Need Help With Motor Turns - did slipper mod, and too fast with 35t

[wanantrdsc]

Just finished my sorta trail truck to give the wife (and me) something to RC together. Did the Blitz slipper clutch mod. Currently running a 35t motor, 88t spur (biggest I can use with mod), and a 23T (seems to be the smallest, but just remembered I had an extra Saturn 27T motor with a 21t pinion - should fit).

Thing is the truck is faster than I wanted it to be. So my options are to drop to the 21T pinion if it fits, and go to say a 45t or 55t motor. I have one of the cheap RC4WD 35T cans, and would just assume get one of their 55T cans. Not looking for an expensive, rebuildable, handwound motor, so that is not an option. I have a GR box on my crawler and love it, but its too slow for my needs too.

So is the 55t motor and the 21t spur a good idea?

Thanks guys

Will post pics when all done.

[JohnRobHolmes]

You will lose power going slower, but if you need slower your option is basically a slower motor. I would say 45t is a good bet, but might as well pick up a 55t too for that price.

[John82601]

Yep, with the slipper clutch mod you've gotten yourself limited on the gearing. You're running 88/23 (3.82:1) on your pinion and spur. A very common crawler ratio is 96/15 (6.40:1). The HPI GRB is 7:1 and, as you've noted, VERY slow. Another alternative would be to get a GD-600 reduction box. The gearing in the box is for 2.5:1 but is adjustable by using a larger pinion gear. Also, by gearing slower than you want to be you can always adjust your wheel speed by gearing back up on the main pinion. To keep you c.o.g. in check, you can mount it clocked 90deg with minor chassis trimming.

The other option as you and JRH pointed out is going with a higher wind motor. My son ran a 65t w/ 3s & 96/15 for a long time. Oodles of torque and buttery smooth in crawling situations.

[wanantrdsc]

Using it for a trail truck, with minimal/very light crawling. So dont need real low gears.

[MikeSSS]

I'm using a 65T motor, I walk about 1 mph on the trails and the WK crawler is fine at that pace. With this motor it can scramble or go slow when climbing and get up to about 4 mph to get off the trail when a bike is approaching. Don't remember the gear numbers, this trail truck / crawler was built in 2007.

Battery duration is about 45 min in a Traxxas Stampede on these trails but more than 1 1/2 hours with the WK using the 65T. This is with a 6 cell, 3300 mah NiMh.