View Full Version : Spur gear

bald eagle
17-03-2011, 12:29 PM
Can anybody give me guidance as to the equivelant spur gear from 64dp to 48 dp? is there a general rule of thumb or do you just measure them side by side? (im sure the side by side one ain't right). any help appreciated. :D

17-03-2011, 03:18 PM
Divide the number of teeth by 64 then x by 48

bald eagle
17-03-2011, 05:30 PM
Cheers buddy :thumbsup:

17-03-2011, 09:03 PM
What do you mean by "equivalent"? The only important thing when comparing different pitch gears is the ratio of the spur to the pinion. If you divide one by the other (doesn't really matter which way round you do it, but always do it the same way) then you'll get the ratio.
It's a simple exercise to do the same with all the spurs/pinions you have in both pitches and then to find the "equivalent" ratio for each combination. 64dp will give you a more granular range of ratios than 48dp or 32dp, though with modern cells it's unlikely that you'll need this as much as in the good ol' days... :p

You can setup a simple gear ratio chart in Excel/GoogleDocs and print it out (or save it to your phone!) for quick reference.

17-03-2011, 11:59 PM
over rated gear ratios,i have a lucky 32dp pinion and a lucky 48dp pinion ,next time u race bald eagle ,if u get within 2 laps of my tyre dust i'l let u smell them but no touching!smelling only (pinions) not my lucky underpants.
u have to be in them to win them!:woot:

18-03-2011, 07:59 AM
Yeah, as I said - back in the day when you geared your car to dump just as it crosses the finish line it was more important. These days if I want to go faster then I go up a pinion. If I want to get more punch then I go down one. Batteries last all day anyway so as long as the motor doesn't burn out I'm good to go!:thumbsup:

Useful if you're doing a one-time conversion from say 32dp to 64dp I suppose, and you want to start with as close to what you got already!

bald eagle
18-03-2011, 11:09 AM
I asked the question as i have a mini xpress that i bought second hand. It came to me with a 64dp spur so want to replace that with the "equivalant" in 48dp. Suppose i shoould have posted in general car talk, but i now have my answer.

Stevo (Darren) not making excuses, but i have been away from racing for a 12 month period so im not so bothered about ya beating me. The thing is, when i get back into the swing of things, normal order shall indeed be restored and you will need them lucky underpants to wipe the tyre dust of ya face pal. :p :thumbsup: