So a 1700kv motor on 6s makes around 43000rpm. This makes the bearings life much shorter and causes high core losses so the motor will run very hot. I found that the sweet spot for inrunner rpm/efficiency ratio is between 15k and 20k rpm so aim for 700-1000kv
Definitely not. For a 100mm wheel, the largest wheel sprocket you can use is 36t.
I think the cheapest fast setup you can get is a gear drive from boardnamics with a high kv motor. Then some @TheGoodMomentum hollow wheels.
That should be a solid setup and cost like $600
You should really be wearing at least $200-$300 in safety gear though
They are both in the US? Shipping would be muuuurdaah 
You could get both used and shipped in 1 box with a low declared value.
Sorry saving money and getting the best isnāt really possible.
Both of those products should be available from eu resellers also
If the drivetrain is properly lubricated, small pulleys can last months with daily use without issues.
So a 700kv with a 9/36t gearing would give me a top speed at about 61mph according to the calculator, would that give enough torque?
Its best to run a brushless motor at 80% of its max unloaded rpm so If you plan to consistently race at 45mph, then 9/36 gearing is ideal.
If you run your motors in the 2500w range then the board should have plenty of torque to get you up to speed on flat ground and small hills. Im not sure how competitive your board would be when racing on large hills though.
Where is that coming from? Speed will change with voltage, so whatās ātop speedā in that case?
Meant to say āmax unloaded rpmā
First up I am not an engineer, there will be others who explain this better than me or do a google search plenty of research papers, forum posts and engineering texts should come up in the results 
Hopefully I have the terminology correct:
When using a pinion with less than about 16t the tooth pitch is undercut so they will mesh. This weakens the gear and also makes it marginally less efficient. This isnāt to say it wont work, or work for an acceptable period of time just that it will be noisier and wear out proportionately faster.
There are times you just need the gear ratio so you go with it, everything is a give and takeā¦
Thats only with gears, not with chains i believe?
Furthermore, pinions can be undercut till 14t before they lose strenght in total.
From the riding experience it sounds like you have I donāt think gearing a board for 60mph is what you want.
I would focus on making a solid board that goes over 30mph and get really good at riding that.
the new BN gearbox with 2.2:1 ratio is perfect for that. Then all you need to get is the infinity hubs and boom you are going like 60mph.
First I donāt want to be argumentative (famous last words before entering an argument). But from my understanding LuuktH you are both right and wrong depending on variable factors that pertain to the spur gears design.
In layman speak: as the pressure angle (pitch) changes so does the tooth root and therefore also the need or not to undercut the gear to get it to mesh (undercutting the tooth removes material from the root weakening spur gear).
Here you can see spur gears with a pitch from 20-30degrees, but you also find examples on both ends of that spectrum. There are always exceptions to be found or other variables to be taken into account.
This page has some concise well laid out information without need to read an entire textbook.
If you are interested in reading source material try some of these.
dang it!
Iām back to beginner access on the new forum, Iām used to being able to edit/add to my postsā¦ sorry.
To summarise:
Whether or not a gear will be undercut depends on more than just the number of teeth, but what is certain (to me) is that for our application whether you have 14-15 or 16t the practical difference will be negligible. The difference is on a curve and 9-11t will be significant whereas 14-16t will not. So at a design or engineering stage if you can design for the latter for an incremental design improvement: Do it! it is a free performance upgrade.
Im talking iso gears eh 
but with standard 20deg gears this is mostly the case, ofcourse you can change modulus etc. to make it work, but thats most of the time adding water to the wine.
Sorry for bombardning you guys with questions but i feel im actually learning stuff! 
So im still slightly confused about 1700 being too high on 6s (22.2 x 1700 = 37,740 rpm) since this build is doing 2500kv on 4s (14.8 x 2500 = 36500) $300 Eboard. Should I make a build thread? - #7 by MoeStooge - ESK8 Builds - Electric Skateboard Builders Forum | Learn How to Build your own E-board and getting 7 miles of range with 26mph top speed, so if i were to go down to 5s (18,5 x 1700 = 31450) its more or less equivalent to the aforementioned build, or am I missing something?
BTW The reason i want that high kv motor is the way they screeeeam 
ever since i did my first punchout on a racedrone Iāve been dreaming of having that sound on my board 
that RPM calculated at 0 load? shit that board you linked was kinda sick bet it sounds like a turbo jet engine
oh nominal voltage accounts for that I guess, but the load should keep the RPM lower.
still think this is not a good recipe
Youāre probably right, but i want to understand! (and a board that sounds like jet engine too!)
Get the boardnamics gear drive.
