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vanderdraay5

difference in rpm

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hi guys im a newbie and need as much help as i can get ,ive bought a sand viper and whilst bashing around on a local ground ive found my sv to be quick but not as fast as id like so decided to buy a absima b spec thrust brushed motor 19t and also bought a hobbywing 1060 esc as someone also told me the tble 02 wouldnt cope under pressure ,has anyone had dealings with this engine and what can i expect on difference in speeds ,ive already fitted the motor and esc but cant get out yet due to cr$ppy weather halting my playtime lol ,ive also read on a sale sight that the tble 02 s would run brushless motors down to 10.5t but whats the difference in t's between brushed and brushless???

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Its hard to compare as brushless motors have so much more torque than brushed motors. The turns don't really line up but you can get an idea from racing classes. The other thing is the quality of the brushed motors. I don't hve any but have read that the Tamiya Super Stock 23t is faster than a lot of cheap lower turn motors.

The silvercan that your Sand Viper came with is 27T. 21.5T has replaced silvercans in onroad racing so thats probably the equivalent.

The Super Stock class used to use 23T brushed and now use 13.5T brushless. Mod is unrestricted but was around 10t - 12t brushed i believe but is now 4.5t - 6.5t brushless.

You also need to gear appropriately for the motor. This means lower gearimg for faster motors, but brushless motors can handle higher gearing than brushed because of the torque they generate. When properly geared there isn't much difference in speed between a 21.5T and 13.5T motor anyway. The issue with a car like the Sand viper is the gearing is largely fixed, so you have to choose a motor based on the gearing you can achieve.

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I run a 17t brushed motor in VLB with a TBLE-02S. It hasn't given me any trouble, with over 50 packs through it, I think the Tamiya esc is better than given credit. My Lunchie gets beat on hard.

A 19t brushed in a light car like a sand viper should be fine with the TBLE-02S.

 

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Since I'm a scaredy cat, I don't use 19t with TBLE02S. It's rated for Sport Tuned (23t?).  As Bromley found out, that could be just Tamiya being cautious (because 1060 is also rated for 60A).  

TBLE02S can run a sensored brushless.  If you are buying Tamiya's brushless, up to 10.5t.  If it's not Tamiya, probably 13.5t is safer.  I get a sense that Tamiya's motors are milder.  Which means other brand's are hotter; other brand's 10.5 might burn out the ESC.  

 

Most brushed motors lose about 20% of RPM when mounted.  RPM is measured without any load.  Brushed motors have about 400g/cm of torque.  And that's at PEAK Efficiency.  At high rpm, the torque drops down quickly.  Tall gears will subdue the high rpm, making the faster motor perform like not-so-fast motor. (You probably don't want to use the 19 teeth pinion because of this reason, but I think Sand Viper's gear ratio is 9.5 and 8 or so?  If so, 19 teeth might work.)  

Brushless motors often have 2000g/cm of torque.  It doesn't lose much rpm under load.  I suspect, this is why Jonathon has been saying that one more tooth in the pinion (with a brushless) really made his cars lively.  

For example, if a brushed motor says 19000 RPM, you can translate that to about 15000 rpm under load.  A 17.5t brushless motor saying 19000 rpm would be about 18000 rpm, because it would only slow down like 5%.  

If you use a brushless, you might want to use a 19 teeth pinion, because the brushless has enough torque.  So that's another way brushless can be faster, even if RPM might be the same for two motors.  

Since you have TBLE02S, a 13.5t brushless with a 19 teeth pinion would get you most speed and power.  (and ball bearings too, if you haven't done it.  Bearings alone can improve about 15% of speed.)

 

 

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yeah i did see that the tble was 60a but just figured everyone had issues before ah well i have a spare now ,as for pinion gear im on a 17t ,so if i put a 19t on my motor i should get a better top speed marginally ,i know im not going to get masses of extra top speed but enough to tell from a standard can also the sv i have comes with bearings already may possibly change the for a sealed set at some stage

 

 

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The TBLE-02 is quite reliable for the most part and has a thermal cut-off, so even if you do overstress it, the chances of doing any lasting harm are minimal. It might get a bit frustrating having to wait for it to cool down, but you can experiment with turns and gearing until you find a combo that lets you run for a whole pack without the cut-out triggering. 

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I ran a similar setup in my DT-03 before I went brushless. I just chose the 17t version of that motor, and ran a 19 tooth pinion. Now that setup resides happily in my Lunchbox.

Even with the 19t motor, you'll find it to be a big improvement over the silvercan anchor. If you have not, you should definitely get ball bearings everywhere.

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