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Old 11-09-2014, 10:48 AM   #31
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I find it hard to believe that a 13.5 + 1S is cheaper than 21.5 + 2S when you account for having to run a receiver pack or buying a specialized 1S speedo. The theory that a 2S Shorty is double the cost of a 1S is simply not true. It's closer to a +150% margin.

That being said, I'm not hoping for failure. On the contrary I'd like to see a resurgence of 1/12th in the U.S. I'm just not convinced this is the "magic bullet". Let's be honest, one of the biggest costs of 1/12th scale (after you get a screamer motor) are tires. But unless I missed it, there is no spec tire requirement in the rules. That seems odd to me that a GT class doesn't have a spec tire.

We run a 1/12th class at our club that requires a spec 21.5 motor/1S battery/gear+spur/tires. It works great for the entry level but is lacking the speed that the experienced racers would want.
If you look at GT12 as a class people go into form another (2S) class, that view makes complete sense. However, we looked at it as a class that people grow out from.

We (BRCA) wanted a class that drivers would grow out to LMP12 (12th scale) from as most people want to go faster as their skills increase. We decided that progression would be easier and cheaper if drivers already had the battery, servo and motor needed to enter our 12th 13.5 Stock class. From that perspective, 2S 21.5 doesn't do it for us.

Nonetheless, there are UK clubs who do run 2S/21.5 and it suits them. We also decided that we were not in the game of making everyone run to the same rules, but we were in the game of offering everyone a class framework that was cheaper and easier to enter than LMP12, TC, etc.

GT12 runs on foams. Rubber tyres don't work on carpet with the low weights in LMP12 and GT12 classes. For technical reasons, rubber tyres will never be as easy to drive for beginners as foams.

We don't have a spec tyre. Each different car (Mardave, Schumacher and the new Zen) has a different chassis and they use different tyre grades to make them work. Having a spec tyre means none of them would work well, which is hardly ideal for the drivers.

The reality is that we all use the excellent Contact tyres so there is a de facto control tyre. Schumacher cars work best on 50sh fronts and either 37sh or 40sh rears deeding on the grip. As the tyres wear like iron, they last a long time. All the cars now have ride-height adjusters so many drivers can wear 2mm to 3mm off their tyres and still have cars that handle. HTH
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Old 11-09-2014, 02:41 PM   #32
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NORCAR - home of the Halloween Classic - has a similar solution they call Gate Spec. Everyone must run the same motor, battery, pinion, spur and tire. The ESC, Chassis and Body are open -- but the new Protoform 1/12th ferrari is encouraged.

Class: 1/12 scale “Gate Spec”

Motor/Rotor: Speed Passion 21.5 (P/N 138215V3)
ESC: Any ROAR approved non-timing ESC in its approved “Blinky” mode.
Battery: Turnigy “A-Spec” 6000 or 5600 mah 1s.
Gearing: 45t pinion and 78t spur.
Tires/Rims: CRC Spec pre-trued.
Body: Open 1/12
Maximum Battery Voltage: 4.20v
Minimum Ground Clearance: 3mm
Minimum Weight: 730g
Maximum Width: 172mm
http://www.norcarracing.com/index.ph..._Classes-Rules
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Old 11-09-2014, 04:47 PM   #33
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Are the 1/12th pan and the GT chassis the same?
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Old 11-10-2014, 02:33 AM   #34
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No. GT12 has fixed camber with the option of rising rate caster. The chassis must be longer than the wheelbase with all the suspension components mounted on top of it. The chassis must also not be flexible enough to act as a suspension component in itself with cutouts etc.
No sealed shocks are allowed in GT12 either, only friction tubes and springs or other alternative like rubber o-rings.

All this is in the rules: BRCA GT12 Rules

BRCA Rules & Equipment Homologation with GT12 and LMP12

...rollmasts aren't allowed either to keep the cars looking realistic (which is a big attraction of the class)
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Old 11-10-2014, 08:14 AM   #35
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I'd think GT12 would be ideal for US 'board' style tracks, as the cars are almost indestructible. The cars themselves are simple and the class has a sensible weight limit, so there's no need for light/fragile parts.

The foam tyres also keep racing cheap; unlike rubber tyres there's no advantage to bolting a new set on.

