Low gearing effect on driveshaft question

[Josh_Br]

I am looking into getting an AX10 RTC, and was planning to also order pinion and spur gears to get my driveline ratio down to around 72:1. I was reading a thread on here about stronger driveshafts needed due to a moter change, and I got to wondering whether this low gearing that I plan to do will hurt the stock AX10 driveshafts, or whether they're strong enough to take it. What do you think?

Thanks,
JB

[bigstu]

You were right when you said it will depend on the motor and how you intend to drive it.
First thing, Overdrive gears in the front, Under drive in the back. Eliminates some of the torque twist you will get with this car and will also help when crawling, to have the front tires pulling more than the rear.

Forget about the driveline ratio.. not important..
14t pinion, stock spur gear, and you are good to go.
I ran stock AX10 driveshafts for quite a while, with just the axial driveshaft rings installed.
There are LOTS of posts about drive shafts.

My advice, go here and get this kit. I know it is expensive, but if you can break it, you accomplished something.
C.I. Maxx Drive Shaft Upgrade Kit

You can also use Traxxas axle shafts for the Slash and Traxxas yokes for the stampede to make some pretty tough drive shafts. Do some searching and I am sure you will find lots of info on them.

The other option for AX10's is going to Junfac, MIP CVD's, or another metal drive shaft.

[Josh_Br]

Thanks for the advice! You're right, that is expensive So let's talk about the gearing - I want the thing to go super slow. I do not care about going fast what-so-ever. I want to stand on the gas an have it creep. I have never driven one of these rigs; you think the way it comes geared is already pretty low?

[ax10]

when i first bought my axial, i went with a very slow combo. I discovered quickly that having some wheelspeed is needed to make it over some obstacles. The stock spur and 14 tooth pinion is pretty slow. I started with a 75 t motor. To make a long story short: Now i have a 35t motor, 12t pinion and 3s. I have excellent slow speed crawlability and enough wheelspeed to jump gaps or steep inclines with loose surface. I hope this helps a bit

[sloppy]

Originally Posted by Josh_Br

Thanks for the advice! You're right, that is expensive So let's talk about the gearing - I want the thing to go super slow. I do not care about going fast what-so-ever. I want to stand on the gas an have it creep. I have never driven one of these rigs; you think the way it comes geared is already pretty low?

If you have never driven one save yourself the money on those pinions and drive it first.. the stock gearing is a good place to start..

[Josh_Br]

Thanks guys, good advice. True, I have never driven one of these, only the Duratrax Cliff Climber that I used to have.

Good point about a little wheel speed being useful.

[92LILREDYJ]

I think a cheap strong drive shaft would be the Rear slash 4x4 shafts. 6852x and you would need a 6828 to go with that.
or order 6828 x2 and a 6850 x2.

[alvaroguisso]

I try to change only at the beginning and the pinion was pleased with the result

[bigstu]

Josh, I will second what most of the other guys here are saying.
All you have to do is watch someone with a Losi crawler. They have exactly what you are talking about.
They have GREAT low speed control. But if you have to hop a gap, or pop the throttle to get the front tires up on an obsticle, or it has rolled over on a flat and you need some wheel speed to get it righted on it's wheels again, the low gearing and slow wheel speed will be the end of all of that.

With the over/under combo, a 35t motor, 3S lipo, and stock pinion and spur combo, I was able to crawl VERY slow and pull the front or rear tires on command.
And like everyone said, take some time, drive it and make a change if you need to.

Mandatory I would suggest at least the over drive front gears. That helps a bunch..
Then go from there.

If all else fails, do some searching for the fastback chassis rigs that have been built here. DickyT ran one for quite a long time with VERY good results, and I had one too..

Good luck

[Josh_Br]

Thanks guys, you are all making sense. It is pretty "newbie" to want to order parts before I've even driven the thing. I think that where this desire for really low end is coming from is from having that Cliff Climber. It was cool, and I even made custom brackets and put AX10 shocks on it so it flexed like crazy with all of the travel, but sometimes it lacked power. A tire would get bound up in a tight place and it would just get stuck, but it seemed like if it had more guts, it would have continued forward and got over the obstacle. Here's a pic of the rig all flexed out, if you want to see it: Duratrax Cliff Climber (modified) | Flickr - Photo Sharing!

Do you have any thoughts on how this AX10 will compare to the Cliff Climber? I assume the AX10 is more capable.

So about the over / under drive. I have read about people changing one or the other, but some people like to change both front and rear. It looks like there are two gear ratio sets available (Axial Racing - AX10 Scorpion Optional Ratio Gear Sets). Any thoughts on changing only front or rear VS. changing both?

Thanks all.

[Jus]

if I was only to run one or the other I'd overdrive the front.. It adds a tiny amount of speed overall whle still basically underdriving the rear. Add both though, and it makes a huge difference in my experience. It can make backing up a little goofy because it binds up the suspension, but going forward it keeps everything stretched out and it climbs excellent and combined with my droop shock setup I noticed almost no torque twist at all.

[ax10]

a couple of things i forgot: I have junfac drive shafts and o.d front gears. I believe the junfacs were $15 a piece. Other than regreasing them twice a year, they have had no issues. The o.d gears has tightened up turning radius a bit.. As stated earlier, backing up is a bit strange.

[Josh_Br]

Ok, thanks again I've been reading on here for a couple hours this afternoon. I am loving all the little technical tweaks you can do to one of these rigs; some tweaks free some not, it's sweet. I've always said I like working on these cars equally as much as driving them, or maybe even more than driving them!