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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 11-26-2008, 10:12 PM   #29791
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All: Rear axle is definitely centered, but I'm not runnig the new BL cone, hub, or graphite pieces.

Trips: Yep I run at Mikes. Carpet is great. Lemme know if you're coming and Ill introduce myself. PM me if you want my number.

Jason: I had my suspicions about that happening with the 18's. Its relieving to hear I'm not going crazy. Ill try your springs. Yang swears by 'em and the .18's I'm running now have a good 8+ runs on them. Good point about ensuring chassis balance before using the coint method. Ill have to take some pics of my layout, but I estimeated I would need roughly 45 grams on the right side to balance the car using the hudy balance pins. I run the 9650 offset to the right, the spektrum micro ffset to the right, and the sphere on the right side. My PT sits in the center up front. Seemed weird I wuld need so much lead to balamce the car. It came in at 875 rtr so I didn't wantt o add any lead, but I might have too.

Hanulec: Thanks for the help. Im liking the new car. Are you suggesting I remove the side shock or side springs when I check tweak? I have been checking the tweak with a speedmind bubble level station. I will back that up with the quarters next time I go out.

One of the oddities I have noticed lately since I have been paying lots of attention to my 12th is that the side springs wobble as I rotate the tweak screw. So the bottom of the spring only really ever touches on an edge unless there is significant tension. This kinda makes it hard to tell when the spring is just barely not touching the link. In fact I am not sure I can get the spring far enough off from the link to keep it from touching entirely. I tried a few new sets of the spring retainers, but I ust couldn't get the screw in it perfectly or the screw isn't going throughthe CF perpendular or something. Kinda bugs me. . . .

the weirdest thing to me is that when the tweak station says the car is tweaked, both side springs seem to be applying equal pressure on the pod and are back off an equal amount of turns. It also drives best like this. When I adjust the tweak screws so the tweak station says it is not tweaked the car drives like its SEVERELY tweaked and it requires turning the right side tweak screw almost all the way in to get it there. But as hanulec mentioned perhaps the problem lies in measuring the tweak on the levels with the center shock attached. I would think with te AE shock not applying any reboud with the through shaft that it wouldn't matter. Hmmm . . .Ill keep y'all up to date if I make any revelational discoveries
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Last edited by andrewdoherty; 11-26-2008 at 10:23 PM.
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Old 11-26-2008, 10:40 PM   #29792
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Try moving your PT on the right as well before adding weight That way you won't have to add as much weight to balance it. My old link cars with springs I could never get to run right with the springs just touching the links...I always ended up putting just a tad of pre-load into them and checking the tweak. If all is fine there the you might have an issue with the wires causing tweak.
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Old 11-26-2008, 11:02 PM   #29793
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Wires touching the body can cause a terrible tweak on any car. Once you get the tweak set put the body on and recheck it. If its off, try rerouting the wires to the motor.
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Old 11-26-2008, 11:05 PM   #29794
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Can you borrow another tweak station to try? It seems odd that the car drives well and the side springs appear to have equal tension but your tweak station gives different feedback.
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Old 11-26-2008, 11:19 PM   #29795
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Good ideas fellas. Ill have to make a list and try them one by one when I get back to the track to source the problem. Thanks David for the call. Hopefully it won't be long before I get this sorted out.
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Old 11-27-2008, 01:37 AM   #29796
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Quote:
Originally Posted by Scottrik View Post
Yeah, we could make a "Welcome to the 1/12 thread" package with:

The rollout primer

Rich Chang's tuning cheat sheet

A link to Mark Payne's blog

A picture of OD's monster caliper
Where can I find the tuning cheat sheet?

EDIT: Found it!
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Old 11-27-2008, 05:06 AM   #29797
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Quote:
Originally Posted by andrewdoherty View Post
Good ideas fellas. Ill have to make a list and try them one by one when I get back to the track to source the problem. Thanks David for the call. Hopefully it won't be long before I get this sorted out.
With the side damper attached, it will be difficult to get the tweak set because it will almost be like having a stuck link or pivot. Pull the side damper and try again on the tweak station.

You will need to move your PT to the left and your switch and wires also to get the car to balance with no weight. If it still isnt right, just go with some weight. A heavy car will run better than one thats out of balance. Keep us posted buddy.
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Old 11-27-2008, 07:34 AM   #29798
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Andrew, after reading whats going on with your car, I might have another suggestion for you. Check to make sure the dampning shock (the shock that lays on its side) is adjusted properly. I started assembling my R5 last night, and noticed that after I installed my dampning shock, that it needed to be adjusted for EQUAL side to side movement. The directions show the shock eyelet (part # 4662) and the shock rod end (part # 4665) being screwed all the way together. When I assembled it to the chassis, I noticed that the side to side movement was unequal. This is a simple fix, as all you have to do is adjust the shock rod end about a millimeter and a half (+ or -) so that the pod will have side to side movement.

