2005 FP Pinion

Does anyone have a tooth count and pitch for the pinion on the 2005 FP motor? Thanks in advance!

The manual says it is 21T, not sure on the pitch but in the past they have been 32P.

Where does it say 21T in the manual? I haven’t seemed to find that.

Ours is a 14 tooth, 32 pitch

Dan is correct. Everyone should have a 14 tooth, 32 Diametral Pitch gear on the FP motor. THe documentation on the list of kit parts says 21 teeth and it is wrong.


Anyone have an idea of how this gear is attached to the shaft - and any success removing it safely. What methods have been used?
Thanks in Advance
Team 476
6th year rookie

The best way to do it would be with an arbor press.

You COULD attempt to cut a wedge out of it with a dremel and remove it that way. I don’t think this is a good method at all, but some teams swear it works. You have to be incredibly careful to make sure that you dont cut into the shaft, or get shavings into the internals of the motor.

Also, I believe Paul posted a drawing for a gear puller that can be made with a mill, on here last year sometime.

How would you press, or pull for that matter, it off? I can’t see how you can support the shaft properly.

First let me say we haven’t received our kit yet so I haven’t seen this year’s motors. Our machinist in just quickly looking at some from prior years said they look like they are “glued” to the shafts. has anyone actually removed these gears from the shafts this year?

Keep the cards and letters coming.

Cut a slot in a plate and slide it on the shaft so it’s supporting the gear.

thanks for all the help- got an answer from the source.
press it off

I am confused.

I just counted the teeth on our F-P motor from this year’s kit and it has 15 teeth, not 14. :ahh: I counted it 4 times and had 2 other people count it.

Can anybody physically confirm the number of teeth on their motor?

Matt B.

This is bad… …will you please post a picture of you motor – especially the sticker on the side, a close up of the gear would be good too.

If you have 15T, then F-P has provided and/or FIRST shipped a mixed lot. Without actually taking the motor of the transmission it is close to impossible to tell the difference. Even off the transmission it can be very hard to make the ID.

Paul Copioli and I can tell you that the folks that service these transmissions for F-P (in the Detroit area in is McNichols Electric just down the block for Beaumont Hospital on 13 Mile) have absolutely no idea which motor is which, in fact, the guy told me he goes SOLELY by the # of teeth on the motor pinion when he sells a motor. Paul and I both told him that this is not really an adequate method, but I don’t think we made a dent.

If I were you, I would a stall the motor (for a short period of time) at 0.8 volts or so and accurately measure the voltage accross the motor and the current. If the current is not about 10 Amps at 0.8V (i.e. the Resistance should be 0.08 Ohms per the spec) ,you have confirmation that you have a different motor than the rest of us.

How many other teams have counted the pinion teeth carefully? Any more 15’s out there?

Joe J.

This is worse: 188 has counted teeth, and the number is 13. I’ve just got off the phone with those involved, and they had separate people count it (twice!). For reference, the identifying marks on the motor are as follows:


We had good luck last year on the hardened gears on the drill motors with a cold chisel a block of steel and a ball peen hammer. I would test this on a softer gear for a motor that you are not going to use or a spare. I just put the chisel (a small one, that didn’t fit to the bottom between the teeth,and not too wide) between two teeth with a helper holding the motor and the block of steel under the gear, and gave it a good whack. It split the gear almost down the center and the remainder came off with a gentle tug with fingers. I don’t know if this is an excepted method, but it did more for us.

I have pictures of one of our F-P motors that has a 15 tooth pinnion. I need to check if the other is the same tonight. I’m not sure how to post a picture. :confused: The part number on the motor is 74550-0642.

Matt B

Ours are 13 tooth - did not check the numbers though -
will look tonight.

How would you handle this if you were FIRST?

This is a pretty tricky situation. Do you let teams basically use whatever Fisher Price transmission they want? Do you give teams options (pick from one of these model)?

I swear that I recall a debate in years past between Bill Beatty and I that more or less ran along the line of “my motor has N teeth,” “mine has N+1” “F-P sent me replacements with N-1 teeth” and so on.

I didn’t know what to make of this then, but perhaps this type of thing has been going on for years.

Anyone have any thoughts on this?

My thought would be that you get what you get as far as what is in the kit for you to use. If you want to go to the bother of getting one of the other parts that other folks got in the kit, feel free to work with F-P dealer/service or trade with another team.

I think this keeps FIRST out of it and it makes it fair if you REALLY need that extra power motor that some other team got.

It will be interesting to see what the variation in performance is on the various motors, but I think for the most part, it won’t matter that much. As with so much in FIRST, we will adjust and move on*.

Joe J.

*of course, this is easy for me to say, I have already made the following statement before the House Committee on Unfair Activities: “I am not now, nor have I ever been a member of the Life-Should-Be-Fair Party” :wink:

Are we sure that these are different motors, or could they possibly be the same motor, with a different gear? After all, the spec. sheet (from Mabuchi, not F-P) deals only with the motor characteristics–the pinion itself is apparently reflected in the F-P (and likely not the Mabuchi) part number.

To see if this theory is correct, it would be useful if team members were to post the tooth count of their F-P pinion (i.e. 13, 14, 15, or something else), the F-P model number (e.g. 74550-0642) and the Mabuchi date code (e.g. TD034701) for their motors, so we can see if the proper motors (per Paul’s data sheet) can come with different gears, but still under one F-P part #.


Team 177 has the number of teeth and markings as Team 188. 13 teeth (and I had two people check it).

Can Dr. Johnson or Mr. Copioli post a (hopefully small) spreadsheet or list of different motors and their relevant specs?