gearbox ratio's

[arch2b]

peter's site has some info in his faq section. i wanted to know if the more knowledgable persons could put up a list for common gearbox ratios and thier respective best uses.
i tend to go by what other suggest as i do not know anything about gear ratio's. all i know applies to mini z's, low t pinions have better torque and high t pinions have more speed.

[killer]

:ö: i am not that "knowlegable" about different "gearbox ratio" but as i understand gear ratio.. it's the same as the Z's ratio but on a 1/87 scale we need much lower gear ratio because small electric motors used on this scale don't have enought torque to spin tires if we use the same gear ratio as on the Z, you may likely to burn ESC or shorten the life of your motor.. now about gear ratio, say 100:1 its 100 times revolution of the pinion or motor in order for it to turn the wheel to complete 1 revolution, the lower the number ( 100- : 1)the faster your wheel to turn but you will sacrifice torque.. the higher the number (100+:1) the slower your wheel to turn, but you'll notice increase in torque department,

now here's what i do to find out the gear ratio of my modified gear set..

¤1. first, mark one tooth of the pinion gear with a fine tip white marker pen (water based).

¤2. mark a spot on motor body use this as a starting marker... then align the marked tooth on the pinion with the spot you marked on the motor.

¤3. with a fine tip white marker pen, mark one spot on the wheel too, then mark another spot on the body of your car/truck.. when the wheel turns this will serve as a counter mark that everytime both mark aligns or meet, it is equivalent to one whole revolution of the wheel.

¤4. now here's the fun part, with all the marked spot aligned, slowly spin the pinion, and count how many times the marked tooth on the pinion gear will pass the mark on the motor until the wheel completes one whole revolution, let's say you come up with this 200 is the number of times of your motor or your pinion revolves in order for it to spin your tire to a complete 1 revolution, then your geared with a 200:1 gear set (whew! ) .

i find this much easier than counting all the gears teeth and compute, though i forgot how to compute it too..

i hope this help!

-æ

[arch2b]

killer- thanks for the info. that is what i'm looking for and will help other beginners especially for thos of using faller parts and other "found" gears.

i got some very helpful information from peter (who will be joining us here about his gearbox ratio's and their uses.

Here a ratio-table:
Article Ratio Ground model-weight amount of driven axles
G30BS 1:30 street light (cars) 1
KG-1064* 1:64 street medium 1
KG-1118 1:120 normal heavy/trailer 1 - 2
KG-1228 1:228 rough normal 1 - 4
KG-1001**1:360 rough heavy 1 - ?

(*) 03/03
(**) relaunch in autumn '03

[killer]

Originally posted by arch2b
killer- thanks for the info. that is what i'm looking for and will help other beginners

:ö: No problem arch! -æ

[Overlander]

Killer, that is well written and some very good info for modelers!

Arch, who and/or what is this info about/for again?

Here a ratio-table:
Article Ratio Ground model-weight amount of driven axles
G30BS 1:30 street light (cars) 1
KG-1064* 1:64 street medium 1
KG-1118 1:120 normal heavy/trailer 1 - 2
KG-1228 1:228 rough normal 1 - 4
KG-1001**1:360 rough heavy 1 - ?

(*) 03/03
(**) relaunch in autumn '03

[arch2b]

overlander- i emailed peter (of tttt-parts.org) about gearbox ratios and he sent me that list for his range of gearboxes and recommended uses. i thought this was good information as it can be used for reference on custom gearboxes as welll. peter said he joind tinyrc (i asked him if he would be kind enough to help out in anyway) under "peters" to anwer any questions and/or offer help, so if your out there peter, stop in once in a while. along with killers solution to finding ratio's, it should be a lot easier to pick a setup. or, maybe i'm wrong?

[Overlander]

No, arch, you are not wrong.

Depending on the kind of driving you want to do is how you determine a high or low ratio. For server off-road conditions like trials competitions or rock-crawling on the Rubicon, low gears (high ratio) are better.

I once built a Jeep CJ-5 that was so low, I could put it 4wd lo, 1st gear and leave the clutch engaged, then I could stand outside on the ground, reach in and start the truck in gear. It would just jolt a little and start to slowly crawl away. That truck was built for crawling over large boulders in the Rubicon.

As was mentioned in a different thread about worm gears, low gears act as breaks and give you excelent control when decending.

Back to TTTT, my UNIMOG was about 350:1. While that is great for trials and crawling, it just seemed to take forever to drive from the Q to the P on my keyboard. My MAN 5t is about 220:1 and is just about right. My next M-1078 project will be about 190:1 and will be perfect for me to just bop around.

