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Smug Monkey

First Post - Hello's All Around & Brat Questions

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Hello everyone,

My wife just ordered a Brat kit as a present for my 34th birthday along with a set of 8 5x11 bearings (to finish off ballracing) , 3300 battery pack, and Sport Tuned motor. I have been out of the Tamiya scene for quite some time, but always wanted a Brat. I will be using an Associated XP2 transmitter from a RC18MT, Dynamite Tazer 12T ESC, and a Hitec ultra-torque servo (all parts I have laying around from other RC toys). My question is, with the Sport Tuned motor, what gearing would you suggest me using when building the Brat kit? Are there 3 spur and pinion gears with this kit? Also, any tips on building the Brat would be appreciated.

Now, a little about myself. I have always held a special place in my heart for Tamiya RC vehicles. When I discovered this site and began reading the many posts of people describing the same feelings I have had, and still do, I knew I found a special place.

My first hobby quality RC vehicle was a Grasshopper bought used out of a bulletin board in the mid 80's. It was beat up, slow, handled like a bouncing brick (if that makes sense), and I absolutely loved it! It looked so cool compared to all of the Nikko toys that were out at the time. I mean come on, there was a driver at the helm of this realistic looking beast!!! It came with a well used Tamiya hump pack and cheap 15 min. quick charger.

After the Hopper went to where all good Tamiya's go came a brand spanking new, box-art-beautiful, Wild One (still my favorite Tamiya model to this day). A classic Tamiya design with realism that would make any afficianado weep! I must have went through 10 pair of those horrible driveshafts throughout my travels with this car. I can still hear that grinding, spinning noise in my head. I am still hoping for a re-release of this classic, with upgraded axles of course.

I then went through a period of other manufacturers and vehicles. A Kyosho Big Brute, gold tub RC10 (which I later traded for a Lunchbox), and a Kyosho Double Dare. While fun, they never really captured that same feeling I got from driving, even looking at, a Tamiya vehicle. I then got out of RC for many years.

I got back into it a few years back with a few nitro's, a mini, a crawler, and a few random electric models. Again, they never captured that same feeling I had when I was younger. Everything except for the crawler, which will be gone soon, has been sold for quite some time. Here's to hoping that the Brat may be able to rekindle some of those great feelings of yesteryear. If so, I see some more re-releases in my future!

Thanks for reading,

Mark D.

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Hi Mark and welcome to the TamiyaClub forums.

Someone will know about the Brat/Frog ORV chassis and suitable gearing for a 23 turn motor. Start with the biggest spur and smallest pinion combination is always a good place to start and then change to speed the car up if the gearing is too short. I'm not a fan of the ORV chassis/gearbox myself, have owned just one and it didn't handle the amount of driving I like to do.

Cheers, Mark

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Hi Mark, welcome to TC.

Your gearing options will depend on what type of ground you're running on.

A nice smooth surface like tarmac, tennis courts etc, will cope with a higher ratio than grass or rough ground.

The 19:49 "speed" gear set will be ok for really smooth surfaces,it will overgear the car a little for rougher ground, not a huge amount though.

you can also use the 18:50 ratio for tarmac etc,this will give you a higher top speed at the expense of a little acceleration.

If you plan on running over rougher ground, particularly grass, go for the lowest ratio 16:52 gearset.

Running on grass offers a lot of grip compared to looser surfaces, for dusty conditions, you can fir the 18:50 for a bit more fun with wheelspins etc :lol: .

The Sport Tuned motor is a nice step up from a silver can & gives a decent performance increase without pushing anything to it's limits.

If you run it hard (or very regularly) the gearbox will begin to spread apart allowing the diff to slip (an inherent problem with the ORV gearbox, solved with the later Super Blackfoot design) this necessitates regular rebuilds of the gearbox to keep it sweet. This IS curable, originally with expensive hopups, but there is also the well know "oldfrogshot screw mod" (oldfrogshot is a TC member, but he hasn't been around for some time). Details of the mod here: Oldfrogshot's screw mod

The Brat is fairly light & can take significantly more power (if the gearbox is modded as above), I have driven one with a 9 turn motor, uttely nuts, but lots of fun.

Stick to the Sport Tuned for now, it's well matched to the ORV, the TZ & RZ motors will give you a healthy performance upgrade when you're ready without hurting runtime much.

As for the build, just take your time & ensure the gearbox particularly runs smooth. Take a little extra care with the tapping srews that go into the chassis, it's easy to overstress the holes trying to do the screws up too tight.

The steering rods are light gauge rod & easy to bend, but as the Brat lacks a decent servo saver this is no hardship.

When you assemble the rear swing arms, make sure the alloy "rear arm stopper" is tight against the chassis, but the swingarm moves freely, any tightness here will wear the swingarm quickly.

Be extra careful when tightening up the front wheel nuts not to overtighten them, the front spindles are known to pull out from the alloy very easily. Not difficult to fix with something like Loctite 600 series adhesives, but very annoying when it happens.

Those are about the only weak points of the standard kit. I've built a couple of these now & it's a nice easy and very enjoable build.

Cheers, Russ.

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Thanks for the warm welcome and the info, guys! I will fiddle around with the gearing and probably start out with the middle pinion and spur. It will be driven on various surfaces like grass, asphalt, and dirt.

I also appreciate the building tips and will follow them during the build. I do not intend on being rough on the Brat. It will live the good life bombing around the yard being chased by my Boston Terrier for the most part. Maybe occasionally venturing onto the street for some road-ripping, or to the local dirt track on days when nobody is racing.

I will be using the lexan body for driving and the hard shell for looks. I really cannot wait to begin this build. If anyone else has some additional useful Brat info please feel free to reply!

Thanks,

Mark D.

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