93T Spur 10T pinion vs a 4:1 reduction

[BroncoAZ]

I was running the RC4WD 4:1 gear reduction with a 18.5T Novak Goat brushless system. No huge surprise that I destroyed the gears in the reduction unit (they have a disclaimer on their web site about it not lasting with the brushless). I removed the gear reduction and found the rig is way too fast. The current gearing is 87T/12T (7.25:1 ratio). I was looking at either placing a standing order for the replacement gears for the 4:1 unit, or going to the 93T spur and 10T pinion (9.3:1 ratio) as a cheaper solution. Will that 28% lower gearing of the 93T/10T combo make much difference? Would I be better off trying one of the HPI reduction units?

 

[mr.freeze]

you could also try replace the gears in the axles with the 43's may help slow you down too.


EDIT: in conjuction with the pinion/spur change

http://www.tcscrawlers.com/Axial-Ra...-for-Axial-AX10-Scorpion-AX30402-p-17254.html

 

[BroncoAZ]

After playing with it a bit last night, I can still crawl without the reduction box, but I'm concerned about cooking the motor in slow speed high load situations. I know it's a crawler motor, but I think the 18.5T is better matched to a LCC.

I looked at axle gears, but at $50 for the pair of axle gears I think I'd just swap motors. If I'm reading the chart correctly it looks like the current Novak 18.5T 3419 motor runs at 2700 RPM max. I'd see a 33% reduction in RPM to 1800 with the SS series crawler 3420 motor, or a 50% reduction in RPM to 1350 with the Ballistic crawler 3619 motor. The motors are $80 and $90 respectively.

http://www.teamnovak.com/products/brushless/motor_spec_chart.htm

Another option would be stepping down to a brushed motor at 65T or 80T. The Goat ESC instructions say it will support brushed.

I'm waiting to hear back from RC4WD to see if the replacement reduction gears are available separately and for how much. I'd also consider going with 3:1 reduction gears if they swap right in. If the replacement gears are not too expensive that is the route I'll go. The first set lasted quite a while and crawled super slow. I don't want to spend $40 for a new reduction box though when I know it won't last.

 

[Sharkey]

i was trying to get a 90t spur for mine, i was told by my lhs that anything bigger than 87t will hit the driveshaft. ive always wondered about it, and i see robinson racing lists a 90t and 93t spur for the axial tranny. can anyone confirm this if it will or wont work???

as far as swapping motors, if you go to brushed stick with a 35-45 turn, 65 or 80 turn is just way too slow, you wont have any wheelspeed.

 

[oldhippie]

I had a 92t spur on my axial. Run it with a 10t pinion, mip shafts (just rubbed) and 500 puller. Worked great "thumbsup" until I changed to a narrow Kamikaze chassis and the spur hit the chassis. Ya can also get a 9t pinion from HR I think.:?

 

[SDheavymetal]

You could try the 3racing High Clearance knuckles. They have 1.6:1 gear reduction and more clearance. You have to use the old dog bones though. 10/16 gears in knuckle.

http://www.rccrawler.com/forum/showthread.php?t=181231&highlight=portal

 

[indiana mudcat]

I run the 2s 18.5, with HD front (stock ratio) gears and underdrive rear. I was running 13/87 gearing but couldn't keep shafts in the front, I switched to 16/87 the other day and I'm very happy with it, still crawls slow and has great wheelspeed, motor temps at 110. Make sure your min drive speed is turned all the way down on the ESC, if it's not the min speed will be high. Your not gonna hurt the motor, it'll take whatever you throw at it. I also suggest a CC BEC to keep ESC temps down and keeping the drag brake in the 4-6 range.

Stay away from those 3racing knuckles, that 18.5 will destroy em in about 5 minute's, I could destroy em in less than a minute.

Soon to come: Super 300's, a return to 13/87, 3s lipo and standing backflips.

 

[BroncoAZ]

I've found that the current level of speed turns me from a crawler into a basher. A broken axle C and a few other parts has verified that I need to slow it down. I haven't gotten a response to the e-mail I sent to RC4WD about new gears for the reduction unit yet. The speed with the 4:1 reduction was slow enough that I was not able to accelerate out of a nose down rollover situation, so somewhere between what I had and what I have now would be good.

I've got the minimum drive on the Goat set to 2%, the lowest setting. The minimum speed is still too fast for precise crawling like I could do with the gear reduction.

 

[rock hard]

45t brushed,cheap and effective.

still run the overdrive up front and under in the rear.
if your dig servo fails in a comp your stll better than you would be with out over and under drive.

and the kits are 32 per at my lhs.
probably cheaper at rpp

 

[indiana mudcat]

I've found that the current level of speed turns me from a crawler into a basher. A broken axle C and a few other parts has verified that I need to slow it down. I haven't gotten a response to the e-mail I sent to RC4WD about new gears for the reduction unit yet. The speed with the 4:1 reduction was slow enough that I was not able to accelerate out of a nose down rollover situation, so somewhere between what I had and what I have now would be good.

I've got the minimum drive on the Goat set to 2%, the lowest setting. The minimum speed is still too fast for precise crawling like I could do with the gear reduction.

Try the ESC on profile2 (expo curve) if you haven't already, other than that 93/10 should give you what you want.

 

[BEELZEBOB]

I would suggest a $20 35t integy lathe, a 13t pinion and the stock axial trans.

i gots wheelspeed. but unlike a BL in a tank of a RC4WD trans, i have low end speed control.
http://www.youtube.com/watch?v=2wGDBxgL_lE

unless you have a losi or a wormgear somethin or other, ditch the BL

 

[rock hard]

I would suggest a $20 35t integy lathe, a 13t pinion and the stock axial trans.

i gots wheelspeed. but unlike a BL in a tank of a RC4WD trans, i have low end speed control.
http://www.youtube.com/watch?v=2wGDBxgL_lE

unless you have a losi or a wormgear somethin or other, ditch the BL

x2 but I run 45 in my sons and its pretty jumpy,yet still has some low end control with a mrc radio

but a cheap brushed motor is fine.

 

[BEELZEBOB]

a Mamba, sidewinder or most any CC ESC will give you that butter smooth control.


hell, i bet my esc w/ the smartsense function may even wake a BL up to crawling.

but for now a warrior 35t is more than i need

 

[indiana mudcat]

Bob you really should drop a brushless motor in that thing and try it before you knock it so much, my min speed and wheelspeed is about the same as that vid on 2s.
I see no reason to buy a motor when a gear change will provide all the OP wants.

 

[BroncoAZ]

Bob, mine with the BL motor crawls as slow as what is depicted in the video, but the wheel speed is not as high. I'm no expert though.

I'm on profile 2 of the goat already. I got an e-mail back from RC4WP on the replacement gears, they are $15. I'm going to ask if the 3:1 and 4:1 are interchangable, and if so I'll get the 3:1. I still want to try the 93/10 combo without the gear reduction, but it looks like the 93 might hit the HR driveshaft joint rings. I'll get a better measurement and see if it will fit.

This crawler is still a loaner, so I'm not planning on replacing major parts unless I break them. I've purchased a set of rovers and a inside the rail skid plate. All of the other changes I've made were just reconfiguring parts that my buddy included or things like 4 link plates I made in the garage. I'm not sure if I want to stick with this Axial with 4 wheel steering, or try a LCC with the factory DIG. I want to attend a local comp or something before I decide. I realize I can't comp the Axial with the 4WS.

 

[Brammer666]

I run a 88/14 set up with my goat and haven't had any problems. it's a beast!

 

[rickb-123]

u can go as be as 93t before it hits