My nephews have started getting into RC and they are loving going to the track to check it all out. My youngest nephew has an SC28 which he just messes with in the parking lot while his brother runs a 1/10 2wd stock buggy at the track. I have a DESC210 that I never put together and now SC is dead for club racing.

I am thinking about putting a slow motor on the DESC210 and giving it to my youngest nephew so he can start getting a feel on the track. When I say slow I mean slow though so he doesn't wreck anything as easy.

I was thinking a hobbywing justock legacy esc which is $30 and a 21.5T or even 25.5T motor as my brother-in-law has tons of old lipos he can use with it. The DESC210 gearing guide only goes up to 21.5T. My brother-in-law has an old cheap spektrum radio but it has no EPA so he can lower the power even more.

Is a 25.5T doable in a 2WD SCT?

I would go with a 17.5t for a 2wd SC. Having driven one before, anything less than 17.5t would barely be able to clear a jump. 17.5 is plenty manageable and still as cheap as running a 25.5 motor and can still be used with a HW Justock.

And as for which motor, I really like the turnigy Trackstar outlaw motors. Good price and great performance.

So you don't think the 17.5T will be too much? I won't be able to turn it down further with the radio as it doesn't have EPA. What about a 21.5t?

Stick something behind the trigger if you dont have an EPA adjustment.

17.5 will be better imo. You can gear it high for lower top speed. Or gear low for more top speed when he gets a handle on driving. The truck will probably go 20mph if that

I think no higher than 4000kv or lower than 7.5t brushless.
I have two 2wd sc10s. One on 8.5t brushless, one on 3800kv brushless. On 2s lipo, they only go about 30 mph.
If that's too fast, put a huge spur gear on with a tiny pinion. That'll slow her up, get more oomph on the low end, and keep the temperatures nice and low so he can hammer on the throttle to his heart's content.
Have fun racing!