MAD2X

Hey now. I bought a LX-T truck off ebay about 8 years ago from someone that used to race it and I still haven't figured out how to select the proper pinion and spur for the different motors I have.

My truck has the XX-T trainy with a Ratio of 2.61:1 whatever that means.
I got pinions ranging anywhere from 11 to 38 and spurs from 72 to 90.
I have 5 motors 3 stock and 2 modified; a Trinity light speed 14T and a Monster horsepower 13T.

The truck came with not motor or gears installed and then the first time I tried the truck I burned one of my stock motors within a minute. Then I tried my "cam super stock" motor with a 28 pinion and 72 spur and it worked fine, good acceleration and about 30mph top speed. Since then I did not try to play around changing my pinion/spur or motors because I don't want to ruin any of them. But I would think that my 2 modified motors are probably faster and I would like to try them out.

I'm looking for some advice selecting the pinion/spur. There must be some sort of guidline so I dont burn my motors. I would like to have has much top speed as possible while still being able to do burnouts. Also I use 6 cell nimh 3800 batteries and it's got a tekkin 411G ESC if it has anything to do with my gear ratio.

I love bashing this truck around, but I'm just looking to get a bit more out of it, please help.

Thanks.

chuckyman

I can't really help you with the setup for your truck, sorry, but if you have all of those extra parts, sell some stuff. Actually, what kind of motor(s) do you have?

MAD2X

Motors are, 2 no name brand I cant tell, then a "cam super stock", the "Trinity light speed 14T" and the "Monster horsepower 13T" are modified. All brushed old motors. But the 2 modified ones are like new. I do have a lot of extra parts but I keep them for the truck I don't want to get rid of it.

chuckyman

Well that's old stuff it seems......I even googled the engines and couldn't find anything on them. And on the extra stuff, I guess you might want to keep it until you find a comfortable setup. In you place, I would try out all of the motors with standard gearing, and see which one runs best. If none of them run to your standards, then I would consider buying a new motor, brushless to be specific.

G33Kster

iTrader: (11)

There are several online speed calculators which can be helpful determining what sorts of speed you'll get out of what gearing combos, etc. I personally like this one, but there are plenty of others out there. I'm not a master at this, mind you, but I'd say you should start out with low gearing, say, 20 pinion 80 spur on your stock motor(s), then work your way up slowly on the pinion as to not burn out the motor under high load. You'll want to run much lower pinion gearing on your 13 and 14 turn motors (try starting at 14 maybe) because they have less torque and may burn up more easily under high load. Check your temps relatively frequently to make sure you're not over-working your motor. I've read that if you can't touch it for more than 2 seconds or so, it's too hot. There's really no straight answer as to what gearing you should use, so it's just experimenting.

MAD2X

Ok thanks all. I looked at the calculator but I can't find any info on my motors so I cant work with that calculator.

So I started experimenting today anyways. And here's what happened.

I tried the 13T modified trinity motor with these gears;

15/87 too much acc. not enough top speed (motor cool)
19/87 nice acc. decent top speed (warm motor but not hot)
28/87 good acc. fast top speed (motor still not very hot can keep fingers on it a while)
BUT MELTED the tamiya connection completely together also short battery life, battery got really hot.
I figured the motor was drawing too much power from my battery.
Cut out tamiya plugs and changed my connections to dean type ones.
21/87 really runs well, all around plenty fast, but battery does not last long like when using my stock motor.

Is it possible that modified motors draws power quicker from my battery pack compared to the stock one?

I'm going back to 30/72 on my cam super stock motor even if it runs a bit slower. The battery last twice as long with that one. I have pinions up to 40 so tomorrow I will try the 32 one to see if it can handle it to get that little extra speed.

G33Kster

iTrader: (11)

Sounds good. Tamiya plugs are only rated for something like 20 amps, so it's no surprise that you melted it with a 13t motor. Yes, lower turn motors draw current more quickly from the battery. Another reason why the battery may be getting hot, and definitely why it isn't lasting long, is that it is of a low capacity. If you're still running NiCd or NiMh (which is often fine for brushed), you probably want a battery of at least around maybe 4000mAh or so. Lower capacity batteries not only last a shorter amount of time, but they cannot deliver as much current. When you try to draw more than it can deliver, it heats up (which in turn gives you even worse performance). Hope this helps