CoolRunning
Rock Crawler
I thought I'd update.
SCX10 has been doing a LOT of crawling of late on 2S. I was not confident to crawl it hard on 3S with the summer heat so I swapped in a 2S lipo and started stress testing it.
In the same situation, my stock Bomber (back on a brushed 35T setup), gets WAY hotter. The brushless system stays basically cool. On a 30 degree C day in the direct sun climbing up and down a big dirt pile slow, sometimes struggling over and over and over to get up tricky bits and running really slow, the HW got to just warm after 10 solid minutes. The Bomber had to have a 10 minute rest after this as EVERYTHING got really hot on 2S. Even the servo got hot after the AE-5 ESC got hot.
Swap in a 3S and you have a good trail truck, 2S for crawling.
I think this experiment showed a few things not initially obvious.
Firstly, that even a cheap brushless system has more torque at the same RPM and wheel speed and secondly, brushless runs cooler and gets longer run times. The 27T that was in the SCX10 would have nuked itself in those 10 minutes as the Bomber was always far cooler than the SCX10 in the same conditions. Thirdly, I now feel that high cell count or brushless does not equal nirvana like people make out.
Running 3S simply adds more power and with power comes heat. 3S on brushed or brushless gets hotter. Without a big ESC and big motor you're going to get heat issues not matter the tech used. Slow produces heat without the appropriate gearing.
If you've geared for speed, you need a seriously big and expensive ESC/motor combo to handle/dissipate it. Hence the popularity of the MMP/Tekin combo. Big and expensive, well build motor and well spec'd ESC.
Gearing seems to be everything in crawlers. If you want to do both crawling and trailing, you need to make a major decision and either compromise heavily on how you drive (how long you can do X) or focus the truck at your preference (crawling or trailing) which often makes the truck less fun.
I'm personally feeling atm that if you cannot afford or justify such a heavy duty and expensive brushless system as the MMP/Tekin, a 2 speed is probably your best bet.
This way you're not compromising on gearing and getting heat problems.
Gear the truck for the speed you want (where it doesn't get hot) on say 3S brushed or brushless and then going to the low ratio so crawling isn't compromising at all. You essentially get no heat issues in either realm and you can always run 2S for seriously hardcore crawling in stinking hot weather.
Brushed or brushless, it doesn't matter as you'll not cook motors and can enjoy the best of both worlds. Also if you stay brushed, you don't risk burning up $500 worth of ESC and motor if you have a failure. A 550 can motor and HW 1080 is under $100AUD, add in a cheap shifting servo and the 2 speed and I'm still only at $300AUD ($200 shy of a MMP/Tekin rig). I'll have all the performance I've wanted for crawling and bashing. An affordable brushless system mated to a 2speed on 3S is also a good option for an all round useful truck.
Lets face it, an SCX10 isn't going to be much fun at 25MPH and will just cost a small fortune to tame the Tekin too (all those billet parts cost major cash). The 550 2speed mod will likely require nothing but regular maintenance from what I've seen. My son has basically been a durability tester for the SCX10 and even on 3S brushless, it just laps it up. Keep the speed of 3S, add in low gear for crawling and you kind of have the perfect SCX10 IMO.
I'm going to do exactly this on my Bomber and then mod the SCX10 with a two speed as well. I imagine they will last a rather long time in this configuration and won't need loads of additional parts thrown at them to hold together.
That is for a future build thread as I need an ESC to sort a Yeti heat problem first. These little trucks cost a small fortune but are a serious load of fun! ;-)
SCX10 has been doing a LOT of crawling of late on 2S. I was not confident to crawl it hard on 3S with the summer heat so I swapped in a 2S lipo and started stress testing it.
In the same situation, my stock Bomber (back on a brushed 35T setup), gets WAY hotter. The brushless system stays basically cool. On a 30 degree C day in the direct sun climbing up and down a big dirt pile slow, sometimes struggling over and over and over to get up tricky bits and running really slow, the HW got to just warm after 10 solid minutes. The Bomber had to have a 10 minute rest after this as EVERYTHING got really hot on 2S. Even the servo got hot after the AE-5 ESC got hot.
Swap in a 3S and you have a good trail truck, 2S for crawling.
I think this experiment showed a few things not initially obvious.
Firstly, that even a cheap brushless system has more torque at the same RPM and wheel speed and secondly, brushless runs cooler and gets longer run times. The 27T that was in the SCX10 would have nuked itself in those 10 minutes as the Bomber was always far cooler than the SCX10 in the same conditions. Thirdly, I now feel that high cell count or brushless does not equal nirvana like people make out.
Running 3S simply adds more power and with power comes heat. 3S on brushed or brushless gets hotter. Without a big ESC and big motor you're going to get heat issues not matter the tech used. Slow produces heat without the appropriate gearing.
If you've geared for speed, you need a seriously big and expensive ESC/motor combo to handle/dissipate it. Hence the popularity of the MMP/Tekin combo. Big and expensive, well build motor and well spec'd ESC.
Gearing seems to be everything in crawlers. If you want to do both crawling and trailing, you need to make a major decision and either compromise heavily on how you drive (how long you can do X) or focus the truck at your preference (crawling or trailing) which often makes the truck less fun.
I'm personally feeling atm that if you cannot afford or justify such a heavy duty and expensive brushless system as the MMP/Tekin, a 2 speed is probably your best bet.
This way you're not compromising on gearing and getting heat problems.
Gear the truck for the speed you want (where it doesn't get hot) on say 3S brushed or brushless and then going to the low ratio so crawling isn't compromising at all. You essentially get no heat issues in either realm and you can always run 2S for seriously hardcore crawling in stinking hot weather.
Brushed or brushless, it doesn't matter as you'll not cook motors and can enjoy the best of both worlds. Also if you stay brushed, you don't risk burning up $500 worth of ESC and motor if you have a failure. A 550 can motor and HW 1080 is under $100AUD, add in a cheap shifting servo and the 2 speed and I'm still only at $300AUD ($200 shy of a MMP/Tekin rig). I'll have all the performance I've wanted for crawling and bashing. An affordable brushless system mated to a 2speed on 3S is also a good option for an all round useful truck.
Lets face it, an SCX10 isn't going to be much fun at 25MPH and will just cost a small fortune to tame the Tekin too (all those billet parts cost major cash). The 550 2speed mod will likely require nothing but regular maintenance from what I've seen. My son has basically been a durability tester for the SCX10 and even on 3S brushless, it just laps it up. Keep the speed of 3S, add in low gear for crawling and you kind of have the perfect SCX10 IMO.
I'm going to do exactly this on my Bomber and then mod the SCX10 with a two speed as well. I imagine they will last a rather long time in this configuration and won't need loads of additional parts thrown at them to hold together.
That is for a future build thread as I need an ESC to sort a Yeti heat problem first. These little trucks cost a small fortune but are a serious load of fun! ;-)
and a 17t brushless sensored motor with stock gearing. 