It's a fantastic indoor class. I love my TC, but you won't find me running that on an indoor track with barriers to hit.
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Old 11-10-2014, 10:16 AM   #36
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Originally Posted by nwagner View Post

That being said, I'm not hoping for failure. On the contrary I'd like to see a resurgence of 1/12th in the U.S. I'm just not convinced this is the "magic bullet". Let's be honest, one of the biggest costs of 1/12th scale (after you get a screamer motor) are tires. But unless I missed it, there is no spec tire requirement in the rules. That seems odd to me that a GT class doesn't have a spec tire.
The key thing to note here is compounds. What do most people run on a 'normal' 1/12 car? 30 & 32 shore tires roughly? Well GT12 cars are considerably heavier (to the tune of nearly 200g) and their CofG is way higher. Run foam that soft on a GT12 and you'll be out of foam very quickly and have a car that is constanly on the verge of grip roll.

The guys in GT12 tend to run 35 or 37 shore rears, and something like a 47 front. They wear like bullets and don't chunk anywhere near as easily as soft foam.

WorldGT tires last forever right? Well that's because they are huge tyres in comparison to the car's size and weight and the car is subsequently well over-tired and running firm compounds is a viable option. GT12 is a similar story; you'll get nothing from bolting on soft compounds because the cars don't work with them. With that and the speeds being considered you can bolt on harder foam and it's all good!

I would estimate that to be a BRCA national front runner in GT12 requires roughly a quarter of the tyre budget needed to do the same in 1/12 scale. What's more, the bodies last forever and all the electronics are interchageable between the cars.

There's no fear of 'failure' here; it's up to other countries/bodies if they want to try adopting the class or not. Regardless of what happens abroad, GT12 has been and continues to be a massive success in the UK.
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Old 11-10-2014, 10:24 AM   #37
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Are the 1/12th pan and the GT chassis the same?
No. The GT chassis must extend from in front of the front wheels to behind the rear axle. The pod floats above the chassis. It's nice because when a car backs into a wall, the pod doesn't take the impact, the chassis does. They very unique and extremely durable.
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Old 11-10-2014, 10:40 AM   #38
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We're running a $48.00 esc and it kicks A$$. The Trackstar Gen II 120A 1S ESC is the real deal. Turn down boost and turbo and it's in blinky. Crank up the reverse force and max brakes, it stops nicely. No need to go expensive. Toss in a $26.00 6000mAh battery from Hobbyking, and the cost drops substantially over 21.5 2S. The Contact brand tires that come in the kit come with an adhesive ring you attach to the outside of the tire. The ring really helps to stop chunking. Even if they are a little chunked, they still work great.

Now for the Testimonial. We've run these cars (All SupaStox) for 8 weeks. The only part that has failed is.... None. Not one. Not one broken or bent part. No smoked ESCs, no burnt up motors. We've all gone through 3 sets of tires and a couple bodies each or so though. Practice night is charge, clean, run, repeat sometimes for 6 hours. And we don't practice alone, the whole crew comes out at the same time. We stop, let everyone catch up and race for a few laps and repeat this process. Our longest "practice race" is almost a half an hour long. And we hit stuff and each other, hard sometimes, and keep going. These things are just plain fun. Seriously you check ride height, clean the fuzz out of the car, charge the battery and it's ready to go again.
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Old 11-10-2014, 10:43 AM   #39
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... but the new Protoform 1/12th ferrari is encouraged. [/url]
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Old 11-10-2014, 12:43 PM   #40
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Who is selling the tires for this class in the US? And how are you gearing with a 13.5T motor, what roll-out in mm?
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Old 11-10-2014, 12:47 PM   #41
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Originally Posted by liljohn1064 View Post
We're running a $48.00 esc and it kicks A$$. The Trackstar Gen II 120A 1S ESC is the real deal. Turn down boost and turbo and it's in blinky. Crank up the reverse force and max brakes, it stops nicely. No need to go expensive. Toss in a $26.00 6000mAh battery from Hobbyking, and the cost drops substantially over 21.5 2S. The Contact brand tires that come in the kit come with an adhesive ring you attach to the outside of the tire. The ring really helps to stop chunking. Even if they are a little chunked, they still work great.

