Thanks! Yup, I suspect the cyclone gearmotor was an industrial conveyor drive or something similar. I only used the motor and throttle, the rest was not acceptable. The motor weighed a ton (7 1/4 lbs!). The Turnigy motor weighs 780gm.
My concern is just for the cute little 1/4 inch pitch #25 chain to the motor. I'm probably over the recommended operating tension. (I suspect that's not too uncommon in this forum.) However, 1/4" pitch allows 10:1 reduction with a reasonable sprocket diameter, so I can live with that compromise.
That looks like a very nice throttle! Any suggestions for the more budget minded consumer?
I've got a VESC, so mapping is easy. Unfortunately, that Cyclone throttle is dead for the first 20 degrees. I'm tempted to see if I can make a mechanical stop on the closed end.
So I tried using my freewheel crankset without pedaling. (See the pic above leaning on the bike rack) Running with just the motor it felt very weak, and sucked battery life. This was with 3S, 4S might be a bit better, YMMV.ScooterMan101 wrote: ↑Oct 14 2018 6:08amFZBob,
I like very much what you have developed here, as much as I like the simplicity of a Friction Drive, I want to change out tires for the different rides I want to do, meaning street tires, then aggressive mountain tires for riding in the loose dirt riding conditions where I live, most MTB riders use the very widely spaced knobby tire the Maxxis Minion. and they run them tubeless at very low tire pressures . That tire or others like it that are necessary for the conditions here , just would not work with a friction drive.
Since I must give my legs and cardiovascular system a much needed rest during rides, I must use a freewheeling crankset.
There is an option,
You do not have to buy the heavy square taper freewheeling cranksets , the lighter weight version is the iSis version . you can just buy the freewheel/crankarms/spider/and BB from a place like Sick Bike Parts,
http://sickbikeparts.com/bottom-bracket ... 48mm-isis/
or buy the iSis BB from a regular mail order bike parts vendor. I see the one from SBParts is 148 mm wide.
If you need high power, unfortunately this is not that... The key to my drive is the #25 chain, which allows the 90T sprocket in a reasonable diameter, and therefore 10X reduction. That, along with the 125Kv motor and 4S gives reasonable crank RPM. At 100 to 300 watts, the little #25 chain is relatively happy. Much more and it starts to complain.ScooterMan101 wrote: ↑Oct 16 2018 9:04amFZBob,
I am looking at RC mid-drives, or perhaps a friction drive if a tire could last at least 1,000 miles.
For me much higher speeds and power are necessary .
What are the MTB forums saying on BB bearing life on the i sis system ? and how long/many miles do they last ?
This chainring might just be big enough for a medium power single reduction with a bicycle chain. Serious. Might be OK on a road bike as long as it didn't drag in corners. There are custom sprocket makers out there who can make these...ScooterMan101 wrote: ↑Oct 17 2018 8:55am
the more threads that show DIY RC Mid-Drives that show up here on E.S. the more likely someone is going to start making Chainrings that are large enough and sell to the DIY Builders.
Making a large chainring for the front would help greatly in making simple RC mid-drives,
Two things to note:
From what I have read in the past here , it is better to have 12-13 teeth on the motor shaft sprocket , and you know what that means more reduction needed.
It looks like you have a 36 tooth cog for your largest cog on the back ?
Jackshaft = 2 stage reduction = a bunch of other builds on E.S.
Love the build!FZBob wrote: ↑Oct 10 2018 5:34pmThat looks like a very nice throttle! Any suggestions for the more budget minded consumer?I've got a VESC, so mapping is easy. Unfortunately, that Cyclone throttle is dead for the first 20 degrees. I'm tempted to see if I can make a mechanical stop on the closed end.
By the way, setting an exponential response curve in the VESC is sweet.
Thanks for the info! Here's a pic of my Throttle. I wouldn't be surprised if they are pretty similar internally. When I get a bit of spare time, I'll try to duplicate your fix.
