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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 12-27-2005, 07:45 PM   #16501
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Jaybee,

I currently run a T-Fource using the side springs instead of the tweek screws on the Tbar. As long as you are setting it up this way the Tbar only acts as a method of attaching the rear pod to the chasis (generally speaking) and Mark's proceedure for tweeking should work just fine.

Greg
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Old 12-27-2005, 08:45 PM   #16502
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Quote:
Originally Posted by outlandr91
Thanks for the info! I have one question.When looking at the front of the car, the steering turnbuckles are level, I think they should be on a slight downward angle where they connect to the servo.I'm using a Hitec HS225MG servo and a small servo saver.I'm thinking of putting a small washer under the ballstud to raise the outside a bit.What do you think?
Guy....The links should be level or just a little bit above level at the servo saver. You might want to think about getting another servo other then the HiTec....for some reason these dont center that well and or hold center....although it was a while ago when I used one. If yours is newer it might not be that bad but just keep that in mind. If you need any help with the front end of the car come see me as I had one of these for a while and I will show you some easy way to check things out.
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Old 12-27-2005, 11:29 PM   #16503
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Quote:
Originally Posted by Greg45231
Jaybee,

I currently run a T-Fource using the side springs instead of the tweek screws on the Tbar. As long as you are setting it up this way the Tbar only acts as a method of attaching the rear pod to the chasis (generally speaking) and Mark's proceedure for tweeking should work just fine.

Greg
Thank you, I'll try that but using Mark's method for checking/setting tweak- is it easier?
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Old 12-27-2005, 11:39 PM   #16504
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Quote:
Originally Posted by Mark Payne
Hi Tom

I am not sure what your tweak is. Does the centre pivot (the football) assembly drop onto the chassis bolts without interfearence? Why are the chassis bolts not perpendicular to the chassis?

In answer to the battery tape question ... in the "Total Tweak Guide" at www.12thrc.com, I explain that I do NOT use the CRC rubber O ring to hold the batteries in. I use battery tape.

So I kind of agree with Greg. I am suspect of the O ring. I have no direct proof but last year I had a lot of tweak problems which made me REALLY think about it. A lot of what you read on www.12thrc.com comes from my tweak paranoia. I now have NO tweak issues but I realise some may think I am a little "over the top". So be it.

Cheers

Mark
Thanks for the response. I nailed it down to the nuts under the football. for some reason they were not parrallel with the chassis. So no matter how hard you would hold the chassis down and tighten up the football after you let go it would be bowed. These cars look so simple when you start
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Last edited by tomdav; 12-28-2005 at 12:51 AM.
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Old 12-28-2005, 02:45 AM   #16505
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Quote:
Originally Posted by outlandr91
Thanks for the info! I have one question.When looking at the front of the car, the steering turnbuckles are level, I think they should be on a slight downward angle where they connect to the servo.I'm using a Hitec HS225MG servo and a small servo saver.I'm thinking of putting a small washer under the ballstud to raise the outside a bit.What do you think?
The steering turnbuckles level should be a good starting point. If you start changing that, you enter the difficult world of ackerman settings.
In a nutshell: ackerman defines if your car generates more toe-in or toe-out when turning the wheels. Max efficienvy should be that your car doesn't generate any toe-in or toe-out when turning.
This setting is mainlly controlled with the position of servo and by placing shimms under ballstuds etc. This is generally something I don't want to mess with too much. I let the boys who are designing these cars figure out the optimum setting!

Another thing that's influenced by placing shimms under the ballstuds is bump-steer. Again in a nutshell: it's how the steering angle of your car changes as the suspension is compressed.

As general advice: mount your servo the way it's described in the manual (same size servo saver, servo position etc.), than you're safe. There's already too much things to adjust on these cars. Just make sure the steering links can move freely without touching any of the suspension parts in any position.

Most people who have a first look at 12th scale think these cars are non-adjustable, and need only to be dialled in with tire selection. How wrong they are!
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Old 12-28-2005, 07:27 AM   #16506
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Jaybee,

Mark's method is very detailed and I would use it to baseline a car the first time I built it and to recheck settings on occasion. It is not something I would try to do between heats or at the track when practicing. It just requires too much attention to detail for that in order to get the results.

I normally use a laser tweek station from Integy at the track and on occasion I use the two cents method. For my level of competition it's fine, but I am going to baseline my car using Mark's method and see how much it helps.

By all means do follow his instructions for building the front suspension. This must be free and accurate or it will cause issues with handling that can be hard to overcome or figure out.

