dezfan
Posts: 1188
Joined: 2/15/2006
From: Columbia,
MO, USA
Status: offline
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Well I thought I would put a guide together to try and make the tranny options available to crawlers more centralized, organized and informative.
If I have made any obvious mistakes or omissions, please let me know so that I can make this guide as informative, complete, and helpful as possible.
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Up first is the venerable Stampede tranny from Traxxas.
The "Pede" as it is commonly known, is a 3 gear tranny design w/ a planetary diff design and a slipper clutch.
The Pede's internal gear ratio is 2.72 to 1.
Pro: Availability, reliability, ease of drive shaft installation.
Con: Physical size, weight, poor slipper design, plastic motor plate.
Diff can be locked several ways w/ JB weld and by relocating one of the planetary gears between the other two being popular.
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Next up is the Evader tranny from Duratrax.
The Evader is also a 3 gear tranny w/ a ball diff design and slipper clutch.
The Evaders internal gear ratio ranges from 3.52 to 4.88 to 1 depending on whether is comes from a buggy or a truck.
Pro: Size, weight, durability, parts availability.
Con: Not available as a stand alone unit unless purchased from e-bay or other outlet. Drive shaft mounting not a direct bolt up affair.
The Evader diff can be locked by removing the balls from the diff, inserting abrasive paper disks between the diff gear and the diff rings w/ the abrasive side facing toward the gear and then tightening the diff extremely tight. It can also be locked w/ JB Weld or other adhesives.
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The XX tranny from Team Losi is another option not commonly seen in crawling.
It us a 3 gear design w/ a ball diff and slipper clutch.
The XX's internal gear ratio ranges from 2.19 to 1 for the buggy version to 2.61 to 1 for the truck version.
Pro: Size, Weight, Durability
Con: Not available as a stand alone unit unless purchased from e-bay or other outlet. Drive shaft mounting not a direct bolt up affair. Parts availability.
The Losi XX trannies diff can be locked by removing the balls from the diff, inserting abrasive paper disks between the diff gear and the diff rings w/ the abrasive side facing toward the gear and then tightening the diff extremly tight. It can also be locked w/ JB Weld or other types of adhesives.
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Another option is the XXX tranny from Team Losi.
It also is a 3 gear design w/ a ball diff and slipper clutch.
The XXX trannies internal gear ratio ranges from 2.43 for the XXXT version to 2.56 for the Matt Francis version.
Pro: Size, Weight, Durability
Con: Not available as a stand alone unit unless purchased from e-bay or other outlet. Drive shaft mounting not a direct bolt up affair.
The Losi XXX trannies diff can be locked by removing the balls from the diff, inserting abrasive paper disks between the diff gear and the diff rings w/ the abrasive side facing toward the gear and then tightening the diff extremly tight. It can also be locked w/ JB Weld or other types of adhesives.
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Next in line is the Sportwerks Raven tranny.
It is a 3 gear design w/ a spider gear diff and slipper clutch.
The Raven St's internal gear ratio is 2.4 to 1.
Pro: Size, weight, ability to lock diff similarly to Stampede.
Con: Not available as a stand alone unit unless purchased from e-bay or other outlet. Part s availability may be an issue, drive shaft mounting not a direct bolt up affair.
The Raven ST's diff can be locked several ways w/ JB weld and by relocating one of the planetary gears between the other two being popular.
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Another rarely seen tranny is the Ultima ST tranny from Kyosho.
Again it follows the 3 gear design philosophy w/ a ball diff and slipper clutch as standard.
The internal rear ratio of the Ultima St tranny is 2.53 to 1.
Pro: Size, Weight, Durability
Con: Parts availability, Not available as a stand alone unit unless purchased from e-bay or other outlet. Drive shaft mounting not a direct bolt up affair.
The Ultima St's diff can be locked by removing the balls from the diff, inserting abrasive paper disks between the diff gear and the diff rings w/ the abrasive side facing toward the gear and then tightening the diff extremly tight. It can also be locked w/ JB Weld or other types of adhesives.
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Lastly in the 3 gear tranny department is of course the Stealth tranny series from Associated Electronics.
IMO, the best trannies ever make for RC use.
There have been 4 generations of the Stealth tranny.
The Gen 1 Stealth was released in 1991 and is the basis for all modern tranny designs used to this day.
It has a 3 gear design w/ a ball diff and the first true slipper clutch. It's internal gear ratio was 2.25 to 1.
RPM offers a update kit for the Gen 1 Stealth that includes new cases and the top gear shaft that lowers the internal gear ratio to 2.65 to 1.
This upgrade keeps the Gen 1 Stealth as a viable tranny option to this day!
The Gen 2 & 3 Stealth B3/T3 tranny were similar in design to the Gen 1 Stealth.
They too were 3 gear designs, ball diffs w/ slipper clutch and a slight case re-design.
The B3/T3 has an internal gear ratio of 2.4 to 1.
The 4th Generation of the Stealth is the B4/T4. Once again improvements were made to the design. Again it is a 3 gear, ball diff design w/ a new slipper clutch design borrowed from Associated Nitro truck.
The B4/T4's internal gear ratio is 2.6 to 1.
Pro: Size, Weight, Reliability second to NONE, quality, parts availability.
Con: Not available as a stand alone unit unless purchased from e-bay or other outlet. Drive shaft mounting not a direct bolt up affair.
All 4 Generations of the Stealth tranny diff can be locked by removing the balls from the diff, inserting abrasive paper disks between the diff gear and the diff rings w/ the abrasive side facing toward the gear and then tightening the diff extremly tight. It can also be locked w/ JB Weld or other types of adhesives.
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Now for something different. This tranny was designed specifically for crawling applications.
The R2 Crawler Transmission from RC4WD.
The R2 internal gear ratios of 10:1 to 30:1 is extremly low.
It has a 5mm output shaft, it is designed to work with Tamiya TLT-1 axle. It also offers multiple mounting applications for a variety of different chassis and platforms.
Pro: Compact size, low center of gravity, ease of drive shaft installation, no diff to lock
Con: Noise (32 pitch gears), cost, availability.
There is no diff to be locked on the R2!
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J Concepts
2007 KC 2.2 Challenge winner - 2007 CMRCRC 2.2 Points Champion - 2 time USRCCA Nationals Qualifier
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2.2 Transmission Guide - 
