Downhill build - Planning phase


  • Downhill runs. Brakes for emergency and the odd/rare uphill. Watch “raw run” vids on YT for reference on the ride feel I’m going for.
  • lightweight. I want to be able to carry this up a hill with no issues if I need to. The battery and motors likely won’t be great for heavy hill climbing.
  • bombing highways that end at a T intersection

Parts I’m starting with:

  • Boundmotor DD motors
  • probably a DV6
  • mini remote
  • ingredients for a battery pack
  • bear grizzly trucks
  • random handful of bushings
  • enclosure I got from someone on the forum, fits about 40 cells, can probably squeeze in a few more

Parts I plan to get:

  • Deck: [TBA]
  • RKP DD truck (preferably matching the wheelbase of a bear grizzly front truck)
  • accessories?


As stated. The goal of this is high speed downhill runs. I plan to run 85mm cags on DD, I was thinking of using hubs but the lack of Thane between the core and the road would seriously impact the performance of slides and other wheel edge techniques, so DD seems the best option for the lack of rolling resistance.

I’m thinking of a deck like the wolf shark or the LY cheese grater. I want something that’ll be easy to keep stable at speed but also help me put more push into my turns with the curvature. Open to suggestions there. Loaded Omakase also looks nice.


83mm wheels, dds and downhill… what could possibly go wrong.


I have both the Boundmotor DDs and LY Cheese Grater if you’re interested. But DDs for emergency braking doesn’t seem strong enough unless you just want it to slow down slightly.


When going fast this is exactly what you want to not eat shit :laughing:

My main concern with this build is how will you dewedge the rear of the board for stability? DKP trucks + downhill = not a good time. Maybe get the revel kit motors instead, or wait for the Fast Board Prototype drivetrain?


not being able to find the right rear truck or drivetrain

my vision is to use RKP, though idk if this is possible
there’s a lot of nice split angle baseplates going around these days, and I wouldn’t want a super agressive dewedge like an urban esk8 (45/0) I’d probably lean towards something like 50/30

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this is exactly what I want. I really don’t want sudden braking like a disc brake. I’ll be using speed checks and slides to slow down, the motors will be more of a backup and/or help for when things get hairy

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So then will you go out with a partially charged battery every time? Cause that’d be decent amount of amps going back in right, if it’s only ever used for braking. If you want RKP not sure you can use Boundmotor DDs maybe torqueboard ones instead. I know someone mentioned converting them to TKPs by just removing the middle of the DKPs. I tried it and it fits fine but not sure how it’d ride…

That’s the plan. Go out with enough to get me to the top of a hill, then bomb down.

I did this with evolve trucks and it really didn’t turn out well, the pivot kept popping out

I’m pretty set on RKP, even if it means I need to use hubs.


Isn’t there also issues with braking if you are going faster than what the setup can handle?

Also PSA: don’t buy tbdds

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If you go faster that unloaded speed of the motors they will start braking as the MOSFETs start to conduct anyway

So for your plan to work you need a board that has a unloaded speed higher than the downhill speed you plan to hit, or the board will brake you and probably blow up because that braking above the top speed will be full brake without control over the current


How can I test unloaded speed? I’ve been thinking of picking up a laser tachometer but do I need one?

Seems most motors I’ve used go far far faster unloaded than loaded so I was just assuming 50-60kph downhill wouldn’t be an issue for anything on the market. I’m no Josh Neuman so I won’t be doing 100kph+ runs if I can help it.

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Voltage x Kv, close enough for your purpose but put a big margin above

Keep in mind that is the current voltage of your battery, not nominal, so if you arrive at the top with the battery almost dead, use that


So the lower my battery voltage, the lower the speed my wheels can go before they lock up?


Yep, I never seen anyone put that to the test, but if you putting your life on it, I would find a way to test that, somehow spin the wheel fast enough on the bench somehow with a grinder or similar

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There’s the drill method but I only know that from checking the true Kv if the motor. Could I attach probes to the phase wires to figure out the voltage produced at max RPM? And use that as a reference for the voltage the battery should be at?


No, I mean testing the full system, battery plugged and everything connected, slowly increase speed above the no load speed and see if anything smokes

For finding your no load speed, use VESC tool with the correct wheel size and it will give you speed

This sounds like breaking things until I figure it out

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Isn’t this inaccurate? Like it’ll be close but not precise?

Call me crazy, but breaking things on the bench seems to be better than breaking things on the hill


Better on the bench than when you are going downhill

Honestly I wouldn’t go down any hill you couldn’t break without motors unless you test your system a lot