The BEST and FIRST Qulbix Raptor mid-drive build!

[DanGT86]

Chains are only loud when run at relatively high RPM around a low tooth count sprocket.

I agree that they are much louder on small sprockets at high chainspeed. My final drive 219 tooth counts switch between 13:94 and 17:94. The 13tooth is way louder than the 17 and they both look tiny. But relatively speaking, are chains ever as quiet, lightweight, or efficient as belts?

Have you messed with regen on any of your astro powered projects?

 

[recumpence]

Chains are only loud when run at relatively high RPM around a low tooth count sprocket.

I agree that they are much louder on small sprockets at high chainspeed. My final drive 219 tooth counts switch between 13:94 and 17:94. The 13tooth is way louder than the 17 and they both look tiny. But relatively speaking, are chains ever as quiet, lightweight, or efficient as belts?

Have you messed with regen on any of your astro powered projects?

Belts are best for high rpm and low torque. Chains are best for low rpm high torque. That is why first stage is often belt with second stage chain.

Yes I have done regen with an Astro. I have found coasting is a better option in my applications.

Matt

 

[LightningRods]

Thanks for all of the feedback. I currently build three drives that will fit the Qulbix frames.

#1- Two stage bottom bracket drive.

Mounts to: Bottom bracket and front of battery box.
Motor reduction in drive unit: From 40:1 to 8:1
Freewheels: Two. One in primary driven sprocket for pedaling, one in BB for motoring without pedaling. (The sample drive in the photo has an optional billet freewheel delete hub in the sprocket)
Regen: No
Can pedal with motor: Yes, at reductions of 30:1 or greater.
Motor runs through bike gears: Yes


#2- One stage bottom bracket drive.

Mounts to: Bottom bracket and front of battery box.
Motor reduction in drive unit: 6:1. Final drive ratio ranges from 11.5:1 to 3:1.
Freewheels: One. One in BB for motoring without pedaling.
Regen: No
Can pedal with motor: No.
Motor runs through bike gears: Yes, or two stage single speed with a single rear sprocket on right.


#3- Swingarm drive.

Mounts to: Swingarm
Motor reduction in drive unit: None. 8:1 reduction to rear wheel is standard.
Freewheels: None
Regen: Yes
Can pedal with motor: Yes, up to the limit of the pedal gearing.
Motor runs through bike gears: No. Single speed on left side.

There are advantages and disadvantages to each one. The two stage drive is best for steep climbing, pedaling with the motor, extending battery range. The one stage is best for going fast, moderate climbing, running over 3000 watts through the bike gears. The swingarm drive is meant to be as simple as possible. Many people avoid mid drives just because of the number of moving parts. The swing arm drive is an alternative to hub motors that is lighter, has reduction gearing, and is positioned close to the fulcrum point of the swing arm.

 

[Luk]

Hi Mike,
i sent you a message for a Q76's swing arm kit .

Best regards

Luk

 

[LightningRods]

Hi Luk,

PM received. Thank you! It's our Independence Day four day weekend here so very little is getting done. I will start building your swingarm drive this week.

I'm looking into 1Omm chain tugs to tension the drive chain for regen.

Best Regards,
Mike

 

[LightningRods]

My new single stage drive installed on the new Stealth FUTR Beta frame:
https://endless-sphere.com/forums/viewtopic.php?f=28&t=89282

 

[LightningRods]

I picked up the wheel from the lacing shop today. No drama. The only disappointment was that the shop couldn't easily find the 12 ga spokes I wanted and so went with 14 ga. Anyone know where to source 12 ga 230mm spokes?

The wheel feels weightless without the hub motor in it. I put the fatty on the scale to see how much it weighs. 17.0 lbs. I would absolutely have a beach cruiser with a big hub motor on it. A full suspension dirt bike? Never.

I'll get to work sizing chains and doing the finish wiring tomorrow. I'm really excited to get this bike rolling with it's new driveline.

 

[madin88]

I picked up the wheel from the lacing shop today. No drama. The only disappointment was that the shop couldn't easily find the 12 ga spokes I wanted and so went with 14 ga. Anyone know where to source 12 ga 230mm spokes

on ebay.com there is a store where you should find them (sapim leader, any length any qty)
however, it would not make any sense to use 12GA IMO. better take the 13/14GA butted sapim strong.

 

[LightningRods]

Found him on eBay. Looks like a great resource. Thanks.

