Standard Bergmeister wheel pullies are usually 60T, motor pulley is normally 15T, most people are using 12S these days, the diameter of Bergmeisters is 150mm
That being said, I wonder why you are choosing 140KV motor which would only give you 37km/hr (23mph). A 200kv motor should be perfect for 33mph
Ok but 140kv naturally has more torque than a 200kv, if geared to the same top speed the wheel torque should be roughly equivalent for both setups.
So the lower kv motor is an advantage as you can use a 20t motor gear instead of a 15t, which will give much better pulley life and less chance of slipping under hard braking.
15t 140kv 36.8 kph
20t 140kv 49 kph
15t 200kv, ok its a bit faster. 52.5 kph
Maybe a 140kv 22t ? 53.9 kph Bit less common than 20t I guess.
I would much prefer lower kv and larger motor pulley given the option.
Higher kv motors I think are only better if you need maximum wattage as they have thicker windings.
Getting anything more than 16T is not that common, as in difficult-to-get because they arenât standard, yes you might get 20T, 22T pullies but never as easy to get and cheaper than regular 15T pulleys, remember you are also increasing weight and rotational weight is a big factor in acceleration and braking thatâs why lightweight flywheels help with acceleration in the car would where I come from.
On the other hand you have thicker windings but that doesnât mean you have more copper, you can get more winding count and the same ammount of copper.
Thereâs a pretty nice technical article around here where torque was compared between two different kv motors with similar weight of copper and torque difference was negligible
The 140kV is coming from us, who want to use them for our mtb. Torque is more important than speed in our case. Thatâs why we asked for this low kV.
This
Maybe to add here that gearing with 190-200kV wouldnât work as we as well need clearance. Looking on a belt drive a 72th wheel pulley is already pretty low to the ground on 8â and I wouldnât want to go below 15th motor pulley as well. Maybe ok with idlers but as I donât have them 
So 1/4.8 on 190+ kV in this case wouldnât really rock the boat 
Ok,
I have an Update on the Currently forming GB for 6880 motors and the Etoxx drive. If you scroll up to post 33 You will see where I was reminded that a level 3 or above member can DO group buys. At first, I thought he was simply pointing out that NOT anyone can DO GB on the forum. Well he was not, he was eluding to the fact that I do not meet the criteria for this Level 3 event. Now In all fairness, I simply didnât know and itâs not easy to determine with the info provided on your own profile stats and the vague requirement description given.
Now, what did I just say?
We can NOT orchestrate GROUP BUYS on the forum because:
Now, What does this Mean? I must hurriedly read 218 post or treads? I really donât have the time. Iâm not sure and im not waiting for it to roll over or accumulate to the proper release point for level 3 access.
What about the Group Buys?
As far as I can tell it can be done through the Hyperionesk8.com website if properly set up.
I will post information on the front page of the site with links to the products created for these buys. final specs and options and instructions on how to place the order on the website.
Because of the Transaction fees from PayPal if used you will need to add 6% if you chose to pay this way. Furthermore, you have the same protection through your card issuing bank and website (Shopify) for fraud and disputes at no extra cost. Please consider this option for payment to save yourself some money. But the choice is yours.
I will confirm info on motors 6880 on the webpage.
Etoxx helical drive prices
2 kits to choose from:
Kit 1
(raw aluminum) Matrix II Helical drive 10/40 kit
includes rear truck extenders
w/aluminum base plates $670 shipped
w/o base plate $570 shipped
Kit 2
(raw aluminum) Matrix II Helical drive 10/40 kit
includes rear truck extenders
w/aluminum base plates $770 shipped
w/o base plate $670 shipped
saving up to $300 off regular price if purchased alone
these prices are solid and our MOR is almost meet. so the more the marrier. This is confirmed by Jens all payments have to be made before anything ships. some variants have production times.
Feel free to PM me with questions and I donât see the need to make a fuss over this with the admins, they are following the rules as we all should, I will have more topics to start and some really cool demo builds to showcase for Our MBS eMTB kits and pre-built line.
I will start a topic specifically about them, prices and options. please look for it. Titled MBS eMTB kits
Thanks for understanding, Cory
Yes, but there are rare exceptions
what if you let a level 3 member organize the GB for you. in fact you still order the motors and distribute them, but the rest will be organized and done by some level 3 member. Wasn´t @pjotr47 your EU partner? he is level 3 and maybe willing to do the forum part for you. (sorry @pjotr47 in case I was wrong with this, just thought i remember to read it somewhere)
Im not to worried, if it comes to that, it will be done one way or the other.
Yeps indeed I am the EU partner. I can set up a topic about this groupbuy it it is necessary. @hyperIon1 I am going to send you a pm.
I think members trusted by the community should have exceptions, @hyperIon1 has been on this forum since forever and have organized group buys before
Just need to move this topic to the group buy category.
Thanks, guys It was a misunderstanding and I wasnât aware that I wasnât level 3, everything is ok and going ahead as planned (tentative) I have to confirm a few more things maytech.
the etoxx GB will be posted tonight and the prices are sweetâŚ
I will find out about having two different KVs but I think a middle ground is preferred versus too many variants,
150kv isnât a bad middle ground for the size of the moto
Ooops,
EDIT : for no confuse I edit all 
my bad, all good !
What are we trying to determine? if the 6880 can will have enough clearance?
well done 