Is that an RD350 back there. I had one when I was in high school, it was a rocket!FZBob wrote: ↑Oct 10 2018 3:00pmI thought you guys might be interested in my RC Mid Drive conversion. I ride frequently in the hills, and I wanted to try just a bit of climbing assist without changing the character of the bike. I ran a Cyclone on and off about 7 years ago, but the benefit to downside ratio was not there, so i shelved it.
viewtopic.php?f=3&t=28621&p=412252&hili ... ne#p412252
I did determine that about 250 watts of assist was a good balance between power and battery capacity.
I had been interested in RC motors since then, and last spring came across the Turnigy 125KV skateboard motor.
Reign Motor z sm 10-10-18.jpg
With 10:1 reduction, this motor could meet my performance criteria. I laid out a few gearboxes in Autocad (I’m an old Mechanical Engineer), but then determined that I could do it with #25 chain and 9T and 90T sprocket from electricscooterparts. The pics show a few different drive configurations I tried.
Reign Motor c sm 10-10-18.jpg
Reign Motor d sm 10-10-18.jpg
Reign Motor a sm 10-10-18.jpg
Reign Motor b sm 10-10-18.jpg
I have been riding the bike hard for the last 3 months - 250 miles and 25,000 feet climb - and I really like it. Everything has been reliable, and I have not snapped any chains at up to 470 watts. The chain has been stretching slightly, but if I need to replace a couple of chains a year that’s OK. The VESC torque control is far superior to the old Cyclone RPM control, making pedaling under power much more fluid and less obtrusive.
The bike is a ’08 Giant Reign with a big fork, really nice shock, wide rims and a 170mm dropper post. It rips downhill! It weighs 33.4lb without the motor, and under 38 with motor and one 4S 5800 pack. (the old cyclone system added 12lb!). This is good for a VERY PLEASANT assist on a 13 mile, 1250 foot climb, aggressive dirt ride with a friend who is 20 years younger, and a natural athlete. I am able to stay ahead of him on the downhills without motor, which means that the bike’s character is intact!
Nope, changing Kv does nothing to change a motor's torque capability, it only changes the voltage/current combinations which produce those same capabilities. A smaller reduction means less torque amplification which means you need a torquier motor which is a bigger motor (or a much much more expensive motor of the same size).falcongsr wrote: ↑Oct 19 2018 1:28pmWould using a 60kV motor such as this one: https://alienpowersystem.com/shop/brush ... 0kv-1800w/ potentially open up higher voltages or simpler reductions?
Thanks! I've been riding it every few days, (I alternate with my non Ebike), and I'm really enjoying it. It has just the right amount of assist to make the climbs feel much easier, and the power blends in very smoothly. I think the VESC controller really contributes. FOC mode is nearly silent, and putting Expo in the throttle response makes it really nice. Once i'm out of the heavy climbing, I don't use assist at all. The bike pedals on flats and slight uphills just like it did without the motor. (I wonder how the 55lb commercial ebikes pedal slight uphills without assist...) I often ride with a guy who is much younger and fitter, and he has taken to requesting that I bring this bike, as I can keep pace with him on his preferred (long) rides. I just installed a 170mm dropper seatpost and wide rims, so downhill flow trails are a blast.neptronix wrote: ↑Oct 19 2018 10:04amNot many things impress me these days because i feel like i've almost seen it all by now.
This? this is super duper cool and i'm rather surprised it works so well.
I always thought it made sense to kind of gimp out a high power density RC motor, and run a simple to build single stage. Just haven't seen anyone really take it on.
Have you thought about adding a tooth or two to the primary gear on the motor, then upsizing the crank gear appropriately? seems like the extra tooth contacting on the primary gear would be a benefit for chain durability. If you have 2.5 teeth contacting, then you could bump it up to 3 at once this way.. Hey, that's 17% more contact.. not huge, but anything helps..