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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 10-21-2007, 02:07 PM   #27196
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Default CR'07 wins Rebellion Race 2007

CR'07 wins Rebellion Race 2007 in mod once again driven by Vesa Yli. This makes it 2 times in a row now. Congratulations!! All the cars in the top 10 were t-bar cars, no link cars (I did not attend LOL)...
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Old 10-21-2007, 04:22 PM   #27197
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Hello
What ESC do you use. I'm thinking of LRP Sphere Competition (Nosram Matrix Evolution) or LRP Sphere TC-Spec (Nosram Matrix ISTC) but don't know if it is possible to unglue heat sink.
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Old 10-21-2007, 07:04 PM   #27198
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Originally Posted by Tral View Post
Hello
What ESC do you use. I'm thinking of LRP Sphere Competition (Nosram Matrix Evolution) or LRP Sphere TC-Spec (Nosram Matrix ISTC) but don't know if it is possible to unglue heat sink.
Here's a pic of Andy Moore's ride at the IIC......I'd use the one he runs
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Old 10-22-2007, 04:06 AM   #27199
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Here's a Q?

I just installed the new IRS lower arms on a couple of my cars this weekend. I knew they were universal, etc, but I had NO idea how low they are. I'm pretty sure I"ll be able to run the fronts down until the bearing shows through.

What are people using to shim these up for initial tire size? Starting with 45-46mm fronts I was using TWO full packs of FibreLyte shims (6mm worth per side) to get my car to 4mm. While this isn't necessarily a problem, per se (though I need 2 more packs to do my third car ) I AM concerned that the 8-32 mounting screw is really only about half way (may less) through the arm at that point. I'm afraid a hard(er) hit could rip this out. Unfortunately these are the "long" Lunsford Ti mounting screws.

What are others who have these arms using to shim to height. I guess at this height I'm just needing "filler". Maybe it's time to dig those 1/16" washers back out that kits came with forever to "shim" front ends.
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Old 10-22-2007, 04:34 AM   #27200
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BMI Racing makes machined aluminum one piece shims for the IRS lower arms in .5mm increments so you can hit any ride height you want with any size tire.

They are sold in sets of 4 in each of 6 height steps from 5mm to 2.5mm. Pics will be on www.bmiracing.com shortly.

IRS also sells plastic shim kits in .200" and .100". By stacking these up you can get by pretty well too. You can get them from IRS or BMI.

Quote:
Originally Posted by Scottrik View Post
Here's a Q?

I just installed the new IRS lower arms on a couple of my cars this weekend. I knew they were universal, etc, but I had NO idea how low they are. I'm pretty sure I"ll be able to run the fronts down until the bearing shows through.

What are people using to shim these up for initial tire size? Starting with 45-46mm fronts I was using TWO full packs of FibreLyte shims (6mm worth per side) to get my car to 4mm. While this isn't necessarily a problem, per se (though I need 2 more packs to do my third car ) I AM concerned that the 8-32 mounting screw is really only about half way (may less) through the arm at that point. I'm afraid a hard(er) hit could rip this out. Unfortunately these are the "long" Lunsford Ti mounting screws.

What are others who have these arms using to shim to height. I guess at this height I'm just needing "filler". Maybe it's time to dig those 1/16" washers back out that kits came with forever to "shim" front ends.
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Old 10-22-2007, 05:40 AM   #27201
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Which part number did you buy?
IRS4221 comes with 2 arms, 4 screws, 4 0.100" thick & 4 0.055" thick spacers.

IRS4220 is just the 2 arms.

With the IRS4221 kit w/spacers and 44.5mm tires, I use one thick and one thin Fyberlite spacers to get a 3.3mm ride height on a 2mm chassis.

I have not broken any arms over 3 months, you just can't over tighten the front screws.

Good Luck
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Old 10-22-2007, 05:47 AM   #27202
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Quote:
Originally Posted by Scottrik View Post
What are people using to shim these up for initial tire size?
I highly recommend using the machined BMI shims that Adrian mentioned. I don't like stacking a whole series of washers because if you hit something they can shift which causes the whole arm assembly to get out of alignment (messing up toe and camber). With the shims BMI the whole front end is a lot more solid.

-Rich
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Old 10-22-2007, 06:53 AM   #27203
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Which part number did you buy?
IRS4221 comes with 2 arms, 4 screws, 4 0.100" thick & 4 0.055" thick spacers.

