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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 01-30-2013, 05:33 AM   #39166
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Originally Posted by Peakki View Post
Anyone else tried Kawada super diff gears?
Bought some, not yet driven though.
18 diff balls on those!

I got tired of newest Xenon gears which keep going bad, no matter what I do.
It would be so nice if Xray did a durable 16/18 ball diff...

btw. Looking at some pics from Xray Racing Cars from Snowbirds. Hagberg has a car with similar electrics layout as a AE R5.2. Interesting.
I've been happy with the Kawada gears I've used.
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Old 01-30-2013, 06:42 AM   #39167
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Originally Posted by howardcano View Post
Hey Jason, that's great.

I did notice the suggestions "Move Battery to Center of Car" and "Move Battery Toward Left Side". I assume that this is for oval racing?
Yes sorry that version I didn't edit that our it's for oval. For battery placement Rear location gives you more steering and frees up the rear end to rotate
The front position will give you less steering and more rear traction
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Old 01-30-2013, 07:01 AM   #39168
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Hello.
Could someone post a good tekin 1S boosted 13.5 setup please.

Thank you.

Dave.
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Old 01-30-2013, 09:49 AM   #39169
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Quote:
Originally Posted by Peakki View Post
Anyone else tried Kawada super diff gears?
Bought some, not yet driven though.
18 diff balls on those!

I got tired of newest Xenon gears which keep going bad, no matter what I do.
It would be so nice if Xray did a durable 16/18 ball diff...

btw. Looking at some pics from Xray Racing Cars from Snowbirds. Hagberg has a car with similar electrics layout as a AE R5.2. Interesting.
What issues have you had with the Xenon VSS gears? I know people who have run the same spur for over a year from them?
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Old 01-30-2013, 09:56 AM   #39170
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How big of a factor for a class like 17.5 or 13.5 blinky is weight on a 1/12?

I have 2 V-Dezign cars, and have been having issues getting one to work as good as the other. They are exactly the same chassis setup (springs, caster kingpin angle, preload, droop, tires...) but the main difference is weight.

The 17.5 car (the one that works quite well right now) - is @ 740gm ready to race. The 13.5 car (the one that isn't working) - is a @ almost 780. I swapped motors between cars and the 13.5 car instantly went 2/10 quicker per lap than it could in the 13.5 chassis. So something has to be up with that chassis.

The reason for the heft on the 13.5 car is the HW 1S ESC and the balance weight (10gm) needed to get the car to be balanced side to side. There were also some heavier wires on the 13.5 car for the chance I ran Mod with it. I replaced those and saved a few gm.

The 17.5 has the very light HW Justock ESC on it, and is perfectly balanced with out any lead on the chassis.

So overall my question is down to - how much of an effect should 40gm have on the handling/efficiency of a 1/12? I am going to test this by pulling the portly 1S off the car and replacing it with a Justock to match my other car (the Justock can handle a 13.5 blinky just fine).

This is more of a question if people found dropping that kind of weight transformed a car, or if it really wasn't that big of a deal.
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Old 01-30-2013, 09:59 AM   #39171
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Quote:
Originally Posted by mtbboy View Post
Hello.
Could someone post a good tekin 1S boosted 13.5 setup please.

Thank you.

Dave.
Won a lot of races with this one:

Start RPM 4569
End RPM 13008
Ramp 3.0
Delay 0.42S
Timing 1: 43
Timing 2: 10
Throttle: 3
Gearing 48mm

Regards Robert
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Old 01-30-2013, 10:26 AM   #39172
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Originally Posted by Clegg View Post
So overall my question is down to - how much of an effect should 40gm have on the handling/efficiency of a 1/12?
I have two CRC XTi's, one has the shorty battery ahead of the VTX1 ESC and the other is configured normally with a Speed Passion 2.1EX ahead of the full battery with both using the airtronics servo and everything else being equal. The lighter car for me is generally about 2 tenths of a lap faster in 17.5 and 13.5 blinky.

The weights for the cars are 727 grams for the normal one and 652 for the light one (and no, that isn't a typo).
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Old 01-30-2013, 10:31 AM   #39173
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Wow that's a damn light car! Isn't 730 the min weight for ROAR races? I could drop more weight on the car with Aluminum hardware, but I figure keeping a few gm above the min keeps me safe for when the tires burn down to nothing and I use a lighter shell at a bigger race.

And that sounds like what I am seeing from a weight/performance standpoint, thanks for confirming!

So now the other question is : is it better to be light and off balance, or heavy and balanced?
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Old 01-30-2013, 10:38 AM   #39174
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Go light, if you can't get it balanced without lead don't worry to much.
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Old 01-30-2013, 11:34 AM   #39175
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Yes, 730 is the minimum for ROAR. We follow very loose rules at our local track and onroad isn't as big as it should be. We usually have a mix of 17.5 and 13.5 cars and the only driver that can match my pace usually runs his slower 13.5 while I run my 17.5 in the normal weight or light weight car.
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Old 01-31-2013, 04:07 AM   #39176
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Default Adjust a main chassis plate Xi

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?
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Old 01-31-2013, 05:26 AM   #39177
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Quote:
Originally Posted by Clegg View Post
How big of a factor for a class like 17.5 or 13.5 blinky is weight on a 1/12?

I have 2 V-Dezign cars, and have been having issues getting one to work as good as the other. They are exactly the same chassis setup (springs, caster kingpin angle, preload, droop, tires...) but the main difference is weight.

The 17.5 car (the one that works quite well right now) - is @ 740gm ready to race. The 13.5 car (the one that isn't working) - is a @ almost 780. I swapped motors between cars and the 13.5 car instantly went 2/10 quicker per lap than it could in the 13.5 chassis. So something has to be up with that chassis.

The reason for the heft on the 13.5 car is the HW 1S ESC and the balance weight (10gm) needed to get the car to be balanced side to side. There were also some heavier wires on the 13.5 car for the chance I ran Mod with it. I replaced those and saved a few gm.

The 17.5 has the very light HW Justock ESC on it, and is perfectly balanced with out any lead on the chassis.

So overall my question is down to - how much of an effect should 40gm have on the handling/efficiency of a 1/12? I am going to test this by pulling the portly 1S off the car and replacing it with a Justock to match my other car (the Justock can handle a 13.5 blinky just fine).

This is more of a question if people found dropping that kind of weight transformed a car, or if it really wasn't that big of a deal.
Balance is extremely important. If the car is not balanced perfectly(this goes for any pan car) you will need to compensate by applying uneven spring tension to tweak the car. This will preload one spring more than the other just to get the car tweaked. Springs ramp up in spring rate as they are compressed so in order to get the same movement left and right with a spring preloaded on one side, you effectively have 2 slightly different spring rates on each side which will make for an ill handling car. I hope this makes sense.

Also take a look at the caster in your front end left and right. Sometimes this can get knocked off a little in a crash causing different caster angles. Shims can be ok but the turnbuckle kicks off inside of the eyelet or upper arm.
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Old 01-31-2013, 05:50 AM   #39178
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@Clegg: If you want an easy way to determine if it's the weight that is making one car handle worse than the other try this: add weight to the light car to get it to match the ill handling one. If it goes as badly then you've found the problem.
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Old 01-31-2013, 11:41 AM   #39179
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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?
There are companies out there that do that but it is generally quite expensive...especially for a one-off chassis. Penguin RC did some great work for me on something I needed a fair amount of so the cost was reasonable. But for 1 chassis plate it will be pricey.

Best bet would be to use some scrap graphite from an old broken chassis and Dremel a piece to mount the servo to.
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Old 01-31-2013, 12:33 PM   #39180
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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.
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