supermoturd
Quarry Creeper
WARNING: Before you even think about converting to the Wraith transmission, there are some things you may want to consider. For starters, this transmission is built more for top end speed than low end torque when compared to a transmission like the RC4WD R2 which has a max advertised reduction of about 30:1. When you look at the gearing calculations in the backs of the Axial manuals, bear in mind that those ratios include the reduction at the differential. You need to divide those ratios by 2.92 to get the reduction at the transmission output. From my calculations, the very best gear reduction that you can manage with the Wraith transmission (motor to transmission output) is 25.1:1. And this can only be accomplished with a 32P 58T spur gear (available from Traxxas and the dust cover should still fit) and a 6T pinion (they do exist and you can get one from RC4WD.) With the stock 87T 48P spur gear and the smallest available 48P pinion, which is a 12T, you get 18.85:1. You can do a little better with the 48P setup by bumping up to a larger spur gear, but the biggest you can install without hitting the U-Joint on your drive shaft is 93T (unconfirmed) and with a 12T pinion you only get 20.5:1, which isn’t much of an improvement. Furthermore, with the larger spur gear, the dust cover will no longer fit. If you want to compare diameters of various gears, you can calculate pitch diameter (approximately the same as the total diameter of the gear) by dividing the number of teeth by the diametral pitch. Eg., an 87T 48P spur gear’s diameter is 87/48 = 1.8125 inches.
Just some food for thought. This is probably not a big deal to most of you since all you ever do is cry about how your rigs don’t go fast enough. But I like to crawl smoothly so it makes a big difference to me.
Anyways, after all of the trouble I went to to install my RC4WD R2D transmission, I ended up being very dissatisfied with it for reasons you can read about here http://www.rccrawler.com/forum/g-made-crawlers/476073-rc4wd-r2-dig-install-r1-chassis.html
After doing some research and getting a lot of helpful input from many of you, I decided to go with an Axial Wraith/SCX-10 transmission together with the Vanquish Products Hurtz dig. I hope it will be worth the effort because the installation is turning into a real headache.
I'm starting with the standard (plastic) Wraith transmission kit with plans to upgrade to the aluminum case that Vanquish Products makes. I may also switch to a 32P spur. Thus far I am pleased with the fit and finish of both the transmission and the Hurtz Dig Unit. I'm using my low profile Savox SC-1251MG, which fits nicely back between the upper links.
The fun ended when I went to install the transmission. I did a dry fit to see where I wanted to drill out the bolt pattern in my skid plate. I realized immediately that my main problem was going to be interference between the protruding ends of the wrist pin on the front driveshaft U-Joint and the big 87-tooth spur gear on the transmission. My solution was to install a shaft extension on the transmission's front output shaft; the idea being to shift the wrist pin portion of the U-Joint out in front of the spur gear.
This worked as you can see in the image above. However, it produced another problem. Namely, with the suspension fully extended/unloaded, the wrist pin on the U-Joint scrubs the rod end on the upper link.
I noticed that it was the same case for the rear.
I'm hoping that this will not be such a big deal since my suspension is rarely fully unloaded. I may try upgrading to JunFac shafts in hopes that their lower profile might buy me some clearance. However, I hate to do that since it will add undesired weight to the rig and strain to the drivetrain. What I am also worried about is the spur gear cover that I ordered. I doubt seriously that it will fit with the front U-Joint riding so close to the spur gear. I may notch it or something. I really need the cover because I crawl on sandstone a lot and my rig is exposed to a lot of grit.
Here are some more pictures for reference.
Just some food for thought. This is probably not a big deal to most of you since all you ever do is cry about how your rigs don’t go fast enough. But I like to crawl smoothly so it makes a big difference to me.
Anyways, after all of the trouble I went to to install my RC4WD R2D transmission, I ended up being very dissatisfied with it for reasons you can read about here http://www.rccrawler.com/forum/g-made-crawlers/476073-rc4wd-r2-dig-install-r1-chassis.html
After doing some research and getting a lot of helpful input from many of you, I decided to go with an Axial Wraith/SCX-10 transmission together with the Vanquish Products Hurtz dig. I hope it will be worth the effort because the installation is turning into a real headache.
I'm starting with the standard (plastic) Wraith transmission kit with plans to upgrade to the aluminum case that Vanquish Products makes. I may also switch to a 32P spur. Thus far I am pleased with the fit and finish of both the transmission and the Hurtz Dig Unit. I'm using my low profile Savox SC-1251MG, which fits nicely back between the upper links.
The fun ended when I went to install the transmission. I did a dry fit to see where I wanted to drill out the bolt pattern in my skid plate. I realized immediately that my main problem was going to be interference between the protruding ends of the wrist pin on the front driveshaft U-Joint and the big 87-tooth spur gear on the transmission. My solution was to install a shaft extension on the transmission's front output shaft; the idea being to shift the wrist pin portion of the U-Joint out in front of the spur gear.
This worked as you can see in the image above. However, it produced another problem. Namely, with the suspension fully extended/unloaded, the wrist pin on the U-Joint scrubs the rod end on the upper link.
I noticed that it was the same case for the rear.
I'm hoping that this will not be such a big deal since my suspension is rarely fully unloaded. I may try upgrading to JunFac shafts in hopes that their lower profile might buy me some clearance. However, I hate to do that since it will add undesired weight to the rig and strain to the drivetrain. What I am also worried about is the spur gear cover that I ordered. I doubt seriously that it will fit with the front U-Joint riding so close to the spur gear. I may notch it or something. I really need the cover because I crawl on sandstone a lot and my rig is exposed to a lot of grit.
Here are some more pictures for reference.
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