Now for the Testimonial. We've run these cars (All SupaStox) for 8 weeks. The only part that has failed is.... None. Not one. Not one broken or bent part. No smoked ESCs, no burnt up motors. We've all gone through 3 sets of tires and a couple bodies each or so though. Practice night is charge, clean, run, repeat sometimes for 6 hours. And we don't practice alone, the whole crew comes out at the same time. We stop, let everyone catch up and race for a few laps and repeat this process. Our longest "practice race" is almost a half an hour long. And we hit stuff and each other, hard sometimes, and keep going. These things are just plain fun. Seriously you check ride height, clean the fuzz out of the car, charge the battery and it's ready to go again.
What is the typical wear rate of the tires on a race day, 3 qualies and a main? And what is the usable life span of the tire, starting diam., to through out diam.?
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Old 11-10-2014, 12:57 PM   #42
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What is the typical wear rate of the tires on a race day, 3 qualies and a main? And what is the usable life span of the tire, starting diam., to through out diam.?
Gearing currently is 66/32 or 70/34 with 49mm rears in the SupaStox. Temps are @ 110* or so, never over 120*. Wear rate is about 1/2mm per day average. The new SupaStox GT uses 4 ride height spacers just like a typical 12th scale, you flip them as the tires get smaller. Usable range of the tires is 50mm to 42mm and then ride height drops too low to be useful, but that is darn near to the rim. These tires can easily last a month unless you run the car until you drop.
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Old 11-10-2014, 12:57 PM   #43
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Who is selling the tires for this class in the US? And how are you gearing with a 13.5T motor, what roll-out in mm?
Stormer!
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Old 11-10-2014, 02:32 PM   #44
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Good 12th GT featured at one of our nationals
http://vimeo.com/87656931
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Old 11-10-2014, 02:55 PM   #45
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Originally Posted by nwagner View Post
I find it hard to believe that a 13.5 + 1S is cheaper than 21.5 + 2S when you account for having to run a receiver pack or buying a specialized 1S speedo. The theory that a 2S Shorty is double the cost of a 1S is simply not true. It's closer to a +150% margin.

That being said, I'm not hoping for failure. On the contrary I'd like to see a resurgence of 1/12th in the U.S. I'm just not convinced this is the "magic bullet". Let's be honest, one of the biggest costs of 1/12th scale (after you get a screamer motor) are tires. But unless I missed it, there is no spec tire requirement in the rules. That seems odd to me that a GT class doesn't have a spec tire.

We run a 1/12th class at our club that requires a spec 21.5 motor/1S battery/gear+spur/tires. It works great for the entry level but is lacking the speed that the experienced racers would want.
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Originally Posted by hanulec View Post
NORCAR - home of the Halloween Classic - has a similar solution they call Gate Spec. Everyone must run the same motor, battery, pinion, spur and tire. The ESC, Chassis and Body are open -- but the new Protoform 1/12th ferrari is encouraged.

Class: 1/12 scale “Gate Spec”

Motor/Rotor: Speed Passion 21.5 (P/N 138215V3)
ESC: Any ROAR approved non-timing ESC in its approved “Blinky” mode.
Battery: Turnigy “A-Spec” 6000 or 5600 mah 1s.
Gearing: 45t pinion and 78t spur.
Tires/Rims: CRC Spec pre-trued.
Body: Open 1/12
Maximum Battery Voltage: 4.20v
Minimum Ground Clearance: 3mm
Minimum Weight: 730g
Maximum Width: 172mm
http://www.norcarracing.com/index.ph..._Classes-Rules

I recently got back into On-Road and the "Gate Spec" class is the main reason! I REALLY like this class as it is very affordable and when I want to move up to 17.5 all I have to do is swap out the motor and tires and set the rollout.

With the Spec class The Gate as put together is very closely matched and fun. A cost controlled way to get into racing is great. We have new racers getting excited about the class too. I was talking to a guy at Church last night (I know him and his boy from Off-Road) and after telling him about the Spec class he is coming out to check it out!

I think the class you have going in the UK is great and could get popular here too but again I like the fact that I can move to 17.5 very easily. With a little luck we can get other track in our area to adopt the Gate's Spec class. That way if I want I can travel too.

Good discussion!

Chris
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