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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.

Click links to go to manufacturer product page. If any are missing please add them!

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!


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 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 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.

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:



JFT (Japan Foam Tire)


Enneti (Xceed)

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 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.

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!
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


Reflex Racing/RSD:


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Old 11-23-2002, 03:56 PM   #1936
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What does Speedmerchant use for a axle and diff? Is it AE?
Also are the diff rings notched like the Carpet Knife?

How are you capturing the diff rings on your Switchblade?

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Old 11-23-2002, 07:29 PM   #1937
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Avink1- it was just a thought I had when I read stormpersons comments on the CRC links.

Stormperson - I did notice in the CRC instructions that there was a little bit about making sure the links do the bind so I guess it is a potential problem area! I've put my money on the CRC...but haven't got the car yet!
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Old 11-24-2002, 08:48 AM   #1938
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Fiddle- I actually took a d-ring and measured on the hubs and with my dremel i cut the excess so that it perfectly captures the d-ring. Thus i converted my diff to a d-ring back in June and it's been working very well.
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Old 11-24-2002, 08:56 AM   #1939
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Default Battery question...

I just started running/practicing 1/12 4-cell mod on an asphalt track with a Associated 12L3. It has a six cell chassis. When you run with four cells, do you place the cells in the forward slots or the rearward slots?
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Old 11-24-2002, 09:07 AM   #1940
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drifter- for mod racing after running for CRC i personally found that i could get t-bar cars (such as their 6pack) to run much faster and more consistently. Yes the t-bars need to be replaced and that will be affected in part by how much you crash or don't crash but the amount of forward bite that t-bars produce really works well in mod. i prefer the Trinity Switchblade because it turns so well and is more maintenance free compared to other cars i have run due to it's beefy design. All of the cars are really good though its just that some have different characteristics. i've seen them all go really fast in the four years that i have been back into rc so you can't really go wrong but help with building, tuning, and maintaining your brand is crucial.
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Old 11-24-2002, 09:08 AM   #1941
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I ran my 1/12 scale 4 cell stock last night for the first time on carpet. I noticed that from a dead stop if I peg the throttle, it would veir to the left, the same thing to the right as well. Kinda unpredictable from a dead stop. Any ideas what to look for??? I've checked the tweak both front and rear and it appears to be perfect. Once I have the car moving it feels fine like the tweak is good. It's just from a dead stop when I hit full throttle. Like I said, it feel great while racing. Hard to get a holeshot the way it is right now. Thanks

I guess which car helps, 12L3...

Last edited by GregH; 11-24-2002 at 11:54 AM.
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Old 11-24-2002, 09:20 AM   #1942
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rc nitro- thanks, cleveland should be great but i will really miss thanksgiving this year with my family. It's Great to hear how you generated interest in 12th scale at your track, i've always been a big fan of loaner cars like they used to do in the early 80's. It would be a lot easier if new people were shown or told about 12th scale when they go into the hobby shops or the race tracks. i can't tell you how often in four years i've heard guys say "these 12th's are cool i wish they had told me about them when i bought my [other] car because i would have gotten one of these instead...". Oh well....
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Old 11-24-2002, 11:20 AM   #1943
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@darnold: thanks for your help, I really appreciate it!
Yesterday I saw my first CRC, they are BIG here with our new 4 cell rules. Didnt like the "feeling" of the rear suspension when holding the car in my hands and moving the rear pod very much, my 12L3 is much smoother! This was true for 4 different cars, so I dont think ist just the setup.
So even if I hate to strap in my batteries with tape, I will stick to my Associated RC12L3, but I am wondering if it would be worth the effort to build a Chassis plate like the Yokomos with different battery palcement (more forward), or if I should stick to the original chassis.
I think the Trinity is a great car, but its impossible get here...
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Old 11-24-2002, 02:52 PM   #1944
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Graphitedust, I prefer to keep the cells as far to the rear as possible so I use the rear slots. I think it's best to have as much weight as possible close to the rear axle, where you need grip, especially in mod....
Bob Seay
Tamiya TRF417, TA05v.2, TRF211XM, M-05ver.2R, XRAY X12, Associated B5m Factory Lite

Go Pokes!!!
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Old 11-24-2002, 05:57 PM   #1945
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i actually (and as do the factory speedmerchant drivers) run the batteries in front (although its a 1/4" difference on the rev. 3), even in mod.

i am not sure about the speedmerchant axle, i personally run a IRS axle, just because i prefer a clamping left side hub. i know its a graphite axle without d-rings, but i am not sure who makes it.
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Old 11-24-2002, 05:58 PM   #1946
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I bought a 12L3 off ebay. What I can gather from the crew at my local track is, the car was set up for carpet. Zero scratches on the bottom was also a good hint. I was wondering if somebody could help me with a good asphalt setup. I know purples up front and pinks in the rear. From there is were I need help. I didin't build the car some I am not real familiar with it. We are racing on an ultra smooth treated (with sugar water) asphalt track. I just need a good starting point.
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Old 11-24-2002, 07:38 PM   #1947
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For asphalt, I'd start off with 020 or 022 springs up front, the thin (062) t-bar, and the pruple fronts/pink rears. I'd run the reactive caster front upper mounts, caster mid or forward to start. Set camber for even front tire wear. I'd run the Associated green shock spring, 30wt in the shock. Nothing on the damper discs. Ride height 3.5 to 4mm front and rear, start level.

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Old 11-25-2002, 04:40 AM   #1948
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darnould: I understand the miss family. We do a family thing here, I am oldest of 5. We definatly have a croud at mom's. Having a 6 year old, I cannot miss family functions.
Did the rent a racer this weekend again. "do you have that 1/12?" handed the car and radio. "Gotta get me one!" Me: There only $150 new. "WOW, I need to go look for one now".
Worth the effort!! I do campain a "Taxi" as you guys refer to them, TC. These 1/12 are ~1/3 the work of a TC
Tire Wear Question: Guys want to know how fast tires wear? I am to green at this, can someone give me an idea? How far down can you run the tires?
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Old 11-25-2002, 07:13 AM   #1949
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xer987 - I disagree with Trips over the reactive castor issue. You are on asphalt and probably have a little bit more open track to race on than the carpet races. You will not need to do snap turns around the end of a board within 12 feet. I would use the castor blocks that are not reactive castor. Reactive castor gives you an ever decreasing turning radius when you enter a corner off power. I think you need a suspension that gives you a constant, consistent turning radius on asphalt. That reactive stuff could make your car oversteer on entry. Then you are all messed up and will get excessive rear tire wear. Other than that, I agree with the .020 or .022 front springs and .063 t-bar. The degree of bumps and that will dictate the shock oil and center spring.
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Old 11-25-2002, 07:43 AM   #1950
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Hey guys, lots of great info in this topic, but I still have a question to ask...

I'm getting a 12th scale soon and can't decide between the CRC CarpetKnife 3.1 or the RC12L3. From what I've read, the L3 seems to be more popular, but I'm really digging the 3 shock suspension of the CRC car. Also, the L3 has a t-bar, is there any advantage to this than to the no t-bar three shock setup on the CRC? Does the one shock on the Associated provide enoughing tuning options to make the car work well anywhere? I'll be mostly running on a high bite asphault track with a few bumps.

Also, where would be the cheapest place to pick up an L3? The CRC I can only find directly through CRC. Thanks for any replies.
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