# RPM of Fisher Price gearbox

What is the RPM of the Fisher Price gearbox using the FP motor.
I have the rpm of the motor, but cant find it for the gearbox and i dont know how to figure it out. Any numbers or suggestions on where to look are welcome.

Thanks for your time and help

2620

This has been discussed recently, but here’s the “simple” way: figure out the reduction of the gearbox.

Let’s say, as an example, that you have a motor that turns at 10,000 RPM and you have a 2:1 gearbox. This means that for every 2 turns of the input gear, the output gear turns once. Your output RPM is 5,000.

Now, a stock FP gearbox is about a 124:1 reduction. So, for every 124 turns going in, 1 turn comes out.

If you want to check the numbers, you can always open up the gearbox and count teeth. This will give the ratios for each set. Multiply to get the final. (This due to the fact that every gearset affects the next one down.)

I don’t have numbers for this years FP motor but the gearbox is 124:1 according to the JVN design calculater. Past FP motors have spun at about 16k rpm so if you divide 16000 by 124 you get about 130 rpm if there is NO LOAD. With all them gears and friction in the gearbox I would estimate more like 110-120 rpm on the output side. Of course, you could always use a watch and count how many turns in 10 seconds and multiply by 6. Just put a popsicle stick in between the prongs and count away.
Bruce

Remember that this year’s F-P comes with a 16-tooth pinion, not 19. So the data given above regarding the gearbox ratio might not be appropriate, since it’s probably based on the 19-tooth version that we’ve been receiving for several years.

You might want to have a look inside (and let us know what you discover).

On Monday we pulled apart one of this years FP gearboxes to see if the gear sizes were different than before. I didn’t check all of the gears (only the useful ones), but the first two stages were exactly the same as the ones in the 19 tooth gearbox. I think the internals of the new gearbox are all exactly the same except for the motor pinion, but someone should check to make sure.