rEvo is up and running

[shaunjohnson]

while waiting on a mamba max and feigao 6XL (temp motor till i get a medusa)
ive got a single VXL in there.
it's an old revo 2.5 and is pretty much stock.

ive finally got it to shift gears too...man it's hard to control when it does that
shoots forward and the dust cloud gets bigger

but...weak tranny points...i wanna know them ALL!!

if i plan to go up to 4s on a medusa 80mm i wanna have a bulletproof tranny..i kinda wanna stay with a shifting tranny so i can swtich to nitro quickly for race meets (on the days that i wanna race with the normal MT's rather than the anything-goes-novice-class).

so RR steel internal gears.
something about a pin in the internals of the tranny.
E-revo diffs (and eventaully a 1/8th diff conversion and losi smart diff)

but i wanna know ALL the weak points!!
btw yes ive shimmed the diffs

shaun

[Unsullied_Spy]

Hiya Shaun, your MM and 6XL should be there next week

It'll be interesting trying to get a Revo to handle 80mm power, I have one in my Muggy and it's insanely powerful. The FoC gear in the transmission is driven by a little pin (2-3mm diameter) and that pin is very prone to shearing under electric power. You've just got to drill that hole out and use a tougher pin and the trans is pretty tough. A piece of hex driver that is the correct diameter should suffice. I wouldn't bother with RR steel gears unless you strip the stock gears. There are a lot of people that do the simple pin upgrade and the stock transmission is pretty tough.

I sent Daniel 1 E-Revo diff, he'll probably want it for himself though They're supposed to be improved over the regular diffs but make sure they are shimmed. 1/8th diffs will greatly improve the durability. There was someone here who managed to fit Muggy diffs into a Revo with only minor modifications to the bulkhead, I'm wondering if a Cen Matrix Buggy diff would drop in since they use smaller gears. The RC-M hybrid diff is a very good upgrade, but it's also expensive. Keep in mind the 1/8th shafts are all 8mm as opposed to the Revos 5mm (I think it's 5mm, not totally sure though). RC-M has a variety of parts available for toughening up Revos, I'd go with 8mm shafts all around if you can afford it.

That tranny pin, the diffs, and the U-joints are the major weakpoints in the Revo's drivetrain. With that 80mm MedUsa you will snap a U-Joint, it's just a matter of time until it happens. The new shafts coming out with the Summitt and BL-Edition E-Revo should be tougher than the stock units, but you may want to look into some CVDs for it.

EDIT: Stickies rule:
http://www.rc-monster.com/forum/showthread.php?t=7441

EDIT Again: Here's all you need to know about the pin mod:
http://www.rc-monster.com/forum/show...8&postcount=45

[shaunjohnson]

thanks man
yeah them sumit driveshafts are on my to-buy list.
i'll get to work on that pin mod asap and do the diffs soon.
yes the 80mm will be pretty crazy and i can feel it now after being shocked at how well the single velineon is going
it's a challenge

i'll look into the 1/8th diffs and yeah 8mm shaft things all round.
has lots to buy, motor mount and pinion/spurs are on my asap list right now.
thanks for the help ;)
shaun

[Unsullied_Spy]

If you think a Velineon is powerful you're in for a system shock! That's a 50mm, 2 pole, slotless stator, chinese-made motor. It's got some power for 1/10th scale 2WDs but it's lacking when it comes to something as big and heavy as a Revo. That 80mm MedUsa has a 4 pole rotor (more torque), slotted stator (again, helps with torque), and is built in the U.S. They're comparable to a Neu but not as expensive, their performance is straight-up impressive for their price.

[shaunjohnson]

i can imagine yes!
ive seen some standing backflips and jesus that must take some power!!
if possible i'd like to get my tranny strng enough to pull off that kinda monuver as i could imagine that being very streefull of the rear diff and tranny, i think most of thoes guys are running the E-maxx tranny though.

i would like an 80mm because of heat!
i deffo will not be mashing the throttle as i prefer control over raw display of power.
and the prospect of silly/stupid torque avaliable is fun

lets just get used to the feigao first then move up
only running a 4s lipo should tame things down a little as log as i gear it to keep the amps down.
and then after all this...put the setup in the rustler and rip the tranny out of it's case

[BrianG]

I think you'll end up shearing the second gear engagement pin/pin housing with that kind of motor. And if you think it's hard to control it now when shifting, wait until you get a motor with at least double the torque in there! You'll be lucky to keep it under control.

TBH, if you want to retain the two speed, a 70mm motor (or even a 60mm motor) would be more than sufficient. The lower gearing of first increases torque, and the higher gearing of second gives you the top-end. If a regular XL motor can handle a single speed mod with tons of starting power AND high speed, an 80mm will do it without sweating at all. The only reason for a two speed is to compensate for nitro's lack of torque. Good luck!

[Semi Pro]

Originally Posted by BrianG

I think you'll end up shearing the second gear engagement pin/pin housing with that kind of motor. And if you think it's hard to control it now when shifting, wait until you get a motor with at least double the torque in there! You'll be lucky to keep it under control.

TBH, if you want to retain the two speed, a 70mm motor (or even a 60mm motor) would be more than sufficient. The lower gearing of first increases torque, and the higher gearing of second gives you the top-end. If a regular XL motor can handle a single speed mod with tons of starting power AND high speed, an 80mm will do it without sweating at all. The only reason for a two speed is to compensate for nitro's lack of torque. Good luck!

that pin sucks i broke it with a 1515 2.5b on 5 cell

[shaunjohnson]

if i fiddle around and have a play with shift point...
does it matter if a brake either the shift pin or the other pin?
like can i still lock it in 2nd after i brake them??
shaun

remember the reason they came out with multi speed trannies is to make up for deficient powerplants which a 70mm BL motor is not. The first gear in a Revo 2 speed is usless when mated with a good BL motor IMO

[shaunjohnson]

thanks,
ok then, so if i kill this tranny i'll just repair it and ditch it for an e-maxx tranny.
that'll kill my plans but dont matter...brushless is worth it

Originally Posted by shaunjohnson

thanks,
ok then, so if i kill this tranny i'll just repair it and ditch it for an e-maxx tranny.
that'll kill my plans but dont matter...brushless is worth it

you dont need to ditch the tranny, you can do a mod where you remove first gear and use 2nd gear has the primary...there is a sticky on the forum and its not hard to do

[shaunjohnson]

yes but i'd keep it ready for nitro.
our club is a nitro club you see but they are running a novice class for the few of us who are running electric.

and an E-maxx tranny will canter the motor over a little better and move it forward a little.

then i'll have a pretty good tranny
but then i'll lose mechanical brakes and that's bad...i wanna keep the temps down so i dont want to make the motor do any breaking.
so a second gear lock job isnt out of the question.

but ive gotta look at my options

shaun

[hailmick]

couldn't you just dial 1st gear out so you start in 2nd makes better sense to me
since you want it primed for the switch to nitro when you fell like it