Noob gearing/motor question

[skunknuggit]

Hey all I'm still kinda new to the hobby. I did some research and I'm still not 100 percent sure about some thing. I have a associated t4 and a trophy rat. The t4 has a hobbywing 8.5t/4000 kv motor and a 22/81 gear setup. The t/r has a castle 5700kv and 32/74 gear setup. And it gets too hot and goes into limp mode. I also have a castle motor that is a little smaller and a reedy 3300 that I guess came with the t/r. My question is should I use one of the other motors for the mor torque from the lower kv or is that not how it works. Or should I upgrade my esc. I'm currently only running on 3s

 

[RustyUs]

What in the world? That's some crazy speeds you must be getting. I can see why things are getting hot.

 

[skunknuggit]

What in the world? That's some crazy speeds you must be getting. I can see why things are getting hot.

Ya the trophy rat is overheating on 50% throttle so that's a bummer. Judging by your reaction and how hard they are to control I'm guessing I'm overdoing it a little. Do you have any recommendations on a combo to go with? I have a side winder 3, hobbywing ezrun max 10 g2 and ezrun sl. I'm beginning to think those are not quite enough. I want to bash one and race the other.

 

[nino]

The ESCs you mention should all work, but you need a 3000-3500KV motor for 3s. Maybe a 3660 can (a bit longer than the standard 3650).

5700 is way too hot and it looks like it's geared very high too.

 

[sylentk]

Are you running a fan? Or a heat sink on the motor?

Other things to thing about.

Maybe gear it down a bit. Not so much top speed, but....heat is not good. Will destroy your electros eventually.

 

[RustyUs]

Ya the trophy rat is overheating on 50% throttle so that's a bummer. Judging by your reaction and how hard they are to control I'm guessing I'm overdoing it a little. Do you have any recommendations on a combo to go with? I have a side winder 3, hobbywing ezrun max 10 g2 and ezrun sl. I'm beginning to think those are not quite enough. I want to bash one and race the other.

The gearing on your Trophy Rat is about what I used to run on my B4, and still run on my T4, with a 17.5T motor... on 2S . Are you doing speeds runs or something with your Trophy Rat?

The Pro2 SC10/Trophy Rat has the same internal gear ratio as the "4 series" rides from Tema Associated. The following is suggested starting points... for 2S use. Throwing a 3S onboard your T4/Trophy Rat and you will likely need to gear down a couple teeth from the starting points.

I don't know what type of, or where, you'll be racing, but generally you'll be limited to 2S unless it's backyard brawlin' with friends. Grab an infrared thermometer for getting your gearing under control. It's the most beneficial tool in the hobby, especially in a situation like you have.

 

[skunknuggit]

The gearing on your Trophy Rat is about what I used to run on my B4, and still run on my T4, with a 17.5T motor... on 2S . Are you doing speeds runs or something with your Trophy Rat?

The Pro2 SC10/Trophy Rat has the same internal gear ratio as the "4 series" rides from Tema Associated. The following is suggested starting points... for 2S use. Throwing a 3S onboard your T4/Trophy Rat and you will likely need to gear down a couple teeth from the starting points.
View attachment 231407
I don't know what type of, or where, you'll be racing, but generally you'll be limited to 2S unless it's backyard brawlin' with friends. Grab an infrared thermometer for getting your gearing under control. It's the most beneficial tool in the hobby, especially in a situation like you have.
View attachment 231408

What kind of temps am I looking for?

 

[sylentk]

What kind of temps am I looking for?

If you get a heat temp monitor, one method would be to take a measure when the car turns off. So that's your max. Don't run that hot. Adjust it, so your car is happy

An old school method was if you can't keep your finger on your motor for more than 3 seconds? That's too hot.

Did you put some ventilation thru the body? That helps too. Like just a 1/2 inch sliver left to right thru the windshield.

My 2cents.

 

[skunknuggit]

What kind of temps am I looking for?

And let's say i stick with theese gears. What route do I need to go? Better esc? I don't think I can run a fan on the motor due to its location

 

[skunknuggit]

Are you running a fan? Or a heat sink on the motor?

Other things to thing about.

Maybe gear it down a bit. Not so much top speed, but....heat is not good. Will destroy your electros eventually.

No I don't have anything on the motor. I don't think I have room to run anything

 

[skunknuggit]

If you get a heat temp monitor, one method would be to take a measure when the car turns off. So that's your max. Don't run that hot. Adjust it, so your car is happy

An old school method was if you can't keep your finger on your motor for more than 3 seconds? That's too hot.

Did you put some ventilation thru the body? That helps too. Like just a 1/2 inch sliver left to right thru the windshield.

My 2cents.

Thanks for the help. I do have alot of holes in the body on the trophy rat. It has the Montecarlo sr10 body on it so it has tons of space underneath but it shuts off even with no body. The motor is censored but it dosnt have thermal protection according to the website so it's the esc. Green light starts blinking and manual says over heat protection. I think I'll just gear down until I figure out some more stuff. Just don't want to buy something and it not be what I need. I've been in this hobby less than 2 months and I have 5 cars lol

 

[skunknuggit]

The gearing on your Trophy Rat is about what I used to run on my B4, and still run on my T4, with a 17.5T motor... on 2S . Are you doing speeds runs or something with your Trophy Rat?

