Re-Gearing

[magiced]

Hi Everyone!

I've just finished my board and it's a hoot, I'm writing up a build log which i should stick up in the next few days. However i think i've got the gearing a bit wrong. As i live at the bottom of a pretty decent hill i designed the board for torque, with a 149kV motor, 10S with a gear ratio of 3.43, 14:48 HTD 5mm 15mm wide belt on 90mm wheels
After a few rides i've realised that:
A)the board tops out at about 16mph, which i though would feel faster but it turns out that i really want more speed out of it
B)The acceleration doesn't change, even up some pretty steep hills, so i have more torque than i need (i'll be double checking this over the weekend by finding some big hills and riding up them!)

I'm going to replace the motor pulley (as it's less effort than changing the wheel pulley as it's just a straight swap) to get a better top speed, but i'm not where to go with the trade-off between speed and torque.

So my questions are, (and i know this is pretty subjective)
1) what feels fast on an e-board? what speed do people get to and think "i'm pushing it more than i'm comfortable with"
2) what sort of gear ratio gives enough torque to handle hills (i think the maximum gradient i have to deal with is about 15-20%)

This table shows the calc i've been doing, based on The SDP centre distance designer: https://sdp-si.com/eStore/CenterDistanceDesigner and parts from belting online: http://www.beltingonline.com/timing-pulleys-bars-272/htd5-pulleys-285/



I've been thinking of a 22 tooth pulley to give me a top speed of 26.6 mph. What do you experienced people think?

 

[torqueboards]

Read this here
https://endless-sphere.com/forums/viewtopic.php?f=35&t=65799&p=1096667#p1096193
https://endless-sphere.com/forums/viewtopic.php?f=35&t=65799&p=1096667#p1096204

To a certain extent low KV and high torque isn't what you want.. At least, that's not what I want and what I found not to be effective.. You want it in the middle of the two.

Because all the torque in the world don't mean squat if your wheels don't spin fast enough to actually move you under load (Ex. 200lbs). It's also much easier to burn out the motors in this setup as you are driving power to your wheels but your wheels aren't moving anywhere.

1) what feels fast on an e-board? what speed do people get to and think "i'm pushing it more than i'm comfortable with"
25-30mph is fast enough for most. More then enough for me.

2) what sort of gear ratio gives enough torque to handle hills (i think the maximum gradient i have to deal with is about 15-20%)
10S/12S Dual motor 200KV-230KV 16T/36T for 1:2.25 with a rider weight of about 190-200lbs. Should get me up 20-30% inclines.

10S/12S Dual motor 170KV 12T/36T for 1:3 (rider weight 190-200 lbs) struggles uphill if you lose momentum. Switch to 16/36T for 1:2.25 works much better. Higher KV would be nicer.

As you can see from the two setups it kind of explains everything.

If I was to get new motors I would be getting 230KV motors and use 12T/14T/16T and a 36T drive wheel pulley for gearing ratios. That should give you more then enough options to adjust based on your rider weight and/or top speed requirements.

 

[magiced]

Thanks for the info, that's helped me decide!