ORV Gearing Options

[Rider400 353]

Can someone explain gearing to me in simple terms? Basically Im running smaller tires on a Blackfoot with stock gearing and I think its slowed the truck down overall, torque and top end. Is it as simple as swapping out the pinion gear to something bigger? What I see is a 18t option but its a shorter shaft than the stock 10t. I understand the motor adapter can be removed to help make up the difference but I think thats what gives the motor the proper clearance from the rear shaft/arm where the shock mounts.

Any advice?

[El Gecko 1343]

18T would only be an option if you had standard Frog gears, but since it's a Blackfoot you most likely have a spur gear marked "Blackfoot" which is 52T.

You must remove the motor adapter so the motor shaft can be relocated to the right place, which will allow you to use a 16T pinion on your Blackfoot. IIRC that's the same ratio as the "high torque" gearset from the Frog.

Unfortunately you can't use certain motors with that setup (Kyosho Le Mans come to mind because of their oversize diameter) because as you suspected, some do impact the trailing arm.

[Albert Attaboy 141]

12 hours ago, Rider400 said:

Is it as simple as swapping out the pinion gear to something bigger?

Yes.

Here's a helpful guide: https://rogershobbycenter.com/rc-gearing-101

[Frog Jumper 3658]

14 hours ago, Rider400 said:

Can someone explain gearing to me in simple terms? Basically Im running smaller tires on a Blackfoot with stock gearing and I think its slowed the truck down overall, torque and top end. Is it as simple as swapping out the pinion gear to something bigger? What I see is a 18t option but its a shorter shaft than the stock 10t. I understand the motor adapter can be removed to help make up the difference but I think thats what gives the motor the proper clearance from the rear shaft/arm where the shock mounts.

Any advice?

 

The easiest way to visualize gears (for me) is to think of a geared bycycle.  If you use the small gear, you get lots of torque, but soon you hit top speed.  You will be cranking away but not getting anywhere.  Once you move to a bigger gear, you can get a lot of speed out of each turn of the pedal.  Once you add a load (like going uphill), moving to a smaller gear makes it easier, while staying in the big gear is hard work.  If you change the size of the tire, a smaller tire will travel less per turn of the pedal, ie it will be slower.  A bigger tire will travel further with each turn of the pedal and be faster.  But moving that huge tire takes a lot of torque, ie a smaller gear.  In the end, it a compromise between the car and the driving conditions and the performance you want...

So yes, by using the 10t pinion and smaller tires, you've effectively slowed the car down.  If you want the car to be faster, but I would use the 16t pinion.

If you are concerned about the shock on that side striking the motor, you can add a spacer inside the shock (both sides) so it doesn't move back as far (I did this on my BarbieFoot 2), or you can use a CRP adjustable motor mount with a Thorp 16t extra long pinion and rotate the motor out of the way (I did this on my Frog Jumper/Black Ranger).  The CRP solution isn't as effective as the spacer.  If you move to a smaller Thorp EL pinion, you will have the shock striking the motor again.  I recommend spacers...

Terry