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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 12-25-2011, 09:23 AM   #37381
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Originally Posted by DesertRat View Post
When running reactive caster, what should be the relationship between its resting angle and its compressed angle? Is the objective to bring the caster angle to zero at full compression or is that a bad starting point? I have read the canned version of what all of the different settings can do for the car performance at X-Y-Z in the corner but what is the preferred motion to go for for maximum corner speed?
Pre RC you would have the same castor on and off power except for the lean of the car. With RC you have less castor hence more turn in going into the corner so you can go into the corner harder. So the balance would be static castor setting to less when turning in

So ultimately if you have the on-power steering you want but need more turn in use more reactive castor. As I've been watching the setup sheets seems the in-line cars are using more reactive yet the SM cars are just using the OS ft end and say they are getting great results and they have no RC

So I guess RC helps set overall castor per track/condition
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Old 12-25-2011, 09:49 AM   #37382
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I hear a lot of different arguments for and against running hardened diff balls.

For those of you who are no longer running the stock steel balls, are you using the ceramic/silicon-nitride balls? Or the tungsten-carbide balls?
I use ceramics and I see NO downside. My diffs are as smooth or even smoother than ever, and so far they have held up forever. My CRC has a set in it with three winter seasons on them and are still perfect. My new CEFX car got the balls out of my old 12L4 which had 2 or 3 seasons on them and are still going strong in the new car.
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Old 12-25-2011, 10:18 AM   #37383
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I use ceramics and I see NO downside. My diffs are as smooth or even smoother than ever, and so far they have held up forever. My CRC has a set in it with three winter seasons on them and are still perfect. My new CEFX car got the balls out of my old 12L4 which had 2 or 3 seasons on them and are still going strong in the new car.
Ive read/heard that the ceramic balls do not allow the diff to be run as loose without slipping... And that it can be beneficial to run looser differentials in the slower blinky(17.5) 12th classes?
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Old 12-25-2011, 12:26 PM   #37384
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Originally Posted by JamesL_71 View Post
I hear a lot of different arguments for and against running hardened diff balls.

For those of you who are no longer running the stock steel balls, are you using the ceramic/silicon-nitride balls? Or the tungsten-carbide balls?
I bought twelve pure silicon-nitride differential balls from Avid at $1 each, and they don't wear out. This is combined with a Slapmaster thrust bearing and I really don't bother doing diff maintenance unless I think its just too dusty. When I do, I just sand the diff rings and clean out the dirt, reassemble, and go. This combination of silicon balls and the thrust bearing is the best money I ever spent on R/C.
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Old 12-25-2011, 12:52 PM   #37385
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Ive read/heard that the ceramic balls do not allow the diff to be run as loose without slipping... And that it can be beneficial to run looser differentials in the slower blinky(17.5) 12th classes?
I don't see the difference. If there is one, it is very negligible.
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Old 12-26-2011, 02:58 AM   #37386
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The biggest (and maybe the only) advantage of steel balls is the price. You can get 100 diffballs for less than 10$. Maybe, steel ball bearing balls are even better than some cheap ceramic balls because of the lower tolerances.

If your laptimes are not all within a few 10th of a second, ceramic diffballs won't make you faster.
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Old 12-26-2011, 03:01 AM   #37387
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Originally Posted by Der Dicke View Post

If your laptimes are not all within a few 10th of a second, ceramic diffballs won't make you faster.
Except with ceramics, you can spend more time on the track and less time wrenching.

OK, probably not really a difference in on track time but I always go for lower maintenance.
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Old 12-26-2011, 07:27 AM   #37388
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As most of the current 1/12th chassis makers are switching to inline battery setups, how much/what is the difference between those that have the cell centrally located and those that have the cell offset with electrics beside it. I'm purely talking about balance/handling here not the practicality of having more space for electronics.
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Old 12-26-2011, 08:28 AM   #37389
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pretty new to 1/12 and was wondering what effect does reactive caster have on the car? thanks
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Old 12-26-2011, 08:51 AM   #37390
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Originally Posted by Conrad View Post
As most of the current 1/12th chassis makers are switching to inline battery setups, how much/what is the difference between those that have the cell centrally located and those that have the cell offset with electrics beside it. I'm purely talking about balance/handling here not the practicality of having more space for electronics.
Id be interested in hearing what differences people have found from a strictly weight-distribution point of view.

