I seem to remember "the rule of 4s". A 4" drive wheel at 400 rpm will give about 4mph. Plenty good enough.
On Tuesday, December 4, 2012 10:26:20 AM UTC-8, [email protected] wrote: > > http://tncscooters.com/index.php?route=product/product&path=52_55&product_id=55 > > Those have a 42 pitch sprocket on them and they are cheaper. I bought > mine from TNC Scooters. In the listing they say 3000 RPM, but that's what > the motor is spinning without the gearbox. Nominal speed is around 400. I > mated mine with a 10 or 11 tooth sprocket. Basically whatever I found that > kept the ratio as close to 1:1 as I could find that fit on a 5/8" shaft. > Some of the guys have bent 1/2" drive shafts so I stepped up to 5/8". I > suck at math so I'm sure someone will chime in on that. > > Derek > > > On Tue, Dec 4, 2012 at 9:49 AM, Andy Kipp <[email protected]<javascript:> > > wrote: > >> Derek, >> >> Thanks for the input. I've actually been thinking about this a bit >> after your comment. The motors I am using >> (http://www.monsterscooterparts.com/24v-350w-motor-dirt-quad.html) >> have a metric ISO 05 (8mm pitch) sprocket. I can find sprockets with >> that pitch easily enough, but nothing with a 1/2 bore (obviously a >> metric sprocket has a metric bore). What might be a cheaper option, is >> to keep the 20 tooth sprocket that the motor comes with and buy the >> ISO 05 sprockets and just bore them to 1/2" for the drive shaft. I >> have a 1/8th keyway broach already so it shouldn't cost me anything >> other then the cost of the sprockets. >> >> This brings me to a second though: what do people typically use for >> their drive ratio? The motors are geared down to 375RPM, so with a >> 1.25:1 drive ratio (25/20), thats about 300RPM on the drive axle. My >> track sprockets are 4" in diameter, so thats a top speed of ~315 fpm >> (3.6MPH), is that too slow? (my math may be wrong, or I may be >> misunderstanding the physics here) >> >> On Tue, Dec 4, 2012 at 6:30 AM, TyngTech <[email protected] <javascript:>> >> wrote: >> > Yep. Frank has the broach and has been providing sprockets for several >> > years now. >> > >> > ST >> > >> > >> > On Tuesday, December 4, 2012 1:39:14 AM UTC-5, [email protected] wrote: >> >> >> >> I thought some of the east coast guys were already doing this sort of >> >> thing? >> >> >> >> Derek >> > >> > -- >> > You are currently subscribed to the "R/C Tank Combat" group. >> > To post a message, send email to [email protected]<javascript:> >> > To unsubscribe, send email to [email protected]<javascript:> >> > Visit the group at http://groups.google.com/group/rctankcombat >> >> -- >> You are currently subscribed to the "R/C Tank Combat" group. >> To post a message, send email to [email protected] <javascript:> >> To unsubscribe, send email to [email protected]<javascript:> >> Visit the group at http://groups.google.com/group/rctankcombat >> > > -- You are currently subscribed to the "R/C Tank Combat" group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] Visit the group at http://groups.google.com/group/rctankcombat
