Alot of guys who are running the t1900 are liking the 19 & 20 tooth pinion's. I was running 16 which was way under geared, and now im running 18 with no problems.

ok then thank you very much for the help i try a 20 then

Running the RX8 with Tekin 1900 motor. Geared 46/19 indoor (WCRC) and 46/20 on large outdoor track (Revs) You can also get away with gearing 46/20 all the time and just limit your throttle.

There is so much talk in here about gearing. There's also been some talk about the loosing control under accelearation.

If found this article (I have also posted in the main room) in RC car action that I have retyped to post for everyone's viewing pleasure. It's got massive amounts of good info regarding gearing --- even how to possibly correct lossing the car under acceleration coming out of turns.

enjoy!

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How to Understand Gearing:
Go beyond the basics

Gearing is simple. If you want more speed, you install a larger pinion gear. For more run time, reduced motor heat, or stronger acceleration, do just the opposite and install a smaller pinion. If you’re a bit experienced, you know that messing with the spur gear works just the opposite – smaller spur equals more speed. Most enthusiasts also know that a single tooth change on the pinion has more impact than a single tooth change on the spur. That covers the basics.

Gear Pitch:
Most of you know that gear pitch indicates the size of the gear’s teeth – the larger the pitch, the smaller the teeth – but people probably don’t know how pitch is determined or why a large pitch number equates to small tooth size. Pitch (specifically known as the pitch diameter) actually refers to the number of teeth that can fit around a 1-inch diameter (specifically known as the pitch diameter). A tooth size that permits 48 teeth to encircle a 1-inch gear is 48-pitch. To have 64 teeth on the same 1-inch gear, the teeth must be smaller, and that explains why 64-pitch gear teeth are significantly smaller or finer than 48-pitch. The pitch of the gears in your car has no effect on the ratio. 100-tooth spur/20-tooth pinion combination is a 5:1 ratio whether you use 32, 48, or 64 pitch gears. That said, certain gear pitches are better suited to certain applications.

32 Pitch:
Nitro vehicles often use 32-pitch gears because the larger teeth are durable. It’s important to note that some vehicles such as 1/8 scale buggies and truggies have 1-module gears, a metric size that works out to 25.4 pitch (more on metric gears in “Metric Pitch”).

48 Pitch:
Rob Robinson of Robinson Racing gets the credit for bringing 48-pitch gears to RC. Until Robinson introduced this in-between pitch, racers had to choose between the bulky 32 pitch and the more fragile 64 pitch gears. Back in the day, Rob was a competitive racer and missed the A-main at a large national-level event due to stripping out two 64 pitch spur gears. This led him to contact outside gear manufactures in a search of a more appropriate pitch for electric off-road use. He found 48 pitch gears, and this new pitch quickly caught on, as 48 pitch gears offer a good mix of ratio options and durability and are now the standard for 1/10 scale off-road use.

64 Pitch:
This is the pitch of choice among on-road racers mainly because of the huge number of available ratios and extra-smooth mesh of the fine teeth. Since on road cars don’t have to endure jumps or more specifically the shock of landing, 64 pitch gears hold up fine even when subjected to brushless power.


METRIC PITCH:
A common cause of some gearing confusion is what’s called “Metric Pitch” gears. The correct term in these metric application isn’t pitch, it’s module. The problems arise when people mistakenly believe these gears are compatible with “American” gears. Always use metric pinions with metric spurs. While the pitch is close to 48- and 64-pitch, they are not interchangeable; 0.8-module, however, is compatible with standard 32-pitch.

METRIC VS. STANDARD:
>>1-module, referred to as “metric 32” is actually 25.4 pitch
>>0.8 is mathematically equivalent to 31.75 pitch, which is close enough to 32 pitch.
>>0.6 module, referred to as “metric 48,” is actually 42.3 pitch
>>0.4 module, referred to as “metric 64,” is actually 63.5 pitch.
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Setting Mesh:
Ever hear of the old trick of using a piece of paper in between the gears to properly set gear mesh? Guess what? That’s wrong. Gearing expert Rob Robinson explains that using the paper method provides far more backlash (play or “wiggle space”) between the gears than is needed. This can lead to increased wear and easily stripped gears due to the reduced surface areas making contact with the excessive backlash. Still have a hard time believing the paper trick is wrong? Think about the gear mesh of the gears inside the transmission of a vehicle such as Team Associated B4.1. The internal gears are set with proper mesh. Rob further explains that properly build gears actually have built-in clearance. That is to say, even if you pressed the gears together s tight as possible, the teeth wouldn’t bottom out on the inside or root out diameter of the gear. So don’t use the paper to set gear mesh unless a “blind” installation absolutely requires it, and make sure you check the mesh at a few points on the spur gear.

