coolink13

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Hello Everyone

Iam building a brushless Emaxx old style. This what I have so far. Aluminum quad battery chassis converted to hold 2 lipo 8000mah 7.4v 4 cell batteries. Gorillamaxx Transmission. 23mm dace adapters with

proline wabash wheels. Spurs wheelie bar. castle creations mambamax speed control with bec. Airtronics 94358 steering servo. Steel center shafts. RPM Turnbuckles. And some typical aluminum parts. Still

have the stock diffs and axles. I will be upgrading the axles at some point. Oh I should mention I do not have a motor yet. I was looking at the Feigao 7XL motor. And searching Ebay for hacker and Neu

motors as well. THIS IS MY QUESTION. What size spur and pinion will I need to reach speeds over 60 mph? And what about gear ratio in stock diffs? Or should I upgrade to a 1/8 bulkhead set up with 1/8

diffs? Thanks

sloppyG

2 2 cell batteries and a 7xl won't get you near 65 mph on any emaxx,

you should be able to get to 35-40 though, head to rc-monster .com and use their speed calculator on their forums for an idea

coolink13

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I have 2 7.4v 8000mah 4 cell batteris. But thanks I will check out the speed calculator. What will I need to 65 mph?

cmerritt

3s lipo, brushless and then gearing


^that should be a good start to get to 65 mph

gmcman

An expensive motor, expensive ESC, expensive LiPo's, then get the plastic diff gear for the Nitro Rustler, or Nitro Sport...can't remember....it's a 54T gear that will mount in the same location as the spur and will hold the slipper pegs as well.

coolink13

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What size gearing? I went to rc-monster.com where sloppyG recommended and I could not find a speed calculator. Are my 4cell 7.4v 8000mah batteries a good start? Thanks

coolink13

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Thanks for Info gmcman!! Did you mean spur gear not diff gear? Thanks again

sloppyG

4 cell would be 14.8 volts
2 cell would be 7.4 volts

I suspect you have 2 -8000mah 7.4v 2 cell packs (which you can run in series to make 4s-14.8 volt 8000mah)
the batteries should be a good start if you have a decent C (discharge) rating (at least 15, although 20 or higher is better)

http://www.scriptasylum.com/rc_speed/index.html is the speed calculator

if you really want to hit 65, you'll likely need more voltage than you have and a very expensive motor/esc package

that speed calculator should give you some good info though

gmcman

Nope, diff gear.....from what I remember it's the diff gear and where the diff balls would go you use the pegs.

coolink13

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Thanks for pic gmcman. But that is the spur gear on the transmission. The pinion gear goes on the motor shaft.

gmcman

Correct.

The spur shown is what I believe is the diff gear on the Nitro Rustler or Sport...used as the spur on the maxx.

coolink13

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Thanks sloppyG. I was able get some info from calculator. Is my mambamax esc good enough for what I want? Or should I get the mambamax? Was also thinking about the neu1515 motor.