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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 01-31-2013, 02:52 PM   #39181
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Quote:
Originally Posted by BenVtec View Post
Hi everybody,

I have a 1/12 scaled CRC Xi with shorty batteries, but the batteries aren't that good. So I decided to change the battery from shorty to normal 1S LiPo (in-line). But it doesn't fit because the chassis is designed for shorty LiPo and there is no space left to place my esc (hobbywing 120A 1S).
The only way to place my esc is to put the servo like it is in the new Xti, at the front between the front wheels. And there's the following problem, there's a big hole for the transponder so I can't place it unless the hole is clossed.
My question for you is, is there someone that can make a main chassis plate without only the transponder hole or has a drawing of the CRC Xi main chassis plate?
here is my xi, the chassis isn't designed for a shorty it is/was a add on piece.
you will need p#'s crc3354 but it should still be on your car as the rod mount, and i think crc3373 is the proper battery stop. then the large "o-ring" that mounts the battery, i found some at my local Napa. And of course a longer ball stud and hardware.

Last edited by jsinclair; 01-31-2013 at 04:00 PM.
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Old 01-31-2013, 04:31 PM   #39182
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Quote:
Originally Posted by Clegg View Post
Maybe I am confusing CRC chassis, but for the Xi aren't you able to just place the full size LiPo across the back of the chassis and have all the room you need for your electronics? It thought that's how It was meant to be used. Small LiPo inline, and full size would be transverse.
You are correct!
But to be in the best balance possition you must have the normal battery in line (like the Xti and other brands are doing with there car's).
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Old 01-31-2013, 04:46 PM   #39183
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The Xi can do a full sized battery in-line but then the electronics end up being placed really wide on the sides of the battery. He basically wants to convert it to be more like the Xti which other people have done before the Xti came out.

Easiest way to do that is going to be to get some scrap something...fiberglass, CF, graphite, whatever. Cut it to fit how you want on the front of the chassis then Shoe Goo the servo to the scrap and Shoe Goo the scrap in place on the chassis.
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Old 02-02-2013, 03:16 PM   #39184
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Default Done

I made photo of the car but some stupid rule on this forum says that I must have to place more threads...
Anyhow,
I manage to place the servo at the front of the car between the wheels!
Tomorrow I'm going to go to the track to test it :-)))
image

Last edited by BenVtec; 02-02-2013 at 03:55 PM. Reason: Photo uploading adding
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Old 02-02-2013, 04:25 PM   #39185
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Default Here it is...I hope

1/12 forum-image.jpg
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Old 02-02-2013, 05:19 PM   #39186
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It looks like one of your motor wires needs to be longer, or it could cause some issues.

I highly recommend 16 gauge wire from TQ.
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Old 02-03-2013, 01:25 AM   #39187
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Default Wires

Quote:
Originally Posted by CarbonJoe View Post
It looks like one of your motor wires needs to be longer, or it could cause some issues.

I highly recommend 16 gauge wire from TQ.
Thanks for the tip Joe, but it looks like it's to short but it isn't.
And I didn't had any 16AWG wire left to put in my car (that's why I used the red wires, sorry I was desperate :-)
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Old 02-03-2013, 02:32 AM   #39188
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A few weeks ago I said that I'd keep everyone in the loop as to whether I had any problems using 16 gauge in Mod in 40+ degree C heat. Well a cool change came through the day of the race, and it was about 18 degrees instead. Result: no issue at all. (4.5 reasonably well boosted.)
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Old 02-03-2013, 04:03 AM   #39189
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Quote:
Originally Posted by Radio Active View Post
A few weeks ago I said that I'd keep everyone in the loop as to whether I had any problems using 16 gauge in Mod in 40+ degree C heat. Well a cool change came through the day of the race, and it was about 18 degrees instead. Result: no issue at all. (4.5 reasonably well boosted.)
This is interesting.

So, I recented changed to a Viper VTX-1 for it's smaller size compared with HW 1S. I am using 14 AWG now, and found that at peak, ESC can go up to 80 degree, but the motor wire register around 50+ degree. I dunno if the motor wire is heated up because of current or just heat from the ESC.

I am from Singapore, so, the weather is around 30+ degree and track temperature is about 40+
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Old 02-03-2013, 07:18 AM   #39190
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What will happen if you put shims underneath the front bulkheads? I would like to run larger front diameter tires without changing the ride height. Will raising the bulkheads change the roll center characteristics?

Cheers.
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Old 02-03-2013, 03:27 PM   #39191
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What will happen if you put shims underneath the front bulkheads? I would like to run larger front diameter tires without changing the ride height. Will raising the bulkheads change the roll center characteristics?

Cheers.
It will raise the roll centre slightly.



In terms of the diagram the whole suspension is shifted up slightly, so the lines from the tyre contact patches to the intersection of the other lines will be steeper, and hence meet higher to define the roll centre.

You can maybe compensate for this by spacing the upper arm mount position on the king-pin with washers. This, in turn, will affect the camber-gain characteristics. Take careful measurements and draw a diagram is a good way to work out what things will do without hitting the track.
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Old 02-03-2013, 07:02 PM   #39192
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Thanks for your help! I might go ahead and use a 1 mm shim and see the effects its has on the handling.
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Old 02-03-2013, 07:18 PM   #39193
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Default Help with 1/12 car

I was running my BMI 12rr today. I noticed that on my 2nd heat of the day and in the main my car would slow down quite a bit about midway and beyond. I have not measured temps over 150 on the motor - A Speed Passion 1cell v3 17.5t. I run a booster.. not a battery, battery for the car is a Turnigy 5000 40c new (1 month old). Gearing on a ozite med bite carpet was 88 rollout with a 78/47. 46mm on the rears. ESC is a old school GTB .

Seem to be fine first 4 mins of the race.. its the last half where its dropping off.. almost like a dumped pack.

Also on the endbell of the speed passion .. is there a specific A B C pin? or they just need to be the 3 phases of the magnets in clockwise direction.. if there needs to be a specific A B C .. how is it marked??

Also with brushless motors.. can you spray out the cans? what way do you clean them?

Thanks for any advice.

James
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Old 02-03-2013, 07:28 PM   #39194
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ABC on your esc should go to ABC on the motor.
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Old 02-03-2013, 07:56 PM   #39195
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Originally Posted by InspGadgt View Post
ABC on your esc should go to ABC on the motor.
Im not new...

The speed passion end bell can be rotated if I take it apart I can put the end bell back on where the C is where the A was.. etc.. unlike a motor with fixed solder points.. So .. is it ok to put the end bell back on anyway? or are their markings that require it on a certain way. Because nothing seems marked to me..

James
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