SCX10 Trans question (speed related)

[devestator_x]

Anyone know what the ratio for the SCX10 trans is? Im thinking of getting one in the spring, but Im not really into crawling. Here's a really brief background...I've got a Stampede and a Wheely King. Both are nearly stock with the exception of motors (an old Trinity Midnight II and a brand new Trinity CO27). The 'Pede is just barely fast enough for me (CO27), the Wheely King (Midnight II) could be a little faster, but with the 4wd, it's still fun.

Here's what Im looking for...a truck thats about as fast as my 'Pede, 4wd, and scale looking. I want to have a Pre-runner style when Im done (something like Bender's SCX10). I also dont have nearly the budget for brushless, so Im going with what I have (and possibly throw a 2s lipo into the mix before summer)

I guess my big question is, with the right pinion/spur combo, could the SCX10 run the same speed as my 'Pede with the same motor? I would transplant the CO27 into the SCX. Like I said, I dont crawl, so I dont need the 35T or 55T torque, the 21 degrees of timing on the 27T makes plenty of torque for how I drive.

[Big Bill]

Maybe the hardened over-drive gear set would help with the over all speed. Cant remember the tooth count for them, should be on the Axial site

[skid]

I don't see it being feasable to get similar speeds with the same motor. The transmission's are close in ratio, so with the scx10 you would still have the reduction(2.9:1) in the axles to overcome.

More voltage or faster motor is going to be needed.

[Katan]

Originally Posted by devestator_x

Anyone know what the ratio for the SCX10 trans is? Im thinking of getting one in the spring, but Im not really into crawling. Here's a really brief background...I've got a Stampede and a Wheely King. Both are nearly stock with the exception of motors (an old Trinity Midnight II and a brand new Trinity CO27). The 'Pede is just barely fast enough for me (CO27), the Wheely King (Midnight II) could be a little faster, but with the 4wd, it's still fun.

Here's what Im looking for...a truck thats about as fast as my 'Pede, 4wd, and scale looking. I want to have a Pre-runner style when Im done (something like Bender's SCX10). I also dont have nearly the budget for brushless, so Im going with what I have (and possibly throw a 2s lipo into the mix before summer)

I guess my big question is, with the right pinion/spur combo, could the SCX10 run the same speed as my 'Pede with the same motor? I would transplant the CO27 into the SCX. Like I said, I dont crawl, so I dont need the 35T or 55T torque, the 21 degrees of timing on the 27T makes plenty of torque for how I drive.

It's possible, I had the same problem in my Hardcore Slash project. The trans without pinion/spur is 2.6:1. You can use an Associated TC3 69T 48p spur on the tranny and a Robinson 35T 48p pinion on your motor. You will need to use Axial high speed gears (14/36) in your axles.

All that gives you a final ratio of 13.17:1
That should be ok.

EDIT: The Stampede has a final drive of 12.34:1 so you would be pretty close.

[devestator_x]

Thanks for your replies guys especially with the comparisons on gear ratios. Ive been around RC's off and on since I bought my first RC10T back in 1992, but yet fully understanding the math behind gear ratios has always eluded me. I get the relation between pinion and spur for torque vs speed, but add that to axles and trans ratios and my mind just goes blank.

So I found info on HPI's site that states a stock Wheely Kings over all gearing is 23:1. I really dont think I could match the 'Pedes speed with what I have for equipment. Well I could, but I think the motor would burn up...It gets pretty hot now in the 'Pede (running 19/90). So I think a little more realistic goal is to just shoot for faster than the Wheely King.

I also found this in an old thread here...
WK axle is 13/38 = 2.923, WK tranny is 15/28 = 1.866, therefore final drive ratio without considering the motor pinion and spur is 5.456

Depending on things go...The 'Pede may get sold as a roller to fund a cheap brushless setup for the SCX10 to get my speed fix while the WK is saved for mud, water, snow.