They do have 12 ga, cut any length. They advertise them as "heavy duty, for pedicab or electric bike." There's no disadvantage to the heavier gauge other than weight, correct? Another issue is that the rim that came with the bike has larger holes for 12 ga nipples. The shop had to use spoke washers on them.

http://www.ebay.com/itm/SAPIM-LEADE...hash=item3d2776001f:m:mIebTXTicM6ns46zgpbmh7g

 

[DanGT86]

Found him on eBay. Looks like a great resource. Thanks.

They do have 12 ga, cut any length. They advertise them as "heavy duty, for pedicab or electric bike." There's no disadvantage to the heavier gauge other than weight, correct? Another issue is that the rim that came with the bike has larger holes for 12 ga nipples. The shop had to use spoke washers on them.

http://www.ebay.com/itm/SAPIM-LEADE...hash=item3d2776001f:m:mIebTXTicM6ns46zgpbmh7g

As far as I know larger spokes do not necessarily make a stronger rim. Properly matched spoke rim and hub do make the strongest wheel.

The way I understand it every RIM has an ideal tension that it should be under. Spokes need to be tightened within a certain range of stretch in order to stay tight. If the spokes are so larger that the required rim tension is achieved without any spoke stretch then they will be prone to loosening. During normal riding at bumps the rim distorts which effectively shortens the distance between the rim and hub. If the spoke at that location is not under adequate stretch then there is nothing to take up the slack. For a brief moment the spoke and nipple are finger tight because they are unloaded. This will loosen them. Think of the spokes as being elastic.

If my understanding is correct then bicycle hubs laced to moped wheels creates a strange situation where the tension required from the rim and moped spokes can possibly be enough to damage the bicycle hub. I think this is why JRH was/is selling those custom moped wheel nipples for smaller spokes than mopeds usually use.

In short, you should always try to match the spoke diameter to the required tension of the rim so:
Bicycle RIM + bicycle HUB = bike spokes

I think 14 is probably fine. I use 13/14 Butted from JRH but apparently his spoke machine is down so I don't know where to go for my next set. That ebay source might be very helpful.

 

[LightningRods]

Interesting stuff. What I don't know about spokes is a lot. Thanks Dan.

 

[DanGT86]

Just relaying what info I soaked up around this forum.

I think because we use motors we all have an instinct to overbuild things thinking we are making them stronger. In the case of bike wheels I always try to remember that the torque my motor puts on the wheel cant be any worse than the what the brake rotors put on them all the time. I don't think anybody pulls as many Gs during acceleration as they do when stopping and I have never seen a brake induced spoke failure on a bike wheel.

 

[LightningRods]

My main concern was getting a good fit between the new spoke nipples and the holes in the rim that came with the hub motor. Those were 12 ga spokes, obviously because of the mass in the wheel. The wheel is so much lighter now that I think 14 ga will be fine. The rim is double wall aluminum. The tires are unusual 24" x 3" which because of the bizarre way that bicycle tires are sized, is actually a 3" tire on a 20" rim. Not to be confused with a regular 20" rim which I'm told is the O.D. of the tire. What a mess!

 

[LightningRods]

I'm working on the details of tensioning the 219 final drive chain on the swingarm drive. I have a handy calculator which tells me the number of chain links needed for a given sprocket set and center to center distance. Using this calculator I determined that one link pair of 219 chain changes the center to center distance on my particular sprockets by .313". I mapped this out on the Qulbix swingarm dropout slot:

So we have wiggle room of +/- two link pairs. The center of the slot's travel is ideal. That's 162 links.

I've ordered these chain tugs to help keep the axle from moving forward under power:

Laid over the 10mm axle and dropout slot they look like this:

The raised bar on the tug that goes into the slot will either fit perfectly or need just a bit of massaging on the front edge. I just ordered them this morning so I'll have to wait until they arrive to know for sure. They were only $18. No way I could have them custom made for that.

Thanks for the feedback on the effects of regen braking on chain tension. I was already worrying about it. The comments helped me stop worrying and start dealing. This setup will be much better for the two way loads of a solid mounted sprocket.

 

[John Bozi]

Cant wait to see this in action.

So curious about the power ratio that it will run. volt to amp... Since it in close relationship to how hub motors operate, single gear, regen, no freewheel, cogging -
What its most efficient RPM top speed will be...

I think it's about 50 / 8 (reduction) about 6 so should run similar to a high turn hub but with heat path path directly on the shell.

Should be a winner. This one may really come down to better weight and heat handling. Only point that it might have for some is the sound of chains in particular when they go off road since it will be spinning always and if there is any safety issues that might arise with a chain jam on a sprocket that doesn't freewheel. But both are points dirt bikes don't report.

Can't wait for the vids, it may well spark an ebike revolution.