Gear Alignment:
Now that you have a better understanding of gear mesh, you need to consider gear alignment. Rob Robinson explains this is one of the most common causes of gear failure. Proper gear alignment ensures that the entire tooth face of two interfacing gears have full contact. Nitro vehicles often have improper gear alignment due to the engine being mounted slightly askew. This reduces the surface area in contact between the two gears and quickly leads to worn-out or stripped gears. Some electric conversions may also have their motors inadvertently mounted on crooked and thus have improper gear alignment..

**PRO TIP:**Professional drivers use gearing to cope with loose track conditions. If the car wants to spin out under acceleration, they will often install a larger pinion to tame the torque output before making any other changes.


Common Pitch Applications:
>> 1/8 Scale buggies (Team Associated RC8, Losi 8ight 2.0, etc..) – 1-module
>> 1/10 Scale electric off-road vehicles (Team Associated SC10 and B4.1, TLR 22, etc..) – 48 Pitch
>> Traxxas E-Revo, E-maxx and Jato – 0.8-module, or 32 Pitch
>> Jammin’ SCRT-10 and OFNA Hyper 10SC – 1-module
>> HPI Savage, Traxxas Revo 3.3 and T-Maxx 3.3 – 1-module
>> Traxxas Stampede, Rustler, Bandit, Slash – 48 Pitch
>> Tamiya TT-01 – 0.6-module
>> Losi Mini LST – 0.5-module


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Reference:

-RC Car Action May 2011 Ed., "How to Understand Gearing: Go beyond the basics" pg. 122 / 123 - Retrieved May 23, 2011.

-Robinson Racing - www.robinsonracing.com

Need some diff fluids for RC8T E ... I"m running the stock 777 right now.. some guys at are track are talking about 50k in the middle.. Or at least 30k.. Can you guys help me out with any suggestions.

I have a problem with my Tekin RX8 with a 2050kv motor. It shut off 3 times last week and I don't know why did that ???? Any one has an Idea why ??? It happen after the jumps. It smack the chassis on the landing. I also have a brand new Batt Max Amps 6500 4s 150c. any Ideas ???

Hey, what diff fluids are you running? I personally like the feel of 5,5,5. Of course a loose but controllable car suits my driving style. I like being able to pitch a car in give it a little power and drift through a corner.

huge thanks to this thread for helping me get my car under control lol.

The moving of the rear hub carrier really helped keep the rear end in check.

What exactly did you do? Simply raise the chamber rod up or down? If so, where did you put it?

I'm curious what this is you're referring to because I'm using the stock set up and it wasn't very nice on clay. I'm going to be trying it in the dirt this weekend. If the a$$ end handles anything like it did on the clay I'll be interested in maybe making this adjustment (soon as I get some clarification.)

Few ideas:

1. Your on/off switch isn't mounted in the hotest location and knocking off after jumps (although I'm going to assume you would have realized that already).
2. Check the holes on the bottom of the TEKIN. If it has 3 that is the older RX8 model. They had issues with the circuit board having a bad connection. Contact TEKIN and they will replace it for you.
3. Check all of your solder connections.
4. What kind of connectors are you using from the ESC to the battery? They could be a culprit as well.

It's most likely one of these suspects.

You might want to subscribe to the TEKIN thread for these questions. Randy is really good about helping people with their TEKIN gear. He can hook you up.

Buon giorno!

been running 5,5,2 but should have ran 5,7,2 this past weekend with all the traction down there

I moved the lower hinge pin location to the upper hole on the rear hub as well as moved the hub to the fully rearward position and I like it a lot more. The upper camber arm is in the stock locations still.

This is on a fairly damp clay indoor track.

Also running 7-7-5 for diff fluids.

Wouldn't the 2K in the rear diff make the car rotate more?

Yeah I heard it was awesome traction but a fair amount of tire wear.

Assuming the on/off switch is mounted correctly (with the 'on' mounted towards the front) it might be that the switch itself is defective.

If it starts to happen more and more often you may want to sent it back under warrantee. If it's out of warrantee, consider eliminating the on/off switch and see if that helps.

FYI: According to my scale, the new 3mm longer chassis is 26 grams lighter than the old one. And after I cut back the chassis guards as recommended with the instruction sheet that came with the chasis, my car was 33 grams lighter than before.

That might not sound like much, but, that is a significant difference in an 1/8 vehicle.

All of the mounting holes are exactly the same except the 4 bolts to the rear diff and the rear chasis brace which have been moved 3mm further back.