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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 02-26-2009, 02:34 PM   #30916
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Yes GRP's are made in Italy but there are several other manufacturers as well.

I suspect these will have the same foam as Jaco just a different wheel but I don't know for sure.

There are really own three types of foam (each type in various shore ratings) used for RC. It's all the same rubber, just comes in different rating systems and wheels.
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Old 02-26-2009, 03:42 PM   #30917
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Default 3.7 lipos

I know everybody is saying this 3.7 battery is working for stock. But has anybody tested using modified winds? Just curious

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Old 02-27-2009, 03:08 AM   #30918
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I know it is all down to personal choice, but I am looking to get into 12th and been offered one of two cars... a BMI 12r and a RC12 R5.....

I know the layout is pretty much the same.... but just wanted some UNBIAS!!! opinions hehehee

Many thanks

Adam
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Old 02-27-2009, 09:16 AM   #30919
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Quote:
Originally Posted by wide_mouth_frog View Post
but just wanted some UNBIAS!!! opinions hehehee

No such thing, if you've never owned or driven either you cannot form any real opinion. If you have owned or driven both then your opinion will be just that your opinion baised on your experience, which by defination will be bias. Go with the BMI.
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Old 02-27-2009, 09:21 AM   #30920
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This is just based on what I have seen and heard. I have only driven a 12R5 for a few laps and never a BMI.

The BMI kicks butt on asphalt. Also a very good carpet car but may have to play with set-up to get it right.

12R5 is good on both but IMO, 12L4 is the way to go on carpet. A lot of people say link cars are quicker on carpet but I have found T-plate cars to be quicker. Of course if you are going lipo, might as well get a link car.
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Old 02-27-2009, 10:24 AM   #30921
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The BMI drives really nice with a lipo. I'm running pretty close to the setup in the manual. I just run 50wt AE shock oil in the Silva shock and the ride hight level at 4-4-4.
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Old 02-27-2009, 10:58 AM   #30922
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I've driven neither, and have friends running both. They both will need some tweaking to suit your driving style and I think they both would work equally as well.
That said I'd opt for the small label American company rather than the big business that sold out to a Taiwan company. my .02
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Old 02-27-2009, 12:08 PM   #30923
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Quote:
Originally Posted by miller tyme View Post
I've driven neither, and have friends running both. They both will need some tweaking to suit your driving style and I think they both would work equally as well.
That said I'd opt for the small label American company rather than the big business that sold out to a Taiwan company. my .02


I love to support the smaller brands... just not sure what spares are like in the UK

Thanks for your help though chaps
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Old 02-27-2009, 02:43 PM   #30924
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Quote:
Originally Posted by wide_mouth_frog View Post
I love to support the smaller brands... just not sure what spares are like in the UK

Thanks for your help though chaps
ACM is BMI UK dealer.
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Old 02-27-2009, 02:48 PM   #30925
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The Bmi car is well supported by AMC. Great service and speedy delivery. I bought my car from them in November last year.

The web site may not be the best; but great service.
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Old 02-27-2009, 09:45 PM   #30926
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Quote:
Originally Posted by Bob-Stormer View Post
Due to the motor climbing the spur gear it's de-compressing it, not compressing it during acceleration. Axle is where it is, can't move forward. The teeth on the pinion push down, tire face wants to move forward. The motion is probably more like a 45 degree angle. The result is the car goes forward but the movement that leads to that is not horizontal (or the shock would never move). If you were to sit your car on the bench and screw the tires to the surface and give it the gas, you'd watch the pod start to lift at the nose, fully extend the shock and finally pull the front tires.
So the axle centerline ie bearings in the pod where axle is attached is above the pod pivot so pod pivots forward; balanced +/- by motor climbing force. Probably why it is possible to see more on power steering by increasing spring and/or increasing droop. For 17.5 stock I definitely feel more on power with more spring. I could also see the motor climbing the axle in mod or 10.5 and lifting the front tires.
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Old 02-27-2009, 10:57 PM   #30927
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Quote:
Originally Posted by bucknuts View Post
So the axle centerline ie bearings in the pod where axle is attached is above the pod pivot so pod pivots forward; balanced +/- by motor climbing force. Probably why it is possible to see more on power steering by increasing spring and/or increasing droop. For 17.5 stock I definitely feel more on power with more spring. I could also see the motor climbing the axle in mod or 10.5 and lifting the front tires.
but isn't that the purpose if the diff...to slip in a bind?
And wouldn't the pivot point Be the axle?
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Old 02-28-2009, 05:00 AM   #30928
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Quote:
Originally Posted by hairy View Post
but isn't that the purpose if the diff...to slip in a bind?
And wouldn't the pivot point Be the axle?
The Diff should not slip. The differential by definition adjust to different rates of wheel speed left to right. Many off-road situations see guys set it to slip to avoid breaking wheel traction. That's not a problem in 1/12 unless you have something major wrong. On carpet if the diff slips, it will heat up and usually within a run or two melt the diff balls into the spur.

I can remember the old days of setting it to slip for a foot or so, but those were loose carpet and not very advanced car designs, hell they used fuel tube as a shock. But not now, perhaps am ever so slight bit in touring to balance front and rear pull, but even then it doesn't really slip it just pulls less than the other end, and definitely not in straight axle carpet cars.
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Old 02-28-2009, 11:25 AM   #30929
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The shock definitely extends under heavy acceleration. Remember back to the early EV10 days when they still used 3 Delta shocks...people were ripping the piston right off the shaft under acceleration until they came out with the bigger shock for the center.
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Old 02-28-2009, 12:17 PM   #30930
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Default balancing l3,l4

Hi my cars seem to run fine but when placed on spikes in the centre of the chassis it tips to one side is it worth fitting weights to balance it even though it does seem to drive ok or not around 60g needed
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