Sounds good, yeah they would work good.
In fairness you could still use the Haggy wheels by themselves, the price is very good to include quality tires/tubes.
Then print your pulleys, buy your belts, motors, motor pulleys(should be metal). You’ll have to find a motor mount compatible with your trucks or make them.
Are you keeping the trucks you have? what are they?
This is the mountain board, wheels and trucks.
Hmmm… that’s true the helical is quite more expensive. Looking at the complete drivetrain; it needs to be closed and sealed tightly to keep grime out and the lubricant in. That makes it more expensive… and an optimal drivetrain.
Look this
Thx for the heads up!
I didn’t know they already out for 9“ too.
If you are going to run pulleys with belts then your options for motor mounts are from vendors on here
@Idea
@okp
@marcmt88
@Nowind
@Rithblu
etc
Those are MBS Matrix I trucks afaik. You should be able to find a wheel pulley that is compatible on thingiverse i.e.
Check first to make sure it is compatible with the wheel hole spacing before printing. Don’t try to use PLA, use Nylon, PETG or similar tough filament, better still buy a pair that are made from POM.
Alternatively you can chain drive them.
But given this is to be done on super-tight budget, check here
Also check here and search in general, good luck
Dude! So many thanks for you input!
What I’m planning to do is design and build the motor mounts… sitting on the southern part of the world (with weak currency and idiotic import duties) does not help if I’m going to import parts on an extremely tight budget. I have decided on a belt drive option.
Thus for a start and to save some time I would need some CAD (or drawing) of the MBS Rockstar hubs (I saw a drawing somewhere) or at least the side with hub’s PCD and a drawing of the mounting section on the trucks. I can measure the current hubs but I don’t trust the wobbliness.
I don’t have the hubs, but maybe this can help you in some way
You welcome, more esk8 for Africa & no problem bru🤘
You can get the hole pattern for the mounts by taking them from a design on thingiverse, grabcad.com is another good resource. Just compare with what your calipers tell you with the wheels
In fact you may be able to find a mount already designed for those trucks, just need to search on them ‘mbs mount’ or ‘mbs pulley’ & of course ‘mbs wheel’
Are you hand cutting or milling them?
Looking forward to a truely Zef build yeh!
Okay, after some… relatively more than just some reading and a bit of doodling I got to a point where I have parameters. I’m designing for range not speed.
Batteries: will be LiPo 10s(depending on cash)p.
Motor: 225KV (will see what I can find but this is based on the theories of Vedder who wrote and did some awesome stuff on this forum)
Motor Mount: Got some CAD and drawings of the MBS trucks and Rockstar hubs still busy with designing but this is least of the problems.
Drive Train: Now this is where it gets interesting… I have chosen a belt drive system. I initially desired and designed for a maximum speed of 45km/h, which requires a gear ratio of 1:7.2. but with a 5m or 3m belt the slave wheel will be too big, resulting in poor ground clearance or to be totally unpractical. The hub of the Rockstars has an outside diameter of 105mm I do not want to exceed this by more than 10mm on the radius. So gear ratio is now 6.5 with GT3 belt, thus pulleys 20T:130T. Also Dont want to go smaller on the drive pulley to extend belt life, max speed is now around 50km/h.
Tomorrow I’ll see what type of belt I can source in South Africa as so far I cannot find a GT belt but have sort off found a local supplier who can supply me with a HTD 3M belt which looks okay. Would have liked to use a 5M belt the pulleys seem to be too big for the board or I’ll have to change the gear ratio.
What do you guys think? Does this make sense other ideas maybe?
Ok… after some more reading and pondering. My max speed is too high thus I figured the other solution is reducing the KV value of the motor. There is no use in sourcing a motor for an application that will never run at its optimum thus I got these 2 motor options Turnigy Aerodrive SK3 - 6364-213KV and Turnigy Aerodrive SK3 - 6364-190KV the one gives 51km/h and the other 45km/h (that is all theoretical now). I chose the drive train ratio to be 1:6. I want as much torque possible and not exceed the wheel hub diameter too far, with 19T:114T the PCD of the drive pulley is only 2mm higher than the wheel hub, I can live with that. A gear ratio of 1:6.5 is nice but the drive pulley becomes too big. Hopefulley tomorrow I’ll be able to chat with a local belt supplier and maybe generate some CAD renders of the motor mount.
Does anyone have an idea on how to have a drivetrain ratio of 6 and not exceeding Ø110 PCD on the drive pulley using 5M teeth pitch.
Why you don’t want to go lower in kV. There are nice 150kV motors out there which will fit your needs.
You can get htd5m belts here
They not as good as continental belts but for me they worked well.
I think they sell other formats too.
I wouldn’t go with 3m belts thou
Hi Andy, I guess I can go lower in KV. Though there are lots of information on ideal motor RPM and most “literature” I read so far points out that the efficiency is best at around 8000 RPM. If I go lower in KV keeping 50km/h as max speed the drive train ratio will be 4.3… I feel that is a bit low and it will compromise torque…? Correct?
Honestly I never went so deep to look into the optimal rpm with a specific kV. I would say my favorite sweet spot is 170kV With a 15/72 gearing you would be around 48km/h with 8“ or better to say 180mm wheels. That gives you still a ok clearance and very good torque. But your average loaded rpm is just at 6700.
If you want to go the high kV, high gearing way, than there is probably no way around a gear drive. Like this from @Nowind with 1:6.25 gearing ratio
Thanks Andy87, I just ran this…Is this accurate compared to real figures?
You get a bit more information on this calculator https://calc.3dservisas.eu/?Pc8xD8IgFATg_8JsDBQo6oqmk4bExO7KUBNJSToa_7vvDuv2vdfjKG91j5M6qNezzmojw0UGuw3iJV7FxpJJ6KiIgNaawxGT8c3IdG3PTiOs6OgBJH07VxO2HZVWscp6Esue_Bc9Jn6nTqKdJm847uASf02Fvx24SzPsSLyg3V8i1wjncQHZlofz-po8jMLABG7ba_X5Ag==
I would measured my wheel diameter and my 8“ wheels not 200mm, more like 180, so top speed will be less for sure.
Why you want to go so high teeth with the motor pulley?
Small correction to that post. I still had 12s in the calculator. So your rpm would be lower with 10s, sorry for that.
20T is what the belt manufacturer sugests for better belt life. That was actually part of my belt question… is the higher T-number on the motor gear really making a difference say if one would use 17T?