
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Nobody said it was a magical formula. Formula 1 teams spend millions of dollars to find a tenth of a second or 50 pounds of down force. And when they produce a new part it performs differently for each of their drivers. Where we race, you run a positively ancient Carpet Knife and are competitive, I run a Serpent link and struggle to beat Chris's Serpent T-bar car. We have 5 or 6 people running 12R5s that all run differently. Steve can't get hooked up and Jason has understeer. All you can do is get a car you think should work and then try to maximize it's potential. In the end it's the guy who gets the most from his equipment that wins.
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Old 07-26-2011, 09:26 PM   #36111
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DesertRat,

Sometimes we have to try things out of the box. In a former life I have worked for top Indy Car Teams and NHRA Pro Stock Motorcycle teams and even with those budgets we sometimes just threw our hands in the air and tried something that made no logical sence and it worked. All of our datalog data says it wouldnt work, but it did.
I wish we had better datalogging for R/C but we don't (Although I am working on that).I didn't say this would change 1/12 racing, I was only trying to say I and many others think it is better. The car I run is from a small MFG. and there is no intent on trying to get $150 out of anyone. We just love 1/12 racing and want to see it get better and want to provide this advantage to other racers if they want it.

Steve Dunn
Indianapolis, IN USA
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Old 07-26-2011, 10:12 PM   #36112
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Geez Even, written just like an Engineer... ;-/

Steve What chassis are you running?
E
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Old 07-26-2011, 10:41 PM   #36113
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Hey Steve, tell your "small manufacturer" to hurry up or he will be the last to market with his new toy.
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Old 07-27-2011, 12:08 AM   #36114
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Quote:
Originally Posted by sdunnmcp View Post
I have been running the inline chassis from another MFG. since February. The car is faster in the turns. Lipo's have changed everything with these cars and I think we are still learning what is needed. Less side roll was achieved by moving the batteries towards the center but not completely centered. We also got more weight up front which helped with more steering.
Keep in mind these changes were for modified, although I think stock will benefit also. In mod there is so much power that a configuration change had to happen and this has helped.
Vegas will be a good test for all the new cars.
More weight up front would mellow the front out a lot. Less weight transfer and greater load on the tires (depending on how much is being loaded already). Most of these changes were made to calm down an already too aggressive car.
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Old 07-27-2011, 04:38 AM   #36115
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I was told by a man who knows a lot more than me (he designed several championship-winning pan cars) that the new 1/12 scale cars lower control arms actually flex more than the old Associated style, and that there may be some advantage in retrofitting the old arms onto a new car, is any of this true?
I run the old Associated front end on my CRC 3.2R and like it very much.I really like the way cars steers. But hey what do I know it's just my opinion.
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Old 07-27-2011, 07:31 AM   #36116
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Originally Posted by LonnyJ1950 View Post
Hey Steve, tell your "small manufacturer" to hurry up or he will be the last to market with his new toy.
We are working really hard at the moment to bring the car to market. We just have a few T's to cross and I's to dot and we should be good to go. Final samples will be here in the next week so we hope to have some pictures to post. I think everyone will be impressed.
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Old 07-27-2011, 11:32 AM   #36117
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More weight up front would mellow the front out a lot. Less weight transfer and greater load on the tires (depending on how much is being loaded already). Most of these changes were made to calm down an already too aggressive car.
Back in the 4 cell days my in-line Darkside car was much more aggressive in steering than the cars I had with the battery across the back.
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Old 07-27-2011, 02:02 PM   #36118
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Originally Posted by InspGadgt View Post
Back in the 4 cell days my in-line Darkside car was much more aggressive in steering than the cars I had with the battery across the back.
Yes but you were placing close to 100grams more weight towards the front with those 4 cells than you are with a 1s lipo. I really love the 1s lipo and have been a huge supporter of it from day one. But it has indeed changed the way our cars handle and we are having to change the way we approach car design as a result.
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Old 07-28-2011, 09:16 AM   #36119
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Back in the 4 cell days my in-line Darkside car was much more aggressive in steering than the cars I had with the battery across the back.
If you have tried the different positions for the battery on a standard car. the forward position makes the car pushy and easy to drive. If you move the battery back then the car is twitchy and loose. Lipo and the weight of the cars have changed setup dramatically. I used to run a super stiff rear end with a soft front end. Now its exactly the opposite. So I would imagine it will change how the new cars are going to be designed.
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Old 07-28-2011, 11:31 AM   #36120
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I have tried different battery positions and found whenever we moved the batteries more forward the car would get more loose. 15 years ago when the only class running was pan car it was all about getting as much weight to the rear of the car to help keep the rear more planted.
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