 

[LightningRods]

Getting very close to done. Just little details now and she'll be ready to ride. Chain tugs for the 219 side and a derailleur style chain tensioner for the pedal side. After that it's mostly wiring.

 

[DanGT86]

That thing is going to be insanely fun! Hubmotor power levels with bike level unsprung weight is a win win. Its made even better because you don't give up regen. Watt for watt I think Single speed direct chain drive is the best high power solution for ebikes.

Glad you addressed the regen axle issues. I was shocked by how easily the regen forces were able to slide my axle. Powered LH motor chain tension kept that side from sliding rearward but the right side took all of the force and made the wheel all crooked. I guess using rim or disk brakes there is always an anchor to the frame that is somewhat holding the wheel in place. With chain regen the interactions of the forces are just harder to visualize than what we are used to. It's almost like the tension on the bottom run of the chain tries to drive the wheel backwards out from under the bike. I need to draw it all out visually to totally understand it but I can tell you for sure that it needs to be dealt with.

Those $18 tensioners are the same ones I use. They work but will likely need to be trimmed in the front. That raised up block portion is in the way for me. Wish they were just disks like an axle washer.

Did yo buy your front 219 sprockets from a regular retail site or do you have a supplier? One of mine is total junk with way too much runout between the bore and sprocket. I'm wondering where to get others someone can vouch for.

 

[LightningRods]

There have been a lot of hub motor Qulbix built. It's good to have some mid drive options available. When you look at how much time and money motorcycle and car manufacturers spend in trying to eliminate grams of unsprung weight from their vehicles there has to be a reason. On a dirt bike you not only get a better ride and fewer trashed rims, you have a wheel that will follow the terrain better and put more power down.

The PowerVelocity sine wave controller that I'll be using on this bike has variable regen, programmable via Bluetooth from an iPhone or Android phone. Because of how insanely hilly my neighborhood is I'm more interested in the braking effect of regen than it's battery charging.

This drive is about as stripped down and simple as it can be. As long as the chains are well managed and run without issue there is not much to go wrong. I can't go any larger on the wheel sprocket because of swingarm clearance. I could run an 11t motor sprocket if I could find one that would fit. The line of sprockets that I had made in Taiwan stop at 12t. Most 11t sprockets are specific to Rotax or Yamaha kart motors and have tapered bores and other funky stuff going on. It would be nice to have the option of 9:1 gearing in addition to the current 8:1.

 

[skeetab5780]

This thing is going to be a beast. Looks like similar reduction to what im using. But im sure your bike is alot heavier so dont be scared to feed it the power!

 

[LightningRods]

Thanks! It should run pretty good.

 

[DanGT86]

Efficiency goes down and noise goes up when you get too small on the front. I think 12-13 is about the smallest you really want to go anyway. The common motor options available are just a few kv too high to cover the whole useful range in just one reduction stage. Adding a 2nd stage is an even worse hit on efficiency. Seems like there is always a compromise.

The kart racing sprockets with the big flat 3 bolt flanges might be a good option for quick changes out in the field. You could sell an adapter that mounts to your motor shaft with 3 tapped holes to mount these.

 

[Luk]

Hi Mike .

I'm ok for this 1Omm chain tugs to tension the drive chain for regen ,
... and a longer chain for my 27,5" swing arm ( 40mm more, 1,57" )

Best regards

luk

 

[LightningRods]

I think the chain tugs are the best solution, Luk. I've built your Big Block motor and started work on your swingarm drive. I'll let everyone know how the chain tugs work once they arrive. They've shipped.

Looking around the internet I've found 11, 10 and even 9 tooth 219 sprockets for racing karts. I understand that they are noisy and will probably not last as long as a 12+ tooth sprocket. It would still be nice to have the option of lower gearing.

 

[Luk]

A belt drive instead the 219 chain ?

 

[LightningRods]

I like belt drives a lot. There are a few drawbacks with them:

They're much wider than chain drives.
They have to be more carefully tensioned than chain drives.
They have to be more precisely aligned than chain drives.
You have to be able to find a pre-made belt in the pitch, width and length you need.

In this application we'd need a wide belt with a fairly large tooth pitch to handle the power. There is barely enough room to squeak a chain drive in. The Gates Carbon Drive belts are only available in a few standard lengths. I'm also not sure that bicycle rated belt will handle this much power. On a bicycle the final drive is usually between 2:1 and 4:1 overdrive. The large pulley doesn't have to be that large. We're trying to get 8:1 reduction. With a coarse pitch on the pulley it would have to be very large to provide 8:1.

I think it has to be chain drive in this application.