HPI RS4 pro 2-speed dimensions

[yf22k]

I know everyone's first response will be its not worth getting a 2-speed transmission for an electric car. To answer this, I run a brushless motor and it hasa lot of power so i'd like to use a 2 speed for longer runtimes. I'd like to have better control at the low end because if i want a lot of speed, my low end is a little querky unless i play with my esc's timing settings. So take my word for it, in my application, the 2 speed will be beificial.

so here's my question: does anyone know the dimensions of the two speed used on the rs4? mainly the minimum width needed to install on a shaft, the bearing size and is it possible to replace the bearing with a 6x10mm one?

To increase my options, what's probably the thinnest 2 speed tranny out there? It doesnt' matter if the 2 speed is made for electric or nitro. I just need the spur gear clutch assembly. I'll probably end up getting hpi's electric pinion gears to run it.


I'm looking for a two speed transmission for other uses. It needs to ride a 6mm shaft and be as thin as possible.

Thanks,
Keith

[Stumper]

I just installed one on my traxxas 4tec.......... I dont have the exact dimensions because everything is at home.... What I had to do the make it work was pretty simple. I bought a stock 4 tec pulley shaft and turned(put it on a lathe) it down on the front half to accept the 2speed assembly. What kind of car are you putting it on?http://www.******.net/media/2speed.jpg http://www.******.net/media/finished---rcp1.jpg

[yf22k]

its actually a motorcycle. And it needs to be a 6mm shaft the whole length. I just need the thickness of the necessary parts without any of those spacers if they're used on the shaft. I'll also need the 1-way bearing sizes,(width, inner and outer diameters)

how well does it perform on your 4-tec?

thanks,
Keith

[Stumper]

To be quite honest, I dont think it works all that well. It doesnt make enough of a difference for me to tell if it works better or not........ But its worth a shot anyways.

[yf22k]

how big of a difference in ratios can you run between first and second gear?


Do you think it'd be possible for you to get dimensions of the assembly sometime?

Thanks,
Keith

[Stumper]

the stuff is at home and im still at work......... so not till later tonight.

[yf22k]

ok whenever you get a chance that'd be great. Thanks,
Keith

[Stumper]

I keep forgeting to bring the parts in with me but I can tell you this. It wont fit on a 6mm shaft..........Its closer to 3mm or so...

[yf22k]

heh its cool. Do you know wha the outer bearing diameter is? I think those bearings can be replaced.

[Stumper]

ok here ya go........ All i have is a tape measure thats in inches!

the whole assemly from front to back is .75 (3/4")
id =3/32"
od = 5/16"

[yf22k]

Thanks stumper,

Hmm its a hair too wide. Is there a spacer included in that or did you just take the dimensions of the widest point?

Hmm i dont' think i'll be able to replace it with the right size bearings either. The shaft is 6mm in diameter. It seems the outer diameter of the bearings in the 2 speed are about 8mm so that probably wont' work too well unless i can find a 6x8 one way bearing. Most one way bearings with a 6mm inner diameter have a 10mm outer diameter

Oh well thanks for your help!
-Keith

[Stumper]

Theres no spacers there........... Do what I did, turn the end of the shaft where the assembly goes down. Take it to a machine shop if you have to.

[yf22k]

hmm i wish i could machine it out but i need the end of the shaft to be 6mm because it runs on a bearing there. The two speed needs to be sandwiched between two bearings on the shaft.

I'll research some more.

Thanks,
Keith

[Stumper]

just turn it down all the way on one end and make a sleeve that attaches with a set screw that hold the bearing at one end.

[yf22k]

hmmm interesting that's not a bad idea.
I'll look into it.

Thanks,
Keith