Gearing Question

[wade7575]

I'm getting a 3905 E-MAXX.Then I'm getting a Nue motor and MMM what I'm wondering is if I leave the E-MAXX 100% stock.I will change the A-ARMS and shocktowers to rpm stuff.I've seen the gearing conversion charts but I do not get them at all.I'm going to be running a Nue 1515Y motor and will be running 16.8 volts,I know what everyones going to say no don't do it get Lipos I'd love to but my check book won't go for it.I know enough about gearing if you guys say run a pinion between 14 an 20 tooth that I need to start with the smallest and going up in size 1 tooth at a time while watching the motor and ESC temps.

[mkrusedc]

I have a 3906. The largest pinion i could fit was a 20 tooth because the can diameter is so large. Neus are very efficient and should not have a heat problem. what kind of speed do you want?

[wade7575]

If I get 40 to 45 MPH I'll be happy.I just want to make sure I do not want under or overgear and toast my ESC.I was looking at the Novak 6.5 but now I will not touch one because they want you to run a 12 tooth pinion and I know from doing alot of research nobody is making a 12 tooth 32p 5MM bore.Nice to see you on this board to and not just at the traxxas board.

[suicideneil]

Okay then, lets take a look at this.

Provided you get good Nimhs, there shouldnt be any issue running them with the Neu- that said, good nimhs can cost almost as much as some lipos. If you take a look at the swang, zippy, and True RC lipos, you will see that a 2s pack can cost as little as around $60, so using two of them in series will be as good, if not better than Nimhs.

Anyway, gearing.
I know Mark uses the 1515 1y, so hopefully he can give some practical advice, as well as using the calculator. Based on the info you supplied (truck, voltage and motor), then 62/20 will get you about 40mph, which is great really. If you only buy one pinion, then make it a 32pitch 5mm bore item with 20teeth. I would strongly recommend getting the 62 and 65 tooth optional spurs for the emaxx 3905- $3 each or so, and it will give you more gearing options to tweak things. The MMM esc should run cool regardless, as will the motor probably, but its the batts that will tend to run hot if overgearing occurs.

As for general upgrades for BL power, the 3905 is pretty solid. The diffs will be first to give probably, and there are various cheap, and not so cheap options; cross that bridge if/when its required.

Buy a smooth can Neu if at all possible, as that will make life easier when it comes to gearing.

The Hvmaxx was good in its day, but it just cant cut it terribly well anymore, not compared to some of the newer motors and escs. Novak are working on new stuff however, but it wont be out for quite a while, same with tekin.

[jayjay283]

here is a pic of a 1515/1y in a 3905 just to show you gearing options shouldnt be a problem as far as clearance goes. thats a 58 stock spur and 22t pin

[lincpimp]

Stock spur is a 68.

[jayjay283]

sorry I meant the spur is from Traxxas' stock, Its a jato spur #3958 direct fit

[lincpimp]

Makes sense! Thanks.

[mkrusedc]

I don't know about the 3905 motor mount but a 3906 can only fit a 51/20 without modifying the mounting plate. The neu can is pretty large compared to Titans. May some one else can be more specific about the 3905.

[wade7575]

mkrusedc Can you not use a smaller spur on your to allow you to use a bigger pinion.

[mkrusedc]

You proably could. I have a Strobe slipper. I think the use Ofna surs?

[wade7575]

When I was asking,I was asking if you could run a smaller spur.

[mkrusedc]

Originally Posted by wade7575

When I was asking,I was asking if you could run a smaller spur.

I just started a thread to ask that. the strobe slippers use Onfa spurs. i don't not if there are other options.

[highflier]

If lipo's are to costly look into the A123's Great option for RC trucks.

Highflier