The Pro2 SC10/Trophy Rat has the same internal gear ratio as the "4 series" rides from Tema Associated. The following is suggested starting points... for 2S use. Throwing a 3S onboard your T4/Trophy Rat and you will likely need to gear down a couple teeth from the starting points.
View attachment 231407
I don't know what type of, or where, you'll be racing, but generally you'll be limited to 2S unless it's backyard brawlin' with friends. Grab an infrared thermometer for getting your gearing under control. It's the most beneficial tool in the hobby, especially in a situation like you have.
View attachment 231408

So in theory if I use say a 3300 kv motor on the same gears on the trophy rat would that help with temps but keep the speed and loose acceleration? Is that the right train of thought or do I have that confused too? Thanks for the help by the way.

 

[skunknuggit]

What kind of temps am I looking for?

Ya I'm just messing around trying to see how fast the tr can go

The gearing on your Trophy Rat is about what I used to run on my B4, and still run on my T4, with a 17.5T motor... on 2S . Are you doing speeds runs or something with your Trophy Rat?

The Pro2 SC10/Trophy Rat has the same internal gear ratio as the "4 series" rides from Tema Associated. The following is suggested starting points... for 2S use. Throwing a 3S onboard your T4/Trophy Rat and you will likely need to gear down a couple teeth from the starting points.
View attachment 231407
I don't know what type of, or where, you'll be racing, but generally you'll be limited to 2S unless it's backyard brawlin' with friends. Grab an infrared thermometer for getting your gearing under control. It's the most beneficial tool in the hobby, especially in a situation like you have.
View attachment 231408

Ya I'm just trying to see how fast i can get it to go... I don't have a lot of places to drive em. It's seems like it's been raining here for the last month so the opening day for the track got canceled. Only tracks I have found around me are a 1/8 offroad outdoor track and a circle dirt track. I have an sr10 that I'll probably put back together if I go down to the circle track. Right now I have parking lots roads or grass and it dosnt seem like any of my 2wd like grass. I have a 4wd on road v100 that gets stuck in my driveway and a cheap Amazon 4x4 that I got rtr with 2 batteries for like 120. It's pretty good for the price but it's definitely a cheapo. I also got a replacement for free after I overpowered the esc lol

 

[CertifiedMike]

The thing maybe missed here... the 3300 kv motor can run at 3s. Maybe with a heavier battery but at lower rpm than the 5700 on 2s.
5700 might be too much kv for that chassis. I didn't do the math.
I bet with more realistic gearing, on 2s, this set up will SCREAM!!!
It might not be the solution but it would be a LOT of fun to mess around with and find out!!!

 

[skunknuggit]

So what would a more realistic gearing combo be. I'm sure it is too fast for this type of chassis but i tried to make it work just for the hell of it. I'm still learning so it's probably a good idea to slow them down a little bit until I figure some stuff out better. Thanks for the info.

 

[skunknuggit]

Ya I'm just messing around trying to see how fast the tr can go

Ya I'm just trying to see how fast i can get it to go... I don't have a lot of places to drive em. It's seems like it's been raining here for the last month so the opening day for the track got canceled. Only tracks I have found around me are a 1/8 offroad outdoor track and a circle dirt track. I have an sr10 that I'll probably put back together if I go down to the circle track. Right now I have parking lots roads or grass and it dosnt seem like any of my 2wd like grass. I have a 4wd on road v100 that gets stuck in my driveway and a cheap Amazon 4x4 that I got rtr with 2 batteries for like 120. It's pretty good for the price but it's definitely a cheapo. I also got a replacement for free after I overpowered the esc lol

So is the limiting factor for gearing/motor cobos heat? Or is there some other sort of metric to figure out what's best. According to what I've read online these esc I have should work... is it just my gearing? Is 3s too much?

 

[CertifiedMike]

A gearing selector or calculator is what you need here.
You can play with theoretical changes and get a good idea of what is going to work or push you too hard.
You can plug current settings in to get an idea of where you're at.

Motors are limited by physics so as not to detonate, blow bearings etc... the manufacturer will tell you what motors can go 3s and in what applications.
Vehicle weight and intended surface use also play into the motor's ability to be 'useful'. A very high Kv, low turn motor can push a low weight, no rolling resistance pan car across polished concrete far easier than the same motor in a 4x4 buggy on rough dirt track.
A lower kv motor will keep the rpms in check. The car won't be overheating and you'll have a more reliable set up.

 

[skunknuggit]

Ok that makes a little more sense. Thanks

 

[CertifiedMike]

https://www.piiatomi.org/rc_calculator/
Its not flashy but it gets you answers.
You are likely to have many more questions though so ask away!
I shoot for a roll out of around 1 inches roll out on my car at least to start.
You'll need basic info thats already posted in this thread plus tire height... easy enough.

 

[skunknuggit]

So what is roll out exactly.

The gearing on your Trophy Rat is about what I used to run on my B4, and still run on my T4, with a 17.5T motor... on 2S . Are you doing speeds runs or something with your Trophy Rat?

The Pro2 SC10/Trophy Rat has the same internal gear ratio as the "4 series" rides from Tema Associated. The following is suggested starting points... for 2S use. Throwing a 3S onboard your T4/Trophy Rat and you will likely need to gear down a couple teeth from the starting points.
View attachment 231407
I don't know what type of, or where, you'll be racing, but generally you'll be limited to 2S unless it's backyard brawlin' with friends. Grab an infrared thermometer for getting your gearing under control. It's the most beneficial tool in the hobby, especially in a situation like you have.
View attachment 231408

Do you mean the 81/22 or the 72/34