Originally Posted by jeffv145
These answers have all been very helpful. I have a bit of small engines experience, but I'm starting to think I'd like a brushless electric instead. I would like to drive in mud/dirt/offroad. I'm looking at the Traxxas slash pretty seriously, but still have a few questions, here's my question list:
* Can brushed vehicles be converted to brushless/ is it a difficult or expensive conversion?
* Can brushless motors be geared down for lower speeds?
* How do four wheel drive cars perform compared to two wheel drive?
* How does the scale effect the vehicle performance (1/10 1/16 etc)
* Should I get a spare battery separate from the included stock battery, and if so what should I get?
Thanks for your help, and sorry for the noobish questions..!!
most brushed can be converted to brushless just by changing the ESC (speed controller) and motor. Some models may require that you get a different pinion gear (gear on the motor) as the gearing required by the new motor may be different from the old. Also, some models might need upgraded gears in the transmission to handle the extra power. Short answer, yes, and it is done very often.
You can gear them down some, but gear down too much and this causes extra heat as the motor will be spinning at top speed more often.
But, some RTR brushless models come with radios that have "throttle end point" adjustments. With this knob, you can turn down the throttle (thus max speed) The adjustment changes the signal the radio sends to the car....so you can give full throttle on the trigger but the radio will only send a 50% throttle signal. My team associated SC10rs radio has this feature. My truck can go 35mph, but I can turn it down to as low as 10-15mph. I have done this often for my 4 year old boy. As he has gotten better, I have slowly increased the speed.
4wd, more traction! Downsides? usually more expensive to buy, and due to the increase in parts you increase the chance of something breaking.
Scale effects performance due to things like ground clearance, tire size and weight. Generally, anything under 1/10 scale doesn't do that well offroad. they are fine on pavement or packed ground, but not grass / soft dirt or sand. Even some 1/10 scale models can have trouble in tall grass. The suspension setup and the size of the tires has a lot to do will how well it can go offroad. 1/10 scale is by far the most popular.
Spare battery is a very good idea. what you get for a battery will depend on what model you buy. Some brushed models have a ESC that will allow you to use a 2s lipo battery (2s equals 2 cells, or 7.4v) but these models will likely come with a 6 or 7 cell NIMH battery. NIMHs are fine, but lipos are better.
Even most brushless models that come with a battery will likely still have a NIMH battery. In this case you really want to buy a lipo battery as your second one.
A great way to help you choose what model you want, is to take any suggestions you get from others and then search youtube. Try to view as many videos of that model in Stock form.
What I would recommend:
Team associated SC10....or the brushless version, the SC10rs.
Traxxas slash, rustler, stampede. All three are available in brushed (xl5) or brushless (vxl) The slash and stampede are also avialible in both 2wd and 4wd forms.
HPI wheely king. a 4wd brushed monster truck. Not super fast but good offroad and plenty of fun. Pops wheelies with ease. Can be upgraded for more speed, or can be converted into a rock crawler.
Also, don't forget a battery charger. Even if you buy a model that comes with a charger, it will just be a crappy slow charger (3-8 hours!)
The above chargers are good value, and they all can charge NIMH or lipo batteries. Most batteries can be charged in 1 hour by those chargers.
My SC10rs can run for 25 minutes on my onyx 5000mah (mah=capacity / runtime) 2s lipo....and my thunder ac6 charger can charge that battery in just over an hour.