i need some help from any admin

[Andrew the RC man]

i saw on RCCA that electric stadium truck shoot out and i saw that you made the trucks geared close to 12.6:1 is that a gear ratio most of us should attempt for, for racing or was that just an arbitrary number??

[Grizzbob]

Well, I'm no administrator, but I'm sure they chose that ratio because they have lots of experience at the track they tested at, & that was likely the best all-around one for it. However, that doesn't mean it'll work as well at any track, they're all different, & need different ratios to be effective.... :)

[StephenB]

They taped a large sheet of paper w/several arbitrary gear ratios written on it, and then Greg, Pond, and Derek took turns throwing darts at it. The number they hit the most out of 3 throws was the ratio they chose...so in a way, it was arbitrary. :p

[ 05-27-2001: Message edited by: StephenB ]

[Obi112]

It definitely depends on the track. I more open track would require a lower ratio and a tighter track qould require a higher ratio (I think that's the right way). Also, it depends on the motor. Less turns on the motor would use a higher ratio, and more turns would use a lower ratio (again, I think this is the right way, but correct me if I switched them).

[Railman]

Higher ratio is not the prefered way to reference gearing. It just confuses people that much more. To me, taller gearing, gearing it up, or gearing for more top end speed would all mean the same thing. This is however a lower gear reduction (ratio) numerical value. The higher the reduction number the slower the rpm is at the axle. The term "gearing it down" is when the output, or axle rpm, is slower. "Gearing it up", or "taller", means that the output, or axle rpm is faster. This is however a lower gear reduction numerical value. If you think in terms of what happens to the output rpm,
(increased output rpm = gearing up, or decreased output rpm = gearing down) it is easier to us the right terminology. I know this seems backwards some times but it's a double negative kind of thing, that being a big reduction means less output rpm, & visa versa. Hope this helps.
;)

[Andrew the RC man]

Stephen- HMPF and i thought you guys were professionals. well i guess i now know what it takes to be good with gearing ;)

[jeepinator]

Higher ratio and lower ratio were clear to me. I immediately recognized that "higher gear ratio" meant that the big number was bigger (e.g. 10:1) versus the big number being smaller (e.g. 5:1) for a "low gear ratio". FWIW, IMHO, I think "higher ratio" and "lower ratio" are the best way to describe what you mean.
I still haven't figured out what "HMPF" is though ... :confused: :p

ALL that said, I have never used anything smaller that a 16 pinion or larger than a 24 pinion, except when messing around (not practicing or racing). Your manual will have some good info on pinion sizes to use. The overall ratio is usually not discussed all that much. Dirt folks usually speak in pinion sizes. The reason is probably due to the two different calculations that have to be made (pinion/spur, and the tranny's ratio) to come up with the final ratio. Laziness probably has a large part in this ;)

[ 05-28-2001: Message edited by: jeepinator ]

[Andrew the RC man]

well maybe i spelled that wrong it is either hmph of HMPF as being insulted in some sumin sumin.....ick i feel like im some redneck trying to talk this morning ;)