However, I think it is difficult to quantify exactly what the "inline battery" feature really does, considering that most of the "inline" chassis are longer and have a slightly wider front-end than their transverse layout brethren.

Quote:
Originally Posted by racer x 1 View Post
pretty new to 1/12 and was wondering what effect does reactive caster have on the car? thanks
I thought we covered this a page or two ago, but maybe that was the AE 12R5 thread.

You need to understand how caster affects the dynamic camber curve of the front suspension. For most strut style suspensions, a greater caster angle will produce a greater camber gain during the suspensions compression arc. From what I understand, the reactive caster tends to increase the caster angle as the suspension compresses. So, at the beginning of the corner, at your turn-in point, you will have less caster... which translates into a very responsive car. As the suspension compresses through the middle of the corner, the caster angle increases... thereby reducing the positive camber of the outside tire, and allowing it a higher degree of grip.

So with reactive caster, you end up with a car that potentially has the "best of both worlds". Ie: Low caster angle at turn-in, which gives the car lots of turn-in steering and response... And high caster angle at corner exit, which gives the car more exit steering.

If you were to simply dial in your caster angle from a static point of view, ie: without any reactive caster, you would have to make more compromises. A lot of static caster can increase your steering at corner exit and increase your straight line stability... which may be favorable at your given track/circuit. But it may make the car a bit too lazy at turn-in/corner entry for your liking. This is a situation where reactive caster could be used beneficially.

However, nothing is as cut and dry anymore with brushless and lipo batteries. The Speed Merchant cars with the "new old school" front end(with no reactive caster) seem to be doing fantastic, especially in the slower stock classes.


Edit: It is also worth noting that with a standard front suspension, with no reactive caster, the camber angle changes as a function of caster angle, toe change(wheels being turned), Steering Axis Inclination, front roll center height, and suspension position(Z-height). With caster as a static quantity, the equation to find the resultant camber angle is complicated enough. With reactive caster, we are adding another 1st order differentiable variable to this equation, as the caster angle is now changing as a function of suspension position.

One would have to measure all the suspension pickup points and length of the control/lever arms and do a full kinematics analysis to determine the true camber curve. I would actually be very interested in seeing the results of that study.

Last edited by JamesL_71; 12-26-2011 at 09:13 AM.
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Old 12-26-2011, 10:24 AM   #37391
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So I currently race both 17.5 12th and touring, and am trying to figure out my motor choice for both of them. I have a D3 as well as a Speed Passion handout from this past IIC with the 10 degree endbell. Is one of these motors better suited to 12th scale than the other? I have tried swapping them back and forth between the two cars and the only real difference I notice is that the SP feels "smoother" than the D3, but not necessarily faster. Lap times are about the same for both, even with gearing changes to account for the SP's timing. Both motors are running fairly cool (come off at 110 degree max after 8 mins), so I can't help but wonder whether I am just missing something. Really though, I am curious whether one of the motors is widely regarded as being better suited for 12th scale than the other one? Any thoughts? Thanks for any and all help or advice, it is greatly appreciated.
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Old 12-26-2011, 08:43 PM   #37392
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I would like to get a 1/12th scale car and be able to run in the winter at the local carpet track. I have a LRP SXX TC ver.1. Do I need to get a booster to run my electronics on 1s, or should I run a receiver pack? Can you guys recomend a cheap decent servo?
Thanks
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Old 12-26-2011, 09:00 PM   #37393
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I would like to get a 1/12th scale car and be able to run in the winter at the local carpet track. I have a LRP SXX TC ver.1. Do I need to get a booster to run my electronics on 1s, or should I run a receiver pack? Can you guys recomend a cheap decent servo?
Thanks
Beau
Not sure on the speedo

Servos, Futaba 9650 or whatever those two good JRs are (I can never remember the number even though I have one). Avoid HiTechs at all costs. I hear good things about Savox and KO but have never tried them.
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Old 12-26-2011, 09:18 PM   #37394
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+1 on the Futaba. It's hard to beat the 9650 on value. It's a proven item, and a reasonable price. The SXX V1 will require a booster or receiver pack.
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Old 12-26-2011, 09:25 PM   #37395
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+1 on the Futaba. It's hard to beat the 9650 on value. It's a proven item, and a reasonable price. The SXX V1 will require a booster or receiver pack.
Which would be better a booster(which one), or a reciever pack( any recomendations on size and brand)?

Thanks for the quick replys
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