IRS4220 is just the 2 arms.

With the IRS4221 kit w/spacers and 44.5mm tires, I use one thick and one thin Fyberlite spacers to get a 3.3mm ride height on a 2mm chassis.

I have not broken any arms over 3 months, you just can't over tighten the front screws.
I bought just the arms since I figured (erroneously, as it turns out) that I already have screws I love (the Lunsford screws use 3/32 hex rather than the easy to strip Phillips head) and a butt-load of shims (4 full sets of FibreLyte shims and 3 sets of CRC).

I'm inclined to get the BMI spacers as mentioned (thanks Adrian [like I couldn't have seen THAT recommendation coming...] and Rich) but would like to get longer screws now since I really would like to be in more "meat" into the arms themselves. I'll see if I can get Lunsford to do some longer screws, then maybe go back to the screws I've got as the shim load decreases.

Now HERE'S a question/observation. I know we've always had to be watching weight if we are close to minimum (and my cars are VERY close) as tires wear, etc. Especially with the machined aluminum, but even with the huge stack of carbon fibre shims I'm using I'd think the weight difference between full stack (large BMI shim) and minimum (smallest BMI shim...I'm guessing we NEVER get to where the arm is flat to the chassis or you'll be dragging the kingpins . Maybe Adrian can weigh the largest and smallest spacers and report either the single or, ideally, the pair weights so we can see how much we need to adjust for.

Thanks all,

Scottrik
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Old 10-22-2007, 07:13 AM   #27204
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I will weigth them tonight if I can find my little scale. They are pretty light though. The thickest ones don't feel like much weight in your hand. A set of 4 is probably a couple of grams.

We though about using delrin but it is only very slightly lighter and it could certainly get mushed the way some of you guys crash...lol!
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Old 10-22-2007, 09:26 AM   #27205
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You can always try those white tamiya 1150 bushings as spacers. That's what I use in my 10th pancar if I need to fill a large gap.
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Old 10-22-2007, 05:08 PM   #27206
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This isnt the best picture but it will give you the idea. They are all referance with dimples for size. There are 6 sizes and they go in .5mm increments. They are specific for the IRS arms.
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Old 10-22-2007, 05:38 PM   #27207
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I don't like using non-metal spacers. The plastic ones can compress and also cause the arm to get cocked if the screw is not in straight. That can cause problems with tweaking the car/uneven chassis heights.

-Rich
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Old 10-22-2007, 05:50 PM   #27208
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I'm likely to go with the BMI spacers...Jason has, as usual, outdone himself with those.

Have any of you gone to longer screws? I was surprised that my existing 7/16" Lunsford screws just reach a little more than half way through the arms when they're perched up there to accomodate 45-46mm tires.

As far as plastic shims, I don't think I'd use the Tamiya bushings but the CRC plastic shims are fine. If you're compressing those you're twisting 'em down too tight Hercules! And I KNOW the carbon fibre ones aren't compressing. In fact I'll hang onto all the white (.010") shims out of my CRC kits as they'll serve the same purpose they do with my FibreLyte shims...they'll make good half-step units with the BMI spacers since they're approx .25mm.
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Old 10-22-2007, 06:15 PM   #27209
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I haven't used any longer screws. I am like you and just use the Lunsford ones. But, mine seem to be pretty long - with the 4mm BMI shims, the screw goes to right below the top of the screw hole.

I forgot about the carbon fiber spacers -- those look awesome.

Hercules. LOL!

-Rich


Quote:
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I'm likely to go with the BMI spacers...Jason has, as usual, outdone himself with those.

Have any of you gone to longer screws? I was surprised that my existing 7/16" Lunsford screws just reach a little more than half way through the arms when they're perched up there to accomodate 45-46mm tires.

As far as plastic shims, I don't think I'd use the Tamiya bushings but the CRC plastic shims are fine. If you're compressing those you're twisting 'em down too tight Hercules! And I KNOW the carbon fibre ones aren't compressing. In fact I'll hang onto all the white (.010") shims out of my CRC kits as they'll serve the same purpose they do with my FibreLyte shims...they'll make good half-step units with the BMI spacers since they're approx .25mm.
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Old 10-22-2007, 10:45 PM   #27210
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This isnt the best picture but it will give you the idea. They are all referance with dimples for size. There are 6 sizes and they go in .5mm increments. They are specific for the IRS arms.
Saw these Sunday and they are a must have. Super trick..
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