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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 10-05-2011, 07:08 AM   #36616
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Quote:
Originally Posted by bucketboy View Post
Thanks for that, I'm running a 10.5 HPI at the mo because I already had one.
As for addative, put all over rear, 1/2 front about 10 mins before a run. Not going to bother changing srings battery position, or any of the other stuff just yet because after running 1/10th TC for the past 15 years its nice to be able to plonk a car on the track and have it go pretty much where you want it to go straight out of the box Might need to review that statement after the first race though

Deffo going to invest in a box of these http://www.ace-safetywear.co.uk/stor...wipe-250s.html

Bb
Be careful with industrial strength wipes not to touch any sensitive bits after using them!

CRC setup, not much to change from kit anyway to get thereabouts. Long arm front end if you haven't already, possibly metal pin brace. Cells forward, 15K in the side dampers. Absolutely everything else as in the kit and instructions and you'll have a good starting point for any track at the UK 12th nationals.

If your HPI 10.5 has the standard rotor try a rollout of 70mmpr.

Trev
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Old 10-05-2011, 07:59 AM   #36617
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+1 on the baby wipes!!

Use them after each time you wipe off your tyres and your hands will be just fine, and they may smell quite plesent as well!

Trev, Fred Hatfield has made up some very long front arms for me to try with that cross brace I am making, will show you at the Ardent national if you are making it there mate (and the rest of the CRC based car I have made!).

Cheers,

Chris.
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Old 10-05-2011, 08:02 AM   #36618
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Quote:
Originally Posted by andrewdoherty View Post
I expect the longer arms will effectively soften your spring rate as well.
Hadn't thought of that, but you are undoubtedly right. Not enough to compensate for the loss of camber gain though. Long arms definitely reduce steering.
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Old 10-05-2011, 08:17 AM   #36619
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Am I blind... or is the battery in the center of that CRC 1/12?

http://rc50.com/modules/coppermine/a...1/IMG_1282.JPG
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Old 10-05-2011, 08:25 AM   #36620
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Originally Posted by JamesL_71 View Post
Am I blind... or is the battery in the center of that CRC 1/12?

http://rc50.com/modules/coppermine/a...1/IMG_1282.JPG
It's the new square lipo...lol

JK yea looks like centered
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Old 10-05-2011, 08:35 AM   #36621
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Originally Posted by andrewdoherty View Post
I expect the longer arms will effectively soften your spring rate as well.
The steering block and spring still have the same relationship, so the leverage put on the spring when the wheel moves up and down should remain the same, right? If the springs were mounted inboard and somehow still attached to the upper arm then it would probably soften the rate
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Old 10-05-2011, 08:55 AM   #36622
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Serzoni, I'm thinking the same way you are.

The only thing that might make the spring feel softer is the change in front roll center with such a long top arm. I haven't sat down to work out the math yet, but it could allow the front to roll more, possibly giving more steering than was lost with the reduced camber gain.

It's also entirely possible I'm thinking backwards since I haven't sat down to draw things out yet either.

I would say with an extremely long top arm, the inner hinge height is going to have more effect on RC and front grip than spring selection and any loss of camber gain. As said before, arm sweep should be the same, so caster and reactive caster feel should remain unchanged.

Basically, I don't know that anyone's ever tried it, so we're all guessing right now.
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Old 10-05-2011, 08:59 AM   #36623
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Serzoni, I'm thinking the same way you are.

The only thing that might make the spring feel softer is the change in front roll center with such a long top arm. I haven't sat down to work out the math yet, but it could allow the front to roll more, possibly giving more steering than was lost with the reduced camber gain.

It's also entirely possible I'm thinking backwards since I haven't sat down to draw things out yet either.

I would say with an extremely long top arm, the inner hinge height is going to have more effect on RC and front grip than spring selection and any loss of camber gain. As said before, arm sweep should be the same, so caster and reactive caster feel should remain unchanged.

