Ring and pinions?

[brushlessboy16]

Hey guys im just wondering what ring and pinion set i should get for my Raze, its standard 1/8th scale size and ratio... i just blew out my rear pinion with the outrunner


I have blown both front and rear pinions so far...... i need a better replacement, i was looking at the Helical cut Duratrax gears but im not sure Any input is accepted :D

[BrianG]

Usually, 8th scale parts are pretty tough. You sure the diff is shimmed right? Also, does the case have any slop? Either of these will cause improper mesh and increased chances of stripping...

[brushlessboy16]

i know, that was my problem, i didnt adjust the shimming from the factory, its got plenty o'slop.... so u think properly shimmed stock replacement?

[BrianG]

I would definitely start there before spending cash on something that will have the same issue. Solve the problem, not the symptom.

I've only stripped one diff and that was because I was too impatient and didn't shim it...

[brushlessboy16]

do u have any links to Diff shimming?
also for you Brian, i have an xbox360 psu, im guessing i need a resistor to get it to startup? but how do i figure out how many ohms of resistance it needs?

[BrianG]

For shimming, you want to shim the pinion have no slop right before the point where you get binding.

Not sure what the PSU specs for the 360 are, but look at the 12v rail (may have several supplies). Usually, they rate TOTAL power, not just on one rail. Look at the current rating for each rail. As far as a loading resistor, it depends on the design. Usually, around 1A loading is fine, but takes experimenting to find out which supply rail is used for the regulation. Normal computer supplies usually need the 5v or 3.3v loaded if any. For the 12v rail, use something around 10-12ohms and 20w. For 5v, use 4-5ohm and 10w. For 3.3v use 3-4 ohm and 10w.

[brushlessboy16]

The Psu is 12v 16.5a, the 5v circuit is 1a, hmmm, is ther anyhing besides resistors that can be used to load it down?

also with shimming, i make it so that the pinion is snug against the spur? or can i slide the diff itself side-to-side?

[BrianG]

For the PSU: Some people use light bulbs, but they are relatively fragile and I don't like getting broken glass in my skin when I reach into my toolbox. Maybe nothing needs to be loaded - there could be some sort of other turn on mechanism. Hard to say though...

For the shimming: There should be no side to side motion - that's probably what's causing your problem. The pinion should be fully meshed into the ring with NO play, but make sure it still runs freely, especially after you get the case together.

[brushlessboy16]

Originally Posted by BrianG

For the PSU: Some people use light bulbs, but they are relatively fragile and I don't like getting broken glass in my skin when I reach into my toolbox. Maybe nothing needs to be loaded - there could be some sort of other turn on mechanism. Hard to say though...

For the shimming: There should be no side to side motion - that's probably what's causing your problem. The pinion should be fully meshed into the ring with NO play, but make sure it still runs freely, especially after you get the case together.

PSU- The supply needs one of the lower voltage circuits pushing current to activate... i connected the green wire to a ground, still nothing so im hoping i can find a way to load it down a little bit :D

As far as diffs go, I want to but just a pinion but they dont sell the individual parts, so im gonna get a helical cut gear set anyway (they sell the pinion and spur serperately) But i cant seem to find any shim kits on tower... am i looking in the wrong place?

[BrianG]

Unfortunately, unless the PSU tells you which rail to load, it's a bit of trial and error.

Can't remember where I got my shims - I think I just collected them over time and happened to have the ones I needed. Just use your bearing size to determine the size of the shims (and don't forget; the shim width cannot span both edges of the bearing or it'll rub).

[brushlessboy16]

Ur saying that it cant touch the inner and outter races of the bearing?
Well ill probably have the gears mid-next week, i got alot of stuff that i need to return to tower, YAY STORE CREDIT!!!

[BrianG]

Originally Posted by brushlessboy16

Ur saying that it cant touch the inner and outter races of the bearing?

Yup. Since the inner and outer races do not turn the same, the shim cannot contact both at the same time. I just mention this because some shims are rather wide...

[brushlessboy16]

alright, well i gotta Re-re-re make the mount for the outrunner.. so i guess ill run it 4wd with the broken pinon for a pack or two