BL e-revo gearing
 

just got a used e-revo and installing a 2000 kv rx8 truggy motor and 4s hyperion batts, the current spur gear is a 54 but the motor is a little large and my 18t pinion will not mest because of the esc and shock holders, so lookin to get a larger pinion depending what the local hobby shop has lets just say a 68t thats what is in the brushed version, what size pinion will get me around 45mph

BrianG's speed calculator is a great tool for this. A 2000kv motor on 4s is going to make it hard to gear for that kind of speed. 58/24 gearing will get you about 45MPH but I don't know if that gearing will actually fit and work. Generally on 4s a top speed of 40MPH is your best bet, after that your going to be stressing your batteries and esc and maybe the motor. How close is your 54/18 to meshing? I would try using the pinion you have and get a 56 or 58 spur and see how that works for you, spurs are cheap, pinions are not. Good luck getting it figured out.

Just my 2 cents here now. Try gearing for about 35 and see how you like that. Personally I have always geared my monster trucks down and had more fun with them. Currently I have a Savage Flux, came geared 44/20, I'm now running 49/17 and have a 52 spur on the way to run 52/15 and possibly drop down to 52/12

Speed calculator
http://scriptasylum.com/rc_speed/index.html

thanks yeah i'll try a different spur its pretty close a few teeth should get it, i'll shoot for 35-40 then, this one might see a little track action

was able to make the gearing work 54/18 but speed was only 25mph i have new hyperion batts, its got racing tires maybe a hair taller than stock, i recalibrated the esc to tx, , i contacted the seller to see if he changed any tranny gear , the truck was acting as a summit when he had it not the case. then i thought my motor is not a 2000kv but it rips in my 3906 e-maxx with 70/18 geared i dont think the motor is less than 2000kv, somrthing is not adding up

How did you verify the speed? Radar gun?

What tires do you have one it?

Plugging in your info into BG's speed calc gives me 30mph with stock tires and that gearing. I am assuming it has a stock 3905 tranny.

5s lipo would be good with that motor. Or even 6s lipo and gear it down some (larger spur)

5s and current gearing = 40mph

6s and a 58t spur = 45mph

I would go with 6s if your esc can handle it.

gps unit,
tires are panthers pin type,
stock e-revo tranny
just seems odd, stock on brushed is a 68t spur than its got to be slow as hell out of the box?

Stock is 18/65, good for about 30mph with brushed or 2200kv BL & 4s lipo/ 14 nimh cells.

that does not make sense, i am geared higher and still slower than stock, i could see me being 5mph slower with stock gearing than the 2200kv motor

Are you sure your batteries are in series and not parallel?

no brian there in series, i feel like i am losing my mind here, the esc reads 4s when powered up - what would you do next?
i just tried another esc with same results
its not the motor
not the esc
not the batts, should i get get a big ol pinion and be good

OK, just as a sanity check, please confirm the following:

- transmission type and any internal mods
- current spur gear tooth count
- tire size (full diameter)
- battery voltage
- diffs used
- current pinion tooth count
- motor used
- radio settings (EPA, trims, etc)
- ESC used
- ESC settings

I know you listed some of this throughout this thread, but something is being overlooked here...

i am not sure about any tranny mods i got this used and i asked if the tranny had been regeared, no
-54t spur
-tire 5"
- batts are 14.5v last i drove it
-revo diffs
-16 pinion
-tekin rx8 2000kv truggy motor
-all settings normal, i use the same MMM in every car, and tx/rx
- esc settings have not been changed


sorry its a 16 tooth pinion i thought it was 18, its funny traxxas says with 54t/18 4s will go 40 mph is that real world facts,

Yeah, according to the information you provided, the top speed is around 26mph. 5" tires are a bit small - stock Talons are 5.9", which would bring your speed up to ~31mph.

A stock revo has a 2200kv motor and 5.9" tires. On 4s, that's good for around 37mph. With tire ballooning, 40mph is easily attainable. 6s would bring the speed up to ~55mph.

Since your tires are that small, you're gonna have to gear up a little to compensate. With those 5" tires, these are the pinions you'll need:
20T = ~32mph
22T = ~36mph
24T = ~39mph
26T = ~42mph
28T= ~46mph

Those figures don't account for tire ballooning. The faster the tire spins, the more they balloon. Unless your tires don't balloon (taped or whatever) I think the 22T or 24T pinions would be what you want.

Tip: When you enter all your data into the speed calc, and then press the "calculate speed" button, a little gears icon will appear next to the calculated speed value. Click on it and a table will open showing the speeds for various pinions (as long as everything else stays the same).

The 5" tire is why you are running slower than stock.

BG put all the relavant data up there^^^

wow thanks guys , so i'm not losing my mind thank god, i dont own talons and assumed they about the same size and the gear change is alittle more drastic than my e-maxx, thanks for all your help guys