RCCrawler Forums

mike5721947 · 07-08-2005, 04:23 PM

ok im trying to find out what tranny to use for a crawler im wanting to build and im wondering whats a good final drive ratio without wheels and tires. im looking to make this with a lathe motor (integty 55t) and stock maxx differentials. but still beable to bash around at a bit higher speeds.

1) whats a good final drive ratio? (probly running jumbomaxx clawdawgs. and stock maxx diffs.)

2)whats the ratio of stock maxx diffs?

3) how do i calculate the final drive ratio? (spur/pinion ratio x trans ratio x diff ratio?)

Jeepjunky · 07-08-2005, 04:40 PM

SEARCH or be flamed! It exists in the confines of this web site!

Try this;

maxx ratios

or this;

Gear Ratio Equation and Chart I Made for us Crawlers...

Hope this helps.

mike5721947 · 07-08-2005, 05:45 PM

well i might use a stampede tranny (final drive is 2.72) so i would have to get 87/18 (stock spur/pinion gearing) and divide the final drive ratio by that right to get the ratio of just the tranny?

for some reason the spur to pinion ratio is 4.83 so would it be 2.72/4.83? or is it a misprint and the final drive ratio is acually the transmission ratio?

so doing it with the final drive ratio from traxxas site acually being the tranny ratio i have a 7.7248 from tranny input shaft to tire. then i also have 12/93 gearing of pinion and spur (7.75) that equals 59.8672 final drive ratio.

now im stuck trying to figure out the speed this should give with 6.25" tall tires.
but i dont know what motor i should run (not really wanting to run the lathe motor as i am also wanting some speed.) i was thinking a mag mayham but there discontinued.

so what motor would give a good amount of torque but still have good speed (als whats a good ratio to do?

mike5721947 · 07-10-2005, 12:30 AM

lets start with this,

whats a good final gear ratio to run on a maxx sized crawler with the integy 55t lathe motor? maybe 65:1? come on someone has to know this stuff.

MudCow · 07-10-2005, 01:58 AM

I have run 63.2:1 (9T pinions / 72T spur) with maxx sized tyres which is very nice.

I ran a good dozen pack thru the truck with terra crusher tyres (almost 7" dia) and the 63.2:1 worked well. The 71:1 would be even better.

I am now running 71:1 (8T pinions and 72T spur) which is even nicer.

Any slower would be more of a hinderance than a help with the terrain we drive here.

Those links above are great for stock ratios.

07-08-2005, 04:23 PM	#1
mike5721947 Rock Stacker Join Date: Jul 2005 Location: port coquitlam, bc, canada Posts: 51	final drive ratio and maxx diff ratio? ok im trying to find out what tranny to use for a crawler im wanting to build and im wondering whats a good final drive ratio without wheels and tires. im looking to make this with a lathe motor (integty 55t) and stock maxx differentials. but still beable to bash around at a bit higher speeds. 1) whats a good final drive ratio? (probly running jumbomaxx clawdawgs. and stock maxx diffs.) 2)whats the ratio of stock maxx diffs? 3) how do i calculate the final drive ratio? (spur/pinion ratio x trans ratio x diff ratio?)

07-08-2005, 05:45 PM	#3
mike5721947 Rock Stacker Join Date: Jul 2005 Location: port coquitlam, bc, canada Posts: 51	well i might use a stampede tranny (final drive is 2.72) so i would have to get 87/18 (stock spur/pinion gearing) and divide the final drive ratio by that right to get the ratio of just the tranny? for some reason the spur to pinion ratio is 4.83 so would it be 2.72/4.83? or is it a misprint and the final drive ratio is acually the transmission ratio? so doing it with the final drive ratio from traxxas site acually being the tranny ratio i have a 7.7248 from tranny input shaft to tire. then i also have 12/93 gearing of pinion and spur (7.75) that equals 59.8672 final drive ratio. now im stuck trying to figure out the speed this should give with 6.25" tall tires. but i dont know what motor i should run (not really wanting to run the lathe motor as i am also wanting some speed.) i was thinking a mag mayham but there discontinued. so what motor would give a good amount of torque but still have good speed (als whats a good ratio to do? Last edited by mike5721947; 07-08-2005 at 10:46 PM.

07-10-2005, 12:30 AM	#4
mike5721947 Rock Stacker Join Date: Jul 2005 Location: port coquitlam, bc, canada Posts: 51	lets start with this, whats a good final gear ratio to run on a maxx sized crawler with the integy 55t lathe motor? maybe 65:1? come on someone has to know this stuff. Last edited by mike5721947; 07-10-2005 at 12:32 AM.

07-08-2005, 04:40 PM	#2
Jeepjunky Pebble Pounder Join Date: Mar 2005 Location: Not where I should be! Posts: 135	SEARCH or be flamed! It exists in the confines of this web site! Try this; maxx ratios or this; Gear Ratio Equation and Chart I Made for us Crawlers... Hope this helps.

07-10-2005, 01:58 AM	#5
MudCow Pebble Pounder Join Date: Apr 2004 Location: Sydney, Australia Posts: 179	I have run 63.2:1 (9T pinions / 72T spur) with maxx sized tyres which is very nice. I ran a good dozen pack thru the truck with terra crusher tyres (almost 7" dia) and the 63.2:1 worked well. The 71:1 would be even better. I am now running 71:1 (8T pinions and 72T spur) which is even nicer. Any slower would be more of a hinderance than a help with the terrain we drive here. Those links above are great for stock ratios.

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