E- revo gearing questions

[sjcrss]

I plan on getting an e-revo, and will be running a quark 125b w/ 7xl...... any suggestions for gearing

What kind of battery setup were you looking at? I've read that the 7xl runs pretty hot, so you would probably be best off to gear for ~40mph.

[sjcrss]

2s2p (4s) maxxamps 8000 lipo's.....i ran this setup with no issues on my gmaxx & it weighed about 11lbs....

Go to this site and plug in some values.
http://scriptasylum.com/rc_speed/_top_speed.html

Front/Rear Differential Gear Ratio: "Traxxas Revo"
Transmission Gear Ratio: E-maxx (3905) 1-Speed or 2-Speed 2nd Gear"
Spur gear: Assuming you're going to be using 32p (0.8mod); 54 56, 58, 62, 65, 68(Stock)
Pinion gear: These can be had from tower, impaktrc, rc-monster, kershawdesign. (Stock is 19t)


This is what you might be looking at:

Differential Ratio: 2.8461538461538463
Transmission Ratio: 1.8333333333333335
Other Ratio: 1
Spur Tooth Count: 54
Pinion Tooth Count: 19
Total Voltage: 14.8
Motor KV: 2382
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 2.84 : 1
Total Ratio: 14.82996 : 1
Tire Circumference (inches): 18.06 inches (458.83 mm)
Total Motor Speed: 35253.6 RPM
Vehicle Speed: 40.66 mph (65.32 km/h)
Estimated Adjusted Speed: 39 mph (62 km/h) - 5% loss
Effective KV Value: 2382

You makee a mistake on the spur gear , the stock e-revo spur gear is 68T, mod .8.
So with your 4s li-po, gear it with a 23T 32pitch pinion, and you'll be in the 39-40m/h

On my e-revo, on 6s, with badland tire (5.85" OD) i'll use a 22T pinion.

Originally Posted by david lamontagn

You makee a mistake on the spur gear , the stock e-revo spur gear is 68T, mod .8.
So with your 4s li-po, gear it with a 23T 32pitch pinion, and you'll be in the 39-40m/h

On my e-revo, on 6s, with badland tire (5.85" OD) i'll use a 22T pinion.

Yeah i do know that 68T is the stock spur, but i was using a 54T spur that traxxas makes for the jato. Since a spur is cheaper than a pinion, i thought i would suggest another spur(~$3) instead of another pinion(~$12).

You'll be ditching that 7xl right quick, if it lasts long enough ;). It's too hot a motor for something heavy as a Revo. 8xl even runs too hot on 4s in my Revo. My 9xl on 4s is good for only about 15 minutes before it's too warm for comfort.

J.

Originally Posted by 83gt

You'll be ditching that 7xl right quick, if it lasts long enough ;). It's too hot a motor for something heavy as a Revo. 8xl even runs too hot on 4s in my Revo. My 9xl on 4s is good for only about 15 minutes before it's too warm for comfort.

J.

Maybee you was over geared with your 9XL, because i've run it in a 11.6lbs truggy with excellent result.
DOn,t think an electric revo weight more than 11 lbs.

Originally Posted by 83gt

You'll be ditching that 7xl right quick, if it lasts long enough ;). It's too hot a motor for something heavy as a Revo. 8xl even runs too hot on 4s in my Revo. My 9xl on 4s is good for only about 15 minutes before it's too warm for comfort.

J.

feigaos will stay cool if you can run them in a meat locker....

[sjcrss]

Well here is all the info in one shot
quark 125b
7xl
2s2p (4s) 8000 maxamps lipo
badland tires

so i should gear it the following
23t pinion
68t spur

[sjcrss]

wow....hmmm, now im not sure how to gear...think i may start out with 22/68

[VintageMA]

I would recommend start out with a 19 or 20T and go from there based on performance.

I think that with my 1515 2.5d and 6s, i'll be not to bad with 22/68, but i've RRP MOD .8 pinion 20T and 21T on the way

[VintageMA]

Originally Posted by david lamontagn

I think that with my 1515 2.5d and 6s, i'll be not to bad with 22/68, but i've RRP MOD .8 pinion 20T and 21T on the way

David - you and I are running the exact same setup with the badlands - and running last weekend on 18/62 (equiv to 20/68) I can see 20/62 (24/68) being a good setup - but the badlands really don't balloon too bad.

You had recommended the badlands setup to me in a pm and I got the tires with the maximizer bead locks and they are a perfect bashing combo.

With the regular stock Talons you might as well take the diameter of 5.9" and add an additional 2" to the diameter if you gear for 35 or more.

SJCRSS - if you have the options of getting a few pinions I would go low and then work your way up, but either way you will love this truck - I've been having a blast with it so far.

I'll try 20/62 at first, and if my component is to hot to my taste and runtime to short, i'll drop it to 20/68