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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 11-02-2008, 09:32 PM   #29671
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Hi everyone,

I did my first runs on saturday during a club training.
I was the only one with a 1/12th and as I'm new to this scale and haven't driving an rc car for a wide, thing weren't such easy. All other were using TC chassis.

The track was smooth (excepted two carpet joints) high traction, it's an oval track with an infield, everything fitting in 75inx35in, the oval track is inclined for some degrees in the straight.

My car is an 12L3, purchased almost two years back, when the 12L4 was AE flagship, knowing the car will suffer some damage.

Here is the used setup:

Front:
Springs: 0.018
Tyres: Jaco Purple brand new
Treatment: none
Toe-in: maybe 1deg, but here are some questions
Caster: 10 deg, all shims backward
Ride height: Approx 4.5mm, I use CRC spacers and get the medium and slim ones on the car

Rear:
Center spring: Green
Oil Shock: not sure, 30wt
Tyres: Jaco Grey brand new
Treatment: none
T-Bar: 0.063in
Ride Height: Approx 4.5mm, spacer 4 up
Roll stpo insert: none

Others
Body: Speed 8
Motor: Co27
Pinion: 18
Spur: 76
Battery: EP4600
ESC: QC2

Now, knowing that, I have some issues and questions. That might sound pretty easy for experienced racers!

Some screws came loose, both from the T-bar as well as the one from the servo support (the L4 one). I haven't put any loctite on the screws to avoid any permanent locking. Do someone have a reference for a little effect loctite? I manage to fix the servo support screws with nylon nuts.

Tweaking the car, well I might grab the manual as reference even if I manage to tweak with two coins and being a bit patient.

The main issue is the front end.

I get plenty of play on the steering. I did change the ball studs and pivot joints when I refresh the car but still the same. Is there any tricks to limit the play? What do you use as ball studs and pivot joints? The point is that I'm not sure the car goes straight (remind the banked track)

Also, I install 0.018 front spring, they were new, the old ones might be 0.016 or softer. After let say 15-20 minutes, they get loose, both wheel can travel freely vertically. Did that happens to someone? I'm thinking to add some spacers on the hinge to compensate the loose travel. When installing, springs were fitting perfectly.

Last one! One of the rear tyre get radially cut from about a centimeter and unglued from the rim. I thought using CA to put everything back in one piece, does that sound right?

One regarding the rear end, or the shock exactly. How do you dismount it?

Every input is welcome, I'll go back to the track in two weeks time.
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Old 11-02-2008, 10:10 PM   #29672
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I just reliezed my font end is loose to. The springs sagged alittle. More on one side to, what should I do?
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Old 11-02-2008, 11:52 PM   #29673
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Arno:
Well.... 12th scale can be difficult when getting started. It will take a while, so keep your chin up. It's a blast when you get it right. From your set up, consider changing this:
Front springs .020
Caster shim front and back
Fr toe slightly out
ride height 3.5mm
shock is good at 30wt & green spring - preload spring for even chassis ride height
rear ride height at 3.5mm

We use CA on the tires all the time, don't glue your fingers!

Assuming that you are using Jaco Prisms, they come out of the box at 1.80" or what is that other number... 47.5mm. Also assuming you have 48 pitch gears with the numbers you provided, your roll out is a bit low for a stock motor on that size of track. I would think that you could easily gear up to a 20-21. Most 12th racers use 64 pitch gears for finer adjustments.

Just roll the ball cup of the shock off with a set of needle nose pliers, snap it back on with the same pliers.

Consider using the same traction compound the touring guys are using. If you are lucky, they are using Paragon. Apply 100% to the rears and 50% to the insides of the fronts for 10 minutes, wipe off with a towel. If you are using Jack the Gripper or TQ, apply for 15 minutes and wipe off. Niftech about 10 minutes, no wipe. Apply more or less to the fronts based on the amount of steering needed.

Some 12th run better with a little slop in the ball cups, don't worry about it right now.

Blue Loc-Tite = no fear.

Good luck!
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Old 11-03-2008, 07:07 AM   #29674
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I was over at gearchart and on a whim I was going to create a chart for MPH using a brushless motor... I could not find the rom for thr brushless motors...
Anyidea where I can find them?

THX
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Old 11-03-2008, 07:40 AM   #29675
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Quote:
Originally Posted by mauromj View Post
I just reliezed my font end is loose to. The springs sagged alittle. More on one side to, what should I do?
Springs are pretty cheap, throw out the set you have now and put in a new set. Check to see how much vertical play there is and take it out with shims. If there is ever any extra play in the vertical movement of the knuckle, replace the springs, as that is an indication that they are collapsed. Consider front springs as a wearable item, and keep a bunch in your spares box. With the AE front suspension, keep an eye on the pivot balls. If they are developing slop, you will want to fix that...
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Old 11-03-2008, 08:56 AM   #29676
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The front springs should have a little bit of droop when the car's at ride height ready to race. If the springs are loose when you have the car up in the air then you have to check things out a little.