Also, check to make sure that the lower front arms (part # 4620) are in the correct position. If you are looking at the instruction book, page 6 at the bottom, bag D step 1, lower suspension arm orientation, the arms are swept back. At first, I noticed that the arms had flat spots in the mounting holes to attach them to the front bulkheads, so I lined them both up with the flat spots down. But when I sat them side by side as if they were on the car, I noticed the arms are molded to have a swept back appearance at the pivot ball. I noticed this because one was swept back, the other was pointing forward. Also, check to make sure the kingpin is riding freely in the pivot balls.

I hope I haven't bored you to death, and this info is helpfull. If you have any questions, please feel free to pm me.
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Old 11-27-2008, 07:34 AM   #29799
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double post
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Old 11-27-2008, 07:46 AM   #29800
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building a 12r5, need opinions on best steering servo. Price is not an issue.
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Old 11-27-2008, 08:17 AM   #29801
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Quote:
Originally Posted by MNF1SAND View Post
building a 12r5, need opinions on best steering servo. Price is not an issue.
I'm not familiar with the 12R5 (yet...got one coming to play around with) so I don't know if it has a mount that limits servo choices or not. For example the CRC's are pretty much set up for the JR 3550/3650 (or they used to be), the DB12R is set up for the Futaba 9602/9650 or the KO PDS949, etc. The challenge is the different servos often have the output shaft in different positions relative to the sides of the servo.

I heartily recommend digital servos in this day and age. Especially if you're not suffering from budget limitations. The positive centering makes them worth their weight in gold for 1/12.

My own limited experience? I feel like the PDS949 is the most responsive and best feeling servo I've used. Unfortunately it's also the most expensive. It also seems (again, to me) to be the strongest/most accurately centering servo I've used. It is digital.

The Futaba 9650 is probably the best value in 1/12 steering servos. I believe it also specs out a touch faster than the PDS949 though I find myself dialing a bit of speed out of both. Works very well, I'm running them in both my DB12R's. Were available for $50 new for a while, I think they may be $60 now. It is also digital.

The JR Z3650 I've used the least though it seems to be a worthy (digital) successor to the former "gold standard of 1/12" the Z3550. Reasonably tough, reasonably fast, reasonably priced. Replacement parts (gear sets and cases) are probably the easiest of all to come by and half the price of either the KO or Futaba. If you're a gram counter I also believe the Z3650 is the lightest of the digital servos.

hth,

Scottrik

Oh--if anybody knows if/what servos the 12R5 is limited to please let me know. SS
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Old 11-27-2008, 11:10 AM   #29802
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The KO 949 has been superceded by the KO 951. Same size, same speed and weight, but up from 38oz of torque to 108
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Old 11-27-2008, 11:23 AM   #29803
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Oh yeah...

MY 949 has 208oz-in when I plug those extra two AAA cells in series to my receiver power!! 'Course running an 8 minute race is like a LONG Top Fuel event...sometimes you make it, sometimes you're streaming expensive smoke.

I may have a small caliper, but I've got enough servo torque to steer my car without linkage attached. Just apply a little Isaac Newton...
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Old 11-27-2008, 12:02 PM   #29804
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Oh yeah...

MY 949 has 208oz-in when I plug those extra two AAA cells in series to my receiver power!! 'Course running an 8 minute race is like a LONG Top Fuel event...sometimes you make it, sometimes you're streaming expensive smoke.

I may have a small caliper, but I've got enough servo torque to steer my car without linkage attached. Just apply a little Isaac Newton...
happy T-day Perfesser! The reason for the upgrade is that in modified class at big races where the bite is very high the cars were generating so much side load that they were overpowering the servos. Not a consideration for 99% of us, but thats why the change. I use the 951 now not because I need to but because it makes me look cool
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Old 11-27-2008, 12:11 PM   #29805
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The reason for the upgrade is that in modified class at big races where the bite is very high the cars were generating so much side load that they were overpowering the servos.
Holy crap! Can you imagine??!! I can barely keep a mod car on the track...servo power is the LEAST of my problems in that endeavor. That said, they're running Mod 1/12 at the big race in Minot in a couple weeks and I'm giving serious thought to having a go. I'd be better off to re-brush one of my 27T stockers and run that, but what the hey--I'll dig my old smooth can Novak 6.5 out and try to keep 'er between the boards.

Happy T-day to you as well!

Scottrik
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