I am experimenting with speed controls and motor combos. You can actually use smaller motors when you have higher gear ratios.

Think of your 10 Speed bicycle: when your in 1st gear, your feet are spinning madly, but you arent going very fast. Perfect for going up steep hills on your bike and you can pace yourself and not use a lot of POWER to climb. If you put the bike in a higher gear, you need more POWER in your legs to keep it going.

This concept can be transferred to currnent (Amps) draw on your batteries and ESC.

For moderate wheeling and cruising, 175:1 is fine.

[me and me lude]

Originally posted by killer
:ö: i am not that "knowlegable" about different "gearbox ratio" but as i understand gear ratio.. it's the same as the Z's ratio but on a 1/87 scale we need much lower gear ratio because small electric motors used on this scale don't have enought torque to spin tires if we use the same gear ratio as on the Z, you may likely to burn ESC or shorten the life of your motor.. now about gear ratio, say 100:1 its 100 times revolution of the pinion or motor in order for it to turn the wheel to complete 1 revolution, the lower the number ( 100- : 1)the faster your wheel to turn but you will sacrifice torque.. the higher the number (100+:1) the slower your wheel to turn, but you'll notice increase in torque department,

now here's what i do to find out the gear ratio of my modified gear set..

¤1. first, mark one tooth of the pinion gear with a fine tip white marker pen (water based).

¤2. mark a spot on motor body use this as a starting marker... then align the marked tooth on the pinion with the spot you marked on the motor.

¤3. with a fine tip white marker pen, mark one spot on the wheel too, then mark another spot on the body of your car/truck.. when the wheel turns this will serve as a counter mark that everytime both mark aligns or meet, it is equivalent to one whole revolution of the wheel.

¤4. now here's the fun part, with all the marked spot aligned, slowly spin the pinion, and count how many times the marked tooth on the pinion gear will pass the mark on the motor until the wheel completes one whole revolution, let's say you come up with this 200 is the number of times of your motor or your pinion revolves in order for it to spin your tire to a complete 1 revolution, then your geared with a 200:1 gear set (whew! ) .

i find this much easier than counting all the gears teeth and compute, though i forgot how to compute it too..

i hope this help!

-æ

counting in the hundreds will takes some time, also what if you forget what you are up to? hehehehe
to do it using maths... just count the teeth and then....

i find it easier to turn the ratios into fractions (e.g. 60:1 = 1/60, 28:3 = 3/28)
then you just multiply the fractions (1/60 * 3/28 = 3/1680 = 1/560)

[killer]

Originally posted by me and me lude
counting in the hundreds will takes some time, also what if you forget what you are up to? hehehehe
to do it using maths... just count the teeth and then....

i find it easier to turn the ratios into fractions (e.g. 60:1 = 1/60, 28:3 = 3/28)
then you just multiply the fractions (1/60 * 3/28 = 3/1680 = 1/560)

:ö: ei, that system of yours looks really simple! , but could you explain it a little bit farther i am not that good in math , can i ask, how did you come up with 1/60, 3/28? does it mean 1gear with 60teeth? or was it a 1:60 gear ratio combined with 3:28 gear ratio so you have a total of 1:560 gear ratio?... as i understand your system, you could use it, if you alredy knew your gear ratio and you want to know how much reduction you would get if you combine it with another gear ratio, but what if i just found some gears hear and combine it with some gears there, how would i know how much gear ratio i have?.. sorry if i got too many questions but your system looks a lot easier than mine, thanks in advance
-æ

[me and me lude]

1/60 is the ratio of teeth

e.g. if you are using a gear with 2 sets of teeth, connecting the motor to one set that has 8 teeth and that is attacted to a set of 16 teeth then you have 1:2 ratio

so the gear looks like

---
---
------
------
------
------
---
---
from the side...
hope i'm making sense....

[Daisycutter]

where do you guys get your gears from? Custom? Where do you get the worm gears from?

[killer]

Originally posted by Daisycutter
where do you guys get your gears from? Custom? Where do you get the worm gears from?

:ö: Daisycutter,

i think we've discussed that before right here;
http://www.tinyrc.com/forums/showthr...5&pagenumber=4

and as for the worm gears, visit your LHS or your nearest toyshop and look for an electric/battery powered model train (1/87 or smaller scale would do), most trains have worm gears on it as they're main drive gears, if your LHS have electric model trains on stock, chances are they have a spare parts available for you.. now for the other gears, your LHS also have a replacement servo gears set of different sizes, and look for the smallest replacement servo gear you can find.