All of the springs will take a set after a few runs. I normally re-shim the springs so that I get the same droop on both sides and it's fine (shim under the spring at the e-clip). If you have to add more than .030" of shims to get the droop correct with 20 front springs they're probably collapsed from a crash and should be replaced.
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Old 11-03-2008, 04:45 PM   #29677
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Hey guys . If anyone was gonna buy a conversion for the L4 whos would you buy? Who has the stiffest chassi also? Thanks..
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Old 11-03-2008, 05:43 PM   #29678
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Not many companies make a conversion anymore that I can think of...most have gone into making their own cars. As far as which chassis is the stiffest that would probably be the Slapmaster due to it's molded carbon fiber chassis.
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Old 11-03-2008, 06:22 PM   #29679
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Just wanted to post some feedback on something I tried this weekend. We have a large low bite carpet track (when not sprayed) that is a little on the bumpy side. I tried one of the Slapmaster low roll center Tplate pivot sockets this weekend and must say it does all it says it will. It kept the car and traction consistent the whole 8 minute run and actually seemed to smooth the car out a little over the bumps (couldnt explain this one). Rear tires seem to wear less as well.

For anyone looking for a little more rear bite without going softer on tires this is the ticket.

Dont forget the Thrust bearing! Best diff investment you'll ever make!

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Old 11-03-2008, 09:09 PM   #29680
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Thanks for the feedback, that will be helpful! I'll fix some stuuf on the car and run it again.

Regarding tyres, I drove with tyres on old rims, the small diameter one. I have a set F/R of Prisms They have the same diameter as the Prisms. The local drivers use Paragon (white and pink can) as far as I could see

Here is the small problem about tyre. On this picture, the foam is cracked/cutted on the side and it is ungued from the rim. I guess using CA won't be a problem to fix the tyre and avoid losing one piece of foam



Also a overview for the car ready to go for the first run.



One forgotten issue, the servo is not centered. When I install it, I thought that was good, but no. the steering links get the same length but I would like to have the axis along the car axis. Is it any was to center it? The chassis is the one from the L3

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Old 11-03-2008, 10:03 PM   #29681
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Thanks Eric!

All of my local tracks use Jack (we affectionally call Jack the Slipper). It's good for touring cars, but it's challenging for 12th scale guys. Jack gets the tires gummy about 6 minutes into a run causing the car to oversteer. The weight bias helps with the "gummies', but if you want to bolt in instant grip to your t-bar ride.... try one of these out. I call them LRCS or low roll center sockets. The ball sits .050" lower, so does the machined socket in the one piece delrin. It does not rake the t-bar or cause clearance issues. The ball is hard coated to last a long time. The 12th scale socket (#116) comes with blue and red 2-56 replacement screws while the 10th scale oval kit (#117) comes with 2 lrcs with either red or blue screws. If you run an oval car ( I know..... 12th scale thread) with a 3 shock rear end without tweak screws, you need two sockets or you will rake the pivot center line.

If your local track gets rolled out every weekend or is just low to med in grip, these sockets are worth a try. If you race on asphalt ....mmmm.... a must! If you race with Paragon, you can probably skip these. Big race like Cleveland, IIC or 'Birds.... too much grip there, it will bind the car down. I use them as a tuning aid when the track is green and when it gets soaked with Jack.

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Old 11-03-2008, 10:39 PM   #29682
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ArnO- Although you can CA the foam as a fix, it will consequently cause a hard spot where the CA is and can cause more tearing or inconsistent wear. I prefer to use contact cement to fix tires as it stays flexible and wears with the tire.

Second thing, ditch the black tape for holding in the batteries and get some fiber reinforced strapping tape. Black tape will stretch out and let the batts move around or come loose.

For the servo issue, if the links are the same length and its still not centered, then the servo itself isn't centered on the chassis. If you can wiggle it into the right position I would adjust the link length so the servo saver is straight. That will keep the ackerman equal in both directions. I would also recommend moving the servo up to the top holes on the mount. The severe downward angle of the steering links will cause bump toe-out which will make the car hard to drive.
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Old 11-05-2008, 06:58 AM   #29683
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Hey guys, I am about to run 4-cell stock at our local track. It's pretty small. I am using Twister tires.(don't know the diameter) What kind of gearing should I use. I will be running brushed motors. I just need something to get me in the ball park. I will be running 48 pitch also.

Thanks
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Old 11-05-2008, 07:58 AM   #29684
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Hey guys,

I'm enjoying my 12R5. Its our first season running brushless and I'm finding a huge variance in roll out for different motors.

As an example:

I'm running 62mm with a Xcelorin 13.5 while a fellow racer is at 55mm with a Speed Passion.

I'm assuming that some motors are better suited for 4-cell 1/12 scale applications than others. Anyone have comments on what 13.5 would be best for a 80x40 track (tight layout with a 80' straight away)?

Any info appreciated.
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Old 11-05-2008, 08:50 AM   #29685
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ordered the slapmaster bearing thingy and pivot ball today. Running 4 cell stock on asphalt with a T-bar car.
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