Basically, I don't know that anyone's ever tried it, so we're all guessing right now.
Since we're guessing...lol...it will give initial turn in but no real steering then once through the corner it will push again. Also probably has better high speed steering but with 12th steering is not "usually" something you have to hunt down unless your like me and like and excessive amount of steering

Just ask Lonny how much steering I like. I let him drive my car once at Tuscon...lol
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Old 10-05-2011, 09:38 AM   #36624
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Better pic... looks to be a new CRC:

http://rc50.com/modules/coppermine/a...1/IMG_1377.JPG
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Old 10-05-2011, 09:43 AM   #36625
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Quote:
Originally Posted by wingman2 View Post
+1 on the baby wipes!!

Use them after each time you wipe off your tyres and your hands will be just fine, and they may smell quite plesent as well!

Trev, Fred Hatfield has made up some very long front arms for me to try with that cross brace I am making, will show you at the Ardent national if you are making it there mate (and the rest of the CRC based car I have made!).

Cheers,

Chris.
Chris, I've seen Fred's car when he tried them, I should have some photos lying around too.

Looking forward to seeing your car at Ardent national. Will be taking plenty of photos, might be doing them for RRCI mag.

Trev
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Old 10-05-2011, 09:46 AM   #36626
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Originally Posted by JamesL_71 View Post
Better pic... looks to be a new CRC:

http://rc50.com/modules/coppermine/a...1/IMG_1377.JPG
Not that much new there to be honest. Cell the other way round, one new piece of carbon. I think using existing chassis holes. All else existing or old parts. And the short cell so it fits.

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Old 10-05-2011, 09:49 AM   #36627
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Originally Posted by JamesL_71 View Post
Better pic... looks to be a new CRC:

http://rc50.com/modules/coppermine/a...1/IMG_1377.JPG
Sweet ride however since we're on topic of what things do I know that crc usually sets servo on angle like it says here in the crc page yet here the servo is flat and steering rods straight

"Also, the Gen-XL comes stock with the servo mounted "up". While some put the servo down and flat, that configuration leads to terrible bump steer as the geometry of the front suspension is compromised in such a position. With the servo up on mounts, the steering tie rods are parallel to the upper suspension arm. As the car rolls in the corners and hits bumps, this parallel position keeps the steering angle consistent. With servo down, each bump and weight transfer initiates a drastic change in the steering angle"

So I won't do a cool drawing but what do you guys think about the different steering setups
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Old 10-05-2011, 09:58 AM   #36628
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Sweet ride however since we're on topic of what things do I know that crc usually sets servo on angle like it says here in the crc page yet here the servo is flat and steering rods straight

"Also, the Gen-XL comes stock with the servo mounted "up". While some put the servo down and flat, that configuration leads to terrible bump steer as the geometry of the front suspension is compromised in such a position. With the servo up on mounts, the steering tie rods are parallel to the upper suspension arm. As the car rolls in the corners and hits bumps, this parallel position keeps the steering angle consistent. With servo down, each bump and weight transfer initiates a drastic change in the steering angle"

So I won't do a cool drawing but what do you guys think about the different steering setups
In reality CRC drivers have always been divided as to having the servo up or down. If adjusted correctly it doesn't really make that much difference. On the car in the photo the servo is probably down just to make room for everything else.

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Old 10-05-2011, 10:04 AM   #36629
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Originally Posted by TrevCoult View Post
In reality CRC drivers have always been divided as to having the servo up or down. If adjusted correctly it doesn't really make that much difference. On the car in the photo the servo is probably down just to make room for everything else.

Trev
I thought it might be down to make stuff fit just curious

On my last car I had it flat with link slightly forward never straight

in the early 90's we used to put link way forward so wheels would turn the same exactly almost
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Old 10-05-2011, 10:08 AM   #36630
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The availability of lots of shims pretty well take the bump steer element out of the equation these days, if done correctly.

Servo angled or flat comes down to personal preference on akermann, and steering aggression.

Since you see both so often, it's safe to say they both work when matched to an individuals preference.
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