lunchie

im looking at getting a stadium blitzer or Blackfoot xtreme for my 5 year old . my eldest son started with a lunchox with a silver can 540, which really was too fast for him, so i'd like to get a slower motor for the next one.

what sort of motor should i get to make the top speed slower?
Ive looked at maybe a 35 turn motor, but what sort of rpm decrease could i expect from it?
id like to make the next car run at around 60- 70% of the speed of the stock 540 until he gets a grip of controlling the truck..

any ideas?

Foxy

Well, the silver can is a 27 turn brushed. To get the brushless equivalent, a rule of thumb is to halve the turns, so a brushless 13.5 is approximately equal in speed to a silver can (actually in reality, due to the better efficiency of brushless, 17.5 is more like silver can performance, but as you go down in turns, the 'halve it' rule becomes more accurate). The 35t will certainly go someway to reducing the top speed, but you may also want to consider a smaller pinion.

I think the 35t will give you about 60% of the speed of the silver can, but its only an educated guess.

If you mean a 35t turn BRUSHED, that may no give you the reduction you wanted. Since I guess you are not planning on changing the ESC you are going to stick with brushed. At least they're cheap. Get the 35t and work with the gearing after that if you need to go even slower.

lunchie

thanks. im just going to stick with a brushed motor and nimh batteries for the time being.

Foxy

Yeh, go for the 35t and then mess with the gearing if its still too quick. Bear in mind, if you do feel like upgrading the ESC and motor to brushless, they last forever and provide much longer runtimes even on nimh batteries.

nitrosportsandrunner

another option is to stick with the 27t motor, and buy a used traxxas XL-5 ESC. It has a "training mode" which will only use 50% power. This will both slow the truck down, and extend the runtime of the battery alot. Then, when he is ready for more speed, its just a press of a button to give him the full speed the 27t is capable of. And then, when he wants even more speed, you have a ESC that can handle a much lower turn motor!
Ive often seen used xl-5 speed controls for $25-$35 on ebay. The blue ones are also waterproof, which doesnt hurt

lunchie

Does the training mode limit the torque too much? I dont want it to stall everywhere when bashing. The only reason I was thinking a motor change was the kits come with an esc already. May get that esc and sell the tamiya one?

nitrosportsandrunner

that tamiya esc is...well, not my fav. It doesnt even have a bec. it has an extra wire you have to plug into the reciever for it to get power.
the 50% mode will be the same as driving it with a 3.5v battery.
I expect it would be the same speed as the slow RC cars from a walmart. In my mind, perfect for a 5 year old. It wont take him long to get the hang of the controls, then he will be ready for 100% power.
And as I mentioned, that esc will allow for a motor upgrade later on. The stock tamiya esc wont allow for much of a motor upgrade (if any)

I have sold stock tamiya esc's for around $25-$30. And you can find a used traxxas xl-5 for about that much.

Nothing wrong with going to a higher turn motor option. the esc option just gives you 3 stages of power...50%....100% of the 27t motor and then a faster motor later on.