Greg
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Old 12-28-2005, 09:40 AM   #16507
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Default 2 stage tires

This has probably been answered before , What size are you guys starting off with for the two stage Jacos F/R ? What is optimum size and what is the throw away size . I run a L4 w/ lowered pods .
thanks Bob
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Old 12-28-2005, 10:22 AM   #16508
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Bob,

Optinum size-front 1.65" rear 1.74", that is what I ran at indoor champs. As for throw away size, you get @3 runs at that size.
For club racing I run @ 1.69 fronts and 1.78 rears, and they would last for @ 2 weeks of club racing.


Walter
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Old 12-28-2005, 10:31 AM   #16509
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Default Balls or No Balls

I noticed that some carpet knives have balls under the tweak springs and mine does not. How come?
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Old 12-28-2005, 11:47 AM   #16510
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Rollover,

Is there anything under the side springs at all?

If not, someone may have removed the balls. In either case you should install them. They act as a perch for the springs to rest on so that when a load is applied the springs sit square.

Greg
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Old 12-28-2005, 03:01 PM   #16511
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I bought the kit new and there were no balls in it.
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Old 12-28-2005, 03:44 PM   #16512
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Quote:
Originally Posted by rollover
I bought the kit new and there were no balls in it.
In the 3.2R there aren't or doesn't need any balls under the springs. The rear cross brace was lowered. What they did was eliminate the balls and put on a shorter stand off, then a longer set screw was added to get the spring to reach the chassie. You can run balls under the springs if you choose, there is room for a shorter set screw and the ball. I have had all versions of the carpet knife from the original to now and have been very a custom to putting them in. At Cleveland this year I took them out and really liked the car.
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Old 12-28-2005, 03:51 PM   #16513
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Quote:
Originally Posted by tomdav
Thanks for the response. I nailed it down to the nuts under the football. for some reason they were not parrallel with the chassis. So no matter how hard you would hold the chassis down and tighten up the football after you let go it would be bowed. These cars look so simple when you start
Agreed 1/12 scale cars are more about small finite adjustments and how you build them makes 100% difference. I think some people run a certain car and don't like it then they get another car and don't like it. It is usually because there is a bind in the car and doesn't allow the car to work well. If you were to talk with some long time successful 1/12 scale drivers you will find that it takes a lot work to build a car properly, alot of people just slap them together and get the same kind of result. If you have any questions about what to look for or how to correct issues please feel free to ask.
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Old 12-28-2005, 04:10 PM   #16514
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Quote:
Originally Posted by Mark Payne
Hi Tom

I am not sure what your tweak is. Does the centre pivot (the football) assembly drop onto the chassis bolts without interfearence? Why are the chassis bolts not perpendicular to the chassis?

In answer to the battery tape question ... in the "Total Tweak Guide" at www.12thrc.com, I explain that I do NOT use the CRC rubber O ring to hold the batteries in. I use battery tape.

So I kind of agree with Greg. I am suspect of the O ring. I have no direct proof but last year I had a lot of tweak problems which made me REALLY think about it. A lot of what you read on www.12thrc.com comes from my tweak paranoia. I now have NO tweak issues but I realise some may think I am a little "over the top". So be it.

Cheers

Mark
Hey, I might have a suggestion. You are absolutely correct that the o-ring can cause the chassie to curl up. If you remove the rear pod assembly and put the chassie on a flat surface is it not flat? You might find that the chassie relaxes when you take off your rear pod. First I always use steel screws for the football plate. second make sure the football plate will easily drop on to the side screws. If it doesn't either the chassie could be slightly off or the foot ball plate. Either is corrected with a dremel in just a couple of minutes. If you are talking about the car fully loaded and the chassie is bowing that would be a normall thing. If your tweak if off by a lot and everything seems to be balanced ie radio gear and rear football not binding it is very possible that the front end is stiffer on one side than the other causing a tweak. You need to go through your front end and set like .005 spacing of play in either side of your front end. If you don't have any play in either side there is no way to judge how much pre-load you have from 1 side to another. Counting shims isn't always accurate. So if you free up your football plate and check your front end and your car tweaks good. Don't worry about the bow in your chassie.
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Old 12-28-2005, 04:38 PM   #16515
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Pulfinator = Mike Pulfer? If so just wanted to congradulate you on your Cleveland Stock 12th scale win this year. Merry CHRISTmas and a Happy New Year to you Mike and your family, please tell your dad i said hello...(i guess the "lil" mike can finally die off.. ...ah memories from the four years i raced in the middle 80's, man that was a long time ago... )
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