Locking the revo in 2nd gear to use motor braking/reverse - Page 4 - RC-Monster Forums

z1nonly · 11.05.2007, 08:19 AM

So after this mod is done, what would be the spur/pinion combo that would make it equivalent to 72/12 on an E-Maxx transmission. That is assuming that the Revo trans is equipped with a close ratio.

Reason I'm asking is because I might end up using a Revo trans instead of an E-Maxx trans for my E-Revo project, and I'll be running the Novak HV6.5 setup.

BrianG · 11.05.2007, 12:33 PM

Welcome to the forums!

Using the close ratio tranny, a 40T spur, a 10T pinion will give you the same speed given the same motor, voltage, etc.

For speeds in the 35mph range, I would go with the wide ratio tranny option, a 40T spur, and a 14T pinion. That seems to work best for me, and the wide ratio seems to let you use a more common set of gears while still offering some adjustment options.

BTW: I used this calculator to get this data...

z1nonly · 11.05.2007, 07:48 PM

Thanks for the welcome, Brian.

Great info you just gave me. I think I'll choose the wide ratio route that you just suggested.

And thanks for the link to that calculator.

jacobsjo87 · 11.12.2007, 01:39 PM

Does anyone have the part numbers for the revo outdrive pins as well as the jato outdrive pins.

11.15.2007, 12:53 AM

revo - #5145
jato - #5149

BrianG · 11.15.2007, 01:57 AM

Before anyone goes out and gets those pins, wait a couple days because I found some errors in a previous post about the pins...

offroader · 11.15.2007, 12:31 PM

Thanks for the info Brian!

BrianG · 11.15.2007, 01:04 PM

OK, the "pin mod" post has been fixed...

gtxracer · 11.28.2007, 04:41 AM

Has anyone else gotten a little "binding" after this mod? It's nothing major, just a tiny bit of resistance once a revolution. I looked at all the gears, they all were fine. There was a little bit of "sawdust" in the case, mostly from the gears and using a big block, then a TZ I suppose. Brushless is gonna help!

BrianG · 11.28.2007, 10:47 AM

If you're getting binding, there could be two causes that I can think of:

1) When you do the 2nd gear lock mod, the 4mm screws you use to lock the clutch may be causing an issue. I noticed that when I threaded those 4mm screws in, the end of the screw sorta "pushed" some plastic out and may get in contact with the output gear. An exacto blade is easily used to trim this.

2) When doing with the larger pin mod, you could be overtightening them. It's hard to explain what's going on, but basically they are too tight causing the gear to flex. Try backing off a 1/4 of a turn.

gtxracer · 11.28.2007, 03:36 PM

I didn't do the pin mod, so it must be the extra plastic. Thanks Brian.

retiredtech · 11.29.2007, 01:33 AM

Are you guys talking about a brushless set-up only or can this be used with a nitro engine ??

gtxracer · 11.29.2007, 02:49 AM

Nitro engines need the one way bearing, so no.

BrianG · **Pinmod V2 -** 11.29.2007, 01:17 PM

OK, after rebuilding a couple of Revo trannys now, I think I have a winning combination. I noticed that whenever a pin broke, it was right where the threads meet the shaft, so that must mean that that spot is the most stressed. So, I modified two of the stock pins so they are about 7mm long each and then threaded both screws on each side of the gear hubs so the shaft tips meet inside the shaft. Below is a pic of the modified screw pin:

When cutting the black FOC pins and the original chrome pins (same size, diff color), the black ones seemed to take longer to cut with the dremel, so I think they are harder.

Also, this mod has an added benefit: Since both sides are now captured, if a pin does break, the broken end won't fall out and mess up the other gears.

Each of the three shafts are different in diameter, so there is easy no "one fix for all" solution. So...

Input shaft: In the gear hub, drill out the side of the gear hub using a 7/64" drill bit to allow for the screw pin threads. Modify two of the stock chrome pins like in the picture above and screw them in. The chrome ones are OK to use here because the pins have less force being exerted on them due to the gearing.

Idler/middle shaft: Basically do the same thing as the previous step, but use two of the black FOC pins instead. The pins here need the extra strength.

Output shaft: Since the output shaft is a softer metal, and has enough diameter, drill out the shaft hole to 2.5mm and use a Revo out drive pin.

I torture tested this setup a couple days ago and it seems to be holding up better.

Matthew_Armeni · 11.29.2007, 01:26 PM

Quote:

Originally Posted by gtxracer

Nitro engines need the one way bearing, so no.

Actually you can do this mod with a nitro engine, but you would lose either low speed punch or some top end. So unless you're throwing a BB in there and want a low rotating mass tranny, there'd be no reason to do it.